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CONSULTING-SPECIFYING ENGINEER (ISSN 0892-5046, Vol. 50, No. 9, GST #123397457) is published 11x per year, monthly except in February, by CFE Media, LLC, 1111 W. 22nd Street, Suite #250, Oak Brook, IL 60523. Jim Langhenry, Group Publisher /Co-Founder; Steve Rourke CEO/COO/Co-Founder. CONSULTING-SPECIFYING ENGINEER copyright 2013 by CFE Media, LLC. All rights reserved. CONSULTING-SPECIFYING ENGINEER is a registered trademark of CFE Media, LLC used under license. Periodicals postage paid at Oak Brook, IL 60523 and additional mailing of� ces. Circulation records are maintained at CFE Media, LLC, 1111 W. 22nd Street, Suite #250, Oak Brook, IL 60523. Telephone: 630/571-4070 x2220. E-mail: [email protected]. Postmaster: send address changes to CONSULTING-SPECIFYING ENGINEER, 1111 W. 22nd Street, Suite #250, Oak Brook, IL 60523. Publications Mail Agreement No. 40685520. Return undeliverable Canadian addresses to: 1111 W. 22nd Street, Suite #250, Oak Brook, IL 60523. Email: [email protected]. Rates for nonquali� ed subscriptions, including all issues: USA, $150/yr; Canada/Mexico, $180/yr (includes 7% GST, GST#123397457); International air delivery $325/yr. Except for special issues where price changes are indicated, single copies are available for $30.00 US and $35.00 foreign. Please address all subscription mail to CONSULTING-SPECIFYING ENGINEER, 1111 W. 22nd Street, Suite #250, Oak Brook, IL 60523. Printed in the USA. CFE Media, LLC does not assume and hereby disclaims any liability to any person for any loss or damage caused by errors or omissions in the material contained herein, regardless of whether such errors result from negligence, accident or any other cause whatsoever.

COVER STORY

30 | Factoring lighting into cooling loadsHow to select, design, and redesign lighting systems so they complement HVAC systems.BY DAVID DUTHU, PE AND NOLAN ROME, PE, LEED AP

DEPARTMENTS

06 | Apps for Engineers

09 | ViewpointCommissioning surges ahead

10 | MEP RoundtableSpecifying systems for new, existing office buildings

19 | Career SmartDoing real things

21 | Codes & StandardsTop 10 things to know about commissioning fireprotection systems

63 | Advertiser Index

64 | 2 More MinutesFive reasons high school students should choose engineering

FEATURES

46 | Interstitial spaces: Managing thedark zones of the buildingEngineers must pay close attention when coordinating mechanical, electrical, plumbing, and fire protection sys-tem design in interstitial spaces.BY ERIN MCCONAHEY, PE, AND JAMEY LYZUN, PE

52 | Case study: Coordinating interstitial spaces in an existing buildingAn existing building—destined as a medical facility—held a few surprises during renovation. BIM and clash detection helped smooth the process.BY CHRIS ST. CYR AND J. PATRICK BANSE, PE, LEED AP

38 | IAQ and energy managementIndoor air quality (IAQ) and energy management are key in K-12 schools and higher education university buildings. This information will help to provide an efficient, effective HVAC system in a school or a university building.BY RANDY SCHRECENGOST, PE, CEM, AND GAYLE DAVIS, PE

56 | Significant changes to the commercial provisions in 2012 IECCSignificant changes to the 2012 International Energy Conservation Code (IECC) impact architects, engineers, code officials, and other building design professionals.BY ANDREW KLEIN, PE, CEM

3www.csemag.com Consulting-Specifying Engineer • OCTOBER 2013

FEATURES

OCTOBER 2013

AUTOMATION & CONTROLS

COMMUNICATIONS

ELECTRICAL

FIRE, SECURITY & LIFE SAFETY

HVAC

LIGHTING

PLUMBING

ENGINEERING DISCIPLINES

ON THE COVER: This office lobby shows the LED spot down-lights used in combination with the T5 fluorescent cove light-ing and daylighting. Courtesy: ccrd partners

SPECIAL REPORT

24 | The state of commissioning in 2013Despite challenges both new and old, and an economy that is improved but still not roaring, commissioning firms remain hopeful about the upcoming year.BY RAY BERT AND AMANDA THOMASON

4 Consulting-Specifying Engineer • OCTOBER 2013 www.csemag.comConsulting-Specifying Engineer • OCTOBER 2013 www.csemag.com

Web exclusivesVisit www.csemag.com/archives for these Web-exclusive articles:

� Energy harvesting power for the Internet of Things

� Generators and transfer switches: Emergency power system solution

The digital edition of this publication is greatly enhanced and has unique content for digital edition subscrib-ers. It also includes interactive tools, such as videos, Web links, and other items. Update your subscription, and receive the digital edition on a new platform in your e-mail in-box: www.csemag.com/subscribe.

Earn continuingeducation on-demandView on-demand webcasts at www.csemag.com/webcast and pass the exam to earn continuing education. Topics include:� Fire and Life Safety: Notification and Emergency Communication Systems� Smart Electrical Systems: Meters, Submeters, and Smart Meters� Critical Power: Standby Power for Mission Critical Facilities� HVAC: ASHRAE 62.1, 62.2, and Air Movement

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Webcast:Modular data center designRegister at www.csemag.com/webcast for this webcast on Thursday, Oct. 17, 2013. The data center market has expanded dra-matically in the past few years, and it doesn’t show signs of slowing down. Many clients and building owners are requesting modular data centers, which can be placed anywhere data capacity is needed. Modular data centers can help cash-strapped building owners add a new data center (or more capacity) to their site, and can assist facilities with unplanned outages, such as disruptions due to storms. Owners look to modular data centers to accelerate the “floor ready” date as com-pared to a traditional brick and mortar. Modular data centers are not for everyone, however—this webcast will explore whether it’s appropriate for your next project.

When engineering systems in office buildings,what’s the most difficult issue you face?

Fire and life safety

Automation and controls

Codes and standards

HVAC

Energy efficiency, sustainability

Electrical and power

Read the Q&A on office buildings on page 10. To viewmore poll results, visit www.csemag.com/poll/cse.

50%

19%

14%

10%

5%

2%

Critical Power: Integrating renewable power into buildingsRegister at www.csemag.com/webcast for this web-cast on Thursday, Nov. 7, 2013. Building owners have more questions and requests on how to integrate renewable power into their buildings. And as the Smart Grid evolves, integration of renewable energy sources is increasing. Possible renewable power technologies include solar, wind, geothermal, and biomass. As the technolo-gies that support increasing use of renewable energy mature, the codes and stan-dards that define their use, interconnection, and interoperability with the grid must keep pace with them. Engineers involved with integrating renewable power into buildings must be aware of the applicable energy codes and standards and how to properly implement them into the building design. They must also evaluate the design objectives, materials, systems, and construction from all perspectives. It’s critical for designers to assess the design for cost, quality of life, expansion capabili-ties, efficiencies, impact on environment, creativity, and productivity.

Consulting-Specifying Engineer is on Facebook, Google+, LinkedIn, Twitter, and SlideShare. Follow Consulting-Specifying Engineer, join the discus-sions, and receive news and advice from your peers.

Facebook:www.facebook.com/CSEmag

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cast on Thursday, Nov. 7, 2013. Building owners have more questions and requests

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Featured Apps

EE BasicsiOS 3.0, Android 1.6Cost: $1.99Company: FPC Ltd.Company Website: http://bit.ly/nZWebIWeb download link: http://bit.ly/qrkwv8 (Android), http://bit.ly/pslzmM (iOS)EE Basics contains a selection of Electrical Engineering laws, equations, tables and reference material that Electrical Engineers may fi nd useful during their day-to-day operations. The contents include circuits, wire gauges, services, motors, drives, fundamental laws and other facets useful for Electrical Engineers out in the fi eld.

Pump Energy Savings CalculatoriOS 3.0, Android 2.2Cost: FreeCompany: Rockwell Automation Inc.Company Website: www.rockwellautomation.comWeb download link: http://bit.ly/YTEkl7 (Android), http://bit.ly/JZgUp3 (iOS)The pump energy savings calculator allows you to calculate your potential energy savings. This tool is designed to compare conventional fl ow control methods with PowerFlex drives and show the differential power consumption of each.

NEMA Confi guration GuideAndroid 2.2Cost: FreeCompany: Summit Electric SupplyCompany Website: http://summit.comWeb download link: http://bit.ly/10kNwkFWith this app you can identify any unknown NEMA confi guration. Just enter in what you want and search for the results. A must-have for electrical professionals.

Box/Conduit Fill ProAndroid 1.6Cost: FreeCompany: Comoving MagneticsCompany Website: http://bit.ly/qHbPEgWeb download link: http://bit.ly/vkPglYCalculate the maximum wires in a conduit, minimum box size, and minimum conduit/nipple size. The calculations use the 2008/2011 NEC code, which will give Electrical Engineers the correct information out in the fi eld.

CFE Media’s Apps for Engineers is an interactive directory of more than 170 engineering-related applications for Android and iOS operating systems, created by various companies. The app helps users do their jobs better and save time, providing a “pre-sort” of relevant mobile engineering applications loaded with various calculators, catalogs, file viewers, measurement tools, and more. www.csemag.com/appsforengineers

Apps for Engineers

With the broadest selection of automatic transfer switches in the industry, Eaton always comes shining through.

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1111 W. 22nd St. Suite 250, Oak Brook, IL 60523630-571-4070 Fax 630-214-4504

CONTENT SPECIALISTS/EDITORIAL AMARA ROZGUS, Editor in Chief/Content Manager

630-571-4070 x2211, [email protected]

AMANDA MCLEMAN, Project Manager630-571-4070 x2209, [email protected]

BRITTANY MERCHUT, Project Manager630-571-4070 x2220, [email protected]

BEN TAYLOR, Project Manager 630-571-4070 x2219, [email protected]

MARK HOSKE, Content Manager 630-571-4070 x2214, [email protected]

BOB VAVRA, Content Manager 630-571-4070 x2212, [email protected]

PETER WELANDER, Content Manager 630-571-4070 x2213, [email protected]

MICHAEL SMITH, Creative Director 630-779-8910, [email protected]

CHRIS VAVRA, Content [email protected]

EDITORIAL ADVISORY BOARDANIL AHUJA, PE, LEED AP, RCDD, President, CCJM Engineers, Chicago

PETER ALSPACH, PE, LEED AP BD+C, Associate Principal, Mechanical Engineer,

Arup, Seattle

J. PATRICK BANSE, PE, LEED AP, Senior Mechanical Engineer,

Smith Seckman Reid Inc., Houston

THOMAS BROWN, PE, Executive Vice President, RJA Group Inc., Laurel, Md.

MICHAEL CHOW, PE, LEED AP BD+C,Principal, Metro CD Engineering LLC, Powell, Ohio

DOUGLAS EVANS, PE, FSFPE, Fire Protection Engineer,

Clark County Building Division, Las Vegas

JASON GERKE, PE, LEED AP BD+C, CXA, Mechanical Engineer, GRAEF, Milwaukee

RAYMOND GRILL, PE, FSFPE, Principal, Arup, Washington, D.C.

DANNA JENSEN, PE, LEED AP BD+C,Associate Principal, ccrd partners, Dallas

WILLIAM KOSIK, PE, CEM, LEED AP BD+C, BEMP,Principal Data Center Energy Technologist,

HP Technology Services, Chicago

KENNETH KUTSMEDA, PE, LEED AP, Engineering Design Principal, KlingStubbins, Philadelphia

KEITH LANE, PE, RCDD, LC, LEED AP, President, Lane Coburn & Assocs., Seattle

KENNETH L. LOVORN, PE, President, Lovorn Engineering Assocs., Pittsburgh

MICHAEL MAR, PE, LEED AP, Senior Associate,

Environmental Systems Design Inc., Chicago

BRIAN MARTIN, PE, Electrical Engineer, CH2M Hill, Portland, Ore.

SYED PEERAN, PE, Ph.D., Senior Engineer, CDM Smith Inc.,

Cambridge, Mass.

BRIAN A. RENER, PE, LEED AP, Electrical Platform Leader and Quality Assurance Manager,

M+W Group, Chicago

RANDY SCHRECENGOST, PE, CEM, Austin Operations Group Manager and

Senior Mechanical Engineer, Stanley Consultants, Austin, Texas

GERALD VERSLUYS, PE, LEED AP, Principal, Senior Electrical Engineer,

TLC Engineering for Architecture, Jacksonville, Fla.

MIKE WALTERS, PE, LEED AP,Principal, Confluenc, Madison, Wis.

Editor’s Viewpoint

Send your questions and comments to:[email protected]

Commissioning surges ahead

When discussing with unedu-cated building owners and tenants the topic of

designing and specifying engineered systems into a building, commission-ing sometimes gets lost in the shuffle. They don’t always understand why a system must be commissioned, re-commissioned, or retro-commissioned. If it was engineered correctly in the first place, doesn’t it work correctly?

In an exclusive report released by the AABC Commissioning Group (ACG), survey respondents reveal a positive outlook on the industry (see page 24). According to a similar report released in August 2013 by the Building Commissioning Association, “Demand for the services of commis-sioning professionals is rising and will continue to rise into the near future.”

What’s pushing this trend toward more commissioning? Several things. First, owners of existing buildings are working to “find” money in a tough economy. By ensuring systems are working correctly and efficiently, owners and facilities staff can lengthen the life of existing equip-ment and ensure system performance is at expected levels.

Second, codes and standards are driving commissioning from several angles. ASHRAE Standard 90.1-2010, for example, now requires HVAC com-missioning for control systems on most

projects greater than 50,000 sq ft. This complexity of building lighting systems has made commissioning of lighting controls an essential part of more and more projects. Commissioning for the most part is voluntary; however, if an owner is contemplating U.S. Green Building Council LEED certification or if ASHRAE 90.1-2010 compliance is required, commissioning is mandatory.

Several guidelines and websites explain and illustrate the commis-sioning process, such as ASHRAE Guideline 0-2005: The Commissioning Process and the ACG Commissioning Guideline. In 2011, the Illuminat-ing Engineering Society published IES DG-29-11, The Commission-ing Process Applied to Lighting and Control Systems, a design guide for the commissioning of lighting and lighting control systems. IES DG-29-11 is intended to be a supplement to ASHRAE Guideline 0-2005. When NFPA released the 2012 edition of NFPA 3: Recommended Practice on Commissioning and Integrated Testing of Fire Protection and Life Safety Sys-tems, a comprehensive commissioning document for the fire protection indus-try was made available (see page 21).

For more on the 2013 Commission-ing Giants, see page 24, and for more on this topic, visit www.csemag.com/commissioning.

Amara Rozgus Editor in Chief


1111 W. 22nd St. Suite 250, Oak Brook, IL 60523630-571-4070 Fax 630-214-4504

CONTENT SPECIALISTS/EDITORIAL AMARA ROZGUS, Editor in Chief/Content Manager

630-571-4070 x2211, [email protected]

AMANDA MCLEMAN, Project Manager630-571-4070 x2209, [email protected]

BRITTANY MERCHUT, Project Manager630-571-4070 x2220, [email protected]

BEN TAYLOR, Project Manager 630-571-4070 x2219, [email protected]

MARK HOSKE, Content Manager 630-571-4070 x2214, [email protected]

BOB VAVRA, Content Manager 630-571-4070 x2212, [email protected]

PETER WELANDER, Content Manager 630-571-4070 x2213, [email protected]

MICHAEL SMITH, Creative Director 630-779-8910, [email protected]

CHRIS VAVRA, Content [email protected]

EDITORIAL ADVISORY BOARDANIL AHUJA, PE, LEED AP, RCDD, President, CCJM Engineers, Chicago

PETER ALSPACH, PE, LEED AP BD+C, Associate Principal, Mechanical Engineer,

Arup, Seattle

J. PATRICK BANSE, PE, LEED AP, Senior Mechanical Engineer,

Smith Seckman Reid Inc., Houston

THOMAS BROWN, PE, Executive Vice President, RJA Group Inc., Laurel, Md.

MICHAEL CHOW, PE, LEED AP BD+C,Principal, Metro CD Engineering LLC, Powell, Ohio

DOUGLAS EVANS, PE, FSFPE, Fire Protection Engineer,

Clark County Building Division, Las Vegas

JASON GERKE, PE, LEED AP BD+C, CXA, Mechanical Engineer, GRAEF, Milwaukee

RAYMOND GRILL, PE, FSFPE, Principal, Arup, Washington, D.C.

DANNA JENSEN, PE, LEED AP BD+C,Associate Principal, ccrd partners, Dallas

WILLIAM KOSIK, PE, CEM, LEED AP BD+C, BEMP,Principal Data Center Energy Technologist,

HP Technology Services, Chicago

KENNETH KUTSMEDA, PE, LEED AP, Engineering Design Principal, KlingStubbins, Philadelphia

KEITH LANE, PE, RCDD, LC, LEED AP, President, Lane Coburn & Assocs., Seattle

KENNETH L. LOVORN, PE, President, Lovorn Engineering Assocs., Pittsburgh

MICHAEL MAR, PE, LEED AP, Senior Associate,

Environmental Systems Design Inc., Chicago

BRIAN MARTIN, PE, Electrical Engineer, CH2M Hill, Portland, Ore.

SYED PEERAN, PE, Ph.D., Senior Engineer, CDM Smith Inc.,

Cambridge, Mass.

BRIAN A. RENER, PE, LEED AP, Electrical Platform Leader and Quality Assurance Manager,

M+W Group, Chicago

RANDY SCHRECENGOST, PE, CEM, Austin Operations Group Manager and

Senior Mechanical Engineer, Stanley Consultants, Austin, Texas

GERALD VERSLUYS, PE, LEED AP, Principal, Senior Electrical Engineer,

TLC Engineering for Architecture, Jacksonville, Fla.

MIKE WALTERS, PE, LEED AP,Principal, Confluenc, Madison, Wis.


CSE: What sorts of challenges do office buildings pose that you don’t encounter on other projects?

J. Patrick Banse: Many challenges involve the way the space is built out. Designing a shell and core space along with finished-out public spaces from HVAC systems that serve both the proposed tenant space and the finished public space—how does this work, and can it be controlled? Also, providing for the need of 24/7 cooling in elevator controller closets and intermediate distribution frame (IDF) rooms when the building is not yet complete presents challenges.

Robert Ioanna: In office buildings, the build-ing façade characteristics play a very important role in sizing and selecting mechanical, elec-trical, plumbing (MEP), and fire protection systems. In addition, the height of these build-ings often induces a stack effect that can wreak havoc with the ventilation control strategies of buildings. This is particularly true in climates such as the northeast that have both extreme hot and cold seasons.

Douglas Lacy: The corporate office proj-ects we specialize in have a project comple-tion schedule that is usually shorter than our other business sectors. With the exception of retail, office projects are by nature one of the fastest-moving project types. They are heavily

influenced by the short-term leasing market and influenced by developer ROI. This often requires design of core and shell construc-tion to start well before a final end-user ten-ant is identified and their project parameters are fully documented. You must be flexible in your design approach and anticipate current and future needs.

CSE: What type of adaptable or modu-lar office buildings have you helped design recently?

Banse: Modular office buildings generally come complete with single point connections for electrical water and sewer services. These are the easy ones. Others are shell spaces that need interior design along with electrical ser-vice size and HVAC requirements for others to build and result in the single point utility connections.

Lacy: The majority of the corporate and medical office projects we work on are developer-driven and can be speculative in nature. Therefore, most buildings must be designed to optimize rentable area ratios and allow for multiple business types to occupy the facilities over their life. The primary focus recently has been in low-rise value offices, such as buildings that have mul-tiple three- or four-story wings in a campus

MEP Roundtable

PARTICIPANTS

J. Patrick Banse,PE, LEED AP

Senior mechanical engineerSmith Seckman Reid

Houston

Robert Ioanna,PE, LEED APVice president

Syska Hennessy GroupNew York City

Douglas Lacy,PE, LEED AP BD+C

Senior associateccrd partners

Dallas

Robert Ioanna,

Douglas Lacy,

Specifying systems for new, existing office buildingsOffice buildings might seem like simple structures from the outside, but engineers engaged in such projects know they can be highly complex, with specialized fire/life safety requirements, laboratory spaces, and other unique needs. Manufacturers provide advice online at www.csemag.com/archives.


arrangement or attached to a central knuckle or lobby that can have future pods added to the floor plate at a later date. This also influences the types of MEP systems we specify and tends to favor distributed components over centralization.

CSE: How often are you called on to retrofit or retro-commission an existing building, as opposed to designing a new building?

Ioanna: A significant portion of our work is being done retrofitting existing buildings. We have seen building own-ers and developers using the core of these buildings while replacing all MEP systems as well as the building façade. Retro-commissioning is increasing in popularity as building owners look to save energy costs and if located in New York City to comply with Local Law 87.

Lacy: We are working on multiple tenant improvement and retrofit proj-ects at any given time along with new construction. Tenant improvements and retrofit projects are a constant and ongoing market segment even in peri-ods of slow growth. Most new office construction projects result from the end user-first exhausting the existing building options in the local market or seeking to build a signature building from the ground up.

CSE: When designing a new Class A office building, what have build-ing owners been requesting lately? What’s the newest trend?

Ioanna: The most educated owners are looking to their MEP engineers to become active participants during the ini-tial stages of the project. We have a high-performance building design approach at Syska that begins with the simple geom-etry/orientation of the building through MEP design construction into operations and maintenance (O&M). Our first man-date is to find ways to reduce HVAC and electrical loads. Second is to use “passive strategies” to cool and power—passive systems such as radiant cooling and natu-ral ventilation. Third, we look to optimize the active systems—the more traditional fans, pumps, chillers, etc. The final step is to figure ways to incorporate renewable energy strategies by implementing solar hot water, photovoltaics, or geothermal where appropriate.

