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PositivEnergy Practice HESNI 2012 Annual Conference

Conversation with HESNI 2012 Annual Conference Attendees about Health Care HVAC Systems ANSI/ASHRAE/ASHE Standard 170-2008 May 4, 2012


• International Experience w/ Local Impact • Leadership Skills facilitate Servicing Sophisticated Clients, Partners

• Management Skills facilitate Servicing Large, New Construction Projects as well as Small, Complex Renovation Projects

• Proficiency in High-Performance Building System Analysis, Design and

Construction Administration

• Culture Relationship-Driven (Service), Mission-Driven (Product)

Overview of PEP


Systems consist of sources and distribution.

FP

FAS

HVAC

SW

BAS

IT

EP

P

NP

G/V

LTG

IC

LS HVAC-Heating, Ventilating and Air Conditioning IC-Instrumentation & Controls BAS – Building Automation F/G-Fuel Oil/Natural Gas LS-Life Safety G/V – Gas/Vacuum P -Plumbing SW-Special Water NP – Normal Power EP – Essential Power LTG – Lighting FAS– Fire Alarm IT – Information Technology FP - Fire Protection

F/G

Systems are living entities that are: -conceived (design) -born (construction) -assessed (Cx) -nurtured (O&M)

SYSTEM PHILOSOPHY


• Laws/Codes/Standards/Guidelines • Climate Analysis • Design Criteria • Systems Description • Materials • Contract Considerations • Calculations • Unresolved Issues

HVAC Systems - Basis of Design


• Laws/Codes/Standards/Guidelines • IDPH 250 Hospitals (effective 9-15-1995) • IDPH 205 Ambulatory Surgical Treatment Centers (effective

dates vary between 1982 and 2010 for different sections) • ASHRAE Fundamentals Handbook 2009, 2005, 2001 • ASHRAE Systems/Equipment Handbook 2012, 2008, 2004,

2000 • ASHRAE Application Handbook 2011, 2007,2003,1999 • ASHRAE Standards (15-2010, 34-2010 55-2010, 62.1-2010,

90.1-2010, 100-2006, 170-2008, 188-proposed, 189.1-2011) • ASHRAE HVAC Design Manual for Hospitals and Clinics, 2003 • NFPA Standards (90A-1999, 99-1999, 101-2000) • FGI/AIA Guidelines for Design and Construction of Health

Care Facilities – 2010, 2006, 2001, 1996



• Laws/Codes/Standards/Guidelines • Compliance is required with laws and codes.

• Compliance is required with standards and guidelines only if

a particular standard or guideline is invoked by a law or code.

• IDPH does not currently invoke ASHRAE Standard 170-2008 • City of Chicago Building Code - 2012 does not currently

invoke ASHRAE Standard 170-2008 • International Mechanical Code - 2012 does not currently

invoke ASHRAE Standard 170-2008



• Laws/Codes/Standards/Guidelines • FGI/AIA Guidelines for Design and Construction of Health Care Facilities – 2010 edition does currently invoke ASHRAE Standard 170. • It is important to note that JCAHO, HFAP and CMMS require compliance with the FGI/AIA Guidelines for Design and Construction of Health Care Facilities so, in turn, as these entities adopt the 2010 edition, compliance with ASHRAE Standard 170-2008 will become widely enforced.



• Laws/Codes/Standards/Guidelines • It is critical that a thorough analysis be done on each and every project in order to determine all applicable laws, codes, standards and guidelines. • Conflicting requirements must be identified and classified as

either simple or complex in terms of their system implications.

• In simple cases, choosing the most conservative solution is usually appropriate.

• In complex cases, variances must be sought in order to satisfy all AHJ’s.



ASHRAE Standard 170-2008 • Purpose is to define HVAC system

parameters (both at the source and out in the distribution) aimed at improving comfort and

contamination control in health care facilities. -Planning -Systems & Equipment -Space Ventilation -Construction


ASHRAE Standard 170-2008

• Scope applies to new

buildings, additions, renovations and

infrastructure upgrades for hospitals, ambulatory care

centers and nursing homes during both the design phase and the construction phase of a project (addresses O&M in an

informational way only).



