Exhausts

IMC 502.1

Is mechanical exhaust required by the Wisconsin Commercial Building Code for the space accommodating aircraft in a hangar?

No, but it depends. The hangar space accommodating aircraft is addressed under section IMC 502.1. Aircraft hangars come in various shapes and sizes, but more importantly, a wide variety of activities can take place within the space accommodating the aircraft. It is the type of activities that will occur within the space and whether those activities will generate dust, particles, gases or contaminants in sufficient quantities to pose a safety or health risk that will determine if mechanical exhaust is required under IMC 502.1. DSPS does not anticipate that a space merely accommodating the storage of aircraft will generate contaminants at a level to pose a risk. When a situation arises where the activities would create contaminants sufficient to warrant mechanical exhaust, the type of exhaust system and amount of exhaust needed will be dependent upon the activities involved. See Q&A on Table 64.0403. 

IMC 502.14

Is it necessary to provide a mechanical source capture system in accordance with section IMC 502.14 if the vehicle tailpipe exhausts are extended to the exterior of a building by non-mechanical means?

No, the practice of temporarily attaching extensions and conveying exhaust contaminants out from the occupied space and to the exterior is an acceptable solution. IMC sections 401.6 and 502.1 provide flexibility in dealing with contaminants from stationary sources such as operating engines of motor vehicles. The language under these provisions recognizes the ability to collect, and/or treat, or convey to the exterior contaminants generated from stationary sources rather than employing a mechanical source capture system under IMC 502.14. Hoses or tubes used to extend vehicle tailpipes are to be of suitable material to be in contact with hot tailpipes and vehicle emissions, and their layout, including the size and length, needs to be effective in conveying the contaminants to the exterior.

SPS Table 364.0403

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.