CSE: Please describe a recent project you’ve worked on—share problems you’ve encountered, how you’ve solved them, and aspects you’re especially proud of.

Banse: We designed the finish out of about 60,000 sq ft of shell space on level

10 of an empty building. The space had the capability to be served by four dif-ferent air systems with about 35,000 cfm of excess air capacity. The solution was to remove one unit (creating added use-able sq ft), use one at full capacity, and use the other two at a partial capacity to keep systems operational and serve 24/7 cooling requirements for IDF rooms and similar spaces. Additionally, the short floor-to-floor height and existing con-ditions required a return air plenum be used with multiple duct paths through and around walls to structure.

Ioanna: We are increasingly being asked to design retrofit office spaces to increase or maximize the occupancy of the building space. In a specific project for a confiden-tial client, it “dense packed” employees by providing fewer office spaces and reduc-ing the workspace per employee. At the same time the client increased the number of teaming, meeting, and small conference rooms. This created many challenges for the building’s MEP systems. The build-ing’s ventilation systems could not support the outside air and cooling load require-ments. We designed separate outside air systems that were integrated to the base building system through controls. We aug-mented outside air as necessary using CO2 monitoring. We converted the overhead air distribution system to an underfloor air distribution system by connecting the base building supply air ducts to multiple

Corporate headquarters, such as Pizza Hut’s structure in Plano, Texas, can be highly complex office structures. This structure fea-tures test kitchens in addition to conventional office spaces. Courtesy: ccrd partners


MEP Roundtable

air towers supplemented with additional cooling coils.

CSE: What factors do you need to take into account when designing building automation systems (BAS) for an office building?

Banse: Several factors, including energy codes, remote access and adjust-ability, 24/7 space and equipment moni-toring, along with measurements, come

into play. Some tenants want the ability to turn on their office suite lights just by entering their card key into the building parking garage. This may also activate the suite HVAC system so that air move-ment and temperature control are available when they enter the suite. It depends upon the sophistication of the BAS and its abil-ity to integrate with security and lighting systems.

Lacy: When choosing a BAS system for a multi-tenant building, it is important to specify an open protocol that provides flexibility for future additions and has the capacity for all the current and future points necessary for the complete build-

out. Proprietary systems tend to both limit competition and increase the cost of upkeep and expansion of systems over the life of a facility.

Ioanna: The key in designing a build-ing management system (BMS) for any facility is to understand the level of monitoring each system requires and the types of specialized systems or spaces each floor contains. If any criti-cal systems are known, certain BAS design considerations must be provided appropriately. Robust and redundant BAS instrumentation, self-healing ring network with managed switches, redun-dant sensors, and failure scenario logic must be accounted for in the equipment sequence of operations.

CSE: Do you find your firm obtain-ing additional contracts to work with the operations and mainte-nance (O&M) staff after the build-ing’s BAS has been designed to ensure it’s performing as intended?

Lacy: Yes, we have seen more interest in this service line. With more facilities seeking sustainability certification goals such as U.S. Green Building Council LEED, Green Globes, and others, the desire to fine-tune and validate system performance is a key focus of ccrd’s com-missioning and energy groups.

Ioanna: Many clients request our ser-vices after the base building design has been completed. We have been writing O&M manuals for equipment or sys-tems, maintenance operating procedures (MOPs), and emergency operating pro-cedures (EOPs). Retro-commissioning services are increasingly popular way to verify the BMS is operating the building mechanical systems at peak efficiency throughout the facility’s lifecycle. We often are asked to help provide the cli-ent with “step by step” procedures during maintenance windows or during emer-gency situations.

CSE: What new types of controls are you specifying into office build-

ings? Is the demand for personal control increasing? Are owners requesting ongoing measurement and verification?

Lacy: The technology and devices types that are being included today have been available in the market for some time; however, due to the desire to track sustainable metrics, we are finding more opportunity to use a wider variety of con-trol strategies in office design. Strategies such as outdoor air monitoring, duct pres-sure reset, supply air temperature reset, and energy totalization packages are now commonplace where they were previous-ly reserved for institutional and critical environment clients. Personal control can be a double-edged sword. While having occupants control their temperature is desirable for occupant satisfaction scores, having occupants with close adjacencies be able to adjust the temperature require-ments more than approximately 3 F may cause ”false loads” in a system or may cause two zones to ”fight” each other. Direct adjustment of airflow may also impact ventilation air reaching the occu-pied zones. With more facilities moving to a totally open concept, careful consid-eration of construction type, air distribu-tion device location, and the likelihood of future occupant or wall relocations should be carefully considered during design before prescribing a unilateral personal control strategy.

Ioanna: Internationally more preva-lent and slowly making its way into our domestic market is intelligent building systems (IBS). The goal of an IBS is to manage and control disparate systems on a common platform. Convergence and automation are two key principles to today’s building technology design. Data, voice, security, video, entertain-ment, wireless systems, HVAC, lighting, electronic building controls including green technologies, and audio/visual ele-ments running on one infrastructure shar-ing ubiquitous networks that are robust, redundant, and secure are possible to achieve when planned and executed with

Syska Hennesy Group’s ongoing projects include the Busan Lotte Town Tower in Busan, South Korea. Courtesy: Skid-more, Owings & Merrill LLP


the common goals in mind—manage and control. The IBS uses an Internet protocol (IP)-based IT network infrastructure for control system communication. Fully net-worked systems transcend integration and achieve system interaction with tradition-ally independent systems. By using the IT network, these systems can work collec-tively to optimize the building’s perfor-mance. Each converged system residing on the IBS network shall use the build-ing’s Ethernet network. A single, redun-dant topology will mitigate downtime by providing alternate means of traffic flow.

Banse: More wireless devices and technology and adaptable and easily changeable BAS programming are two that come to mind. We see more demand for proper system control and function than for personal control—make the systems work within design parameters. They want the ability to monitor and record utility use of chilled water, air-flow, domestic water use, and electricity use on a floor-by-floor and a tenant-by-tenant basis.

CSE: What’s the one factor most commonly overlooked in electrical systems in such buildings?

Lacy: The most overlooked item tends not to be technical in nature. Identifying what the requirements for tenant power will be in the final leasing agreements continues to be a challenge. Core and shell design often starts and progresses before the developer, leasing agents, and tenant brokers have finalized the lease language. While engineers can design to codes and standards and can anticipate some abnormalities based on previous engineering experience, there inevitably will be unique requirements requested by tenants in their leasing negotiations. Promoting these discussions to happen early in the design process as to avoid costly change orders is imperative to a successful project and satisfied clients.

Ioanna: A major issue with existing building electrical distribution systems is identifying non-compliant systems. There

are a lot of installations grandfathered in place that if evaluated on current codes are noncompliant. When grandfathered equipment is modified, this equipment often needs to be replaced. There could be clearance issues and parts might not be readily available as well. Often increas-ing construction costs are unanticipated by the owner.

CSE: Describe a power quality issue you encountered, and provide details about how you overcame it.

Ioanna: On a commissioning effort we had a power quality issue with gen-erator-UPS system compatibility. The generators were sized without consider-ing harmonics and leading power factor

caused by the UPS filters’ contents and the performance of the UPS. This caused the generator to hunt (up-and-down volt-age and frequency). The solution was to lower the UPS recharge current to reduce harmonics when generators are feeding the UPS system and the filters were engaged at relatively higher UPS load-ing. We have had power quality issues with chiller motor controllers such as variable frequency drives (VFDs). This may cause a zero sequence current acti-vating the upstream breaker with ground fault protection (GFP). The solution is to increase the GFP setpoint (current and time delay) to mitigate this starting/tran-sient condition.

CSE: What type of backup or standby power systems have you specified into an office building?

Lacy: The backup power systems tend to be divided by building class. Low-rise value office buildings tend to use only battery backup for life safety lighting and

fire alarm systems, and hydraulic or bat-tery return for elevators. Class B mid-rise and high-rise as well as Class A buildings tend to employ diesel standby generators. In the developer market there tends to be a separation between generators used for “base building” purposes such as life safety functions and those generators used to back up tenant purposes such as IT and call center operations. Also, a portion of most facilities, regardless of class, requires a UPS for the IT equip-ment rooms.

Ioanna: Traditionally we have supplied standby power with diesel or natural gas-powered generator sets. We also typically provide 90-minute battery backup power for fire alarm system and lighting. The critical building loads are typically run

through UPS to mitigate momentary power interruption caused by power transients/abnormality. We have seen an increased request for the use of co-generation, micro-turbine, and fuel cell systems in metropolitan areas. This is due to the availability and low cost of natural gas. These systems sized for partial load or peak shaving load show very attractive levels of return on investment (ROI).

CSE: What unique fire suppres-sion systems have you specified in office buildings?

Banse: Most office buildings are fully sprinklered, but occasionally a pre-action fire system or a clean agent fire suppres-sion system such as FM-200 is required or requested by a particular tenant.

Ioanna: In addition to traditional wet sprinkler systems, we are seeing a trend toward more clean agent suppression systems, or foam systems and mist-type sprinkler systems that provide better extinguishing capability for the specific

“While engineers can design to codes and standards and can anticipate some abnormalities based on previous engineering experience, there inevitably will be unique requirements request-ed by tenants in their leasing negotiations.” —Douglas Lacy


MEP Roundtable

hazard present. This is becoming more prevalent in the generator rooms, the fuel oil storage rooms, main distribution frame (MDF)/telecom rooms, and also broadcasting spaces.

CSE: What unique egress, mass notification systems, or emergency communication systems have you specified into such buildings?

Ioanna: We have designed several buildings using staged evacuation and/or relocation of occupants strategies by deploying in-building fire emergency voice/alarm communications systems (EVACS). This is done for the purpose of notifying and instructing occupants in an emergency. These systems have a one-way emergency communications systems for live voice evacuation messages; and a two-way in-building emergency communication consisting of two-way supervised telephone service for emer-gency responders and the building’s fire safety team. The fire department com-munication are designed and installed in accordance with NFPA 72: National Fire Alarm and Signaling Code and operate between a fire command center and ele-vators, elevator lobbies, emergency and standby power rooms, fire pump rooms, areas of refuge, and inside enclosed exit stairways. We have also specified emer-gency responder radio systems in certain specialized buildings that require radio

coverage for firefighters. Locally in New York City, we have specified auxiliary radio communications systems (ARCS) that provide for an in-building radio sys-tem to be installed throughout high-rise and/or large footprint buildings for fire department use. First responder radio coverage must also be evaluated for all new and existing buildings in accordance with the International Fire Code.

CSE: What are some important factors to consider when designing a fire and life safety system in an office building? What things often get overlooked?

Banse: I think it is most important to discuss during design and provide for the integration of the BAS and fire alarm sys-tems along with security system. Is there smoke control needed, stair pressuriza-tion, should egress locks unlock with or without a delay? Which system actually does the controlling of smoke dampers and HVAC equipment operation during a fire event? Is the HVAC system an active or passive smoke control system? What is the fireman’s control panel supposed to do (how much equipment and damp-ers does it control)? There are so many things to coordinate that if there is little or no coordination provided, something will always be left out.

Ioanna: Pitfalls for owners and manag-ers to watch for:

Assembling the right project team:� Hire a professional engineering/con-

sulting firm specializing in the design of fire/life safety systems. Many MEP firms do not have this expertise.

� Hire a reputable fire alarm contractor (who represents the manufacturer) and an electrical contractor (who performs the installation).

� Depending on the size of the proj-ect, hire a construction manager (CM) or general contractor (GC). A GC will be required for patching, painting, and other related GC work not covered by the fire alarm team or electrical contractors.

During the bid process, consider open-bid, performance-based specifi-cation. Note: Your current fire alarm service provider may not be capable of bidding on a newer technology fire alarm system.

� Owner may need to maintain two fire alarm contractors during the con-struction phase.

� Consider non-propriety type systems.

Design considerations:� Have the design professional perform

a complete building survey and develop a design criteria, deficiency list, and build-ing code/standards analysis. Develop a construction budget.

� Determine the exact occupancy and use of the building.

� Determine what type of fire/life safe-ty is required.

� Contact local landmark and historic preservation commission (HPC).

� Determine what areas of building will be affected.

� Obtain pre-approvals from both land-mark and HPC and the authority having jurisdiction (AHJ, usually the fire depart-ment or building department).

� Will the building be occupied during the system upgrade?

� Do we need to keep an active fire alarm system?

� Can the existing system be off-line?� How do you switch systems?� Coordinate with all systems (HVAC,

elevators, fire protection, security).

Medical offices, in addition to sharing some of the same needs as conventional office buildings, have specialized needs, such as laboratory areas. Courtesy: Smith Seck-man Reid Inc.


MEP Roundtable

CSE: What unique requirements do office building HVAC systems have that you wouldn’t encounter on other structures?

Lacy: The system types used in office buildings tend to be fairly similar to those in other building types. However, the cost model and ROI for office properties is much shorter than that of institutional clients. Therefore, we have seen clients requesting more sustainable system fea-tures to reduce overall energy consump-tion, but within the same construction budget as their previous projects. Many office building budgets have not been prepared to accept the cost of premium associated with systems such as airside energy recovery or a move away from direct exchange (DX) or other air-cooled equipment.

Ioanna: Office buildings pose a unique requirement in that there are multiple times per year where both heating and cooling are required simultaneously. Very often the south perimeter and the interior zones of the building require cooling, while the rest of the perimeter spaces require heating. Sizing and select-ing HVAC systems in an energy-efficient manner while maintaining indoor com-fort becomes the design challenge.

Banse: System design that allows actual metering of services such as elec-trical, chilled water, domestic water, and air capacity used on a floor-by-floor or a tenant-by-tenant basis. It seems that space leases are getting more restrictive, and anything to help identify actual costs based on utility use is becoming part of the negotiation.

CSE: What is the most important indoor air quality (IAQ) issue you typically encounter in these proj-ects, and how do you address it?

Ioanna: One of the most common issues that cause IAQ issues revolve around the initial cleaning and quality of the air post-construction. The odors/

contaminants tend to linger for a long time unless specifically addressed prior to construction completion. In order to address this, we specify requirements for air changes and filter changes prior to occupying the space. The second issue comes from operators locking out outdoor air control systems post-construction. This seems to happen when the building operators become frustrated by the level of sophistication of the system or by the lack of commis-sioning to verify it’s operating properly. We advise owners to commission their buildings in all four seasons and also retro-commission every 3 to 5 years. We also design the outside air con-trol strategies as simple as possible so building operators feel comfortable and confident about the systems in place.

Lacy: Delivering the appropriate ventilation air quantities and removing unwanted odors are the most impor-tant. While deploying carbon filtration banks can mitigate most odor challeng-es, proper placement of roof-mounted equipment and consideration of pre-vailing wind patterns can help to avoid cross-contamination between exhaust and outdoor air streams. Analyzing the equipment placement beyond mere adherence to code minimum standards is important.

Banse: Several issues come to mind, such as proper filtration, delivery of properly conditioned air, maintenance of required pretreated outside air rates, and minimizing the infiltration of untreated outside air. Of these, main-taining clean air and the proper quan-tity of ventilation air will mitigate the other two. A good BAS set up along with trained staff helps ensure these goals can be met.

CSE: Describe any unique ventila-tion challenges you’ve overcome.

Ioanna: New corporate workplace policies implemented by our clients have placed an emphasis on maximiz-ing real estate space. Thus architects

are “dense packing” more people onto floor plates than in years past. They are placing more people in smaller spaces that are requiring higher amounts of outside air while increasing load densi-ties. Higher amounts of outside air raise HVAC operation cost. The opportunity becomes how to minimize the outside air while maintaining acceptable indoor air quality conditions. We have used various CO2 monitoring and control strategies to minimize outside by modi-fying outside air damper and variable air volume (VAV) damper positions in concert with modifying supply tem-peratures and consequently fan speed.

Banse: Some of the unique chal-lenges involved using large existing exhaust fans and large pretreated out-side air units originally designed for 500,000 sq ft or more, but having the need to only serve 15% or so of finish-out space initially. Trying to use the fans for much smaller air quantities and have them operate within their stable points of operation created a challenge, not only operationally, but also in how to avoid using unnecessary energy to accomplish the task while making the systems balanceable. One method used was to allow the discharge air to recir-culate to the fan inlet to create needed airflow for the fan. This project is still in the balancing stage with good results anticipated.

CSE: How have you worked with the architect, owner, or other play-ers to ensure the building envelope goals are achieved while maintain-ing aesthetic appeal?

Banse: Working with architects involves discussing glass types, loca-tion, required wall and roof insulation, and exterior and interior shading types and benefits at a minimum to achieve energy goals and meet minimum code requirements.

Read the longer version of this online at: www.csemag.com/archives.

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Last summer, I took on a project to install new siding and a new roof for a small shed, which was prob-

ably last done about when President Ken-nedy announced we were going to the moon. That kind of project gives you a little time to think, but most of the time I was cutting, nailing, staining, and paint-ing. Since then, every time I walk by it, I experience an-out-of-proportion amount of pleasure for what it took, prompting the question: Why is that? Is a tangible sense of accomplishment so unusual that it is that satisfying?

In our daily lives, it’s easy to become virtual, communicating by e-mail and social media, catching sports scores and news, etc. With such a high percentage of our lives spent on the computer, a tan-gible sense of accomplishment can be eva-sive, even after working all day. Actually making or doing something is, of course, behind the pleasure of many hobbies—if you’re fortunate enough to have such hob-bies and can make time for them.

The point of all this is that if you’re a person who doesn’t have a regular feel-ing of tangible accomplishment like you would get in the trades, for example, get-ting more actively involved in anything can make you more effective. A heavy dose of reality comes when you’re the one cutting or nailing or painting, not just proj-ect managing those who do. It’s easy to sit in the bleachers, critiquing and observing what is being done, right or wrong. It’s far different to be on the field trying to make things happen. To this point, a quote from Theodore Roosevelt is prominently posted above my computer monitor as a constant

reminder to do real things and not fall into the trap of observing from afar:

It is not the critic who counts, not the man who points out how the strong man stumbled, or where the doer of deeds could have done them better. The credit belongs to the man who is actually in the arena; whose face is marred by dust and sweat and blood; who strives valiantly; who errs and comes short again and again; who knows the great enthusiasms, the great devotions, and spends himself in a worthy cause; who, at the best, knows in the end the triumph of high achievement; and who, at the worst, if he fails, at least fails while dar-ing greatly, so that his place shall never be with those cold and timid souls who know neither victory nor defeat.

The nature of many of our jobs is that we are often not the ones in the field or in the factory, selling, servicing, or mak-ing things. You may be in the boardroom, headquarters, or anywhere else in which you are by nature working, removed from the field of action. To help you more effectively interact with others in ways that are relevant, here are some things to consider:

� Don’t hesitate to “get your hands dirty” in anything; it will help keep your perspectives real and practical in all that you do.

� As much as is practical, spend time with people who do the real work. One day in the office with a person who estimated, designed, and man-aged controls projects and a day in the field with an installer taught me invaluable insights during a transition from the HVAC field to controls. It wasn’t about becoming an expert; it was about understanding the business from project realities.

� Organizations such as Engineers without Borders and Habitat for Human-ity are just two of thousands of organiza-tions that need tangible actions that your training and time can provide.

John Suzukida was Trane’s senior VP of global marketing and strategy prior to founding Lanex Consulting in 2002, which focuses on strategic planning and product-to-solutions business model transitions. He has a BSME and Distinguished Alum-nus Award from the University of Illinois. He was a presenter at the 2012 Career Smart Engineers Conference.

Career SmartJOHN SUZUKIDA, PE

Minneapolis

Doing real thingsGetting your hands dirty on the job can teach invaluable skills.


reminder to do real things and not fall into

Photos courtesy: John Suzukida

40 Under 40: The Consulting-Specifying Engineer 40 Under 40 program was born out of Consulting-Specifying Engineer’s ongoing mission to foster mentoring in the engineering industry. 40 of the most talented young professionals supporting the building community are nominated by their mentors and honored throughout the year in print, online, and in person.

Product of the Year: 2013 marks the 9th year that Consulting-Specifying Engineer holds the annual Product of the Year (POY) contest. It is the premier award for new products in the HVAC, fi re, electrical, lighting, and plumbing systems engineering markets. Look for the POY winners online at www.csemag.com/POY.

MEP Giants: The MEP Giants program features the top mechanical, electrical, plumbing (MEP), and fi re protection engineering fi rms, listed by total MEP design revenue. For 33 years, the MEP Giants list is used by many engineering fi rms to track their growth and prominence within the MEP engineering industry. Please look for the full MEP Giants special feature on www.csemag.com/giants.

Webcasts: Need some continuing education? Look no further than www.csemag.com/webcast. Topics covering every vertical—critical power, lighting, fi re and life safety, HVAC, codes and standards, data centers— give engineers a great opportunity to learn about the latest industry practice while getting FREE CEU credits.

eNewsletters: The wide array of eNewsletters gives engineers a way to stay on top of the latest news in a convenient and easy-to-read electronic format. Sign up for Fire & Life Safety; Electrical Solutions; HVAC; Pure Power; Product and Media Showcase; Codes & Standards; Newswatch: Hospitals; and Newswatch: Data Centers.

www.csemag.com: CSEmag.com is a highly rated industry website with industry news updated throughout the day, a top-notch search engine that segments results by category, and thousands of archived articles. You’ll also fi nd Webcasts, videos, case studies, and eNewsletters—an all-around go-to site to gather information and fi nd solutions.