• Scope considers

chemical, physical and biological contaminants that can affect the delivery of medical care to patients; the convalescence of patients; and the safety of patients, health care workers and visitors.


ASHRAE Standard 170-2008 • Sponsored jointly by

ASHRAE and ASHE – unique! • Reviewed by public four (4)

times • Approved by ASHRAE

Standards Committee 6-21-2008

• Approved by ASHRAE Board of Directors 6-25-2008

• Approved by ASHE 7-18-2008 • Approved by ANSI 7-24-2008 • Consensus standard

currently under continuous maintenance by ASHRAE SSPC

• Written in mandatory and enforceable language so it can be more easily invoked by AHJ’s



The standard was created, in part, because of the risk that the 2003 ASHRAE HVAC Design Manual for Hospitals and Clinics would be invoked by various AHJ’s (in much the same way that the ASHRAE Applications Handbook has been invoked over the years including IDPH) – AHJ’s invoking documents written in a form that is not a proper standard could create confusion , problems or liability. The standard also creates an opportunity to incorporate new research and technology without having to write another book.



• Compliance applies to

both new buildings as well as additions and alterations to existing buildings/systems/spaces; the documentation required includes plans, specs, BoD and calcs; alternates to the prescriptive criteria put forward can always be put forward to the AHJ for their approval


ASHRAE Standard 170-2008-Errata 4-15-2011 • Changes reference from “AIA

(2001)” to “AIA (2006)”. • Only one (1) errata issued

because this standard is under continuous maintenance (not unusual).


ASHRAE Standard 170-2008-IC #170-2008-1 • Dated 8-18-2010 • Put forward by Ron Lyon of

KJWW • Addressed the use of an AII

room used during the occupation by a patient requiring AII versus a patient simply requiring normal acute care.

• Pressurization should remain unchanged – i.e. negative all the time

• This IC was codified in the subsequent Addenda F issued 2-3-2011.

• Important to submit Requests for Interpretations – helps clarify the proposed intent!


American College of Surgeons – Guidelines for Optimal Ambulatory Surgical Care and Office-based Surgery, 2000

• Class A: Minor Surgical Procedures Performed Under Topical and Local Infiltration Blocks with or without Preoperative Sedation (Spinal, Epidural, Auxiliary, Stellate Gangloin Blocks, Regional Blocks, Supraclavicular, Infraclavicular, and Intravenous Regional Anesthesia are Excluded)

• Class B: Minor or Major Surgical Procedures Performed in Conjunction with Oral, Parenteral, or Intravenous Sedation or Performed with the Patient Under Analgesic or Dissociative Drugs

• Class C: Major Surgical Procedures that Require General or Regional Block Anesthesia and Support of Vital Bodily Functions


ASHRAE Standard 170-2008-Addendum (a) • Approved by ASHRAE



• Approved by ASHE 6-2-2009 • Approved by ANSI 6-25-2009 • Changes NICU temp range

from 70-75 F to 72-78 F (warmer)

• Changes “corridor” to “patient corridor” in Inpatient Nursing

• Clarifies RH range to be anywhere within the specified temperature range

• Clarifies “monitoring device alarm” to be “pressure monitoring device alarm”


ASHRAE Standard 170-2008-Addendum (b) • Approved by ASHRAE



• Approved by ASHE 9-24-2009 • Approved by ANSI 11-16-2009 • Clarifies filtration for PE

rooms as “HEPA” ilo “MERV 17”

• Changes separation requirements for relief air in order to distinguish relief air from exhaust air

• Adds requirement to minimize air leakage through filter bank assemblies


ASHRAE Standard 170-2008-Addendum (b)

• Requires each OR to have individual temperature control

• Requires that differential pressure of .01” wc be maintained between morgues and autopsy rooms and adjacent spaces to those morgues and autopsy rooms


ASHRAE Standard 170-2008-Addendum (b) • Changes particular design

parameters for specific rooms (refer to table 7-1) • -new entry of Intermediate

Care Area (ICA) • -CCU, ICU, WICU and ICA

have no pressurization requirements

• -defined “RH” as “Design RH”

