Security Seal Facebook Twitter GooglePlus Pinterest Newsletter Sign-up

Conversion Factors

MultiplyByTo Obtain
Atmosphere29.92Inches of mercury
Atmosphere33.92Feet of water
Atmosphere14.7Pounds per sqare inch
Atmosphere1.058Tons per square foot
Barrels (oil)42Gallons
Boiler Horsepower33,474Btu per hour
Boiler Horsepower34.5Pounds water evaporated from and at 212F
BTU0.0010307Pounds water evaporated from and at 212F
BTU per 24 hr0.00000347Tons of referigeration
BTU per hour0.00002986Boiler horsepower
BTU per hour0.000393Horsepower
BTU per hour0.000293Kilowatts
BTU per inch per sq. ft. per hour per F0.0833Btu per foot per sq. ft. per hour per F
Cubic feet1,728Cubic Inches
Cubic feet7.48052Gallons
Cubic feet of water62.37Pounds at (at 60F)
Cubic feet per minute0.1247Gallons per second
Feet of water0.881Inches of mercury (at 32F)
Feet of water62.37Pounds per square foot
Feet of water0.4335Pounds per square inch
Feet of water0.0295Atmospheres
Feet per minute0.01136Miles per hour
Feet per minute0.01667Feet per second
Gallons (U.S.)0.1337Cubic feet
Gallons (U.S.)231Cubic inches
Gallons of water8.3453Pounds of water (at 60F)
Horsepower550Foot pounds per sec
Horsepower33,000Foot-pounds per min
Horsepower2,546BTU per hour
Horsepower42.42BTU per minute
Horsepower (boiler)33,475BTU per hour
Inches of mercury (at 62F)13.57In. of water (at 62F)
Inches of mercury (at 62F)1.131Ft. of water (at 62F)
Inches of mercury (at 62F)0.4912Pounds per sq in.
Inches of mercury (at 62F)70.73Pounds per sq ft.
Inches of water (at 62F)0.07355Inches of mercury
Inches of water (at 62F)0.03613Pounds per sq in.
Inches of water (at 62F)5.202Pounds per sq ft.
Inches of water (at 62F)0.002458Atmospheres
Kilowatts56.92BTU per minute
Latent heat of ice143.33BTU per pound
Pounds of water at 60F0.01602Cubic Feet
Pounds of water at 60F27.68Cubic Inches
Pounds of water at 60F0.1198Gallons
Pounds of water evaporated from and at 212F0.284Kilowatt-hours
Pounds of water evaporated from and at 212F0.381Horsepower-hours
Pounds of water evaporated from and at 212F970.4BTU
Pounds per square inch2.309Ft. of water (at 62F)
Pounds per square inch2.0416In. of mercury (at 62F)
Tons of refrigeration12,000BTU per hour
Tons of refrigeration200BTU per minute
Tons (Long)2,240Pounds
Tons (Short)2,000Pounds
Watts44.26Ft. pounds per min
Watts0.7378Ft. pounds per sec
Watts0.05692BTU per minute
Watt-hours2,656Ft. pounds


EDR to Pounds of condensate per hour (Divide EDR by 4) • EDR to GPM (Multiply EDR by 0.0005)
EDR to BTUH at 1 psig steam pressure (Mulitply EDR by 240) • EDR to boiler horsepower (Divide EDR by 140)
EDR to Grate Area in Square Feet (Divide EDR by 196) • BTUH to EDR (Divide BTUH by 240)
BTUH to Boiler Horsepower (Divide BTUH by 33,475) • PSIG to Feet of Water (Multiply PSIG by 2.31)
Boiler Horsepower to Pounds of Condensate per hour (Multiply BHP by 34.5) • Boiler steaming rate (regardless of type or manufacturer) = 1/2 GPM per 1,000 sq. ft. EDR
Fuel Values:Maximum copper tubbing flow rates and BTUH loads (at 20° Δ T)
No. 1 fuel oil = 135,000 BTU per gallon1/2" = 1-1/2 GPM = 15,000 BTUH
No. 2 fuel oil = 140,000 BTU per gallon3/4" = 4 GPM = 40,000 BTUH
No. 4 fuel oil = 155,000 BTU per gallon1" = 8 GPM = 80,000 BTUH
No. 5 fuel oil = 150,000 BTU per gallon1-1/4" 14 GPM = 140,000 BTUH
No. 6 fuel oil = 153,000 BTU per gallon1-1/2" = 22 GPM = 220,000 BTUH
Natural gas = 1,000 BTU per cubic foot2" = 45 GPM = 450,000 BTUH
Natural gas = 100,000 BTU per Therm
Manufactured gas = 550 BTU per cubic foot
Propane = 2,250 BTU per cubic footFahrenheit to Celsius = (°F - 32°) / 1.8
Celsius to Fahrenheit = °C x 1.8 + 32°
Propane = 92,000 BTU per gallon
Electricity = 3,415 BTU per kWh
Anthracite coal = 13,700 BTU per poundStream Fan Coil loads in Pounds of Steam per hour =
Bituminous coal = 12,500 BTU per pound CFM X ΔT of air (in °F) / 800
Wood = 14,000,000 BTU per mixed cord
Average water temp °FOutput in BTUH per sq ft. EDR
*(also for 1 psi steam)
Pump Head Rule of Thumb:
Measure longest run in feet. Allow 6 feet of pump head per 100 feet
(this includes an allowance for the fittings and the boiler)