Subscribe today at

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Supporting Engineers In-Personand Offering High-Value Content Online and In-Print


Commissioning and Integrated Testing of Fire Protection and Life Safety Systems is an overall benefit for projects, with its

no-nonsense approach that will assist in validat-ing the intended system design, performance criteria, and proper installation and operation of these systems. In the United States, the 2012 edition of NFPA 3: Recommended Practice for Commissioning and Integrated Testing of Fire Protection and Life Safety Systems is the only national document providing guidance about commissioning and integrated testing for fire protection and life safety systems. Although the document has been out for over a year, many people do not know of its existence or fully understand it. Understanding the process out-lined in NFPA 3 related to commissioning of fire protection and life safety systems is criti-cal. Another source of information is the Build-ing Commissioning Assn. (BCxA), which is a national organization for building commission-ing, including fire protection and life safety. The following is a list of 10 key items, not in order of importance, that you should know about commissioning fire protection and life safety systems:

1 Commissioning is a process: NFPA 3 defines fire and life safety commissioning

as “A systematic process that provides docu-mented confirmation that building systems func-tion according to the intended design criteria set forth in the project documents and satisfy the owner’s operational needs, including compli-ance with applicable laws, regulations, codes, and standards.” NFPA 3 provides the outline of the process related to the steps in commissioning and the documentation of the commissioning.

2 Agent of the owner: A fire commissioning agent (FCxA) is working as an owner repre-

sentative, and as such is an agent of the owner. This is a different role, with different responsi-bilities, than engineer of record, installing con-tractor, or local authority having jurisdiction (AHJ). The FCxA is another set of eyes and ears overlooking the commissioning of the fire pro-tection and life safety systems and ultimately helps to assure the successful design and opera-tion of these systems. The FCxA is a member of the overall full building commissioning team, headed by the commissioning agent (CxA). If the only systems being commissioned are fire

By DaviD Joseph LeBLanc, pe, FsFpe, Rolf Jensen & Assocs. Inc., Framingham, Mass.

Codes & Standards

Top 10 things to know about commissioning fire protection systemsFire protection engineers should use NFPA 3 as guidance on commissioning fire protection and life safety systems.

Commissioning and integrated testing can include multiple fire protection systems, such as fire alarm, fire pump, and special suppression systems. The photo is of aqueous film-forming foam (AFFF) system discharge that, in one test scenario, functionally tested the operation and interface of the fire alarm, fire pump, AFFF special suppression, drainage, and secondary containment systems. Courtesy: Rolf Jensen & Assocs.

protection and life safety systems, then the FCxA leads the commissioning effort.

3 Special knowledge and expertise: The FCxA (or FCxA team) should

have special knowledge and expertise related to the specific fire protection and life safety systems to be commissioned. This includes general industry practices on how to properly test these systems and an advanced understanding of the systems’ installation, operation, and maintenance.

4 Commissioning team brought in during design: It is critical that

the FCxA team be brought in early to allow review of the design documents, including compliance with the owner’s project requirements (OPR). Issues identified by the FCxA during the design phase and modified on paper are much easier, less expensive, and less impactful to the construction schedule when compared to design/installation modifications during construction after system installation.

5How to test a system: NFPA 3 out-lines a process but does not iden-

tify exactly how to functionally test a specific fire protection or life safety system. The specific NFPA standard that deals with that specific fire pro-tection or life safety system identifies testing requirements (e.g., NFPA 72 for fire alarm and emergency com-munication systems). Furthermore, industry practice and manufacturers’ written recommendations are also uti-lized in the development of the critical testing plan.

6 Commissioning is not acceptance testing: In the industry, people often

interchange the terms “commission-ing” and “acceptance testing,” but these terms are not interchangeable. Accep-tance testing does not equal commis-sioning. Acceptance testing is typically

done either with an engineer of record or a local AHJ for final acceptance of the system. Commissioning is a systematic process with documentation that extends from design through installation, testing, and training.

7 Comprehensive test scenarios: It is critical that a testing plan with

identified comprehensive test scenarios be developed so that all stakeholders understand what will be tested and the coordination of these efforts. The vari-ous test scenarios can include an indi-vidual system test, an integrated system test verifying sequence of operation, or integrated tests between multiple sys-tems. It is also important to test not only what the systems are supposed to do, but also what they are not supposed to do. As an example, consider a smoke control system that should initiate upon activa-

tion of an atrium sprinkler system water flow. One test would be to verify that the smoke control system initiates with the atrium sprinkler system waterflow. Another test scenario would be to activate a non-atrium sprinkler system waterflow and verify that the atrium smoke control system does not initiate. There are also a multitude of scenarios to develop, such as proper operation on loss of building power or prioritization of events.

8 Full-load testing: It is very impor-tant to during the commissioning

testing,to conduct a full load test with no bypasses, silence, or disconnections between systems. This includes testing of the fire protection and life safety sys-tems on emergency or standby power. The intent of these tests is to create real-world scenarios that may occur in an operational building and verify the fire protection and life safety systems per-form as intended.

9 Existing buildings: NFPA 3 also addresses commissioning of exist-

ing systems that were previously com-missioned, referred to as re-commis-sioning (re-Cx), and commissioning of existing systems that were never com-missioned, referred to as retro-commis-sioning (retro-Cx).

10 Adopted codes: NFPA 3 can be adopted/required by the owner,

project requirements, or contract require-ments. Some mandatory commissioning requirements have also made into build-ing code requirements. For example, the International Building Code (IBC) has requirements for commissioning smoke control systems, referred to as smoke control special inspections.

David Joseph LeBlanc is vice president at Rolf Jensen & Assocs. He has a master’s degree in fire protection engineering, is a registered fire protection engineer in various states, is a committee member of NFPA 3 and NFPA 4, is a fellow of SFPE, and has more than 20 years of experience as a fire protection engineer.

Codes & Standards

It is critical that a testing plan with identified comprehensive

test scenarios be developed.


Upcoming NFPA 3 code changesIn the 2015 NFPA code cycle, NFPA 3 is being split into two separate NFPA documents.

The 2015 edition of NFPA 3 will remain a recommended practice, but will focus only on commis-

sioning. The Integrated Testing of Fire Protection and Life Safety Systems is being broken out as a

separate new NFPA document, NFPA 4. The 2015 edition of NFPA 4 will become a standard and

will not be a recommended practice, due to the committee decision about the criticalness of inte-

grated testing between multiple systems. The updated NFPA 3 and the new NFPA 4 are scheduled

for a 2015 edition release. The NFPA window of time for public input and comments for the 2015

edition of NFPA 3 and NFPA 4 was recently closed.

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Despite challenges both new and old, and an economy that is improved but still not roaring, commissioning firms remain hopeful about the upcoming year.

By Ray BeRt and amanda thomason, AABC Commissioning Group, Washington, D.C.

The state of commissioning in 2013

Does 2013 looks just like 2012? Maybe. But while the numbers for the commissioning (Cx) market

seem to indicate a somewhat idle industry, respondents to an exclusive survey reveal a more positive outlook. There is a hint of business “picking up”—that a lack of significant growth from 2012 is neither a surprise nor a letdown, but instead reflects an economy still finding its new legs.

There was an overall increase in Cx busi-ness among firms surveyed. Almost half (47%) report that commissioning compris-es 20% or less of their business, whereas in 2012, that number was 50%. Moreover,

firms reporting commissioning to be 85% or more of their business increased, from 22% last year to just less than 30% this year. The trend was reflected in respondent commen-tary, where half of the remarks indicated that either all or at least certain segments of com-missioning were on the rise.

The optimism regarding the increase in work was great news. Unfortunately, the ideal commissioning situation, wherein the Cx provider is an experienced and independent third-party provider hired directly by the owner and engaged during a project’s earliest stages, continues to be more the exception than the rule.

Table 1: Based on information provided in the 2013 MEP Giants data collection, these firms have the largest amount of MEP design revenue attributed to commissioning services: Courtesy: Consulting-Specifying Engineer 2013 MEP Giants

Table 1: 2013 MEP Commissioning Giants

Firm name Total MEP design revenue

Commissioning percentage of design

billings

2013 Cx total revenue

Black & Veatch $1,042,980,000 10% $104,298,000

Jacobs Engineering Groups Inc. $1,549,650,401 2% $30,993,008

URS Corp. $550,000,000 5% $27,500,000

Sebesta Blomberg $31,185,273 53% $16,528,195

HDR Inc. $121,765,835 10% $12,176,584

Smith Seckman Reid Inc. $52,870,865 18% $9,516,756

exp $158,380,000 6% $9,502,800

Stantec Inc. $107,000,000 8% $8,560,000

Optimation Technology Inc. $50,158,420 16% $8,025,347

WSP $63,975,420 12% $7,677,050

Special report:

More than 40% of firms said that they are hired as an independent third-party 85% to 100% of the time, and this has remained a constant since 2011. Similarly, a little more than half of this year’s respon-dents indicated that they are hired directly by the owner or the architect.

Regarding one of the key concerns of Cx providers—at the point they’re brought onto a project— the numbers appear to be about the same as last year’s. As with last year, 42% of the time, respondents report that they aren’t brought on until the construction phase. How-ever, that number was 46% in 2011. Has a slow trend toward earlier participation begun? Seeing how firms respond to this question in 2014 will be interesting.

New this year, ACG asked those who have been retained in the early stages of a project what factors or strategies they thought helped them to gain early job involvement. By far, three factors stood out:

n The level of education or awareness building owners have of the benefits of early commissioning engagement

n U.S. Green Building Council LEED or various code requirements mandating early participation of Cx providers

n A Cx firm’s reputation, experience, and established relationships.

Building types, sectors, and Cx scope Many in the industry have predicted

a shift in focus toward existing build-ing commissioning. Statistically, this year showed no additional push in that direction, with 74% of firms’ commis-

sioning business still coming from new construction. However, in response to an open-ended question about trends, many respondents reported that they still antici-pate this direction in the future.

When their firms did perform exist-ing building Cx, ACG asked what their clients’ motivations were. The highest priority reported was energy cost reduc-tion. But right behind that, the No. 2 rea-son was building performance. As one respondent put it, “Reliable building sys-

tem performance outweighs other owner issues. The main cause of inefficient operation is frequently improper system operation.”

Providers still see roughly the same mix of facility types, with commercial office build-ings being the most common, at nearly a quarter of the total. Higher education dropped off by a few percentage points, whereas central utility plants gained a few.

The private sector still pro-vides the largest percentage of Cx work, accounting for 39%—the same as 2012—but is another example of a jump from 2011 (33%) to 2012,


Figure 1: Cx providers are still not being retained in the early (design and pre-design) stages of a project often enough, when commissioning would deliver the most value to building own-ers. Courtesy: AABC Commissioning Group

Figure 2: Commercial office buildings remain the most com-mon facility type commissioned, and central utility plants grew slightly in 2013. School projects continue to be strong. Courtesy: AABC Commissioning Group

Figure 3: All sectors remained the same, except for federal, non-military jobs, which decreased, a trend also noted in the comments of many respondents, who indicated a general decrease in government work. Courtesy: AABC Commis-sioning Group

For new construction projects,when do you begin your Cx work?

Pre-DesignPhase18%

ConstructionPhase42%

Design Phase40%

Other21%

Approximately what percentageof your commissioning jobs are:

Pharmaceutical1.5%

CentralUtility Plants7.5%

HealthcareFacilities

13%

Laboratories/Research 8%

HigherEducation

13%

K-12 Schools11.5%

CommercialOffice24%

Military23%

Municipal11%

Other3%

Approximately what percentage ofyour commissioning jobs are:

Private Sector39%

StateGovernment

15.5%

Federal (non-military) 8%


only to level out this year. All other sec-tors in the survey stayed the same, with the exception of federal, non-military jobs, which decreased from 11% to 8%, a trend also noted in the comments of many respondents’ who indicated a gen-eral decrease in government work.

HVAC, domestic hot water, and light-ing/lighting controls remain the most frequently commissioned systems. This comes as no surprise since those are the three systems currently required at mini-mum to meet the LEED commissioning prerequisite.

Other building systems commissioned showed the same or a slight decrease in frequency, including building envelope, from 15% in 2012 to 12% this year. And while respondent comments didn’t explain this dip, they didn’t seem all that phased by it either, anticipating a growth nonetheless in building envelope com-missioning.

One decrease of note was the number of Cx providers who partner with other firms to commission various systems out-side the scope of their firm’s expertise. While that number had jumped substan-tially in 2012 to 71% from 55% in 2011, it plunged this year, with only 47% of respondents subcontracting to other firms. Whether this is a trend or a short-term strategy by Cx firms to bring more

types of services in-house to combat the impediments of a still recovering econ-omy, only time will tell. This is another area to keep an eye on in 2014.

Energy management services Energy management work continues to

be incorporated in Cx firms’ suite of ser-vices. The number of firms that provide these services, separate from traditional commissioning, dropped slightly from 80% last year to 75% in 2013. However, this simply could be due to the fact that,

as some respondents mentioned, their firms are now combining energy-relat-ed work with commissioning. In other words, perhaps less of a distinction is being made as energy management ser-vices become more and more common. (ACG’s energy management initiative, in fact, is built in significant part on the idea that comprehensive energy manage-ment services are best delivered within a commissioning-based framework.)

Moreover, more companies reported that they performed more types of ener-gy management services. For example, energy audits, energy savings calcula-tions, energy modeling, and measure-ment and verification all saw increases from last year.

There was good news among respon-dents concerning how often their firm was involved in implementing recom-mended energy conservation measures. Those who were involved 20% of the time or less dropped from 72% to 61%, while those who saw their firm’s involvement roughly half of the time increased by 10%, from 12% to 22%. And even though only 5% of firms were involved in implementing recommended measures 65% to 100% of the time, that number represented a slight increase from 2012.

2013 commissioning report

Figure 4: Building envelope dropped slightly, yet many respondents commented that they still anticipated a growth in this area of commissioning. The other systems in the survey remained the same or decreased slightly. Courtesy: AABC Commissioning Group

Figure 5: Increases among those who saw their firm’s involvement roughly half of the time and 65% to 100% of the time represent a push in the right direction regarding the Cx firm’s involvement in the implementation of energy measures. Courtesy: AABC Commissioning Group

On approximately what percentage of your projectsare the following systems commissioned?

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Lightin

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Data c

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rs

Fire a

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ction

Secu

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ystem

s

Eleva

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201320122011

8070605040302010

0

If you provide energy audits, approximately whatpercentage of the time is your firm involved in the

implementation of energy measures?

20%

or l

ess

25%

-40%

45%

-60%

65%

-80%

85%

-100%% % % %

20132012


In general, of the respondents who addressed whether energy management work would increase in 2014, a little over half thought it would. Most of the other half predicted it would remain the same, and only a small percentage (5%) thought they would see a decrease in energy-related work.

Cx and LEED The U.S. Green Building Council’s

LEED rating system remains a key driver of commissioning work due to its “fundamental commissioning” requirement, a prerequisite to obtaining a LEED-certified building designation, as well as the optional credit it offers for “enhanced commissioning.” The industry is currently awaiting LEED version 4, which is slated to be released in fall 2013 and is expected to include important changes to the commissioning requirements.

LEED-driven jobs rose again this year, with 70% of respondents indicating that most (65% to 100%) of their firm’s recent Cx jobs involved LEED projects, a 12% increase over last year’s 58%.

Another 12% increase was seen in the amount of LEED projects pursuing the enhanced commissioning credit, with 52% of responding firms citing 65% or

more of their LEED projects pursuing the credit and 23% citing that 85% to 100% of their firm’s LEED projects were doing so. Considering that those num-bers were 28% and 15%, respectively, in 2011, it is safe to say that the enhanced commissioning credit continues to plays a major role in LEED-related Cx work.

Challenges and trends Regarding the top commissioning-relat-

ed challenges firms face, five themes have clearly emerged over the past three years. Although the five categories might switch places year to year, they remain the most common struggles in the industry:

Finding qualified personnel. Finding, hiring, training, or retain-ing qualified personnel remains an

issue, though not as prevalent as last year, and one much less emphasized than the other four.

Obtaining work. While obtaining work made the top five again, it decreased slightly from last year.

Economic factors contributing to this difficulty remain the same among com-missioning providers: an economy still in recovery and slow to generate new construction, and a decline in federal and other public projects.

Understanding of Cx value, late engagement. These issues are grouped together here as they

seem to have a cause-and-effect rela-tionship. As noted above in the article, even though commissioning providers

ACG collects new data

T his year, a few new questions were added to provide a broader perspective on what is impact-ing the industry and where firms saw it heading. Is the trend toward codifying commissioning

a concern? Are any new technologies proving useful? And finally, are firms reaching beyond the American borders to procure work?

CODES: When asked for comments or concerns regarding commissioning being incorporated into building codes, ACG got a variety of answers. On the positive side, respondents felt that such regula-tion might ensure consistency within the industry, help raise the bar for commissioning services, and create business. Others responded that they felt code-mandated commissioning would be a welcome development as long as they mandated that Cx providers be certified, independent, third-party entities.

However, just as many respondents were concerned that the collision of codes and commissioning would serve only to commodify the industry, enabling less qualified competition to flood the market. Some respondents felt that in their current form, codes that address commissioning lack clear defi-nitions and are too open to interpretation, especially by authorities having jurisdiction (AHJs), and therefore unenforceable.

NEW TECHNOLOGIES: In a world where new technologies seem to arrive on the scene daily, we wondered which ones commissioning agents (CxAs) were finding useful. Many mentioned that por-table electronics such as tablets, iPads, and smartphones were facilitating Cx work. Online software such as cloud-based systems were said to be helpful. Wireless technologies, both in terms of access to controls and monitoring, made the list as well. And finally, some respondents said that recently improved data loggers were proving helpful tools.

NEW MARKETS: Since the general outlook on the market in the United States was rather pessimistic in 2012, the survey asked if anyone was looking abroad for more commissioning opportunities. The responses indicated a resounding “yes.” Separated into regions, many respondents reported that they had worked, were currently working, or planned to work in the Middle East. Following closely was Latin America. Asia and Europe were also frequently mentioned. A few respondents listed Africa, and some firms indicated that they work worldwide. Clearly, there are opportunities all over the world for commissioning work.

Figure 6: A little over half of responding firms said 65% or more of their LEED proj-ects were pursuing the LEED enhanced commissioning credit and almost a quar-ter said 85% to 100% of their firm’s LEED projects were doing so, both significant increases from 2011. Courtesy: AABC Commissioning Group

201320122011

20% or less

What percentage of your LEED projects pursuethe Enhanced Commissioning Credit?

35

30

25

20

15

10

5

025%-40% 45%-60% 65%-80% 85%-100%

20122011

20% l 25% 40% 45% 60% 65% 80% 85% 100%

Finding qualified personnel. Finding, hiring, training, or retain-ing qualified personnel remains an

5

Obtaining work.work made the top five again, it decreased slightly from last year.

4

Understanding of Cx value, late engagement.are grouped together here as they

3

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continue to extol the benefits of early involvement in a project, and despite mandates in building rating systems that require it, predesign participation remains infrequent. Could this be the result of another top challenge cited by survey respondents, that many building owners still don’t understand the value

of comprehensive commissioning? The two seem inexorably connected.

Competition, pricing, and con-densed Cx scopes. These interre-lated issues—often noted as such

by respondents—continue to present challenges to Cx providers, though they fell from the No. 1 spot held last year. Of

particular concern to respon-dents was the abundance of firms offering “commission-ing lite,” which in turn cre-ates a downward pressure on fees. Providers are still too often faced with the choice of doing a limited scope on a given project or not getting the job at all.

Scheduling. Coming in strong as the No. 1 challenge this year was

what was described in 2011 as the problem of “herding cats.”

In other words, getting the various players on the commissioning team on the same page, so that project schedules remain on track, continues to be a hitch. Respondents cited several examples of issues impact-ing the project schedule, including getting documentation on time and correctly filled out and the old agitator, being told systems are ready for testing when they’re not.

Finally, respondents were again asked to share their thoughts about possible upcom-ing trends in commissioning. The majority indicated that they anticipated the same three trends that topped the 2012s ACG sur-vey: an increase in retro- or existing build-ing Cx projects, more demand for build-ing envelope Cx, and a decline in projects focused on LEED certification.

Ray Bert is executive director and Aman-da Thomason is director of communica-tions at the AABC Commissioning Group (ACG).

2013 commissioning report

METHODOLOGYFor the third year, the nonprofit AABC Commissioning

Group (ACG) conducted a survey of nearly 500 companies that provide commissioning services to learn about their biggest concerns and obstacles, what kind of work they are doing now, and what they expect to be doing in the coming year. With nearly 160 firms responding (32% response rate), ACG has a good idea about what has changed since the survey was first conducted in 2011, and in what direction commissioning firms are expecting the industry to go. As with previous years, all of the companies surveyed are professional, independent firms that are not engaged in contracting or manufacturing work.

Competition, pricing, and con-Competition, pricing, and con-densed Cx scopes.lated issues—often noted as such

2

Scheduling. in strong as the No. 1 challenge this year was

1

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Some federal, state, and city energy codes, standards, and guidelines now restrict building lighting

power density (LPD) to as low as 0.60 W/sq ft. This restriction is requiring the architectural and engineering design teams to fully comprehend and evaluate the contribution of lighting to the build-ing cooling and heating loads for retrofit applications. Designing lighting systems so that they complement the HVAC sys-tems design to a net reduction in build-ing energy use requires close interaction

between the lighting designer, architect, and project mechanical and electri-cal engineers. It is the challenge of the team to develop a lighting layout that not only provides quality illumination to the space, but also reduces overall energy consumption.

One challenge the design team faces in developing a lighting strategy is to incorporate components that can be accurately modeled by HVAC cooling load and energy analysis software. With a renewed focus on sustainability and

How to select, design, and redesign lighting systems so theycomplement HVAC systems.

BY DAVID DUTHU, PE, and NOLAN ROME, PE, LEED AP, ccrd partners, Houston

Factoring lightinginto cooling loads

Learningobjectives� Understand how lighting choices affect a building’s overall energy efficiency.

� Discover key factors of lighting design that impact a building’s cooling and heating loads.

