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Break Out Session 3: Group A: Ventilation and Air Quality Chris Cosgrove, Cosgrove FDS, Inc.

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Presentation on theme: "Break Out Session 3: Group A: Ventilation and Air Quality Chris Cosgrove, Cosgrove FDS, Inc."— Presentation transcript:

1 Break Out Session 3: Group A: Ventilation and Air Quality Chris Cosgrove, Cosgrove FDS, Inc.

2 CCAC National Workshop Ottawa, ON – May 14, Purpose CCAC Subcommittee on air quality HVAC Basics Current guidelines (CCAC, Other) Issues related to air quality Current technology and impacts What issues are you facing today? What guidance is required?

3 CCAC National Workshop Ottawa, ON – May 14, Temperature, humidity specific for species housed Reliability/Redundancy Maintenance Operations Energy conservation Failure modes to prevent loss of life Filtration levels Pressure gradients Balancing Use of Airlocks Know Your HVAC System…

4 CCAC National Workshop Ottawa, ON – May 14, Silencer Electronic motor Fan Terminal unit Humidifier Room sensor Temperature sensor Humidity sensor Pressure sensor Filter Cooling Coil Heating Coil Heat Recovery Coil (Cooling) Heat Recovery Heating Damper Variable Frequency Drive Constant Volume Drive Silencer Heat Recovery coil Supply Fan Return Fan Filtration Level Humidifier Heating Coil Cooling Coil Exhaust Outside Air Supply HVAC Main System

5 CCAC National Workshop Ottawa, ON – May 14, Temperature sensor Humidity sensor Air Flow sensor Heating Coil Terminal unit Humidifier Ventilated Cage Racks Supply air To Exhaust Room HVAC Control

6 CCAC National Workshop Ottawa, ON – May 14, Redundancy

7 CCAC National Workshop Ottawa, ON – May 14, HVAC Outdoor Design Criteria ASHRAE 1% Conditions(1% of the hours in the year, outside air conditions will exceed design criteria) Summer 90°F (32.2°C) at 50% RH – Worst case scenario : 50% more energy in outside air Winter –16°F (-27°C) – Systems are designed with –20°F (-29°C) Understand your conditions and what is acceptable for research

8 CCAC National Workshop Ottawa, ON – May 14, Ventilation Rate Calculation H = 9 feet W =16 feet L = 40 feet T = 20 AC/h Volume V = 9 x 16 x 40 V= cuft

9 CCAC National Workshop Ottawa, ON – May 14, Heat Gain Calculations Thermal Gains Type – Sensible (heat) – Latent (humidity) Breathing out Perspiration Water Evaporation Sensible heat load is what is used to calculate the heat load (Btu) of the space

10 CCAC National Workshop Ottawa, ON – May 14, Heat Load / BTU Output ASHRAE publishes Btu outputs Available for most species Based on weight & metabolic rate

11 CCAC National Workshop Ottawa, ON – May 14, Heat Loads & Higher Density Std. MIHD MouseHD Rat Room Size / s.f.400 Total Cages Animals / Cage331.5 Animals / Room Animal Btu / Hr per room Avg Blower Watts-40 Avg Btu / Hr-136 Cages / Blower Blower Btu / Cage Blower Btu/ Hr per room Blower % Rm Btu-10.1%7.7%

12 CCAC National Workshop Ottawa, ON – May 14, Filtration

13 CCAC National Workshop Ottawa, ON – May 14, Pressurization Scheme is mandatory for a good vivarium design. Level of flexibility can have an impact on the cost and design Primary containment can impact decisions Dependent on use and type of primary containment Pressurization

14 CCAC National Workshop Ottawa, ON – May 14, Air Balance

15 CCAC National Workshop Ottawa, ON – May 14, If the room is positive pressure – measure supply CFM If the room is negative pressure – measure exhaust CFM Pressurization

16 CCAC National Workshop Ottawa, ON – May 14, CCAC Guidelines In order to maintain potential air contaminants below acceptable levels, it is recommended that there be 15 to 20 air exchanges per hour in a room. This recommendation, however, does not take into consideration the efficiency of air distribution, the number of animals held or how they are being held.