• -twelve (12) different laboratories are now allowed to use re-circulating air room units

• -Endoscopy room name is changed and supply airflow rate reduced from 15 AC/HR to 6 AC/HR


ASHRAE Standard 170-2008-Addendum (b) • Changes particular design

parameters for specific rooms (refer to table 7-1) • -stipulates that a Triage

room does not need to be a waiting room for patients awaiting chest x-rays for diagnosis of respiratory disease – it can be used for any type of patient

• - stipulates that a Radiology Waiting room needs to be considered a waiting room for patients awaiting chest x-rays for diagnosis of respiratory disease


ASHRAE Standard 170-2008-Addendum (c) • Discontinued by ASHRAE

Standards Committee after comments received from first public review

• Would have added an exception to “6.4 – Filtration” that would have required re-circulating room units to be equipped with filters having a MERV rating of 7 or higher located upstream of the heating and/or cooling coil.


ASHRAE Standard 170-2008-Addendum (d) • Approved by ASHRAE

Standards Committee 6-26-2010 • Approved by ASHRAE Board of

Directors 6-30-2010 • Approved by ASHE 7-9-2010 • Approved by ANSI 7-10-2010 • Reduces the minimum RH level

down from 30% to 20% for many “Surgery and Critical Care” spaces: • Class B & C OR’s • Cystoscopic OR’s • C-Section OR’s • Treatment Rooms • Trauma Rooms • Laser Eye Rooms • Class A OR’s


ASHRAE Standard 170-2008-Addendum (d) • Reduces the minimum RH

level down from 30% to 20% for Gastrointestinal Endoscopy Procedure Rooms


ASHRAE Standard 170-2008-Addendum (d)

• Rationale was research undertaken by ASHRAE at the request of the State of California because they were responsible for enforcing the provision of booster humidifiers that were required by design but were hardly ever needed because the RH rarely dipped below 30% - so booster humidifiers were provided and then promptly turned off, never to be used again. Other States had similar enforcement dilemmas. So, ASHRAE Standing Standard Project Committee (SSPC) 170 undertook the research which represented both ASHRAE and FGI. ASHRAE enlisted the help of NIH, AORN and the CDC.



• Process included assessing the use of flammable anesthesics, static electricity, viral infections and surgical site infections (SSI’s); SSI’s are caused by bacteria and fungi, not viruses; SSI’s are more dominant with prolonged periods of high RH over 60%, not low RH.

• As a result of all the multi-disciplinary research, NFPA 99 reduced their lower limit RH level from 35% to 20% and ASHRAE Standard 170 reduced their lower limit RH level from 30o% to 20% (as did FGI).

• Conclusion—lower RH might affect comfort but not infection control.


ASHRAE Standard 170-2008-Addendum (d) • ASHRAE Standard 55 – Thermal Environmental Conditions for Human Occupancy addresses Tdb, RH, Tmrt and Air Speed.

• No minimum RH level identified w.r.t. thermal comfort although ASHRAE acknowledges that non-thermal comfort factors may place a lower limit on space RH.


$- $100.00 $200.00 $300.00 $400.00 $500.00 $600.00 $700.00

20% 25% 30% 35% 40% 45%Relative Humidity of Interior Space (%)

Annual Cost to Humidify a 600 sf OR



15 25 35 45

Ann

ual S

avin

gs ($

)

Space Relative Humidity (%)

waterside economizer


airside economizer



• Results include: • Elimination of booster

humidifiers including steam piping, condensate piping, trim, controls, stainless steel ductwork, drain, insulation, etc.