� Learn issues to consider when evaluating alternative lamp technologies.


energy conservation, the financial sup-port for product development in lighting technologies has spawned a wide array of new lamps and control devices available to design architects and engineers. How-ever, performance data may not always be presented in an equivalent manner regarding energy usage and quality of light. As design teams take advantage of this new technology, it will be criti-cal that correct comparable performance data be obtained and incorporated into not only building cooling and heating load analysis and energy modeling, but also into photometric software programs that allow the design team to study, test, and implement lighting designs.

According to the U.S. EPA Energy Star Building Upgrade Manual, lighting is typically the largest source of waste heat, representing approximately 35% of electricity consumed in commercial buildings. That waste heat translates into heat gain, which significantly impacts the building cooling and heating loads. Although other factors also influence the final cooling/heating load analysis, the lighting system contributes a major por-tion of internal heat gain. This internal heat gain, for certain climates or building configurations, can be useful when the building is in the heating mode. When the building is in cooling mode, however, lighting heat gain can be detrimental, due to the increase in the cooling load and the capacity of the cooling equipment required to maintain space thermal com-fort conditions.

In many retrofit applications, reduced building lighting loads and correspond-ing reduction in the cooling requirement may result in reduced full-load opera-tions of the HVAC systems. This can save significant amounts of energy used for lighting and cooling the building, lower energy cost and may prolong the service life of existing HVAC components. An additional benefit is that the resulting

excess cooling capacity could be used to serve future cooling load requirements, provide redundant capacity for existing critical loads, or allow replacement cool-ing equipment capacities to be lower, i.e. right sized for the lower loads, further reducing operating expenses.

New energy codes and standards In the past few years, several revised

energy codes and standards have been released. Understanding the basic requirements of the standard applicable to the specific project is imperative in designing and modeling lighting systems

Figure 1: The lighting in the ccrd office includes a combination of daylighting (north side of building shown), high-output T5 lamps, and LED spot and cove lighting. Courtesy: ccrd partners

Figure 2: The ccrd office lobby includes LED spot downlights used in combination with high-output T5 fluorescent cove lighting and daylighting. Courtesy: ccrd partners

Creating efficient office lightingA remodel of ccrd’s 17,000-net-sq-ft commercial office space in a circa-1929 office in downtown

Houston took advantage of both energy modeling for HVAC load analysis and a lighting optimization simulation analysis to determine the impact on yearly energy consumption. The baseline model, which used the existing space design, was modeled with its existing lighting (2x4-ft recessed lay-in return air T12 light fixtures) that had previously been retrofitted from to 2-lamp T8 fixtures. The existing lighting demand was 10 kW (input power). This retrofit design was compared to the same space, using dimmable energy-efficient solid-state high-output T5 high output and LED luminaires with occupancy sensing control and natural daylight from the existing north-facing palladia windows, resulting in a reduced peak power demand of 8.2 kW.

In comparing the two analyses for the floor cooling and heating load requirements, the existing design had required approximately 7 cooling ton-hrs per year consumption, while the remodeled floor require 6 cooling ton-hrs per year consumption. Peak heating demand increased from 92 kBtuh to 125 kBtuh as a result of the redesign, with energy consumption increased from 500 therms to 592 therms. Replacing the 2-lamp T8 parabolic fixtures with programmable, occupancy based T5 high-output lamp pendant luminaires and LED downlights offset with natural daylighting allowed for a yearly reduction in energy consumption of 16%. As a result of decreasing the lighting W/sq ft, the heating consumption increased by 15%.

The majority of load reduction was due to lighting controls and use of daylighting for the space. The existing lighting design was based on manual occupant switching. As occupants left for the day, lights would be switched off; when the cleaning staff switched lights on after-hours, lights would be left on overnight. To reduce lighting consumption, the renovation took advantage of vacancy sensing. With a vacancy sensor strategy, lights are turned off automatically soon after an area is vacated, but occupants must turn lights on when they re-enter the space. In the renovation, lights tied to a vacancy sensor turn off 2 hours after they are energized after-hours. After the cleaning crew has left the space, lighting would reduce to 30% of the design level in the space, rather than remain at 100% design level with switching.

This illustrates the benefit of application of lighting modeling and energy/load modeling in devel-oping a lighting retrofit design that is unique to the building by incorporating daylighting and task lighting, employing new energy-efficient LED technology, and controlling supplemental lighting in order to achieve energy savings, enhanced lighting, reduced equipment cost, and improved comfort and aesthetic benefit for the tenant.


that provide optimal performance and are cost effective on a lifecycle basis.

Recently implemented codes and stan-dards that have an impact on the design of lighting systems for retrofit applications include the Energy Policy Act of 2005 (EPAct 2005), 2012 International Energy Conservation Code (IECC) and ANSI/ASHRAE/IES Standard 90.1-2010, the State of California 2013 Building Energy Efficiency Standards, Title 24, Part 6 (and Associated Administration Regulations in Part 1), and the City of New York City LL85: Energy Conservation Code and LL88: Lighting Upgrades & Sub-Meter-ing Code.

These codes and standards as well as voluntary sustainability programs—such as the U.S. Green Building Council (USGBC) LEED certification program, the Green Building Initiative (GBI) Green Globes program, ASHRAE Stan-dard 189.1-2011, and the U.S. EPA Ener-gy Star program—represent a paradigm shift in the way architects and design engineers have to consider not only the initial impact of lighting in the calcula-tion of heating and cooling loads, but also ongoing operating conditions and retro-commissioning of existing systems. In

fact, some code authorities and the U.S. Army (UFC 1-200-02 High Performance and Sustainable Building Requirements) have adopted all or portions of these stan-dards for some specific building types and/or locations within their jurisdiction.

For design team members, these chang-es highlight the importance of collabora-tion in selecting the lighting technology to employ on a specific project. Design of today’s energy-efficient and innovative lighting systems requires a total effort by the design team in evaluating alternative lighting system impacts on interior space planning, lighting fixture layout, furniture and fixed equipment layout, and lighting controls, resulting impact on HVAC cool-ing and heating loads, and ultimately the energy use and utility costs to operate the building.

Building configuration and load calculations

Calculating space cooling and heat-ing loads requires many aspects of the building design to be considered. Factors that affect the heating and cooling loads include:

� Type of building� Building configuration and floor area

� Wall to window ratio� Building orientation on the site� Thermal performance of the build-

ing envelope� Impact of external shading devices

or adjacent buildings� Ground reflected solar radiation� Climate conditions� Indoor design requirements� Internal heat gains, including plug

and process loads� Building occupancy schedules� Energy consuming equipment

operating schedules � HVAC system types� Sequences of operation of the

HVAC systems.

For retrofit applications, engineers must know the size and efficiency of existing heating and cooling systems and how the building equipment is operated in order to accurately predict energy consumption and peak demand. Typically, large high-rise buildings are dominated by high inter-nal loads, and consume more air condi-tioning and heating than most low-rise applications due to the size and density of the building occupants and equipment heat gain. According to the EPA, high-rise buildings present the best opportunity for energy savings. Each kWh of reduction in annual lighting energy use yields an additional 0.4 kWh of annual reduction in HVAC energy.

For smaller, exterior envelope-dominat-ed buildings, the net impact of a lighting retrofit may result in a net HVAC penalty, particularly for buildings in cold climates. This means that for each kWh in light-ing energy reduced, the building HVAC system net energy consumption may rise as a result of additional annual heating energy used. In other words, a reduction in lighting load may result in an increase in building heating load, which results in no net change or an increase in total energy consumption if the reduction in energy used for cooling is less than the additional heating energy required over the course of the year. Empirical data shows that or the majority of scenarios, lighting upgrades are more likely to reduce cooling costs and

Factoring lighting into cooling loads

Figure 3: In this solid-state lighting luminaire (fixture) performance curve, the efficacy of LED light sources has already surpassed that of incandescent, halogen, high-intensity discharge, and linear fluorescent lamps (LFL), and will continue to improve. Courtesy: U.S. Dept. of Energy

Figure 3: In this solid-state lighting luminaire (fixture) performance curve, the efficacy

Lum

inai

re e

ffic

ien

cy (

lm/W

)

250

200

150

100

50

0

Year2010 2015 2020 2025

DOE LED goal: >200 lm/W

Top luminaire efficacy for HID and LFL

85:high-efficacy 2012 products

HID and LFL: 60-115


increase heating costs. When calculating building cooling

loads, the designers must consider the components that comprise the heat gain due to lighting. These factors can vary such that at any given moment, the heat equivalent of power supplied instanta-neously to the lighting is not necessarily that which equates to the instantaneous cooling load.

Of the three basic types of heat trans-fer, convection and thermal radiation are the major contributors to lighting heat gain while conduction is negligible. Both convection and thermal radiation transfer heat to the space, which results in 100% of the lighting power becoming cooling load. However, it is important to recognize that the convective component represents an instantaneous heat gain, while heat gain due to thermal radia-tion is delayed because the heat is stored within the surfaces in the room such as ceilings, floors, walls, furniture, etc. This is true for all types of lighting technolo-gies (LED, fluorescent, incandescent, etc.), although the fractions attributable to radiation vs. convection will differ.

The 2013 ASHRAE Handbook —Fun-damentals presents a detailed discussion of the various parameters that influence the calculation of cooling loads due to lighting heat gain. Of those presented, key factors encountered repeatedly in the new energy codes and standards are the fractions of heat gain and the special allowance factor (SAF).

The fractions of heat gain consider the assignment of the components heat output by the luminaire. Cooling loads typically account for heat generated by in-ceiling (or recessed) luminaires, which are made up of two key parameters:

n Ceiling plenum fraction: The frac-tion of the lighting power that heats the return air that is directed through the light fixture (zero for surface mounted and pendant hung light fixtures and task lights)

n Space fraction: The fraction of the lighting power converted to heat gain in the conditioned space.

In lighting retrofit upgrades for com-

mercial office buildings, the design typi-cally includes recessed fluorescent light-ing fixtures, which will release heat to the space and direct heat to the return air ple-num or to the ceiling cavity. It is impor-tant to distinguish these components even though total cooling load imposed on the cooling coil remains the same. The larger the fraction of luminaire heat output that is picked up in the return airstream for air return luminaires and directed back to the cooling coil, the better the overall energy performance and interior comfort due to the reduced fraction of heat that goes to the conditioned space. This channeling of the lighting heat to the ceiling ple-num helps reduce the room cooling load,

thereby reducing the supply airflow (and resulting fan energy) required for space conditioning.

The SAF is the ratio of lighting fix-ture total power consumption, includ-ing lamps and ballast, to the nominal power consumption of the lamps, which includes the luminaire lamps and ballasts (for fluorescent fixtures). As a reference, an incandescent lamp has an SAF of 1.0. To demonstrate the progress made in the development of energy-efficient fluores-cent lighting over the past several years, an historical comparison is made between the 1977 and 2013 ASHRAE Fundamen-tals Handbook. In the 1977 Handbook, the SAF for fluorescent luminaires was as high as 2.19 for 32-W single lamp T-12 high-output fixtures. For a rapid-start 40-W T-12 lamp fixture, allowance factors vary from a low of 1.18 for two

lamps to a high of 1.30 for one lamp. These SAF values accounted for the losses in the magnetic ballasts, then com-monly used in the fixtures.

Recent ASHRAE research has found that the SAF ranges between 0.87 and 0.90 for T-8 luminaires with electronic ballasts and between 0.98 and 1.02 for with other lamp types. Electronic ballasts can lower electricity consumption below the lamps’ rated power requirement, which represents a significant advance in lighting technology and provides a valuable tool for the designers reduce cooling loads and enhance energy performance. Electronic ballasts operate the lamps at a higher fre-quency (>20,000 Hz), offer additional controls options for lamps, and consume less power than magnetic ballasts.

The current ASHRAE Handbooks present little data on LED lighting, no doubt due to the rapid development in solid-state LED technology. However, a review of recently published manufac-turers’ data for solid-state LED lighting indicates the SAF is further impacted to the positive when considering the light output per unit and quality of light pro-vided to the object area.

Recent developments in solid-state LED technology show superior perfor-mance for both the space fraction and radiative fraction numbers. As compared to incandescent fixtures, the fraction of heat transfer due to radiation vs. convec-tion is typically much higher for LEDs resulting in more of the lighting load being stored delaying its conversion to room cooling load. Also, because LEDs emit little or no infrared (IR) or ultravio-let (UV) radiation more of the radiated energy is in the form of visible light. Considering that not all published data on LED technology is equivalent at this time, the design engineer has to carefully evaluate data such that the values are nor-malized for proper input into the cool-ing load analysis and energy modeling software. It is necessary for the design engineer to calculate the heat generation performance for each component of the luminaire as a fraction of the total light-ing heat gain by using judgment to esti-

The 2013 ASHRAE Handbook —

Fundamentals presents a detailed discussion of the various parameters

that influence the calculation of cooling loads due to lighting

heat gain.


Simulating daylighting

mate heat-to-space and heat-to-return percentages.

Reduction in LPDFor lighting retrofits in commercial

office building spaces, the LPD load analysis should include all luminaires that are added, replaced, or removed. Lighting alterations that involve only the replacement of lamps and ballasts must also comply with the LPD requirements.

This cooling load analysis should include the wattage of line voltage luminaires containing remote ballasts, transformers at the labeled maximum wattage of the luminaire, or the combination of values for auxiliary manufacturer’s literature or a nationally recognized testing laboratory.

In the case of lighting power calcula-tions for ballasts with adjustable ballast factors, calculations for load impact should be based on the ballast factor that will be

used in the space, provided the ballast fac-tor is not user-adjustable. In commercial applications using specialty lighting for display or architectural purposes, such as line voltage track or plug-in busway, local-ized load impact should be considered in the overall load calculations.

Lighting controls Updates to energy codes and standards

have already caused the retrofit and new


At the Glumac headquarters in Portland, Ore., designers implemented daylighting control to achieve energy savings by lowering lighting

energy use typical to the existing office layout. The result: Actual lighting power density (LPD) measured less than 0.3 W/sq ft. By exposing the ceiling and replacing a closed upper/spandrel area with SolarBan 70 XL glazing, daylight penetration into the space increased by an average of 12 ft. With this increased daylight, the risk of glare also increased.

However, the existing building has 18-in. deep external columns located 5 ft on center around the entire perimeter, which effectively act as vertical external shades and provide glare control at various times of the day. The surface of the columns is exposed aggregate concrete, with white aggregate and cement. Although the material is light in color, its rough texture casts shadows over much of the surface, which limits the glare potential. To further enhance this lighting benefit, motorized window shades are pro-vided, automatically controlled to raise and lower as needed to eliminate glare in early morning and late afternoon time periods.

The daylighting was simulated using the Radiance plug-in for Autodesk Ecotect. Radiance calculates a single point in time light level in LUX. To calculate the lighting power reduction for the simulation, it was assumed that if the daylight level was greater than 430 LUX, then the lights would

be turned off. If the daylight level was less than 430 LUX, the remaining percentage of the light would be supplied by the office lighting. The light-ing power reductions due to daylighting were calculated for the affected perimeter and open office spaces at 9 a.m., 12 p.m., and 3 p.m. for the 15th day of each month.

To simulate the effect of daylighting using the Department of Energy’s eQUEST energy modeling program, the baseline hourly lighting schedule for the affected spaces was reduced by the calculated percentage of light available from daylighting as calculated using Radiance. Between the points calculated using Radiance, the available daylight reduction was calculated as a percentage of the two points. Weekday and weekend schedules were created for the east and west sides of the building for the open office and circulation areas. Annual schedules were created that switched the reduced lighting power schedules on a monthly basis. These revised lighting schedules were used in the proposed design simulation.

The baseline model simulation has daylighting allowing the installed lighting levels to be reduced by 50%. As a result, credit has been taken only in the proposed model simulation for the installed system’s ability to reduce lighting levels beyond 50% and turn lights off when sufficient light is available.

Table 1 shows the total building system effects from lighting modeling and luminaire reduction toward payback analysis. Courtesy: Glumac

Table 1: Enlightened energy manager (EEM)

Energy Energy costs (with

equivalent kWh and therms)

Energy cost

savings

Measure cost

(incremental cost)

PaybackElectric (kWh)

Steam (kBtu)

Chilled water (kBtu)

Total (kBtu)

Baseline 194,210 340,600 291,000 1,294,400 $22,289 - - -

EEM 1 – HVAC (including exceptional calculations for chilled sails and server room heat recovery)

114,395 204,700 183,700 778,800 $13,822 $8467 $78,000 9.2

EEM 2 – lighting 163,787 939,300 280,800 1,233,100 $20,420 $1,869 $17,000 9.1

Combined EEMs 83,580 263,700 159,700 708,576 $11,764 $10,525 $95,000 9.0


building markets to transition from less efficient lamps and luminaires to more effi-cient devices. Energy consumption can be further reduced by taking advantage of the new technologies to control lighting sys-tems that use high-tech lamps and ballasts.

Automatic lighting controllers can dim or switch lighting based on time of use, occupancy, daylighting level, or a combi-nation thereof. Lighting systems in com-mercial office buildings are often left on for long periods of time due to low occu-pancy in a space or a cleaning crew work-ing into the evening. Having the ability to control lighting by turning off lights that are no longer required or that are left on in unoccupied spaces, or using daylight-ing when available can present additional energy saving opportunities. Some light-ing control strategies currently being used by designers include:

n Vacancy or occupancy control (lights are turned on and off or dimmed accord-ing to occupancy)

n Scheduling (lights are programmed to turn on and off according to work schedules)

n Daylight harvesting (electric lights are automatically dimmed or turned off in response to the presence of daylight)

n Demand response (power to electric lighting is reduced in response to util-ity curtailment signals or to reduce peak demand power charges to a facility)

n Tuning (light output is reduced to meet the occupants’ needs)

n Adaptive compensation (light levels are lowered at night to take advantage of the fact that occupants need or prefer less light than during the daylight hours).

Improved power quality Poor power quality is a concern in

buildings because it wastes energy, reduces electrical capacity, and can harm building and tenant equipment. In some cases, it can negatively impact the build-ing’s electrical distribution system itself.

Power quality is a condition of the power supplied to equipment. The power supply may contain transients and other

short-term under- or over-voltage con-ditions that may result from switching operations, faults, motor-starting, light-ing disturbances, switching of capaci-tors, electric welding, and operation of heavy manufacturing equipment that may contain harmonic content. Harmon-ics are integral multiples of the funda-mental (line) frequency involving non-linear loads or control devices, including electromagnetic devices (transformers, lighting ballasts) and solid-state devices (rectifiers, thyristors, phased-controlled switching devices).

Upgrading lighting equipment with new, high-power-factor and low total

harmonic distribution characteristics can help improve power quality in an exist-ing electrical system and possibly free up electrical capacity. In many cases this benefit can justify the cost of a lighting upgrade. For instance, the measured watts of low-power-factor ballasts are approxi-mately the same as the measured watts of the high-power-factor (above 90%) type when connected to the same load. The low-power-factor type draws more cur-rent from the same power supply and, therefore, larger supply conductors may be necessary. The use of high power-factor ballasts permits greater loads to be carried by existing wiring systems. Many public utilities have established penalty clauses for the use of low power-factor equipment.

DaylightingThe use of natural daylight to provide

up to 140 lumens (lm) of light compares favorably with the 90 lm/W from most electric lighting systems. Systems that take advantage of daylight to supple-ment electric lighting present one of the best ways to reduce building light-ing energy consumption by balancing loads and peak demand and creating a more desirable indoor environment for occupants. In designing daylighting into a retrofit building condition, there are four basic criteria to consider:

1. Harvestable light: Amount of light that can be brought into the space for effective use via skylights, light shelves, clerestory windows, or light pipes.

2. Interior material and color impact: Balancing the use of specialized reflective materials and interior colors to use the light’s benefits.

3. Glare: Direct sunlight into a space can cause uneven luminance ratios that are distracting to the occupants and cause not only irritation, but also hot-spots in the space. Bouncing light or allowing diffuse daylight from certain exposures such as north, can aid in glare reduction.

4. Control of electric lights: For day-lighting to be most effective, lighting controls are required to maximize perfor-mance. Automatic sensing control presents an approach that ensures electric lighting will be reduced when enough ambient day-light is available to illuminate the space. The application reduces the opportunities for over-dimming, under-dimming, and/or rapid-cycling of the lighting devices, thereby assisting in reducing the cooling load and energy savings.

Another daylight control opportunity is to enable the use of automatic win-dow shade control as part of the space lighting plan. HVAC load analysis typi-cally incorporates the benefit of window shading devices commonly modeled in cooling load analysis software programs. In calculating the value of daylighting benefit, items to be evaluated include the

Having the ability to control lighting by

turning off lights that are no longer required

or that are left on in unoccupied spaces, or using daylighting when available can present

additional energy saving opportunities.

time of day, season, available light, and controls that can raise or lower shades to optimize daylight contribution.

Efficient lighting sources With the advent of efficient lighting

sources such as linear fluorescent lamps,

solid state LEDs, and high-intensity dis-charge (HID) lights, it is critical to be able to assess the actual impact of the lighting device performance. The combi-nation of lamp, ballast, and heat extrac-tion fixtures helps maximize efficiency while balancing the considerations of

lighting quality and quantity. The designer has the option avail-

able to choose from a variety of types and manufacturers for each application depending on efficacy, color quality, and service life within the HVAC load analy-sis. Whenever possible computerized energy modeling can be used to assess the HVAC load components of a given lighting design allowing the designer to overlay and model the results of lighting performance within the designed space.

The use of light modeling software enables the architectural/engineering design team to preview the design of lighting within a BIM model and quickly understand the impact on the user space. In most cases more than one simulation may have to be developed to identify the optimal lighting arrangement for a space. Once the modeling layout is agreed upon by the team, load data can be imported to the HVAC load analysis program.

