... F 3600 Flame Speed(In Oxygen), Ft. /Sec 10.9 Flame Speed(In Air), Ft. /Sec 1.7 Primary Flame ... Heat Value, BTU/cu. Ft: 255 Secondary Flame Heat Value, BTU/cu. Ft: 2243 Total Heat Value, BTU/ ... cu. Ft: 2498 Total Heat Value of gas, ... BTU/cu. Ft: 21800 Volume to weight ratio, ...