• Energy consumption reduced • Energy cost reduced • Water consumption reduced • Chemical use reduced • Maintenance reduced in a very

congested busy area of a hospital

• Reduction in disruption to Clinical staff

• Easier contamination control if moisture source is removed from OR suite

• Reduce risk of fogging in an OR


ASHRAE Standard 170-2008-Addendum (e) • Approved by ASHRAE



• Approved by ASHE 1-28-2011 • Approved by ANSI 2-3-2011 • Clarifies that an AII room that

is being retrofitted can be provided with a re-circulating unit fitted out with a HEPA filter


ASHRAE Standard 170-2008-Addendum (e) • Clarifies that exhaust

ductwork removing air from AII rooms, bronchoscopy rooms, ED waiting rooms, nuclear medicine labs, radiology waiting rooms and lab chemical fume hoods must be under negative pressure within the building unless it’s in an equipment room, in which case it must be sealed to SMACNA Class A.


ASHRAE Standard 170-2008-Addendum (f) • Approved by ASHRAE



• Approved by ASHE 1-28-2011 • Approved by ANSI 2-3-2011 • Clarifies that dP shall be

between an AII or PE room and the corridor whether or not an anteroom is provided

• AII anteroom (-) to corridor; allows reduction of airflow with non-AII patient from 12 AC/HR to 6 AC/HR (i.e. contact isolation or droplet isolation)

• PE anteroom (+) to corridor


ASHRAE Standard 170-2008-Addendum (f) • Addresses a new category of

room called a Combination AII/PE for a patient that is immunosuppressed and has an airborne infectious disease

• Patient room must be exhausted to the outdoors

• Anteroom (-) to corridor and anteroom (-) to patient room

---OR--- Anteroom (+) to corridor and

anteroom (+) to patient room


ASHRAE Standard 170-2008-Addendum (g) • Approved by ASHRAE



• Approved by ASHE 1-28-2011 • Approved by ANSI 3-3-2011 • Adds definition of “patient

care area” • Defines supply air outlet

types for “single bed patient rooms”

• Allows displacement ventilation in “single bed patient rooms” with 6 air changes per hour


ASHRAE Standard 170-2008-Addendum (h) • Approved by ASHRAE

Standards Committee June 25, 2011

• Approved by ASHRAE Board of Directors June 29, 2011

• Approved by ASHE May 16, 2011

• Approved by ANSI July 27, 2011

• Filtration requirements clarified w.r.t. any space in which a recirculating unit is allowed.

• Clarified that gravity type (convection) heating or cooling units and radiators shall not be used in an OR or other special care spaces.


ASHRAE Standard 170-2008-Addendum (h)

• Spaces that are to be negatively pressurized (i.e. physical therapy, hydrotherapy, general lab) but do not have to have that air exhausted to the outdoors shall have the supply airflow rate used to calculate the required AC/HR rate (typically, a negatively pressurized space has the AC/HR rate applied to the exhaust airflow while a positively pressurized space has the AC/HR rate applied to the supply airflow).

• The filter requirements are to be applied to the minimum outdoor air brought into a space through an HVAC system.


ASHRAE Standard 170-2008-Addendum (h) • Recirculating units such as

fan coil units, heat pumps and active chilled beams are now permitted in certain spaces such as Intermediate Care Rooms, Patient Rooms, LDRP’s, LDR’s, Patient Corridors, X-Ray Rooms, Labs, Pharmacy, Exam Rooms, Medication Rooms, Treatment Rooms, Hydrotherapy Rooms, Physical Therapy Rooms, Sterile Storage Rooms, Clean Linen Storage Rooms, Clean Workroom and Clean Holding Rooms


ASHRAE Standard 170-2008-Addendum (h) • Airflow rates shall be any

AC/HR rate required beyond the minimum outdoor air requirement.

• The outdoor air provided to the space, which is delivered via a separate, independent HVAC system, must be properly conditioned (i.e. heated, cooled, humidified, dehumidified, filtered, cleaned, etc.)

• The recirculating unit must serve only a single space.

• MERV 6 filtration upstream of any local cooling coil


ASHRAE Standard 170-2008-Addendum (h) • Certain spaces such as ED

Waiting Rooms and Radiology Waiting Rooms can have HEPA filters added into the airstream drawn from those spaces and have that air subsequently returned to a recirculating fan system.


ASHRAE Standard 170-2008-Addendum (i) • Does not exist.


