1.1 Scope 1.
1.1 This standard applies to newly produced, direct gas-fired door heaters, hereinafter referred to as heaters, constructed entirely of new, unused parts and materials, whose purpose is to temper air at a door when the door is opened directly to the out-of-doors. Air to the heater may be taken from the building, ducted directly from outdoors or a combination of both, and the products of combustion generated by the heater are released into the air st