The importance of accurate cooling load analysis and modeling of light-ing systems is key to optimizing over-all HVAC system performance. Taking advantage of computer-based model-ing and light simulation programs has enabled the design team to consider lighting options that can provide signifi-cant benefit to the project. New light-ing technology, when incorporated with enhanced lighting control, does present potential initial increase in first costs to the project. However, it is incumbent on the design team to develop designs that ultimately provide financial benefit, on a life cycle cost basis, as well as HVAC system performance optimization while providing the occupants with a space that is comfortable.

David B. Duthu is board principal at ccrd, where he has more than 37 years of experi-ence in the fields of mechanical engineering design, technical engineering design, and project management. Nolan Rome is associ-ate principal and lead mechanical engineer for ccrd and has been responsible for the design of all types of health care facilities including hospital expansions, cancer cen-ters, and imaging centers in multiple states.


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IAQ and energy management are typically major concerns for any build-

ing operations and maintenance (O&M) staff. This is particularly true for K-12 schools and college/university buildings. In many cases, these two efforts are in direct competition with each other for budgetary dollars.

Facing shrinking annual budgets, facil-ity managers are continually pressed to reduce annual energy operating costs while maintaining occupant comfort. The U.S. EPA estimates the annual energy expense for K-12 and higher education institutes is $8 billion and $2 billion, respectively. With this in mind, design-ers have an increasing responsibility to

design HVAC systems that balance the owner’s require-ments, up-front construction expenses, occupant comfort, and IAQ and energy savings.

Standards and guidesASHRAE “writes stan-

dards for the purpose of establishing consensus for: 1) methods of test and classification standards; 2) design standards; 3) proto-col standards; and 4) rating standards (in limited cases). Consensus standards are developed and published to define minimum values or acceptable performance whereas other documents, such as guidelines may be developed and published to encourage enhanced perfor-mance.”

Figure 1: This multi-zone (three zones in this case) AHU shows supply and return fans and electri-cally controlled outside air and relief/exhaust dampers. The system includes an airflow measur-ing device, which provides feedback to the building controls system allowing for monitoring and control of the amount of OA provided into the building through the AHU. As the ventilation needs of the building change, the AHU can provide an appropriate mix of outside and return air from the space. All graphics courtesy: Stanley Consultants

Figure 1: This multi-zone (three zones in this case) AHU shows supply and return fans and electri-

Indoor air quality (IAQ) and energy management are key in K-12 schools and higher education university buildings. This information will help to provide an efficient, effective HVAC system in a school or a university building.

BY RANDY SCHRECENGOST, PE, CEM, and GAYLE DAVIS, PE, Stanley Consultants, Austin, Texas

IAQ and energy management

Learning objectives� Understand the codes and standards that guide indoor air quality and energy efficiency requirements.

� Learn how to design HVAC systems to meet a building’s load requirements.

� Understand key equipment and controls interactions to improve energy efficiency.


ASHRAE Standard 62.1-2010: Ventila-tion for Acceptable Indoor Air Quality is the reference standard for IAQ. ASHRAE Standard 90.1-2010: Energy Standard for Buildings Except Low-Rise Residential Buildings is the reference standard for energy efficiency.

Standard 62.1 provides guidelines for the design of HVAC systems and equip-ment. It covers areas of IAQ management such as designing for air balancing, exhaust duct and outdoor air (OA) intake locations, filtration, moisture control, and ventilation system controls. Controls can be manual or automatic, but should allow the system to be operated to provide the required amount of OA for the building spaces whenever they are occupied. This can be problematic for O&M groups where either the staff or their collective knowledge is limited. Many of these individuals may resist systems that are new or perceived to be more complicat-ed than the existing systems—or that may create increased costs to their maintenance or energy budgets.

The increased intake of OA can sig-nificantly impact the cost of energy

through increased cooling and heat-ing requirements dictated by the design of new or retrofitted HVAC s y s t e m s . T h i s energy impact can be quantified with energy modeling software or by spe-cifically measuring the OA flow changes and then calculating the cost impacts based on utility rates. Energy changes, and thus costs, will be influenced by many factors such as the climate where the building is located, the building type and construction, the type and efficiency of the building’s systems (specifically the type of HVAC system), the occupancy and usage of the building, and ultimately how the building or sys-tems are operated and maintained.

Standard 90.1 provides guidelines for building energy efficiency. It covers areas such as building envelope, building light-ing, HVAC equipment efficiency, HVAC

systems, service water heating, and system controls. Standard 90.1 sets the minimum energy efficiency requirements and system design requirements; similar to other standards, over the years it has adopted code language to increase state adoption and improve enforceability.

Each new edition of Standard 90.1 requires the Dept. of Energy (DOE) to issue a determination on whether the new edition will improve energy effi-ciency in commercial buildings over the existing edition. On Oct. 19, 2011, the DOE released a final determination that Standard 90.1-2010 would achieve 18.2%

Figure 2: This is a diagram and control sequence of a single duct VAV box (often abbreviated as SDB). This type of VAV box is typically used for cooling only applications in the interior zones of building spaces. The BAS will monitor the space tem-perature (T) in the area of the SDB, and send a signal to open/close the SDB damper for control of the supply air. The flow element (FE) in the inlet to the SDB provides feedback to the BAS that the damper has been adjusted as directed, and will send a signal that allows the BAS to control the static pressure in the zone ductwork to minimize energy.

Figure 3: A parallel fan powered VAV box (often abbreviated as FPB) is typically used for cooling and heating applications in the perimeter zones of building spaces. The BAS will monitor the space temperature (T) in the area of the FPB, and send a signal to open/close the SDB damper for control of the primary cold supply air from maximum (space to hot) to minimum (space to cold). The flow element (FE) in the primary air inlet to the FPB provides feedback to the BAS that the damper has been adjusted as directed, and will send a signal that allows the BAS to control the static pressure in the zone ductwork to minimize energy. If the temperature in the space continues to drop after reaching minimum primary airflow, the fan in the return air inlet of the FPB will turn on to mix warmer plenum air with the primary air, and total airflow will approach maximum again. If the space continues to call for heating, the reheat coil valve in the return air side of the FPB will modulate open to a maximum position to provide the required heating sup-ply air. As the space warms up to satisfy the temperature, the sequence reverses itself.

Figure 2: This is a diagram and control sequence of a single

Figure 3: A parallel fan powered VAV box (often abbreviated as


energy savings above buildings bound by Standard 90.1-2007. Every state has 2 years to adopt Standard 90.1-2010 or update its existing commercial building codes or standards to its requirements. With this 2011 determination, states had until Oct. 18, 2013, to file compliance certifications with DOE or request an extension. Check local codes or standards for state specific adoption and amend-ments.

Efforts to reduce energy consump-tion have led facility managers or the O&M staffs tasked with minimizing energy usage within their facilities to adjust controls setpoints, lockout/over-ride controls, turn off HVAC equipment overnight, or disconnect HVAC devices such as OA dampers (or close and shut

them completely). Ironically, even though meant to save energy, we have found economizers and heat/energy recovery wheels disabled, primarily due to a lack of understanding of their function or the perceived increased maintenance efforts they require. These efforts often increase energy consumption and reduce IAQ.

ASHRAE’s Advanced Energy Design Guides (AEDG) series also provides design and energy efficiency recommen-dations for various building types. While the AEDG series was developed based on previous ASHRAE 90.1 Standards, the recommendations can still be applied to buildings designed to ASHRAE 90.1-2010 for additional energy savings. These AEDGs provide recommendations on building envelope, fenestration, lighting

systems, HVAC systems, service water heating, and plug/process loads arranged by climate zone. Although the AEDGs are centered on new construction, the recom-mendations can be applied to renova-tions. While many of the AEDG recom-mendations are simply selecting between systems, the owner should be brought in to the design process to ensure that goals are being met and that maintenance staff has the expertise to service the systems.

With the exception of very few areas, the K-12 and higher educational facili-ties generally have higher ventilation rates than most other areas. This has been studied and shown to assist in providing healthy environments and contributes to fewer days missed by students and teach-ers, as well as improved learning.

HVAC system types and design considerations

The type of HVAC system installed and the amount of OA ventilation required play a large part in the overall building energy usage. When designing new, or retrofitting existing, HVAC systems, the interaction between OA ventilation requirements and the energy needed to condition that amount of airflow should be part of the systems’ considerations so the equipment can be sized and controlled properly to account for all the energy impacts. These systems not only require bringing in the required ventilation air, but the designer also must ensure this air is delivered into the individual occupied spaces when needed.

Many different types of HVAC sys-tems are used in K-12 and higher edu-cation buildings today. The building system types vary from packaged roof-top units to central station air handling units (AHUs), with single or multiple zone variable air volume (VAV) termi-nal units. Figure 1 shows a typical AHU schematic, and Figures 2 and 3 VAV box schematics. Some systems use water or ground-source heat pumps and/or fan coil units (FCUs) with a de-coupled AHU for OA ventilation needs. These de-coupled AHUs are sometimes referred to as

Figure 4: This figure illustrates that the SDBs and the FPBs primary or supply air inlets are connected to zone ductwork, either interior or perimeter (or a combination) as the building’s design layout requires. In Figure 1, three zones of ductwork are shown. Within each zone duct, there would be a static pressure sensor, which sends signals back to the BAS as the pressure changes in the ductwork due to the SDB and FPB primary airflow dampers open/close based on space requirements. These static pressure readings are used to control AHU fan speed through signals to the fan’s VFD while monitoring the OA requirements and AHU discharge air temperatures.

Figure 4: This figure illustrates that the SDBs and the FPBs primary or supply air



dedicated outdoor air system (DOAS) units, which provide reliable OA with improved energy efficiency in most cases. The more segregated the systems are, the easier it may be to provide the required ventilation air to the spaces.

Design HVAC load calculations, equipment selection

The first step in designing any effi-cient, effective HVAC system is to per-form an accurate building load calcu-lation and energy model. Whether the project is new construction or a renova-tion, a thorough understanding of the building environment is critical. Many components affect HVAC loads and energy consumption including build-ing envelope, fenestration (glazing and doors), lighting, plug loads, occupancy, and sequence of operations, to name a few. The 2013 ASHRAE Handbook-Fundamentals Chapter 18 and Standard 90.1 provide methods and guidelines for developing HVAC load calculations and building energy modeling. Remember, heating and cooling load calculations are not the same as building energy model-ing. Energy models analyze the proposed design energy requirements as the sys-tem operates over an extended period of time, typically 1 year or more. Load cal-culations measure the energy the HVAC system must add or remove from the zone to maintain the design conditions.

Most commercially available load calculation software produce peak and block load estimates. Peak loads assume every zone is at the maximum cooling or heating load simultaneously. Typically, equipment selected for peak loads will be oversized and does not require any rule-of-thumb oversizing. However, the engineer must consider the accuracy of existing building information and apply oversizing carefully to ensure proper equipment selection.

Consider sizing main equipment (such as air handlers, chillers, and boilers) based on zone block loads while sizing terminal units, piping, and ductwork based on peak loads. Right-sized main

equipment reduces equipment costs, reduces energy consumption, increases dehumidification performance, and increases occupant comfort. Sizing some equipment such as terminal units, piping, and ductwork based on peak loading may increase energy efficiency by reducing fan or pump power.

Accurate HVAC load calculations lead to accurate equipment sizing. The design-er should apply equipment safety factors carefully to avoid unnecessarily over-sized equipment. Oversized equipment

may short-cycle due to limited turndown ratios, reduce dehumidification capacity, or lower equipment life.

Key energy savings opportunitiesThough many different HVAC sys-

tems and control strategies exist, the following items can create an impact on energy costs and system efficiency. Review Standard 90.1 and the AEDG for climate zone specific requirements and select the heating and cooling equipment efficiencies based on the

Case study: Art center HVAC upgrade design

An arts building for a confidential university client was a one-story section of approximately 20,000 sq ft supporting varying art/design functions such as photography, fabric design and

weaving, ceramics and sculpture, printmaking, life drawing and painting, woodworking, and metal castings. Many of the functions of the rooms had been modified over the years with very little changes made to the original HVAC equipment.

After completing a validation and feasibility study and cost estimate, a design was developed to address the identified deficiencies of the HVAC systems. The recommended HVAC and power upgrades included remedial upgrades to maintain appropriate ventilation along with the proper air conditioning requirements for each room to function safely in the removal of varying levels of accumulated par-ticulates (sawdust, sanding, and dust) and noticeable odors (paints, solvents, and other chemicals) in eight different areas. The upgrades included replacing all the older HVAC equipment (air handling units or AHUs, exhaust and relief fans) and ductwork, along with all the electrical and controls upgrades required to make the systems fully functional. Everything would be remotely monitored and controlled from the campus utility energy management system.

The HVAC system was modified with new AHUs and variable air volume (VAV) terminal units—some fan powered—where required. The VAV units served classrooms or related office and other spaces within the building and were controlled by a thermostat for the cooling and heating needs of the space it served. Based upon the space use and ASHRAE Standard 62.1 requirements, the ventilation rates for the spaces were added together to get the total required outdoor air (OA) necessary for the AHU serving its associated VAVs. One key to these systems upgrades was the controls required to ensure the ventilation air was provided where and when it is needed. In most spaces, and particularly in educational facilities, the occupancy rates fluctuate during the day so the ventilation air requirements change and create opportunities for improved energy use. The additional design consideration for these systems was the requirement for operating various exhaust systems for contaminate removal.

Combinations of items were included in the HVAC system design for demand control ventilation (DCV) strategies. These items included occupancy schedules and lighting sensors (CO2 sensors were not used), airflow measuring stations (AMS), and fan pressure optimization control to reduce OA to the spaces if they were not occupied.

To reduce the impact of increasing OA, the design for the building’s DDC system’s controls sequence started with a building occupancy schedule, which sets the overall times when the building will gener-ally be occupied (e.g., 6 a.m. to 8 p.m.). Design for full DDC control of OA and return air dampers with feedback from the OA AMS is helpful so the facility energy management system (FEMS) will know and can adjust the amount of OA coming into the building. Including occupied/unoccupied signal inputs from space or lighting occupancy sensors so the system is more aware of room occupancies will ensure the VAV boxes maintain minimum ventilation airflow to the spaces. The FEMS should “poll” all the VAV boxes and reset the static pressure (SP) setpoint within the ductwork to ensure that no VAV damper is more than 90% (adjustable) open. The AHU is provided with a variable frequency drive (VFD) so its fan can be modulated to meet this duct SP set point reset strategy.

The engineering team did not use CO2 sensors, which are sometimes used in spaces where large occupancies may occur, such as auditoriums. These devices provide input signals indicating the levels of CO2 and will override temperature controls and allow for more supply air into the spaces. This control strategy can also be added to the AHU to reset the OA damper to a more open position so additional OA is drawn into the entire system if needed. The use of CO2 sensors can enhance overall system control and provide additional energy efficiency, but using these sensors correctly can be difficult and usually adds costs to the system that many owners, and particularly K-12 schools and universities, are sometimes reluctant to spend.


climate specific tables in either docu-ment as deemed appropriate.

Chilled water systems can be designed for high temperature differentials of 12 to 18 F delta T, low supply water tempera-tures (38 to 40 F), and variable flow with modulating valves. Selecting a chiller for a higher delta T can reduce equipment cost and energy use when compared to the traditional 10 F delta T. This design strategy can reduce pump energy (lower flow) and piping installation cost (smaller pipe sizes); how-ever, lowered leaving water tem-perature does use more chiller energy that may not be offset by perceived gains in pumping and fan energy savings. The manu-facturer’s minimum chiller flow rate should be maintained when setting the minimum pump flow. The total annual system energy use must be considered.

Another aspect of selecting a lower supply water temperature is that it may increase occupant com-fort by allowing for a reduction in the supply air temperature and dew point at zone equipment. Low-temperature chilled water systems allow the supply air temperature to be lowered from the traditional design temperature of 55 to 48 F or lower. This type of air-side design is now called a cold air system. The lower supply air tempera-ture requires less airflow, yielding a smaller fan, duct, coils, etc. Another energy sav-ings opportunity is to implement a chilled water temperature reset schedule. The temperature can be reset based on outdoor air temperature, zone cooling demand, or both. The engineer must take care to avoid “dumping” cold air on the occupants by selecting high aspirating diffusers or using fan-powered terminal units to provide tem-pered mixed air.

HVAC heating water systems designs should be centered on high-efficiency condensing boilers with design tempera-ture differentials of 30 to 40 F. Condens-ing boilers achieve higher efficiencies by condensing water vapor in the flue gases

and reclaiming this waste heat to preheat the return water. Most condensing boil-ers require return water temperatures of 140 F or less to achieve efficiency lev-els above 85% dependent on firing rate. The designer must carefully select the entering supply water temperature to ensure that the return water temperature is correct. Again, this design results in lower pump energy, and lower installa-tion costs. Similar to the chilled water

system, the heating water system should use a temperature reset schedule.

DOAS coupled with water- or ground-source heat pumps, fan-coil units, or sin-gle-zone VAV systems can reduce energy consumption by removing the ventilation OA conditioning and dehumidification load from the zone heating and cooling loads. A separate DOAS unit will heat, cool, and dehumidify the OA to deliver dry, neutral air to the space that has the added effect of offsetting the space latent load. DOAS configurations may include direct exchange (DX) coils, chilled water coils, indirect gas-fired heating, hot water coils, steam coils, and an energy-recovery device. DOAS can be used in conjunc-tion with single zone or multiple zone systems. A designer can use the following strategies to further reduce DOAS system energy costs.

Consider supplying cold OA, rather than neutral temperature air, directly to the zone. This can reduce reheat energy and partially meet the zone sensible cool-ing load. The terminal HVAC equipment should then be right-sized to account for the reduced cooling load. Please note that there are many design paths that can be taken and many other factors such as space humidity should also be considered during the design process.

Incorporate demand control ventilation (DCV) with modulat-ing dampers and airflow measur-ing stations in the DOAS. DCV can use a combination of space carbon dioxide (CO2) sensors in heavily occupied zones and occu-pancy sensors in normally unoc-cupied/limited occupancy zones. Moreover, the occupancy sensors can control the lighting and set back the VAV box airflows to minimum and ultimately control the main HVAC system. The VAV boxes can receive building auto-mation inputs including building schedules (see Figures 2 and 3 for VAV box schematics). Stan-dard 62.1 outlines when a sys-tem must use DCV. The control

sequence of operation can be complex, but a general guide is presented in Stan-dard 62.1. Remember to account for building pressurization; the DCV mini-mum OA setpoint must be equal to or greater than the total exhaust airflow.

Exhaust air energy recovery is used to recover energy from the exhaust air-stream and to the OA stream. This can be achieved with sensible heat exchange devices (sensible energy transfer only) or total energy exchange devices (sensible and latent energy transfer). During cool-ing conditions, the OA is precooled and/or partially dehumidified. During heat-ing conditions, the OA is preheated and/or partially humidified. Commonly used air-side energy recovery devices are run-around loops, plate heat exchangers, total energy wheels, and heat wheels. Refer to Standard 90.1 Table 6.5.6.1 that provides


Figure 5: This possible control scenario of the AHU dis-charge air temperature is based upon the OA tempera-ture. This is just one method of attempting to save addi-tional energy with the climatic and space temperature conditions will allow for it.

Figure 5: This possible control scenario of the AHU dis-

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Louvered Gravity Ventilator

Equipment Screen

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Spun Aluminum Roof Exhaust

Hooded Gravity Ventilator

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Louver

Intake Damper

Utility Fan

Make-Up Air Unit

Upblast Roof Exhaust

Kitchen Hood

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exact conditions when an HVAC system requires energy recovery. The require-ments are based on climate zone, percent OA, and design supply airflow. When an energy recovery device is required, the system must have a minimum 50% effectiveness.

The exhaust and outdoor airflows should be balanced as near as possible to maximize energy transfer and to maintain building pressurization. Bypass damp-ers must be installed around the energy recovery device when an HVAC system uses an air-side economizer. It is impera-tive to downsize the heating and cooling equipment based on the adjusted design loads with energy recovery. Right-sizing the heating and cooling equipment will have a cascading energy savings (such as reduced pumping power, downsized chillers, and boilers).

Air-side economizers provide free cooling when outdoor conditions are able to fully meet or partially meet the cooling load. A typical starting point in a cooling predominate climate would be equivalent to the selected design discharge air tem-perature of the building AHUs such as 55 F, but there may be instances where the designer could select other temperatures to meet the project’s needs. Standard 90.1 does not require economizers in climate zones 1A or 1B because of limited opera-tion hours in these hot, humid climates. All other climate zones require econo-mizers on systems with a cooling capac-ity greater than or equal to 54,000 Btu/h. In more humid climates, the designer should use an enthalpy-based control sequence to minimize unwanted moisture entrainment.

System controlsControl sequences are a key ele-

ment in achieving energy management and savings. In an effort to standard-ize control sequences and aid in the design process, ASHRAE developed a set of control sequences for commonly used HVAC systems. These sequences provide a good starting point for the designer to expand ASHRAE’s sequence

to suit the particular HVAC system and state codes/standards, and to meet the owner’s requirements. Furthermore, Standard 90.1 requires that spaces be grouped into similar thermostatic control zones controlled by a single thermostat. For example, exterior zones and interior zones cannot be zoned together.

Standard 90.1 requires that building automation systems (BAS) employ time-of-day schedules and have night setback/

setup temperature setpoints. This is pre-ferred over programmable thermostats because the occupants cannot override the zone setpoint. The AEDG suggests using optimal start controllers to deter-mine the time required for each zone to meet the occupied temperature setpoint and delay system startup as long as pos-sible. Standard 90.1 requires optimal start controls for individual air systems with a supply air capacity greater than 10,000 cfm. Optimal start controls save energy by reducing the HVAC system run-time hours.