ASHRAE Standard 170-2008-Addendum (j) • Approved by ASHRAE

Standards Committee tbd • Approved by ASHRAE Board

of Directors tbd • Approved by ASHE tbd • Approved by ANSI tbd • Will address filtration for

several residential health care occupancies among other things.


ASHRAE Standard 170-2008-Addendum (k) • Approved by ASHRAE


of Directors tbd • Approved by ASHE tbd • Approved by ANSI tbd • Will address the requirement

to exhaust to the outdoors all the air from an AII room and will provide limitations w.r.t. the reuse of that air stream for energy recovery.


ASHRAE Standard 170-2008-Addendum (l) • Approved by ASHRAE



• Approved by ASHE 12-9-2011 • Approved by ANSI 1-26-2012 • Adds Operating/Surgical

Cystoscopic Rooms and C-Section Delivery Rooms to Class B and C Operating Rooms


ASHRAE Standard 170-2008-Addendum (l) • Approved by ASHRAE



• Approved by ASHE 12-9-2011 • Approved by ANSI 1-26-2012 • Adds four (4) specialty rooms

to the category of D/T Spaces: • Dialysis treatment area • Dialyzer reprocessing

room • Nuclear medicine hot lab • Nuclear medicine

treatment room


ASHRAE Standard 170-2008-Addendum (m) • Approved by ASHRAE



• Approved by ASHE 12-9-2011 • Approved by ANSI 1-26-2012 • Clarifies that spaces that

have positive or negative pressurization requirements should have fully ducted return or exhaust systems, respectively.


ASHRAE Standard 170-2008-Addendum (m) • In addition, this addendum

clarifies that the following spaces that have no specific pressurization requirements should have fully ducted return air systems: • Recovery rooms • Critical care units (CCU) • Intensive care units (ICU) • Wound intensive care

units (WICU) • Intermediate care areas

(ICA)


ASHRAE Standard 170-2008-Addendum (n) • Approved by ASHRAE


of Directors tbd • Approved by ASHE tbd • Approved by ANSI tbd • Will address how designers

may determine outdoor air flow rates when the system serves multiple spaces.


ASHRAE Standard 170-2008-Addendum (o) • Approved by ASHRAE


of Directors tbd • Approved by ASHE tbd • Approved by ANSI tbd • Will address office-based

surgery.


ASHRAE Standard 170-2008-Addendum (p) • Approved by ASHRAE


of Directors tbd • Approved by ASHE tbd • Approved by ANSI tbd • Will address Nourishment

Rooms.


ASHRAE Standard 170-2008-Addendum (q) • Approved by ASHRAE


of Directors tbd • Approved by ASHE tbd • Approved by ANSI tbd • Will address Pharmacies.


ASHRAE Standard 170-2008-Addendum (r) • Approved by ASHRAE


of Directors tbd • Approved by ASHE tbd • Approved by ANSI tbd • Will address new definitions

such as “absorption distance” and essential accessories”.

• Will address coordination of requirements within the FGI Guidelines.

• Will address several new equipment requirements.

• Will address contamination control in coughing areas.


ASHRAE Standard 170-2008-Addendum (s) • Approved by ASHRAE


of Directors tbd • Approved by ASHE tbd • Approved by ANSI tbd • Will address coordination of

requirements within the FGI Guidelines.


6.0 Systems and Equipment

• 6.1 Utilities

• 6.2 Air Handling Unit Design

• 6.3 Outdoor Air Intakes and Exhaust Discharges

• 6.4 Filtration

• 6.5 Heating and Cooling Systems

• 6.6 Humidifiers

• 6.7 Air Distribution Systems


Systems and Equipment – 6.1 Utilities

Ventilation Required on the Essential Power System • Airborne Infectious Isolation Rooms • Protective Environment Rooms • Class B and C Operating Rooms including C-Section

OR’s and Cysto OR’s


Systems and Equipment – 6.1 Utilities • Reserve Heating Capacity (n + 1) Required

for Sterilization, Dietary, and Space Heating for Operating, Delivery, Birthing, Labor, Recovery, Intensive Care, Nursery, and Inpatient Rooms

