Element D Services Heating Ventilating and Air Conditioning ODG010107 D304203 Vivarium Exhaust and Ventilation System Part 1. General 1. This section supplements Design Guideline Element D3042 on exhaust and ventilation with specific criteria for projects involving design of Vivariums. 2. Refer to Design Guideline Element D3042 for the following: a. General design criteria related to Exhaust and Ventilation. b. Special Contract Document Requirements and products applicable to the Project. Part 2. Design Criteria GENERAL 1. In general, Vivarium exhaust systems shall comply with animal room, procedure and support room ventilation air requirements of AALAC, NIH, CDC, and OSHA. 2. Each Vivarium exhaust air system shall have a corresponding supply air system to comply with laboratory, hood exhaust air, cage rack wash, and Vivarium (animal) room ventilation exhaust air change requirements listed below: Room Description Occupied AC/ hr Unoccupied AC / hr Necropsy 20 10 Cage Wash Area 40 20 Surgery 20 10 Animal Holding 20 20 Quarantine Room 20 20 Laundry Room 15 10 Bedding Storage 6 6 Chemical-Waste Storage 10 10 Bio-Waste Storage 10 10 Radioisotope Storage 10 10 Micro PET 20 10 Micro CT 20 10 Central Supply Store 6 6 Procedure Room 20 10 3. Air change rates noted above are minimum air change rates during occupied periods. Actual air change rates may exceed the stated rates due to sensible heat gain or make-up air requirements. Page 1 of 5
4. Vivarium exhaust fans and 30 percent roughing filters and 99.97 percent HEPA filter banks shall be an N+1 redundant system capable of maintaining constant volume with the capacity to exhaust the listed rooms at required minimum ventilation design air change rates. 5. Exhaust fans shall be direct drive and controlled to maintain the exhaust air requirements to meet air change rates and building pressurization requirements. Exhaust fans shall be controlled to compensate for loading of exhaust air filters. The minimum allowable stack height to be a minimum 15 feet above centerline height of air intake or roofline. The stack discharge air velocity shall be equal to or greater than 3500 fpm. 6. During unoccupied periods in necropsy, surgery, and procedure rooms, the air change rate may be reduced to 50 percent of the occupied air change rate. Cage wash areas may be reduced to 10 air changes per hour when unoccupied. 7. The switchover from occupied period to unoccupied period will be accomplished via interlock with the room light switch. Occupancy interlock shall be with cage wash equipment control panel for cage washrooms and procedure rooms. The room light switch will not be used to setback the air change rate in animal holding rooms. 8. Emergency power shall be available to animal holding rooms, quarantine rooms, procedure rooms to maintain a controlled environment and air change rates during loss of normal power. 9. Biological Safety Cabinets shall have a face velocity equal to or greater than 100 fpm. Constant volume bypass type hoods will be utilized. a. Class II, Type A BSC- no ducted exhaust is required. The exhaust air outlets from a Class II, Type B1, B2, B3, and Class III BSCs shall be connected to the building exhaust air system. b. Some of the Class II Type B2 BSCs will utilize bag-in/bag-out 99.97 percent HEPA filters within the BSC cabinet. 10. If substantial Organic Chemistry area is included, variable volume type hoods with restricted bypasses will be utilized for those spaces. 11. Specify welded stainless steel Type 316L ductwork (18 gage minimum) for exhaust air ductwork routed in inaccessible areas, cage washer, cage washroom and where exhaust air gases are not compatible with galvanized steel or for decontamination purposes. Remaining exhaust duct can be constructed using galvanized steel. 12. Design dedicated exhaust duct distribution systems to separate clean areas from dirty areas for prevention of cross contamination. 13. Label exhaust ducts used to transport contaminated air from Biological Safety Page 2 of 5
Cabinets and Necropsy with Caution Biological Hazard using black on red background at 20 foot intervals. 14. Exhaust ducts used to transport air from Biological Safety Cabinets where radioisotopes are used must be labeled with the standard Caution Radiation symbol: magenta on yellow background at 20 foot intervals. Equip Biological Safety Cabinets with proper filtration components to capture potential contaminates. Maximum duct velocities shall be based on the medium being transported and also based on noise criteria where noise generated from air moving at a high velocity can create a disturbance. 15. Exhaust ducts from both clean and dirty animal rooms shall have cleanouts at the bottom of vertical duct riser sections and at all changes in direction. 16. Exhaust duct elbows shall be radius type. Do not design turning vanes in duct fittings of the dedicated Vivarium exhaust distribution system from animal holding or procedure rooms. 