Multiple-zone VAV systems must employ a supply air temperature reset schedule based on OA temperature, zone cooling demand, or a combination. See Figure 5 for supply air temperature reset. For example, the BAS monitors OA temperature and resets the supply air temperature up or down. Overrides are typically included to reset the supply air temperature to the minimum if the zone humidity exceeds an upper limit setpoint. Additionally, interior zones and telecom rooms must be designed to meet their

cooling loads at the warmest supply air temperature. Failing to do this will result in undercooling when using out-door temperature reset or the supply air temperature will never reset when using zone demand control. While this strategy increases fan energy use, it decreases both cooling and reheat energy consumption.

Furthermore, Standard 90.1 requires systems with direct digital control (DDC) of individual zone boxes that report to the central control panel and have a stat-ic pressure reset schedule based on the zone requiring the most pressure. Typi-cally, the static pressure is controlled so that one zone damper is 90% open. This requires the fan be equipped with a vari-able frequency drive (VFD). The VFD will modulate the fan based on the sys-tem’s cooling demand and will reduce the building electrical load when the spaces are not fully occupied. The VFD lower limit should be set based on the motor manufacturer’s lower limit.

Providing ventilation air for IAQ and maximizing HVAC system designs for energy savings is interwoven with owner requirements, interdisciplinary coordi-nation, equipment selection, and design iterations. As equipment efficiencies approach the law of diminishing returns, overall system efficiency and building efficiency will become the subject of future standards and codes.

Randy Schrecengost is a project man-ager/senior mechanical engineer with Stanley Consultants. He has extensive experience in design and project and program management at all levels of engineering, energy consulting, and facilities engineering. He is a member of the Consulting-Specifying Engineer editorial advisory board. Gayle Davis is a mechanical engineer with Stanley Consultants. He has experience in the design of HVAC systems, boiler plants, compressed air systems, plumbing sys-tems, steam distribution systems, central heating, and cooling plant design. He is also experienced in commissioning and retro-commissioning.

In an effort to standardize control

sequences and aid in the design process, ASHRAE

developed a set of control sequences for commonly used HVAC

systems.

xyleminc.com© 2013 Xylem Inc. Bell & Gossett is a trademark of Xylem Inc. or one of its subsidiaries.

e is coming. 01.21.14

NERGY



As mechanical, electrical, plumb-ing (MEP), and fire protection engineers, it’s easy to say that

we are responsible for ensuring building functionality, public health, and comfort while maintaining the highest affordable energy efficiency. In reality, most of our time is spent trying to fit large things into small spaces (ducts, equipment), or mul-tiple small things in the same space (pipes, conduits). All of this co-existing complex-ity happens in the dark zones of interstitial spaces. The success of the production side of our work depends on playing a coop-erative, proactive, and intelligent game in that shared sandbox because dreaming up the ideas behind our designs and analyz-ing their effectiveness is less than half the battle and less than half the cost.

Most of us have experienced that these dark zones of the building usually do not attract architectural attentiveness until there is a cost driven need to reduce floor-to-floor height or to increase ceil-ing height.

With façade costs running $100 to $150/sq ft, the appeal of shaving 6 in. off each floor can begin to have multi-million-dollar repercussions and the drive to increase ceiling heights can be directly linked to a desire for more daylight pen-etration and higher property values.

Engineers must pay close attention when coordinating mechanical,electrical, plumbing, and fire protection system design in interstitial spaces.

BY ERIN MCCONAHEY, PE, and JAMEY LYZUN, PE, Arup, Los Angeles

Interstitial spaces:

Managing the dark zones of the building

In the conventional solution—combining the claims of structure and services—the ducts that carry air to and from the center are hung from the floor, then hidden behind a false ceiling. This zone of darkness is further stuffed with equipment for lighting, electricity, smoke detectors, sprinklers, computers, and other building “controls.” The section is no longer simply divided by the discrete demarcations of individual floors: it has become a sandwich, a kind of conceptual zebra: free zones for human occupancy alternate with inaccessible bands of concrete, wiring and ducts … Idealism vs. philistinism: the section becomes battlefield; white and black compete for outright domination. The dark zone is not only strictly “useless” for the future inhabitants of the building; it also become conceptually inaccessible to the architect, who has become an intruder in his own project, boxed in, his domain a mere residue of the others’ demands.

—Rem Koolhaas, Pritzker Prize-winning Architect, in S,M,L,XL, The Monacelli Press, 1995

Interstitial: Of, forming, or occupying interstices: “the interstitial space.”

Interstice: A space that intervenes between things; especially: one between close-ly spaced things

—Merriam-Webster Dictionary

Learning objectives� Understand the interrelationship of mechani-cal, electrical, plumbing (MEP), and fire protec-tion systems in interstitial space.

� Know when building information modeling (BIM) can assist in design and clash detection.

� Understand how digital tools and new tech-nology can facilitate the coordination process.


In either case, the burden of such change is primarily borne by the services team because the redesign implications are much greater than just moving a plane in elevation. Moreover, due to the ever-more transparent 3-D environment in which we all work, there is a great pressure from our clients to “optimize” the space we use, without a full understanding of the constructability, support, or future main-tenance concerns that should be inherent in good design.

The ‘old school’ approachThere are times when building informa-

tion modeling (BIM) is touted as a pana-cea for all coordination problems. Having worked in 3-D virtual environments for the past 13 years, these authors believe that the key to good coordinated design is … well, good coordinated design. We see that engineering teams often start too quickly in 3-D models, routing through apparent voids and filling space “because it’s there,” leading to crazy incoherent dis-tribution routes that stem from the luxury of technology-enabled intellectual sloppi-ness. As with all computer-based things, “garbage in = garbage out.” We still have to see the solution in our heads in order to draw the solutions in our software. So we advocate for early phase old-school approaches that remind us of the true

inter-relationships that arise from first principles (see Figure 1).

As noted in the quote above, the section is the key flashpoint of coordination, if not a battleground, then at least an area requiring multilateral agreements. Agreeing on logical inter-stitial space depths does not require fancy software, but it requires a sketch that includes real dimensioned sizes, inclusive of sup-port, insulation, and slope. Because ducts are often the largest things in the ceiling void, engi-neers must understand that ceiling depth is directly driven by the heat load in the area served, the distance between risers, and the type of HVAC system used.

Starting with the last item (type of HVAC system), it is clear that air as a heat transfer fluid takes up much more cross-sectional space as compared to water: an 18x18-in. supply duct on a recent job was replaced with a 1.25-in. chilled water pipe once the engineering team changed from a variable air volume (VAV) system to a local water-based cooling system (chilled beams) and a 48x48-in. duct is equivalent to a 2–in. pipe. The size of ducts is directly driven by the heat per sq ft to be absorbed multiplied by the floor area served. On a recent job, we provided this simple table (Table 1) to our clients to demonstrate that it was within their capacity to choose how

deep the ceiling ducts would be based on how many risers they provided to us.

Table 1 was provided as a simplified space planning exercise for a supply only duct condition. This table can be used on its own as a quick way to convey the rela-tionship between the number of vertical distribution points (risers) relative to the horizontal distribution and ceiling height requirements. The same strategy can also be applied in combination with other duct and piping systems to provide a more in-depth understanding of this relationship. It is up to the designer to determine the level of information needed to achieve the appropriate horizontal-vertical balance when negotiating space demands with the architect and owner’s facility planners.

On other jobs, at early phases, we use hand sketches or simple computer gener-ated sketches to further demonstrate the

Figure 1: Steps 1 through 3 identify three different techniques that engineers have used to assist in multi-trade coordina-tion and visualization. All techniques are effective in outlining the agreements made by discipline engineers while coordinating throughout a project. Step 3 (below right) shows an example of how new software can be used to generate quick outputs that document traditional hand sketches in a more visual way. All graphics courtesy: Arup

Figure 1: Steps 1 through 3 identify three


complexity of the combination of all ser-vices in the ceiling (Figure 2), taking into account cable tray, sloped piping, duct-work, and ceiling depths.

With early diagrams and concerted effort on a recent museum project, we worked with structural engineers to deter-mine how to best optimize routing of ser-vices through structural elements, where lower voids were left clear for sprinkler and electrical routing.

The danger of drawing sketches as in the past was that one would never have the ability to imagine every nonstandard con-flict such as those places where there were inevitably crossing services that would limit access. Engineers should continually review non-standard areas to ensure that these loca-tions will work as per the originally envi-sioned design. It can be useful to keep the following list close by when reviewing these sectional relationships: any architectural voids, mechanical/electrical/IT rooms, risers,

elevators/stairs, slab depressions, pattern-breaking geometric forms in the building, braced frames and shear walls, and entries into raised floor cavities. Catching conflict in these types of areas is a specific benefit of using the BIM features that are available in current software tools.

Using modeling toolsComputer processing, software pack-

ages, and cloud-based storage have devel-oped over the past decade to allow new opportunities for architects and engineers to coordinate and manage the dark zones at the design phase of a building project (Figure 3). New digital tools allow the design team to better understand 3-D con-straints, to produce a more accurate model, and to track and resolve conflicts with other disciplines as the design is devel-oped. With the appropriate amount of time and fee, new software literally allows for a design team to leave no stone unturned.

However, most project schedules must limit the amount of stone turning to what is reasonable and required.

The latest digital tools can provide a designer with vivid renderings and instan-taneous sections to give all model users a better awareness of the unique conditions of the building project. Both the engineer and the architect can use renderings to bet-ter understand how systems will fit or co-exist with the architecture and with other systems. The section becomes augmented into three dimensions with the ability to rotate a view to truly understand the con-straints and conflicts for any specific loca-tion. This has changed the way designers and BIM technician draw solutions from the start. For documentation purposes, it is quite easy in most current software to draw planes to generate working sections and cut-lines along a model as it develops.

Advancements in software have allowed for the inclusion of “smart” com-

Interstitial spaces

Figure 2: Simple sketches show key multi-system coordination relationships in double-wall construction in an art gallery (left) and computer-generated section of services in typical ceiling void (right).

Simple sketches show key

elevators/stairs, slab depressions, pattern- However, most project schedules must

Clients can choose how deep the ceiling ducts would be based on how many risers they provided to the engineering team.

Table 1: Ceiling duct depthNumber of risers

Area served

Total cfm leaving riser

Supply duct leaving room or riser cross section area in sq ft

Supply duct leaving room or riser in ceiling (width x height, sheet metal only)

1 23,760 sq ft 25,500 28.33 120x34-in. (3.5:1 aspect ratio)

2 11,880 sq ft 12,750 14.2 86x24-in. (3.5:1 aspect ratio)

4 5940 sq ft 6375 7.1 56x18-in. (3.1:1 aspect ratio)


ponents that have embedded installation clearances, inlet/outlet dimensions, and handedness (Figure 4). With the inclu-sion of actual components and fittings, the likelihood of conflict will be reduced. The long-winded annotation that described how to connect a system together within a 2-D plan has now been replaced by a coordinated 3-D model that shows the same information more clearly to other stakeholders. An added benefit is that this model can now be viewed in the field using a tablet. Intelligent building compo-nents improve the accuracy of the design model, and allow for more accurate equip-ment schedules and quantity takeoffs. Smart components allow disciplines to extract data for load calculations and also to have embedded characteristics to facili-tate other disciplines to complete their own calculations. The use of smart components is one progression as the design industry transitions from 3-D coordination to more comprehensive BIM.

On a recent 500,000-sq-ft health care project, Autodesk Revit MEP was used at early stages to improve the accuracy of the mechanical load calculation model and reduce the data entry required. The software enabled the team to export floor areas, room names, and other characteris-tics into a format that could be read by the load calculating software.

As the design progressed to construc-tion documents, a strategy was developed with the architect to assure that changes to room names and dimensions would enable the team to easily update the load calcula-tion software with limited rework. Dynam-ic sections were used by the team through-out the drawing production to determine bottlenecks and coordinate with the other trades. Finally, the use of smart components allowed for the development of air balance tables and schedules. For a project of this size and type, these systems were found to significantly improve the accuracy of the calculations and schedules and to reduce time required for manual efforts.

For example, on a large museum proj-ect, scripts that interrogated the model were used to establish sheet metal quantity and pipe lengths in order to expedite the work of the cost estimator. This not only allowed for a more accurate understanding of the amount of ductwork and pipework, it also gave the engineering team an accurate understanding of insulation, jacketing, and hanger costs. On a courthouse project, par-tial models were submitted with requests for information (RFIs) in order to help visualize actual conditions in the field and to facilitate more accurate solutions. On multiple projects, the shop drawing review process also has been made much easier by using overlay tools to compare contrac-

tor shop drawings to the original design documents. And finally, on a recent col-lege project, the Arup team used equipment room renderings to convey equipment room access to the school’s facility personnel.

One additional advancement is the use of remote file servers and cloud-based storage that allow teams to download other discipline models and track prog-ress in real time. If all team members are working in the same platform, con-flicts can truly be resolved as the design evolves. Third-party software with clash detection can also be used to compare multi-trade models (even those devel-oped with different software) and iden-tify interference. Now, more than ever, software tools allow designers to be pro-active in coordinating with other trades as they work while ensuring that nothing is missed through clash detection and diagnostics.

The risksWith so much power in the hands of

a modern design team, there is an argu-ment that mistakes may never again be made. Clearly, that is not true. Just like the adoption of the typewriter, comput-er-aided design (CAD), and word pro-cessing, there are changes to the entire design process that require attention of all project team members. Tried-and-true methods must still be implemented. For instance, the use of BIM does not replace the need for strong planning and com-munication among the design team. In fact, because there is often an exchange of progress models, there can often be a need to increase the level of commu-nication.

It should also be acknowledged that 3-D design and BIM frequently can be

Figure 3: A timeline identifies how and when advancements in technology gain prominence within the architecture and engineering industry. The “Market Place-ment” scale is intended to convey the usage within the market by charting early adoption through standardized ser-vice offering.


more time consuming than 2-D drawing production, especially at early stages. 3-D and BIM design can take additional time to coordinate fittings and review sec-tions in 3-D. Because of this, it is essen-tial to match the level of development of the model with that of the other trades to minimize rework. To revisit the previous point of “garbage in = garbage out,” in the integrated model, if any one compo-nent is poorly conceived, it can impact all other services. While cloud-based storage does allow for access to the latest infor-mation, it does not necessarily guarantee that all information has been fully con-sidered. Good designers know that the design process can be iterative. Thus, it is important to ensure that the designers try to increase the level of development of their own model in step with those of the other disciplines.

In traditional procurement methods, changes to the mechanical or plumbing system often may not have been appropri-ately conveyed to the electrical engineer in the haste of a project deadline. The risk of neglecting to communicate key coor-dination items is always greater when

time is short or project teams are large. On more recent projects, we have experi-enced expedited schedules and integrated project delivery (IPD) procurement. In these cases, the contractor detailed coor-dination can overlap the design schedule. Thus, engineers must not only determine when to begin detailed coordination with-in the design trades, but they also must ensure that design iterations do not impact completed coordination by the contractor trades. Even with cloud-enabled project access, judgment and communication are essential factors that contribute to a successful process. Particularly at early stages, team members must coordinate allowances based on their judgment of where the model will end up as opposed to the exact dimensions at which it cur-rently stands.

One way to balance engineering allow-ances with design model integration in a way that other trades can follow is to develop a BIM execution plan that defines the level of development (LOD) at each stage of the model. The level of develop-ment may be defined uniquely within the execution plan or refer to specific lan-

guage on LOD as defined by the Ameri-can Institute of Architects within the E202 BIM Protocol document. With the latter, LOD 100 through LOD 500 is defined to give other model users an understanding of the precision of the existing model in terms of scheduling, pricing, fabrication, and construction.

The LOD of the model should also inform the confidence that a team may have in optimizing floor-to-floor and equipment room sizes. As identified in Figure 5, some of the components that would be incorporated in the final instal-lation would not be identified within the design model. For instance, duct/pipe accessories and anchorage are often described in equipment schedules, speci-fications, or typical details as opposed to in the plans. In seismic zones, there can be even greater challenges in incorporating diagonal bracing for seismic support. Even at later stages, contractor shop drawings may not consider all clearances required for phasing, installation, or future main-tenance. Because of this, good judgment must still be used when evaluating the benefits of reduction in floor heights or

Interstitial spaces

Figure 4: “Smart objects” or product families are prominent tools in modern design software packages. Intelligent components have characteristics that identify installation clearance, scheduling, and coordination characteristics.

� Smart objects allow modification of duct or pipe sizes, insulation thickness, and more. Properties can be modified without having to redraw the system� Components are inserted into the model as parts with true inlet/outlet sizes. Ducts and pipes are then connected to the device with appropriate fittings.

Figure 4: “Smart objects” or product families are prominent tools in modern design software packages. Intelligent components

SMART OBJECT: Terminal box

SMART OBJECT: Diffuser


in reducing spatial allowances of equip-ment rooms.

Working as a teamIt is essential that design teams and

BIM operators have a strong awareness of how much information is needed and how extensively tools are to be used at early stages of a project. In general, many of the tools require additional setup. For instance, additional effort may be needed to define a family of parts for a particular smart component or to establish a process to export infor-mation into another type of software. The team must determine which pro-cesses will be used and how information must be transferred between your firm and outside entities.

Because there must be much more cohe-sion between all models, the design team must invest early, not just in establishing ini-tial setup of the files, but also in establishing a process for importing and merging future, more detailed data. It is recommended that a BIM execution plan be used to document the process for file transfer, the level of detail that will be identified in the model, and the area of responsibility for each entity. BIM managers must also be named to take own-ership of each firm’s model, to monitor file sizes, and to assure that automated processes continue to function.

The authors have experienced substan-tial benefits in the use of BIM through the automation of manual processes and the accuracy of the model. Further, BIM allows the development and visualiza-tion of alternate solutions, which then can be communicated to our clients. Spatial access in ceiling voids and mechanical rooms can now be communicated quite easily by directly exporting a screen shot from the maintenance personnel’s point of view. Scripts can be used to determine actual quantities of components to facili-tate more efficient and accurate costing. At later stages of a project, as the models become more stable, we see substantial benefits in reviewing contractor shop drawings and eliminating or reducing RFIs from the field.

At this point, we have not found research to identify whether the time cost of production is in fact offset by the more efficient construction administra-tion process that is enabled by BIM. The value of the process is heavily depen-dent on management of change during construction. While the software does present new challenges and require new and more defined roles, it is essential to our profession to assure that efficiency is maximized. We continue to use pilot projects to advance the automation and integration processes available. We also

have experienced the benefit of using external consultants to assure the proj-ect models are correctly set up and that the most efficient functions within the BIM tools are being fully used.

BIM is here to stay, and our profes-sion must continue to explore software capabilities to fully use and optimize all of the benefits and to advocate with software providers to develop tools to fit our industry needs.

Erin McConahey is a principal in mechan-ical engineering at Arup’s Los Angeles office. During her 18 years with Arup, she has worked internationally and now leads multidisciplinary design teams on a wide variety of project types. She served on the editorial board of Consulting-Specifying Engineer for 6 years and was a 2008 40 Under 40 award winner. Jamey Lyzun has more than 12 years of experience on projects throughout North America, Asia, and the Middle East. In a range of projects types and sizes, Lyzun has applied many of the techniques outlined to assure that integrated strategies at the design phase can lead to trade coordination at construc-tion phase. Lyzun is a 2013 40 Under 40 award winner.

CD model by engineer� Equipment shown in dimension, but may not be specific

to manufacturer� Pipework shown with necessary clearance, but may not

indicate all valves� Coordination based on interim routing from other

disciplines.

Construction model by contractor � Equipment drawings provided by manufacturer and inserted into drawing � Specialties and accessories indicated at equipment connections � Routing from other disciplines will be based on contractor shop drawings.

Figure 5: The comparison model between the design engineer and the contractor conveys that judgment must still be used at design stages to assure that systems will fit as planned. The reason is that specialties, clearances, access, and other characteris-tics may not be included within a model until the contractor commences its work.

Figure 5: The comparison model between the design engineer and the contractor conveys that judgment must still be used at The comparison model between the design engineer and the contractor conveys that judgment must still be used at

Read the longer version of this online at: www.csemag.com/archives.


What do you do with an existing 1.2 million-sq-ft empty shell building when the owner says

it wants to build out about 200,000 sq ft on three different levels and place some of the highest profile areas such as a high-volume education center and an imaging center on level 1, which just happens to have the shortest floor-to-floor height (14 ft) in the building? You accept the chal-lenge, of course.

The program defined fitting out of about 70% of level 1 with an entry lobby, café, imaging center, facilities offices, education center, and emergency department. About 50% of level 4 was fit out with an operat-ing room (OR) suite, post-anesthesia care unit (PACU), endoscopy, central sterile, and patient beds. Level 10 included a clinic and filled about 70% of the available space.

More specifically, the challenges were: � The level 1 imaging suite with two

MRI rooms, a nuclear medicine area, a PET/CT room, a CT room and a con-ventional radiology room with support spaces

� Place a high-profile education center consisting of two large conference rooms and pre-function space with 10-ft ceilings and several smaller conference rooms adjacent to the larger rooms

� On level 5, fitting large ductwork between existing hangers of a chilled water pipe rack

Figure 1: This section shows ductwork routed up to level 2 above due to con-gestion above level 1 ceiling. All graph-ics courtesy: Smith Seckman Reid Inc.

Figure 1: This section shows ductwork

An existing building—destined as a medical facility—held a few surprises during renovation. BIM and clash detection helped smooth the process.

BY CHRIS ST. CYR and J. PATRICK BANSE, PE, LEED AP, Smith Seckman Reid Inc., Houston

Case study:Coordinating interstitial spacesin an existing building


n Field investigate existing conditions, integrate as-built information, and create a 3-D design model in Autodesk Revit MEP to aid the design process.

The coordination processThe project was designed in Autodesk

Revit and Revit MEP, which allowed for real time 3-D modeling of mechani-cal ductwork and piping with archi-tectural walls and ceilings. The model was updated weekly by the architect. The existing structure information was imported into the project model and used to avoid beams while using the open pans for duct and piping offsets. Importing and being able to see sloped sanitary waste and vent piping aided in the design coordination efforts.