• Not required if the ASHRAE 99% dry bulb is greater than or equal to 25 F


Systems and Equipment – 6.1 Utilities

• Reserve Cooling Capacity (n + 1) Required

if the Cooling Load is Greater Than 400 Tons

• Not required if the ASHRAE 1% dry bulb is less than or equal to 85 F


Systems & Equipment – 6.2 AHU Design

• Air Handling Unit Casing

• Prevent Water Intrusion

• Resist Corrosion

• Permit Access for O&M

• Air Handling Unit Interior Surfaces

• Comply with ASHRAE Standard

62.1-2007

• Resistant to Mold Growth

• Resistant to Erosion

PositivEnergy Practice HESNI 2012 Annual Conference Systems & Equipment – 6.3 OAI

• OAI must be at least 25 feet from cooling towers and exhaust discharges

• OAI must be at least 6 feet above grade and 3 feet above a roof

• OAI must be protected from public access (moderate and high-risk)

• OAI must prevent entrainment of wind-driven rain with features to drain away precipitation

• OAI must have birdscreen mesh (no smaller than ½ inch)

PositivEnergy Practice HESNI 2012 Annual Conference Systems & Equipment – 6.3 Exhaust Discharges

• Exhaust discharge from AII Rooms, Bronchoscopy, ED Waiting Rooms, Nuclear Medicine Labs, Radiology Waiting Rooms, Laboratory Chemical Fume Hoods shall comply with the following: • Exhaust Ductwork in Occupied Spaces is

Negative • Exhaust Ductwork in Equipment Rooms can

be Positive if Sealed • Discharge at least 10 feet above roof level • Discharge not less than 10 feet from OAI,

windows, and occupied areas that are higher than the exhaust discharge

• Minimize recirculation of exhausted air back into the building


Systems & Equipment – 6.4 Filtration

• Refer to Table 6.1 for Filter Efficiency Requirements

• Filter Bank 1 must be upstream of heating and cooling coils such that all mixed air is Filtered

• Filter Bank 2 must be downstream of wet Cooling Coils and Supply Fans

• Filter Bank 2 Filters shall have Sealing Interface Surfaces

• Filters with Efficiency Greater than MERV 12 must have a Differential Pressure Monitor

• Emphasis on Eliminating Bypassed Air


Systems & Equipment – 6.4 Filtration

Table 6-2 Space Designation Filter Bank 1-MERV

Filter Bank 2-MERV

Class B and Class C Surgery; Inpatient and Ambulatory Diagnostic and Therapeutic Radiology; Inpatient Delivery

and Recovery Spaces 7 14

Inpatient Care, Treatment, Diagnosis, and those Spaces Providing Direct Service or Clean Supplies and Clean

Processing 7 14

Airborne Infectious Isolation Rooms 7 14

Protective Environment Rooms 7 HEPA Laboratories, Class A Surgery 13 N/R

Administrative, Bulk Storage, Soiled Holding Spaces, Food Preparation Spaces, and Laundries 7 N/R

All Other Outpatient Spaces 7 N/R Skilled Nursing Facilities 7 N/R


Systems & Equipment – 6.4 Filtration U.S. Standards

Particle Size Range, µm Applications

ASHRAE 52.2 ASHRAE 52.1

MERV Particle Size Range Test

3 to 10 µm 1 to 3 µm 0.3 to 1 µm Arrestance Dust Spot

1 <20% - - <65% <20%

>10 Residential, light, pollen, dust mites

2 <20% - - 65 - 70% <20% 3 <20% - - 70 - 75% <20% 4 <20% - - >75% <20% 5 20 -35% - - 80 - 85% <20%

3.0 - 10 Industrial, dust, molds, spores

6 35 - 50% - - >90% <20% 7 50 - 70% - - >90% 20 -25% 8 >70% - - >95% 25 - 30% 9 >85% <50% - >95% 40 - 45%

1.0 - 3.0 Industrial, Legionella, dust

10 >85% 50 - 65% - >95% 50 - 55% 11 >85% 65 - 80% - >98% 60 - 65% 12 >90% >80% - >98% 70 - 75% 13 >90% >90% <75% >98% 80 - 90%