17 CCAC National Workshop Ottawa, ON – May 14, CCAC Guidelines While this recommendation may be effective for large numbers of animals housed in conventional caging with less than ideal air distribution (most systems), the requirement may be considerably higher for animals housed in static filter top cage units or less in rooms where animals are housed in ventilated cage units.

18 CCAC National Workshop Ottawa, ON – May 14, CCAC Guidelines The problems posed by the static isolator systems are now being addressed by steady replacement with isolator systems in which each cage is individually ventilated. Therefore, it is no longer useful to specify environmental parameters, frequency of air changes, etc., without specifying the type of equipment to be used for primary containment. This may vary considerably between and among species. The impact of the overall HVAC system must be evaluated at the cage level.

19 CCAC National Workshop Ottawa, ON – May 14, The guideline of fresh-air changes per hour has been used for secondary enclosures (the room) for many years and is considered an acceptable general standard. Although it is effective in many animal-housing settings, the guideline does not take into account the range of possible heat loads; the species, size, and number of animals involved; the type of bedding or frequency of cage-changing; the room dimensions; or the efficiency of air distribution from the secondary to the primary enclosure (the cage). In some situations, the use of such a broad guideline might pose a problem by over ventilating a secondary enclosure that contains few animals and thereby wasting energy or by under ventilating a secondary enclosure that contains many animals and thereby allowing heat and odor accumulation. ILAR Guidelines

20 CCAC National Workshop Ottawa, ON – May 14, ….Even though that calculation [total-cooling-load calculation method] can be used to determine minimal ventilation needed to prevent heat buildup, other factors such as odor control, allergen control, particle generation, and control of metabolically generated gases might necessitate ventilation beyond the calculated minimum. When the calculated minimal required ventilation is substantially less than 10 air changes per hour, lower ventilation rates might be appropriate in the secondary enclosure, provided that they do not result in harmful or unacceptable concentrations of toxic gases, odors, or particles in the primary enclosure. ILAR Guidelines

21 CCAC National Workshop Ottawa, ON – May 14, Air Quality Considerations Temperature (Heat Load) Relative Humidity Gases – NH3 – CO2 Allergens – MUP Particulate Chemicals – Pheromones – Other Chemicals

22 CCAC National Workshop Ottawa, ON – May 14, Air Quality Considerations Air Quality for People Air Quality for Animals What should we monitor and why? – Micro-environment – Macro-environment

23 CCAC National Workshop Ottawa, ON – May 14, Trends & Issues Animal Welfare Research Impacts Operating Costs Energy Conservation Environmental Health & Safety Flexibility Adaptability of Existing Facilities

24 CCAC National Workshop Ottawa, ON – May 14, Technology Ventilated Caging Other Primary Containment Systems Room Air Distribution (CFD Analysis) Personnel Protective Equipment Demand Based Ventilation

25 CCAC National Workshop Ottawa, ON – May 14, Demand Based Control Study of vivarium room contaminants shows: – Most vivarium areas are “clean” about 98+% of time – Most vivarium areas have multiple “events” per week These events with elevated levels demand higher airflows Events can result from VOC’s/ammonia or particles

26 CCAC National Workshop Ottawa, ON – May 14, Demand Based Control Reduce 10 ACH minimum down to 8 ACH: – Projected savings from extrapolating current data: Savings should increase to 51.3% Potentially reduce min further to 6 ACH: – Savings likely depends on animal loading Reduce ACH min in support & procedure areas – Apply DBC to bring min ACH to 4 ACH Implement VAV exhaust fan control strategy – Sense exhaust air plenum for air cleanliness – Reduce exhaust fan exit velocity when air is “clean” – Potentially of cutting exhaust fan power in half

27 CCAC National Workshop Ottawa, ON – May 14, What Are Your Issues? Air Quality Personnel protection Research impacts Facility Operations Mechanical Design Institutional Standards


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