The owner-provided “as-built” draw-ings from the previous installing con-tractors were used and useful to some degree, but they also proved that as-built documents do not always show all con-ditions. For example, electrical conduit and racks were not shown or indicated on the as-built drawings. Field investi-gation aided the process, but the project schedule and design team scope of ser-vices did not allow for extensive field verification work.

The design team used Autodesk Navisworks collision detection, which

identified major element clashes that were then adjusted to fit, but did not allow for complete coordination due to unknown vendor conditions, such as pneumatic tube and low-voltage cabling not being part of the architecture/engi-neering design model.

Reality during constructionThe contractor’s responsibility as part

of its scope was to create a fully coordi-nated multi-discipline 3-D model (virtual design and construction) to be used for

clash detection and installation. Each subcontractor (mechanical, plumbing, electrical, fire protection, low-voltage cabling, pneumatic tube) laid out its systems as indicated on the design draw-ings but with more detail, and included required offsets, hangers, conduit with required radius bends, and cable tray. The design team participated in these coordination sessions to make design decisions as needed while the coordina-tion proceeded.

While looking at the contractor’s model, some areas were quickly identi-fied as needing modification to fit in the available space due to undocumented existing conditions (large conduit racks in the middle of available above ceil-ing space) and unforeseen conditions. In the level 1 area, this created a dom-ino effect: When one duct moved, so did three others, which identified the need to relocate some ductwork up to the floor above to shorten the level 1 horizontal duct runs while still making connections to the duct risers at the chases (see Figure 1).

When an existing chase wall was opened during construction, the team discovered a large vertical conduit rack installed within a duct chase against an exhaust duct riser negating the planned duct connection. 3-D modeling could not have noted that condition as the conduit was not visible nor indicated on existing drawings (see Figure 2).

The coordinated model in Figure 3 shows the ductwork, terminal units, pip-ing, and offsets along with light fixtures to fit the limited above-ceiling space of level 1. The contractor’s coordination model provided the guidance for larger items to fit and meet the design intent and criteria while leaving the means and methods of installation to the individual trades. It also confirmed the need for this

Figure 3: This screen shot shows completed areas of level 1 showing finished coordi-nation efforts.

Figure 2: Removal of a chase wall revealed a vertical conduit rack prevent-ing exhaust duct connection.

The design team used Autodesk Navisworks

collision detection, which identified major

element clashes.


model type to be part of the project con-struction scope.

Level 5 (the mechanical floor) had a 20-ft floor-to-floor height, which by most standards (and imagination) seemed more than adequate to route ductwork and piping from the existing air handlers to the central core chases. However, existing conditions, such as chilled water piping routed at low eleva-tions (10-ft above finished floor close to the AHUs) and supply and return ducts serving the multiple electrical and inter-mediate distribution frame (IDF) rooms adjacent to the shafts, made coordina-tion more difficult than expected. Supply

ductwork from two air units had to route above 20-in. chilled water piping but between hanger rods. Design drawings including 3-D modeling of systems do not typically show placement of hangers, but in this case working with the con-tractor during field coordination allowed the duct placement to be shown and the design duct dimensions accurately reflected with the existing conditions (see Figure 4).

Another area on level 5 that required a coordinated effort involved duct and pipe routing between an existing main electrical room with floor mounted AHUs outside the room and adjacent

air handlers with existing disconnects and variable frequency drives (VFDs). Differing field conditions from exist-ing drawings pre-empted accurate 3-D modeling, but the field determined solution to relocate chilled water piping serving the electrical room air handlers and removing and relocating the large air unit disconnects and VFDs allowed the ductwork and piping to be installed while maintaining proper clearances with the resultant conditions reflected on the contractor’s coordinated model.

Successful coordinationWorking in a 3-D Revit model pro-

vides many opportunities to coordinate during the design process, but even with Navisworks collision detection, it does not provide contractor installa-tion drawings, nor should it be expected to. Because not all trades are incorpo-rated into the model, it will not show all items needed for installation by the contractor. What the design model does, however, is more clearly show the design intent to allow for early coordi-nation with architectural design (e.g., ceiling heights) with MEP above ceiling needs prior to the construction admin-istration phase and also allow the con-tractor to better implement its means and methods for a workable installa-tion. New construction models will differ from existing condition models in that existing buildings will always have unknown conditions that cannot be accurately reflected in a model and must be field determined and resolved as the construction proceeds.

Chris St. Cyr is a senior mechanical designer with Smith Seckman Reid. He has more than 24 years of mechanical design experience, with the past 15 years in the design of health care facilities. J. Patrick Banse has more than 35 years of experience in the consulting engineering field with the past 30 years in health care design and engineering. He is a member of Consulting-Specifying Engineer’s edi-torial advisory board.

Case study: Interstitial spaces

Figure 4: Level 5 duct/pipe rack was coordinated to fit between existing hanger rods.

Dealing with existing building conditions

Existing air handling units (AHUs) were set in place on level 5 and had no piping or duct-work connected. Supply air and return air duct risers were in place located in a central

core chase with ductwork directed down to the lower floors. Exhaust risers began at various levels and routed up to fans in the level 11 penthouse within 2-hour rated chases. Domestic water risers, medical gas risers, chilled water, and heating water risers routed vertically from level 1 up and from level 5 down, also in the central core chases. Strategically placed exit stairs, elevators, electrical rooms, and intermediate distribution frame (IDF) rooms were also placed adjacent to the vertical duct chases in the core. Existing duct taps with fire smoke dampers were installed through the chase walls at varying intervals.

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DE-1 Consulting-Specifying Engineer • OCTOBER 2013 www.csemag.com

Designers and managers of com-mercial buildings face increased demands to improve energy effi-

ciency to reduce energy consumption, driven by local and state energy codes and standards like ASHRAE Standard 90.1 and ASHRAE Standard 189.1, and guidelines from the U.S. Green Building Council.

For example, Cold Spring Harbor Laboratories is a private, nonprofit research/education institute dedicated to exploring molecular biology and genet-ics to improve diagnosis and treatment of cancer. This world-famous biomedi-

cal research campus on the north shore of Long Island, New York, is committed to energy efficiency measurement in all facilities throughout its campuses, guid-ed by the New York City Energy Conser-vation Code and New York state codes. The Alfred D. Hershey Building on one of the campuses of Cold Spring Harbor Laboratories is the home of microscope imaging and 3-D rendering and image analysis. Hershey Laboratory—rededi-cated in June 2012—required a major improvement in its HVAC system.

The main goal of the upgrade was to provide improved temperature and humidity control and to reduce energy consumption of the condenser refrigera-tion units by at least 30% annually.

Open ground source loop In 2009, the institution decided to

move forward with an ambitious HVAC system upgrade in the form of a direct expansion (DX) split unitary system for cooling and heating the interior space of the laboratory.

A ground source heat pump system was selected to upgrade the HVAC with ground source condenser water because the lab did not allow for an unattractive cooling tower and because this system can achieve much greater energy effi-ciency than a DX split system.

These water source heat pump systems are efficient at transferring heat, when used in conjunction with a plate and frame heat exchanger that maintains a very small temperature difference between the ground loop and building loop. Water source heat

Ground source water is one of the fastest growing applications of renewable energy in North Ameri-ca. Cold Spring Harbor Laboratories upgraded its Alfred D. Hershey Building with a direct expansion split unitary system.

BY JOSE R RODRIGUEZ, PENG, Wallace Eannace Assocs. Inc., Plainview, N.Y.; MIKE SAMMUT, PE, AKF Group, New York City; andARSLAN ASOVIC, BSCET, AKF Group, New York City

Ground source heat pumpsystem upgrade

Case study: HVAC upgrade

DE-2www.csemag.com Consulting-Specifying Engineer • OCTOBER 2013

pumps recover excess heat from the build-ing’s interior and move it to the building’s perimeter. They are also quite suitable for New York, whose aquifers produce a lot of water.

An open loop ground source water system is also known as a “pump and dump” system. With an open loop sys-tem, the groundwater is pulled up from one supply well (the “pump” well) and pumped through a plate and frame heat exchanger, then it is pumped back to the “dump” injection well. See Figures 2 and 3 for a diagram of the mechanical room and schematic description of the open loop system.

Design and optimization A plate and frame heat exchanger

offers high thermal performance because the corrugated pattern is pressed into each plate to produce highly turbulent fluid flows; this also allow specification of a very small approach temperature (as low as 1 to 5 F), which is sometimes useful in a ground source water application.

Described below is a three-step algo-rithm to properly select, design, and optimize the heat exchanger to achieve the best value of the ground source water temperature variation. It is based on the authors’ experiences from past projects in both the U.S. and Canada.

STEP 1: To select a heat exchanger, the engineer must know five of the six parameters:

� Heater capacity � Temperatures on the hot side (in or out)� Temperatures on the cold side (in or out)� Flow rate on the cold side and/or hot side

Based on five known parameters, calculate the capacity and surface area required for transferring heat to the media using the following equations:

Q = U x A x LMTDQ = gpm x 500 x P x C x CF x ∆T

A =

Where:Q = heat load (capacity) in Btu/hrU = overall heat transfer coefficient in Btu/Hr/sq ft/FA = heat transfer area in sq ftLMTD = logarithmic mean temperature difference in Fgpm = flow rate in gallons per minuteP = specific gravityC = specific heat in Btu/lb FCF = fluid correction factor to take into account changing specific gravity and specific heat

∆T = fluid temperature rise in F

The value for the LMTD is strongly influenced by the direction of the media flow. The most effective configuration is a counter flow configuration in which fluids flow in opposite directions.

The LMTD can be calculated using the difference between the incoming and out-going temperatures of the two fluids (the hot water side and the cool water side) according to the following equation:

LMTD =

Where:∆T = T1 – t2 temperature on the hot side end

∆t = T2 – t1 temperature on the cold side end

Figure 1: The Alfred D. Hershey Building, a Cold Spring Harbor Laboratories build-ing, is the home of microscope imaging and 3-D rendering and image analysis. Hershey Laboratory—rededicated in June 2012—required a major improve-ment in its HVAC system. Courtesy: AKF Group

Figure 2: The mechanical room houses the piping in the attic of Alfred D. Hershey Building. Courtesy: AKF Group

Codes and standards

Regardless of the type of the heat exchanger used, construction and fabrication are governed by the American Society of Mechanical Engineers (ASME) under BPV Code, Section VIII Divi-

sion I: Design and Fabrication of Pressure Vessels.ASME codes use mandatory guides for fabrication of pressure vessels, which include rules and

recommendations for material selection, design, testing, and inspection of the heat exchanger. The codes cover all aspects of the construction of heat exchangers except the types of service loads (other than pressure) and the thermal design.

AHRI 400-2001 with Addenda 1 and 2: Liquid to Liquid Heat Exchangers was developed for plate and frame heat exchangers because many applications in commercial HVAC systems were designed with very close temperature approaches. AHRI developed testing requirements more stringent than those traditionally used, such as total heat transfer rate ≥95% of published and tested pressure drop ≤110% of published.

QUXLMTD

ΔT−∆t ln ( ) ∆T

∆t

DE-1 Consulting-Specifying Engineer • OCTOBER 2013 www.csemag.com

The number of transfer units (NTU) is a dimensionless value that character-izes the performance of a heat transfer based on the LMTD and the temperature change occurring in the unit.

The importance of the NTU value lies in the fact that heat exchangers are capable of generating a given NTU for each fluid, and this value is dependent upon their specific plate construction.

The pressure drop through the plate depends on type of the corrugation, which can be predicted using the fol-lowing equation:

NTU= ∆T/LMTD

If NTU > 3 (long angle corrugation patterns). Those plates have the highest heat transfer rate and highest pressure drop.

If NTU ≤ 3 (short angle corrugation patterns). Those plates have lowest heat transfer rate and lowest pressure drop.

Select the small heat exchanger model capable of handling the flow, surface area, and NTU for the winter

conditions and summer conditions of the ground source water.

STEP 2: Compare the surface areas calculated in step 1, equation 3, for win-ter conditions and summer conditions. Choose the model with the largest sur-face area between the two seasons (for instance, winter conditions).

STEP 3: Using the heat exchanger model selected (winter heat exchanger) in step 2, simulate the flow and tempera-ture of the smallest surface area (summer condition) on the heat exchanger model with the largest surface area (winter heat exchanger).

Based on our experiences, an accept-able deviation of the inlet and outlet temperatures of the heat exchanger is approximately +/- 3 F. If the inlet and outlet temperatures are close to the acceptable value, a solution has been achieved; otherwise, repeat step 1 and continue until a solution can be reached that is closer to the deviation point.

Most plate manufactures typically use

30 F angles for short angle patterns and 60 F angles for long angle patterns in forming the plate corrugation.

Recommended specifications of a heat exchanger

Most engineers determine flow and capacity of the heat exchanger based on water. Generally speaking, the heat exchanger’s flow and capacity with anti-freeze fluid is not the same as water, and the selection shows different operating values because an engineer does not con-sider the effects of the glycol solution. In this case the flow should be adjusted by approximately 16% to compensate for the effects when you are using a 50:50 ratio of glycol: water at 100 F.

Keep in mind that when you select heat exchangers for winter and summer duties, select the units for both seasons with the same plate corrugation and avoid selecting mixed plates due to the effect on the pressure drop.

Often, engineers mistakenly select the largest area of the two seasons and the heat exchanger works only for one season and not the other because the plate corrugation type selected (NTU) and pressure drop were not satisfacto-rily chosen.

Engineers should be concerned about the debris in the groundwater that could travel to the plate heat exchanger. Most manufactures offers two options for avoiding this problem:

1. Specify a port strainer on the plate heater. This reduces the possibility of plugging by preventing unwanted solid particles from entering the channel of the plate’s package.

2. An automatic back flush system (ABS), commonly used in the Northeast, is the most expensive solution. The ABS automatically cleans the plates and frame heat exchanger without interrupting nor-mal equipment operation.

The ABS consists of a four-way reversing valve that fits into the supply and return piping, allowing the reversal of the water flow direction in the heat exchanger. This flow reversal has been

Case study: HVAC upgrade

Figure 3: This shows an example of the ground source open loop systems with plate and frame heat exchanger isolation loop. Courtesy: AKF GroupFigure 3: This shows an example of the ground source open loop systems with plate

DE-4www.csemag.com Consulting-Specifying Engineer • OCTOBER 2013

found to significantly reduce the fouling in the plate and frame heat exchanger. The flow reversal is controlled by a con-trol panel mounted to the plate and frame heat exchanger or at a separate location as desired by the customer.

Plate materials of the heat exchanger are regulated by ASME BPV Code, Sec-tion VIII Division I: Design and Fabrica-tion of Pressure Vessels. Usually they are built on stainless steel or titanium plates, determined by the groundwater. In most cases, stainless steel plates are specified in ground source water. If the water has a high concentration of chloride, titanium plates should be use to avoid corrosion problems in the future.

Future performanceGround source well water combined

with the plate and frame heat exchanger give the owner and designer a more effi-cient heat source and heat sink because the plate and frame heat exchanger can maintain a small variation of the water temperatures between the ground loop and the building loop with a minimal heat transfer loss.

At Cold Spring Harbor Laboratories, the proper selection, optimization, and specification of the heat exchanger should be suitable to perform with groundwa-ter temperature variation all year long to maximize the energy savings of the buildings.

More importantly, plate and frame heat exchangers are the most widely used for ground source water systems because they are easy to maintain, flex-ible because plates can be added in the future, and compact for space saving in a mechanical room.

Jose R. Rodriguez is a technical services engineer with Wallace Eannace Assocs. where he has more than 15 years of experience in HVAC and plumbing. Mike Sammut, partner at AKF Group, has more than 30 years of experience in HVAC. Arslan Asovic is project engineer at AKF Group and has more than 10 years of experience in HVAC.

Table 2: Surface area, NTU value, and pressure drop calculated for summer condi-tions. Courtesy: Wallace Eannace Assocs.

Table 3: Surface area, NTU value, and pressure drop calculated for winter conditions. Courtesy: Wallace Eannace Assocs.

Table 4: This shows the results of the simulated heat exchanger. Courtesy: Wallace Eannace Assocs.

Summer (S) Winter (W)

Hot Cold Hot Cold

Tag Service gpm T in (F)

T out (F)

gpm (S/W)

T in (F)

T out (F)

T in (F)

T out (F)

T in (F)

T out (F)

HX-1 CW LOOP 205 80 65 155/205 55 75 67 57 55 65

Table 1: Use this to calculate the surface area required for the heating and cooling load. Courtesy: Wallace Eannace Assocs.

Summer (S) HX-1

Surface area (sq ft) NTU Pressure drop (psi)

231.42 2.8 9.2

Winter (W) HX-1

Surface area (sq ft) NTU Pressure drop (psi)

446.7 5 6.31

Winter HZ with summer duty results

Hot Cold

gpm T in(F)

T out (F) gpm T in

(F)T out

(F)Surface area

(sq ft)Pressure drop

(psi)

205 80 62 154 55 78 446.7 6.3

Heat exchanger selection and optimization

The selection process is a trade-off between the overall heat transfer coefficient (U), which has influence on the surface area, and pressure drop, which influences the pump head on

the HVAC system. In general, low pressure drop increases the surface area of the heat exchanger, thereby increasing the unit’s initial cost, and the U value influences the type of chevron pattern plates to be used and pressure drop as well.

See Table 1 to calculate the surface area required for the heating and cooling load.Using the equations described in step 1, calculate the surface area required to perform the

duties using the LMTD and NTU values for summer and winter conditions. Results of the calcula-tion are shown in Tables 1 and 2.

The key to selecting a heat exchanger is to select the smallest model with the same type of plate corrugation for both seasons (winter and summer) capable of handling the flow.

Next, simulate the heat exchanger with the largest surface area and plate corrugation type for the unit selected with the temperatures and flow profiles of the other season to obtain the duty value required for the season; see Table 4 for the heat exchanger solution.

An optimal solution has been achieved when temperature, flow, and pressure drop are within the acceptable limits.

Application notes:Glycol system implications on the heat exchanger specification:n A glycol/water system affects the heat transfer of the heat exchanger and the pump noise.n Glycol does not carry heat as well as a water-only system.n Engineers must pay attention to the corresponding flow increase of glycol solution to maintain

the minimum flow of the chiller and the corresponding pressure increase on the pump and pipe to prevent a noise problem.

Recommendation: Do not use chromate water treatments or galvanized fittings because they might react with the glycol solution.


The 2012 edition of the International Energy Conservation Code (IECC) expanded the code requirements

for building systems and equipment over those of the 2009 edition to focus on con-servation over the life of the building. A major formatting change was also made in that the residential and commercial provisions were split up to provide the commercial provisions in the front with a “C” preceding each section and the residential provisions in the back with a preceding “R.”

The code sections noted in this article are merely to facilitate discussion of the poten-tial requirements that may be applicable in

the 2012 IECC. This article is not intended to be a replacement for any of the referenced code/standard documents.

Section C401, Scope & Application of Commercial Energy Efficiency, has been modified to require new build-ings designed using the prescriptive approach to comply with an additional efficiency package option in Section C406 and buildings designed using the performance-based approach to have energy costs ≤ 85% of the standard ref-erence design building. Compliance with ASHRAE Standard 90.1 is still available as an option. The new section, Addition-al Efficiency Package Options (C406),

Significant changes to the 2012 International Energy ConservationCode (IECC) impact architects, engineers, code officials, and otherbuilding design professionals.

BY ANDREW KLEIN, PE, CEM, A S Klein Engineering PLLC, Pasco, Wash.

to the commercial provisions in 2012 IECCto the commercialSignificant changes

Learningobjectives� Understand the significant changes in the commercial provisions in 2012 IECC.

� Learn about the newly added sections to the code.


requires new buildings to comply with at least one of three subsections: efficient HVAC performance, efficient lighting, or on-site supply of renewable energy (see Figure 1). Individual tenant spaces must comply with one of the first two unless the entire building complies with the on-site supply of renewable energy specifi-cations or the tenant scope falls within the limitations of an alteration as noted in C101.4.3.

Lighting and efficiencyThere were several changes regard-

ing lighting, some of which increase the number of options available to designers and others that are more restrictive with the intent of increasing overall efficien-cy. The exception to complying with the Electrical Power and Lighting Systems (C405.1) for dwelling units within com-mercial buildings was made more strin-gent by increasing the required number of permanently installed high-efficiency lighting fixtures from 50% to 75%. Lumi-naries of rated power less than 100 W, equipment rooms and electrical/mechani-cal rooms, and daylight spaces complying with Section C405.2.2.3.2 are excluded from the Light Reduction Controls Sec-tion (C405.2.1.2) requirements.

The 5,000-sq-ft threshold on automatic time switch control devices (C405.2.2.1) was removed, and all buildings are now subject to the requirement. Occupancy sensors are now required in all meeting rooms, storage closets, and other spaces 300 sq ft or less (C405.2.2.2) and must be either manual on or controlled to automati-cally turn on the lighting to not more than 50% power. Additionally, daylight zone controls can no longer exceed 2,500 sq ft (C405.2.2.3), and the prescriptive approach requires compliance with new Section C405.2.2.3.2, Automatic Daylighting

Controls , which requires the capa-bility to automati-cally reduce lighting power in response to available daylight. Dedicated controls are now required per a new section (C405.2.3) for dis-play and accent lighting, supplemen-tal task lighting, and other similar specif-ic applications.

The interior light-ing power allow-ances in Table C405.5.2(1) have decreased for fire stations, offices, retail, and warehouses. The total interior lighting power allowance (C405.5.2) can now be determined using the building area method as well as the returned space-by-space method using newly added Table C405.5.2(2). The space-by-space method was previously known as the “tenant area or portion of building method” in the 2003 IECC before being removed in the 2006 revision.

