Given: An appliance may be installed in residence of ordinary tightness. The combustion air will be obtained by infiltration air. How many cubic feet of air are required per 1000 Btuh of the appliance?

Given: An appliance may be installed in residence of ordinary tightness. The combustion air will be obtained by infiltration air. How many cubic feet of air are required per 1000 Btuh of the appliance?