Ventilation

IBC 1020.6

An existing school (Pre-ICC) proposes to change the HVAC system from unit ventilators to a central ventilation system. The existing school has transfer grills in the door and utilizes the existing corridors for air movement. Given the alterations to the HVAC system may the existing corridors continue to be utilized for air movement?

Yes, as long as the corridors are existing, they may continue to be utilized for air movement. Only those corridors constructed under the IBC will be subject to the Section 1020.6 prohibition on use of corridors for air movement.

SPS Table 364.0403 – 5/24/2011

I have a space with a use that is not an exact match to one of the uses listed in SPS Table 364.0403. The most similar occupancy listed in SPS Table 364.0403 says “NR” in the exhaust column of SPS Table 364.0403, does this mean that no exhaust is required?

No. Although picking the most similar occupancy is appropriate for the “general people ventilation” of occupancies that relates to fresh outside air, the same is not true for exhaust. If there is not an occupancy match in Table 364.0403, refer to IMC chapter 5 to determine if exhaust is required and how much exhaust is needed to create the expected air quality.  Before Wisconsin adopted the IMC, almost all ventilation and exhaust requirements were contained in a table in SPS 364. The IMC breaks ventilation and exhaust requirements into two chapters. When it comes to exhaust, Table 364.0403 is not the driver to require mechanical exhaust ventilation except where there is an exact match.

SPS Table 364.0403, SPS 364.0404, IMC 404, and IMC 502.13

What are the minimum ventilation requirements for an “Enclosed Parking Garage?"

IMC 502.13 allows the use of IMC Ch. 4 which provides two options. Additionally, IMC 404 as modified by SPS 364.0404, provides two additional options involving intermittent exhaust system operations. Any one option may be applied assuming all requirements are met. Each option is addressed below.

1. IMC/SPS Table 364.0403 references “Enclosed Parking Garages.” A minimum exhaust rate of 0.5 cfm/sf of floor area is required to be addressed from the space. The exhaust fan(s) would be required to operate continuously per IMC 502.13. Note that appropriate make up air would also be required per IMC 403.1. 

2.  IMC/SPS 364.0403 footnote “I” states that a mechanical ventilation system is not required in garages having a floor area of 850 sf or less AND used for storage of 5 or fewer motorized vehicles.

3. IMC 502.13 recognizes the use of IMC 404 as amended by SPS 364.0404(1). Applying SPS 364.0404(1), a minimum exhaust rate of 0.05 cfm/sf of floor area would be required at all times and the system would then be required to automatically exhaust a minimum of 0.75 cfm /sf of floor area upon detection of vehicle operation or the presence of occupants by approved automatic detection devices. An occupancy sensor has been recognized by the Department as an acceptable automatic sensing system. Other sensing options may be applied as approved by the Department based on justification provided with the plan submittal. Note that appropriate make up air would also be required per IMC 403.1. 

4. IMC 502.13 also recognizes the use of IMC 404 as amended by SPS 364.0404(2). Applying IMC 404 & SPS 364.0404(2), a minimum exhaust rate of 0.75 cfm/sf of floor area would be required to be addressed a minimum of 5 hours per day. Additionally, CO & NO2 detectors would be required to be installed. Note that NO2 sensors are required to be installed if ANY diesel fueled motorized vehicles are anticipated to be stored at ANY future time. Both detectors would be required to have thresholds set at nor more than 35 parts and 1 part per million, respectively. Installation is required such that if the detector set points are exceeded, the exhaust fan(s) will operate for a period of time over and above the minimum 5 hours until such time that the set points were no longer exceeded. Note that appropriate make-up air would also be required per IMC 403.1.

SPS 364.001(2) and (3), SPS 364.0202(f), and SPS 364.0403 – 4/2018

What ventilation requirements are to be met for boat or off-highway vehicle storage and indoor drive through self-service storage facilities?

SPS 364.0202(f) defines a boat that is dry stored and not operated in the building in which it is stored as not being a “motorized vehicle.” A “Motorized vehicle” is intended to apply to motorized equipment transporting people and goods for pleasure, construction or commerce, rather than equipment dedicated to warehousing and yard operations, such as forklifts; or for grounds and facility maintenance, such as lawnmowers; or for amusement facilities, such as go-carts. Other off-highway vehicles such as excavation and construction equipment, snowmobile and ATV/UTV storage, lawnmowers and other equipment stored by a lawnmowing or landscaping company, etc. should be provided with mechanical exhaust ventilation as required for enclosed parking garages. Per SPS Table 364.0403 Note “o,” ventilation is not required for indoor drive through self−service storage facilities in which a customer may temporarily park a motorized vehicle for purposes of loading and unloading materials, provided the motor is not running.