Fenestration Several updates regarding fenestra-

tion were made that could potentially increase construction costs. The rating of visible transmittance (VT) was added to the Fenestration Product Rating section (C303.1.3) and its corresponding Table C303.1.3(3). The maximum allowable fenestration area as a percent of wall area was reduced from 40% to 30% (C402.3.1). Increased fenestration is permitted, how-ever, with daylighting controls provided that at least 50% of the conditioned floor area is within a daylight zone and the VT is greater than or equal to 110% of the solar heat gain coefficient (SHGC). Automatic daylighting controls specified in Section C402.3 must comply with the dimming requirements in section C405.2.2.3.2.

Values were modified in Table C402.3, Building Envelope Requirements:

Fenestration, and the maximum SHGC for projection factor (PF) values more than 0.2 are calculated with the newly added complementary Table C402.3.3.1, SHGC Adjustment Multipliers. Area-weighted PF values are no longer permitted to be calcu-lated and used (C402.3.3). See Figure 2 for a description of glazing properties.

A new section was added (C402.3.2) that requires building areas of certain occupan-cies greater than 10,000 sq ft with ceilings greater than 15 ft to have at least 50% of the floor area as a daylight zone under sky-lights. Furthermore, the skylight area to daylight zone must be at least 3% with a VT of 0.40 or the skylight effective aper-ture must be at least 1% as determined by newly added Equation 4-1, Skylight Effec-tive Aperture. Four exceptions were added, excluding the following:

� Climate zones 6 through 8� Designed lighting power densities

<0.5 W/sq ft� Areas where existing objects block sunlight for more than 1,500 daylight

hours per year from 8 a.m. to 4 p.m.� Spaces where daylight zones under

rooftop monitors are greater than 50% of the enclosed floor space.

Within the affected occupancies, all lighting in daylight zones is required to

Figure 2: The solar heat gain coefficient (SHGC) is the percent of the solar heat that is transmitted through glazing. Similarly, the visible transmittance (VT) is the percent of visible light that is transmitted through glazing. Horizontal projections above windows may allow an increased SHGC per section C402.3.3.1. Courtesy: A S Klein Engineering

Figure 2: The solar heat gain coefficient (SHGC) is the percent

Figure 1: Pictured is a hospital build-ing that has chosen on-site supply of renewable energy as the choice for compliance per newly added section C408, Additional Efficiency Package Options. Courtesy: Apollo Solutions Group


be controlled by multilevel lighting con-trols (C402.3.2.1), and skylights in most of those areas must have a measured haze fac-tor >90%, with the exception of skylights designed to exclude direct sunlight from entering occupied spaces (C402.3.2.2).

A maximum SHGC of 0.40 in climate zones 1 to 3 for vertical fenestration ≥ 6 ft above the finished floor (C402.3.3.2) and a maximum SHGC of 0.60 in climate zones 1 to 6 for skylights above daylight zones provided with automatic daylighting controls (C402.3.3.3) are now permitted. A maximum U-factor of 0.9 in climate zones 1 to 3 and 0.75 in climate zones 4 through 8 for skylights above daylight zones pro-vided with automatic daylighting controls is also permitted (C402.3.3.4).

Requirements and limitations on how the SHGC and VT for dynamic glaz-ing is to be calculated and used are now

specified (C402.3.3.5). Area-weighted averages are permitted to satisfy U- factor requirements within and only within each fenestration category listed in Table C402.3 (C402.3.4), potentially lowering the cost of construction.

Air leakage Except for climate zones 1 through 3, a

continuous air barrier is required around the thermal building envelope (C402.4). Subsection C402.4.1.1 details the con-struction requirements of the air barrier and subsection C402.4.1.2 lists three com-pliance options, one of which is required to be met: materials, assemblies, or full building testing (see Figure 3). A table of maximum fenestration assembly leakage rates is provided in Section C402.4.3.

Unless required to comply with IBC Section 715 or 715.4 or UL 1784, doors

and access openings from condit ioned spaces into shafts, chutes, stairways, and elevator lob-bies shall meet the fenestration require-ments or be sealed per a newly added section (C402.4.4). Stairway, shaft, and outdoor air intakes and exhausts shall be provided with motor-ized dampers limited to a leakage rate of 4 cfm/sq ft. Gravity dampers meeting a 20 cfm/sq ft leakage rate are permitted as an exception for outdoor intakes and exhausts in climate zones 1 to 3, buildings less than 3 stories, as exhaust and relief dampers, and where the design outdoor air intake or exhaust capacity is ≤ 300 cfm. Dampers smaller than 2 ft in

either dimension are permitted a leakage rate of 40 cfm/sq ft (C402.4.5).

Building envelope Several other changes were made to the

requirements of other building envelope elements. Edge joints between insulation layers are explicitly required to be stag-gered when two or more layers of con-tinuous insulation board are required and lack manufacturer installation instructions (C402.2). Skylight curbs other than those included as a component of an NFRC 100 rated assembly must be insulated to the lesser of the roof insulation level or R-5 (C402.2.1). With the exception of certain roof coverings or shading, low-sloped roofs (< 1/6 grade) directly above conditioned spaces in climate zones 1 to 3 must comply with one of the four roof reflectance and emittance options listed in newly added Table C402.2.1.1 (see Fig-ure 4). Opaque thermal envelope assembly construction (Table C402.1.2) is now per-mitted to comply with ANSI/ASHRAE/IESNA Standard 90.1 Appendix A.

A requirement was added regarding slabs-on-grade (C402.2.6) that protects insulation extending away from the build-ing with pavement or a minimum of 10 in. of soil. An exception was added exclud-ing the requirement for perimeter insu-lation where the slab-on-ground floor is >24 in. below the finished exterior grade.

Pipe insulation Exposed outdoor piping insulation

must now be protected from degradation, and use of adhesive tapes is not permitted (C403.2.8.1). Some exceptions to piping insulation requirements (C403.2.8) were also modified. The temperature range in exception 3 was decreased from 55 to 105 F to 60 to 105 F. Exception 5 no longer applies to piping 4 ft or less in length but instead to strainers, control valves, and balancing valves on piping with a diameter of 1 in. or less. Exception 6 was added that applies to buried piping conveying fluids ≤ 60 F.

Table C403.2.8, Minimum Pipe Insu-lation Thickness, was expanded, and the insulation thicknesses for very hot fluids

2012 IECC changes

Figure 3: Fans set up in the doorway of a building to perform a full-building blower test, a compliance option listed in Sec-tion C402.4.1.2. Courtesy: Retrotec Inc.


and steam were increased tremendously; however, a footnote was added allowing a thickness reduction for direct-buried heating and hot water system piping. An exception was added to Section C404.5, Pipe Insulation, for heat-traced piping sys-tems, specifying that they must meet the insulation thickness requirements per the manufacturer’s installation instructions.

A minimum insulation of R-3.5 is now required for radiant panels, associated U-bends and headers, and the bottom sur-faces of structures incorporating radiant heating (C402.2.8).

Mechanical systems Several changes were made to

mechanical system requirements in the update from the 2009 to 2012 IECC. More equipment was added to Tables C403.2.3(1) through (8) and values were modified—mostly to be more restric-tive, which could increase the costs of construction. Table C403.2.3(5) was modified to decrease minimum gas and oil-fired boiler efficiencies, however. Liquid-to-liquid heat exchangers must now meet the test procedure AHRI 400 (Table C403.2.3(9)).

Section C403.2.3.1, Water-Cooled Centrifugal Chilling Packages, an excep-tion to Section 503.2.2 in the 2009 IECC, is now its own subsection. The Adjust-ed Maximum Full Load kW/ton was replaced with the Adjusted Minimum Full-Load coefficient of performance (COP). The equations defining terms have changed to be functions of Celsius instead of Fahrenheit and refer the user to Table 6.8.1C of AHRI Standard 550/590 instead of Table 503.2.3(7). The range of fluid temperature leaving the evaporator and condenser was increased from 38 to 102 F to 36 to 115 F, and a lift between 20 to 80 F is now required for this section to be applicable.

Automatic start controls capable of automatically adjusting the daily start time of the HVAC system are required for each HVAC system (C403.2.4.3.3). The occupant load requirement for demand control ventilation (C403.2.5.1) was

lowered from 40 people to 25 people per 1000 sq ft, however an additional excep-tion was added excluding the demand-controlled ventilation provided for pro-cess loads only.

Fans and air movement The scope of the prescriptive HVAC

systems and equipment requirements (C403.3) expanded due to the removal of the second paragraph exempting cer-tain fan systems. Variable air volume (VAV) fan control (C403.4.2) expanded the applicability of the section from VAV fans with motors ≥10 hp to motors ≥7.5 hp; however, an additional exception was added excluding vane-axial fans with variable-pitch blades. Static pressure sensors used to control VAV fans shall be positioned such that the controller set-point is ≤1/3 the total design fan static pressure with the exception of systems with zone reset controls (C403.4.2.1). Sensors located past duct splits need a sensor in each major branch.

Some exceptions to energy recov-ery ventilation system requirements were modified (C403.2.6). Exception 3 was modified to also require that the exempt space not be cooled, and excep-tions 5 and 6 now refer to climate zones instead of specific climate qualities. Furthermore, exception 8 was added which excludes systems where the larg-est source of air exhausted at a single

location at the building exterior is <75% of the design outdoor airflow rate, and exception 9 was added that excludes systems expected to operate <20 hours/week at the outdoor air percentage cov-ered by Table C403.2.6. Single-zone VAV systems must now comply with the constant volume fan power limita-tion (C403.2.10.1) with the newly added exception of vivariums. Exception 3 excluding fans exhausting air from fume hoods in the 2009 edition was deleted, and additional devices were added to Table C403.2.10.1(2), Fan Power Limi-tation Pressure Drop Adjustment.

Economizers The entire Economizer Requirements

section (C403.3) and all of its subsections were modified extensively in the 2012 update. Exceptions to the requirements were added including systems expected to operate <20 hours/week, systems that serve residential spaces where system capacity is less than five times the require-ment listed in Table C403.3.1(1), and others. Climate zones 2A, 7, and 8 now require economizers (Table C403.3.1(1)), and the economizer requirement was also made more stringent by decreasing the cooling system requirement from 54,000 Btu/h to 33,000 Btu/h.

Compliance with Sections C403.3.1.1.1 through 4 is mandatory, and Section C403.3.1.1.2 requires that economizer

Table 1: Building commissioningCode section Scope of requirements

C408.2 Evidence of mechanical systems commissioning and completion must be provided by the registered design professional prior to the final mechanical inspection

C408.2.2.1 System balancing of supply air outlets and zone terminal devices

C408.2.2.2 Balance and pressure test hydronic systems

C408.2.3 System functional testing in all modes of sequence

C408.2.3.2 Calibrate, adjust, and confirm HVAC controls

C408.2.3.3 Functionally test economizers

C408.2.3.4 Preliminary report of commissioning test procedures and results

C408.2.4.1 The building can pass final mechanical inspection once the building owner acknowledges receipt of the preliminary commissioning report

C408.2.4.2 The code official may request a copy of the preliminary commissioning report

C408.2.5.2 Operations and maintenance manuals are to be provided to the building owner

C408.2.5.3 A written system balancing report describes activities and measurements

C408.3.1 The control hardware and software of lighting systems are calibrated, adjusted, and programmed

Table 1: Newly added section C408 contains all of the systems commissioning requirements. Courtesy: A S Klein Engineering

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damper sequencing with mechanical cooling equipment cannot be controlled by only mixed air temperature except for systems controlled from space tempera-ture, such as single-zone systems. Sec-tion C403.3.1.1.3, High-Limit Shutoff, now refers users to newly added tables C403.3.1.1.3(1) and (2), and section C403.3.1.1.4 requires excess air relief to avoid over pressurization. Economizer Design (C403.4.1) limits the maximum water-side pressure drop to 15 ft of water, and economizer systems are required to be integrated with mechanical cool-ing systems. Economizers also cannot increase building heating energy use.

Commissioning Mechanical Systems Commissioning

and Completion Requirements (C403.2.9) is a new section that introduces the added Section C408, System Commissioning. Section C408 covers commissioning of

the building mechanical systems and electrical power and lighting systems, and it contains requirements that are aimed to be more process-oriented. Mechanical

2012 IECC changes

Figure 4: Low-sloped roofs (< 1/6 grade) directly above conditioned spaces in cli-mate zones 1 through 3 must comply with roof reflectance and emittance require-ments listed in newly added Table C402.2.1.1. Courtesy: A S Klein Engineering

systems in buildings where the total mechanical equipment heating and cool-ing capacities are less than 600,000 Btu/h and 480,000 Btu/h, respectively, and systems serving dwelling units in hotels, motels, and boarding houses are exempt. Requirements concerning commission-ing plans, system balancing, functional testing, and reports/documentation are specified, and mechanical commission-ing must be completed prior to passing the final mechanical inspection. Table 1 provides brief descriptions of the indi-vidual commissioning and completion requirements within Section C408.

As the 2012 International family of codes is adopted, it is imperative that design professionals understand the changes since previous editions and the impacts they have on construction. This article touched briefly on all significant changes and points the reader to the appropriate sections of the code for fur-ther detail and context.

Andrew Klein is president of A S Klein Engineering, a professional engineering firm that represents businesses and orga-nizations throughout the building code and standard development process. The firm provides technical committee repre-sentation, building code advocacy, and building code consulting services.

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Engineering is personal. So is the way you use information.CFE Media delivers a world of knowledge to you. Personally.

To do your job better each day, you need a trusted source of information: CFE Media – Content For Engineers.

CFE Media is home to three of the most trusted names in the business:

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Product & Literature Digest

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PUBLICATION SERVICESJim Langhenry,Co-Founder and Publisher, CFE Media630-571-4070 x2203; [email protected]

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Letters to the Editor Please e-mail your letters [email protected] Letters should include name, company, and address,and may be edited for space and clarity.

Information For a Media Kit or Editorial Calendar, e-mail Trudy Kelly at: [email protected].

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www.csemag.com Consulting-Specifying Engineer • OCTOBER 2013 63

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Zip

Reader Company Page Service # Phone # Web site Send Info

Armacell........................................... 28 ....................11 ..............888-570-DUCT ............... www.armacell.us .................................... �

Baldor Electric Company ................ C-2...................1 ................479-646-4711 ................. www.baldor.com .................................... �

Carlo Gavazzi, Inc ........................... 36 ....................13 ..............847-465-6100 ................. www.GavazziOnline.com/BAS .............. �

Climate Master, Inc ......................... 15 ....................7 ................800-299-9747 ................. www.climatemaster.com ....................... �

Eaton Corp ...................................... 7 ......................5 ................412-893-4052 ................. www.Eaton.com/transferswitches ....... �

Firetrace Industrial .......................... 29 ....................12 ..............480-607-1218 ................. www.� retrace.com ................................ �

Generac Industrial Power .............. 1 ......................2 ................800-436-3722 ................. www.generac.com/industrial ................ �

Greenheck Fan Corp ....................... 43 ....................15 ..............715-359-6171 ................. www.greenheck.com ............................. �

Honeywell Environmental &Combustion Controls ..................... 5 ......................4 ................763-954-5094 ................. www.specifyhoneywell.com ................. �

International Exposition Co ........... 18 ....................9 ................203-221-9232 ................. www.AHREXPO.COM/ATTEND17 ......... �

Lutron Electronics Co ...................... C-4...................19 ..............888-588-7671 ................. www.lutron.com .................................... �

MCG Surge Protection .................... 60 ....................17 ..............800-851-1508 ................. www.mcgsurge.com .............................. �

MTU Onsite Energy ........................ 17 ....................8 ................507-625-7973 ................. www.mtu-online.com ............................ �

Mitsubishi ElectricCooling & Heating .......................... 37 ....................14 ..............800-433-4822 ................. www.mitsubishipro.com/new-controllers . �

Reliable Controls ............................. 8 ......................6 ................250-475-2036 ................. www.reliablecontrols.com/contact ...... �

Schneider Electric............................ 2 ......................3 ................847-397-2600 ................. www.schneider-electric.com ................. �

Solutions for Engineers .................. 20 .......................................630-571-4070 ................. www.csemag.com .................................. �

Trane ............................................... 23 ....................10 ..............651-407-4189 ................. wwwTrane.com/Foundation ................. �

XYLEM GLOBALHEADQUARTERS ............................. 45 ....................16 ..............914-323-5700 ................. www.xyleminc.com ................................ �

Yaskawa America, Inc .................... C-3...................18 ..............800-927-5292 ................. www.yaskawa.com ................................ �

PUBLICATION SERVICESJim Langhenry,Co-Founder and Publisher, CFE Media630-571-4070 x2203; [email protected]

Steve Rourke, Co-Founder, CFE Media630-571-4070 x2204, [email protected]

Trudy Kelly, Executive Assistant630-571-4070 x2205, [email protected]

Kristen Nimmo, Marketing Manager630-571-4070 x2215; [email protected]

Elena Moeller-Younger, Marketing Manager773-815-3795, [email protected]

Michael Smith, Creative Director630-779-8910, [email protected]

Paul Brouch, Director of Operations630-571-4070 x2208, [email protected]

Kate Steel, Production Coordinator,630-571-4070 x2217, [email protected]

Rick Ellis, Audience Management Director303-246-1250, [email protected]

Michael Rotz, Print Production Manager717-766-0211 x4207, Fax [email protected]

Maria Bartell, List Rental Account DirectorInfogroup Targeting Solutions847-378-2275, [email protected]

Claude Marada, List Rental Manager402-836-6274, [email protected]

Letters to the Editor Please e-mail your letters [email protected] Letters should include name, company, and address,and may be edited for space and clarity.

Information For a Media Kit or Editorial Calendar, e-mail Trudy Kelly at: [email protected].

REPRINTSFor custom reprints or electronic usage, contact: Nick Iademarco, Wright’s Media 877-652-5295 x102, [email protected]

PUBLICATION SALESMidwestMatt Waddell [email protected] West 22nd St. Suite 250 312-961-6840Oak Brook, IL 60523 Fax 630-214-4504

ALPatrick Lynch [email protected] W. 22nd St., Suite 250 630-571-4070 x2210Oak Brook, IL 60523 Fax 630-214-4504

West, TX, OKTom Corcoran, [email protected] W. 22nd St., Suite 250 215-275-6420Oak Brook, IL 60523 Fax 484-631-0598

NortheastRichard A. Groth Jr. [email protected] Pine Street 774-277-7266Franklin, MA 02038 Fax 508-590-0432

InternationalStuart Smith [email protected] Global Media Ltd. +44 208 464 5577 Fax +44 208 464 5588

1111 W. 22nd St., Suite 250, Oak Brook, IL 60523630-571-4070 Fax 630-214-4504


Amajor milestone in every young person’s life is choosing how to spend the rest of his or her

professional life. Based on personal experience, here are five reasons I think high school students should apply to engineering programs.

1. Large selection of engineering paths gives career flexibility.

Entering an engineering program opens the door to multiple branches of engineering. Many schools require the student to complete a general first-year curriculum (math, science, English, and computer skills) before moving forward in an engineering specialty. This allows the student to explore and firm up his or her engineering interest.

2. Engineering occupations are high-paying.In a recent U.S. Bureau of Labor Statistics (BLS) The

Editor’s Desk (TED) report, STEM (science, technology, engineering, and mathematics) occupations were classi-fied as high-paying. The mean annual wage for all STEM occupations was $77,880; only 4 of the 97 STEM occupa-tions were below the U.S. average of $43,460. The highest paying STEM occupations of $100,000 include manage-rial, petroleum engineers, and physicists. The BLS reports that civil engineers made $77,506/year (2010) or $37.29/hour, mechanical engineers made $77,560/year (2012) or $38.74/hour, and electrical engineers made $87,920/year (2012) or $42.27/hour. The bachelor of science degree is the entry-level education requirement.

3. Engineers’ job outlook is positive. The BLS’s June 15, 2011, TED report indicated that

technical jobs in STEM represented approximately 6% of U.S. employment (nearly 8 million jobs). The largest STEM occupations were computer support specialists, computer systems analysts, and computer software engineers; each had employment of approximately 500,000.

The BLS Occupational Outlook Handbook projects positive job growth from 2010 to 2020. Employment for

civil engineers is expected to grow 19% from 262,800 to 313,900; mechani-cal engineers is expected to grow 9% from 243,000 to 264,500; and electrical engineers is expected to grow 6% from 294,000 to 311,600.

4. Engineers’ work is fun.Civil engineers plan, design, con-

struct, and manage physical infrastruc-ture such as buildings, bridges, tunnels, transportation systems, wastewater treatment systems, coastal and ocean facilities, and public works. Mechanical engineers apply principles of mechan-ics, dynamics, and energy transfer to the design and analysis of complex build-ings and to the testing and manufacture of machines, engines, power generating

equipment, vehicles, artificial components for the human body, and other products. Electrical engineers apply engi-neering concepts to power generation, transmission, and distribution of power.

5. Engineering work is challenging.Engineers work in a professional environment where

there is an opportunity to learn and grow through on-the-job and formal training using the most up-to-date technologies. There will never be a shortage of new challenges, as engi-neers are constantly faced with having to adapt solutions and change technology to move with the trends and needs.

Based on the above reasons, if any young person has strong STEM aptitudes, has completed the STEM course-work, and has a desire to work in problem solving and help the world, entering the engineering program is the right choice as a means to a better life economically, job satisfaction, and a good career.

Sonny K. Siu is a senior electrical engineer at Jacobs-KlingStubbins. He has been in the engineering business for more than 30 years. His elder son received his PhD in mechanical engineering controls (robotics) from UC Berkeley in May 2013, and his younger son just began at UCLA in electrical engineering.

2 More Minutes

Five reasons high school students should choose engineering

A flexible career path and positive job outlook are among the benefits.

SONNY K. SIU, PE, PMP,JACOBS-KLINGSTUBBINS,

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