Recommended State & Local Amendments to the
2012 Edition of the International Residential Code (IRC)
Issue: Range Hood Makeup Air
2012 IRC Section Number: M1503.4 Makeup Air Required
Recommended Amendment:
Modify the section as shown below:
M1503.4 Makeup air required. Exhaust hood systems capable of exhausting in excess
of 400 cubic feet per minute (0.19 m3/s) shall be provided with makeup air at a rate
approximately equal to the difference between the exhaust air rate and 400 cubic feet
per minute. Such makeup air systems shall be equipped with a means of closure and
shall be automatically controlled to start and operate simultaneously with the exhaust
system.
Exception: Where all appliances in the house are of sealed combustion, powervent, unvented, or electric, the exhaust hood system shall be permitted to exhaust
up to 600 cubic feet per minute (0.28 m3/s) without providing makeup air. Exhaust
hood systems capable of exhausting in excess of 600 cubic feet per minute (0.28
m3/s) shall be provided with a makeup air at a rate approximately equal to the
difference between the exhaust air rate and 600 cubic feet per minute.