Energy Efficient VivariumsPeter Rumsey, P.E., Rumsey Engineers, IncGlen Berry, NCARB, Design for Science

Why Vivariums?

Rapid Growth in Vivarium Construction and Use

High Energy Intensity – Typically 1.5 to 2.5 more energy intensive than traditional labs

High Steam UsageHigh Air Change Rates

Criterion #1: Guide for the Care and Use of Laboratory Animals

Excellent reference manual for planning and design of vivarium facilities.

The Guide was written in 1996.

Page 32: “The guideline of 10-15 air changes per hourhas been used for secondary enclosures for many years and is considered an acceptable general standard.”

The Guide does not mention ventilated cage racks, as they did not exist as a tried/tested/proven product for animal holding in 1996.

Criterion #2: NIH Design Guidelines

Another excellent reference manual for the planning and design of vivarium facilities.

Published in 2003

Does acknowledge ventilated cage racks as an acceptable form of housing rodents.

Page F.70: “The air-handling system design should comply with the requirements described in the Guide for the Care and Use of Laboratory Animals.”

Page F.71: “If microenvironments are employed for animal holding, the minimum ventilation requirement may be reduced to 10 air changes per hour plus the sum of the microenvironment airflow.”

Concept #1: Understand the difference between primary and secondary barriers.

science laboratories: The chemical fume hood is the primary barrier, and is the primary method of capture and containment of volatile chemical fumes.

BSL3/4 labs: The biological safety cabinet is the primary barrier, and is the primary method of capture and containment of airborne pathogens.

vivaria: the ventilated cage rack is the primary barrier of rodents, and is the primary method of controlling air change rate, temperature, and humidity of the housing environment.

In all of the above, the room is the secondary barrier, and should always be thought of as such. The room cannot and should not provide the same level of capture/containment as the primary barrier.

Building Basics

Location – 30 miles south of San Francisco on coast

Size – 115,000 sf – 15,000 s.f. vivarium on ground floor (~50 double sided 144 count cage racks)

Purpose - Biomedical Research

Cost – approximately $610/sf

Minimum LEED Silver and 30% energy savings

Lab Space – Daylight Simulation

Vivarium Floor Layout

Holding Rooms

Cage Wash Area

Mechanical LoadingDock

Vivarium~15K sfBasement Floor

Open Cage Racks

Ventilated Cage Racks

Concept #2: The secondary barrier (the room) envelope does not need to provide the same level of capture and containment as the primary barrier.

Then (Lab planning and design): 10-12 air changes per hour

Now: 6 air changes or 1 cfm/sf with even lower rate for unoccupied mode.

Then (vivarium planning and design): 10-15 air changes per hour

Now: still 10-15. Has not addressed the role of the ventilated cage rack as the primary barrier.

Perhaps we can allow the equipment to solve the energy consumption problem, by reducing the effective envelope for which the air change rate is required. Similar to the function of a chemical fume hood or biological safety cabinet……

HVAC Systems

Dedicated AHU – 40,000 CFMTwo fans one for redundancy

Chilled Water SystemOne 300 ton – peak use full buildingOne 100 ton – peak use vivarium only

Generator - 600 kWBack-up for all Vivarium uses except steam AHU, Lights, Chiller, Pumps,

Open Cage versus Ventilated Cage

Air Change Rates

Typical Open Cage Rack Holding Rooms15 to 20 Air Changes per hour (approx. 3-4 cfm/sf)

Ventilated Cage Rack Holding Rooms10 air changes per hour (approx. 2 cfm/sf)

Vivarium Options Considered In Schematic Design

Option 1 - All Open Cage Racks in Holding RoomsAHU: 49,000 cfmAHU and Chiller Costs: $613k

Option 2 – 50% Open Cage Racks/50% Ventilated Cage Racks

AHU: 40,000 cfmAHU and Chiller Costs: $482k

Option 3 – 100% Ventilated Cage RacksAHU: 36,000 cfmAHU and Chiller Costs: $442k

Vivarium Options Costs

OptionVivarium HVAC

Costs

All Open Cage Racks $819,000

50% Open / 50% Ventilated $723,000

All Ventilated Cage Racks $663,000

Selected Option

CFD Analysis

Purpose Determine Optimal Placement of Supply and Return Diffusers in Open Cage Rack Rooms

CASE A

Supply

Return

CFD Results – 1000 cfm, 55 deg F

CASE B

Supply

Return

CFD Results – 1000 cfm, 55 Deg F

CASE C

Supply

Return

CFD Results – 1000 cfm, 55 Deg F

CFD Results – 850 cfm, 55 Deg F

STEAM SYSTEM ANALYSIS

Getinge CageTunnel Washer

Cage and Rack Washer

Steam Load Summary

EquipmentRegular Steam

Clean Steam Comments

Peak Ave Peak AveTunnel Washer 2400 - - - 1000 lbs/hr dryerCage & Rack Washer 600 - - -

Medium Sterilizer(26 x 37.5 x 60") - - 335 185

Can find alt. equip 10% lower steam, such as Getinge 700LS

LSR Sterilizer - - 800 450

Autoclave - 1st floor - - 60 5610% additional savings possible

Autoclave - 2nd floor - - 60 5610% additional savings possible

Medium Autoclave - 3rd floor - - 335 185

Can find alt. equip 10% lower steam, such as Getinge 700LS

Autoclave - 4th floor - - 60 5610% additional savings possible

Autoclave - - 60 5610% additional savings possible

Autoclave - - 60 5610% additional savings possible

Glasswasher (future) - - 300 -

TOTAL 3000 - 2,070 1090

60% OF STEAM DEMAND IS IN THE WASHERS

Tunnel Washer

Manufacturer High Pressure Steam Use (lbs/hr)

SteamRequirements if supplemented with 140 deg F Hot Water

Can use low pressure steam

Getinge 1200 600 - 950 No

IWT Technoplast 661 Not recommended No

LYNX 1400 Not recommended Yes

Steris 1300 Not recommended Yes

Cage and Rack Washer

Manufacturer High Pressure Steam Use (lbs/hr)

HP SteamRequirements if supplemented with 140 deg F Hot Water

Can use low pressure steam

Getinge 800 400 Yes

IWT Technoplast 600 Not recommended No

LYNX 1200 600 Yes

Steris 1400 Not recommended No

Other Strategies for Lower Energy Use in Vivariums

Improved venting strategies for ventilated cage rack systemsImproved fans on ventilated cage racksUnoccupied or lower occupancy turn downAutoclaves improvementsLow energy lightingDemand Controlled ventilation

Others??

Conclusion (food for thought)

Let the primary barrier (fume hood, BSC, ventilated cage rack) define the envelope for air change rate and environmental controls. Reduce the secondarybarrier (the room) air change rate to lower levels that save energy and still provide a safe working environment.

Animal Holding Rooms:Use Ventilated Cage Racks Room - 6+ air changes per hour occupiedRoom - 4+ air changes per hour unoccupied

Thank Youwww.RumseyEngineers.comwww.designforscience.com