### How do you calculate GPM? - FIA, Inc

GPM =8.33lb./gal x 1 BTU/lb F x 60 min/hr x ''T F BTU/hr Where 8.33 x 60 x 1 = 500 The formula we use to de-termine system flow rate as-sumes a mass flow rate of 500lbs. per hour for each gpm, which means at a 20 ''T, 1 gpm will convey 10,000 BTUH (500