0.3 - 1.0 Hospitals, Smoke removal, bacteria

14 >90% >90% 75 - 85% >98% 90 - 95% 15 >90% >90% 85 - 95% >98% -95% 16 >95% >95% >95% >98% >95% 17 - - ≥99.97% - -

<0.3 Clean rooms,

Surgery, chem-bio, viruses

18 - - ≥99.99% - - 19 - - ≥99.999% - - 20 - - ≥99.9999% - -


Systems & Equipment – 6.5 Heating, Cooling Systems

• Cooling coil drain pans must comply with ASHRAE Standard 62.1-2007

• Sloped 1/8” per foot • Drain outlet at lowest point • Trap seal • Minimum drain pan dimensions

• Chilled water supply temperature for ceiling-mounted radiant cooling panels must be greater than the space dewpoint temperature


Systems & Equipment – 6.5 Heating, Cooling Systems

• Ceiling-mounted radiant heating panels in AII Rooms, PE Rooms, and Burn Units must have smooth, flat, cleanable surfaces;

radiant floors may also be used


Systems & Equipment – 6.6 Humidifiers

• Humidifiers are required when internal moisture sources are insufficient to maintain minimum RH levels indicated in Table 7.1

• Chemical additives must comply with FDA requirements

• No reservoir or evaporative pan humidifiers – only direct steam injection types can be used

• High RH limit set at 90% is required • Humidifier control valves must close when the

AHU is not operating


Systems & Equipment – 6.7 Air Distribution Systems

• Maintain pressure relationships as specified in Table 7.1 in all modes of operation

• Provide ducted return air paths • Design must account for filter loading • Access doors required for inspection and cleaning


Systems & Equipment – 6.7 Air Distribution Systems

• Group A: Outlets mounted in or near the ceiling that discharge air horizontally.

• Group B: Outlets mounted in or near the floor that discharge air vertically in a non-spreading jet.

• Group C: Outlets mounted in or near the floor that discharge air vertically in a spreading jet.

• Group D: Outlets mounted in or near the floor that discharge air horizontally.

• Group E: Outlets mounted in or near the ceiling that project primary air vertically.


7.0 Space Ventilation

• 7.1 General

• 7.2 Room Specific Requirements

• 7.3 Critical Care Units

• 7.4 Surgery Rooms

• 7.5 Support Spaces


Space Ventilation – 7.1 General

• Table 7.1 defines design parameters • Air movement should always be from clean to less clean • VAV systems cannot compromise pressure relationships

or minimum air change requirements • Air change rates shall be based on supply for positive

pressure rooms and shall be based on exhaust for negative pressure rooms

• Refer to ASHRAE Standard 62.1 for ventilation rates for spaces not listed in ASHRAE Standard 170

• Air changes can be reduced when a space becomes unoccupied provided that required air pressure relationship is maintained

• Higher air change rates may be required to maintain room temperatures


Room Porosity Determines delta Airflow Required to Achieve the Design delta Pressure

0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

2,000

-0.01 0.01 0.03 0.05

Offs

et A

ir Fl

ow (C

FM)

Differential Pressure (inches w.g.)

Space Ventilation – 7.1 General


• Permanently installed device required in order to constantly monitor differential pressure

• Local visual monitor required • All air to be exhausted directly outdoors • Existing rooms that are retrofitted may

recirculate air through units equipped with HEPA filters

• Dedicated exhaust system is required for AII rooms (multiple rooms can be serviced by a single system)

• Exhaust grilles should be positioned behind and above the patients’ bed

• Room envelope must be sealed • Differential pressure should be -0.01” w.g. (-2.5

Pa)

Space Ventilation – 7.2 Room Specific Requirements (AII)


Space Ventilation – 7.2 Room Specific Requirements (PE)

• Permanently installed device required in order to constantly monitor differential pressure

• Local visual monitor required • Supply air diffusers should be positioned above

the patients’ bed • Return air grilles should be positioned near the

patient room door • Existing rooms that are retrofitted may

recirculate air through units equipped with HEPA filters

• Room envelope must be sealed • Differential pressure should be -0.01” w.g. (-2.5

