Air supply.
Municipal Code of Chicago § 18-28-927.5
in effect18-28-927.5 Air supply.
Ventilation air to the recirculating direct gas-fired industrial air heater shall be ducted directly from outdoors. Air to the recirculating direct gas-fired industrial air heater in excess of the minimum ventilation air specified on the heater's rating plate shall be taken from the building, ducted directly from outdoors, or a combination of both. Where outside air dampers or closing louvers are used, they shall be verified to be in the open position prior to main burner operation.
Source: City of Chicago, Municipal Code of Chicago (American Legal Publishing, codelibrary.amlegal.com)URL: https://codelibrary.amlegal.com/codes/chicago/latest/chicago_il/0-0-0-2688526Fetched: 10/24/2026