17. Provide exhaust air thimble connections in animal holding areas for flexible hose hook up at each cage rack. 18. Filter all Vivarium exhaust using exhaust filter unit housings. Each filter unit housing shall have a bank of 30 percent efficient pre-filters followed by high capacity 99.97 percent HEPA filters. The last final filter will be comprised of a bank of charcoal absorbers. 19. Route the cage washer room exhaust duct through the building roof at a distance of 25 feet and downwind from any outside air intake. Specify the minimum allowable stack height to be a minimum 15 feet above centerline height of air intake or roofline. The stack discharge air velocity shall be equal to or greater then 3500 fpm. 20. Food Storage and Cold Rooms are refrigerated spaces where the air cooled condensing units for conditioning the rooms are typically located in an interstitial space or equipment room penthouse. AIR DEVICES 1. Refer to Sound Criteria in Design Guideline Element D3002. 2. Exhaust square panel face Omni directional diffusers with round necks shall be provided in open areas. Increase neck sizes for the diffuser since they are being used for exhaust air purposes. 3. Animal holding rooms and procedure rooms can be exhausted with the use of thimble connections and ventilated and conventional cage racks. Electric actuated air valves shall be used to control the exhaust airflow rates via feed back signals from air measuring stations and setpoints (adjustable) from the building automation system (BAS). Page 3 of 5
4. The animal surgery room shall have two sidewall exhaust grilles with the bottom of the grilles are located at opposite corners of the room, and 6 inches above the finished floor. Locate grilles in opposite corners of the surgery room. 5. Necropsy room shall have side wall exhaust grilles with the bottom of the grille located 6 inches above the floor. Size the exhaust grille and exhaust hood to properly exhaust the Necropsy room to maintain required air change rate and to keep the room negative with respect to adjacent spaces. Provide an exhaust duct connection for the downdraft necropsy table. Part 3. Special Contract Document Requirements 1. Include a single line riser diagram drawing of the general building and dedicated ventilation exhausts and building pressure relief systems in the Contract Documents. 2. The riser diagram drawing shall show isolation dampers, modulating control dampers, exhaust fans with percent system capacity ratings, and exhaust air flow rates. This single line riser diagram shall be initially provided in the Schematic Design Submittal. 3. Locate exhaust discharge where air cannot be easily reintroduced into the building outside air intakes. Part 4. Products 1. Refer to Master Construction Specification Sections. 2. Refer to Design Guideline Element D3041 for additional criteria on outside air intakes. 3. Evaluate the use of runaround coils and energy recovery components as appropriate to the application. 4. Evaluate the use of a separate AHU using 99.97 percent HEPA final filter bank designed for and dedicated to the surgery room. Using a surgical room recirculation rates as indicated in the Table shown in Part 2 of this section, and a minimum outdoor air change rate of 4 air changes per hour. The return air grilles would be used in place of the exhaust air grilles. 5. Class II, Type 1A Biological Safety Cabinets will be UL listed and equipped with 99.97 percent high capacity HEPA filters. This particular class of cabinet does not have to be hard ducted; a general exhaust air grille can be located near the Type 1A cabinets to exhaust odors. 6. Preferred direct drive exhaust fans shall be similar to Strobic axial fans. Exhaust air plenum with modulating face and bypass control dampers. Page 4 of 5
7. Specify Phoenix (Accel II) or TriaTek Venturi Air Valves and BACnet compatible systems are to be used to control the exhaust airflow rates from the individual room or spaces. System must also be able to integrate with Edstrom Watchdog Monitoring System. 8. The cage wash system exhaust fans shall be constructed as backward inclined blade types. Shafts shall be polished carbon steel and shall also have a phenolic coating applied to all fan parts that are directly in contact with the exhaust airstream. 7. Specify welded stainless steel Type 316L ductwork (18 gage minimum) for exhaust air ductwork from the Biological Safety Cabinets, necropsy room, cage washer, and cage washroom. Remaining exhaust duct can be constructed using galvanized steel. 8. Ductwork and air devices shall be constructed or fabricated from non ferrous materials when used or near imaging rooms or suites. Follow the manufacturer s recommendations for material, sizing, and routing duct used for cryogenic exhaust of magnetic resonance imaging equipment. Document Revision History Issue Date Revision Description Revisor 01-01-07 Initial Adoption of Element Rev. 1 Rev. 2 Rev. 3 Rev. 4 Rev. 5 Page 5 of 5