Pa)


Space Ventilation – 7.2 Room Specific Requirements (AII + PE)

• Two (2) permanently installed devices required in order to constantly monitor differential pressure

• Local visual monitors required • Supply air diffusers should be positioned above

the patients’ bed • Exhaust air grilles should be positioned near the

patient room door • Room envelope must be sealed • Differential pressure should be -0.01” w.g. (-2.5

Pa) • Anteroom (-) to corridor and (-) to patient room ---OR--- Anteroom (+) to corridor and (+) to patient room


Space Ventilation – 7.3 Room Specific Requirements (WICU)

• Burn unit patient rooms and NICU spaces that require booster humidifiers (40%) shall be provided with independent temperature and relative humidity control


• Sterilization Rooms • Exhaust hoods shall be provided for steam and ETO sterilizers

• Imaging Procedure Rooms • Ventilation same as Class A Surgery • Ventilation same as Class B or C Surgery if Anesthetic Gases

are Administered

Space Ventilation – 7.4 Room Specific Requirements (Surgery Rooms)


Class B and C Operating Rooms 0.01” w.g. positive pressure at all times Primary supply diffuser array at 70% of surgery area (12” overhang beyond the surgical table) Primary supply diffusers at 25 to 35 CFM/SF At least two (2) low sidewall return grilles (bottom at 8” AFF) on opposite sides of room Each OR shall be provided with independent temperature and relative humidity control

Space Ventilation – 7.4 Room Specific Requirements (Surgery Rooms)


Questions? Comments?


Question #1 Does CMMS invoke ASHRAE/ASHE Standard 170 directly? Answer #1 Immediate response by the author was “No” followed up by some research that confirmed that CMMS does not directly invoke Standard 170. Question #2 If the indoor relative humidity was driven down from 40-45% to 20%, why was it not driven down to 0%? Answer #2 Initial response was that, practically, 0% relative humidity cannot be achieved. If the committee wanted to allow relative humidity levels to float and potentially fall below 20%, the designation “N/R” would have been used. As for the committees’ decision to purposefully choose 20% as the lower limit, that decision appears to have been made after an extensive literature search found that no clinical study had looked at relative humidity levels lower than 20%.


Question #3 Are there any plans to address the redundancy of HVAC system components beyond the steam and cooling sources? Answer #3 None that the author is aware of but it’s logical to extend the redundancy beyond the sources in order to eliminate obvious “weak links in the chain”; technical and economic feasibilty studies in this area are important as well communication between all team members. Question #4 Are there any plans to drive the prevalent minimum total air change rate down below 6 ac/hr? Answer #4 None that the author is aware of but the standard does allow reductions if supplementary heating and/or cooling subsystems are used.


Thank You!


References -Paul Ninomura, P.E.; Judene Bartley, MS; Christopher Rousseau, P.E. : “Health Care Standard Update”, ASHRAE Journal March 2011

-Christopher Rousseau, P.E.; “Standard 170-2008 Update”; Arkansas ASHRAE Chapter Meeting February 2011 -Judene Bartley MS; Russ Olmsted MPH; “Behind the Change in ASHE/ASHRAE Standard 170”; Engineered System magazine, February 2011 -Richard D. Hermans, P.E.; “Breath of Fresh Air – A Look at New Health Facility Ventilation Standard”; Health Facilities Magazine, January 2009 - Ed Tinsley P.E.; “ASHRAE Standard 170”; Alabama ASHE Chapter Meeting, October 2008 -Joanna R. Turpin, “Standard Operating Procedure”; Engineered System magazine, July 2005 -Various ASHE and ASHRAE alerts including the June 8, 2010 “Demystifying the Myth” proceedings


• PositivEnergy Practice • 115 South LaSalle Street • Suite #2800

Chicago, IL 60606 • www.pepractice.com

• Laurence V. Wilson, P.E. • ASHRAE HFDP, LEED AP • Director • 312-374-9219 office • 312-405-7031 cell • [email protected]

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