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Natural Gas Flow Meter BTU to SCFH


How To Calculate CFM or CFH from BTU per Hr for a Thermal Mass Flow Meter

The most common unit for measuring natural gas is the therm.

A therm is 100,000 British Thermal Units (BTUs), a quantity of energy, and it is also equal to 29.3 kilowatt-hours or 105.5 mega-joules.

A therm's worth of natural gas contains 96.7 cubic feet/therm, or about100 cubic feet/therm.

Since the energy in natural gas is equivalent to the gas's volume, you can freely convert between BTUs per hour and cubic feet per minute (CFM).

To calculate the CFM (ft3/min) or CFH (ft3/hr) for 500,000 BTUs per hour of Methane we have:

500,000 BTU/hr ÷ 100,000 BTU/therm = 5 therms/hr.

5 therms/hr × 96.7ft3/therm  = 483.5 ft³/hr.

483.5 ft3/hr ÷ 60min/hr = 8.06 ft3/min

Watch this quick video to see EXACTLY how to calculate the SCFM or SCFH flow rate for a 500,000 BTU/Hr boiler.

Below is a typical Mass Flow Meter for this small boiler...

Selecting the Flow Meter:

500,000 BTU/Hr Mass Flow Meter Natural Gas is 8.3 SCFM