Posted by: nedpelger | February 10, 2010

Useful Facts when Converting Construction Units

I’m finalizing the first four construction phone apps and want to add some helpful facts to the Converting Units for Construction program. While it’s helpful to have all the units available to convert weights, volumes and densities, it’s even more helpful to have a few sample densities listed that keeps the process in perspective. For example, finding that steel weighs 480 pounds per cubic foot (pcf) while aluminum weighs 165 pcf and wood about 35 pcf may help you solve some real problems on the jobsite. I have a list of densities below (do you think more would be helpful? Anything specific you’d suggest?):

Density of Common Units in pounds per cubic foot (pcf):

Aluminum: 165 pcf

Brick: 120 pcf

Concrete: 145 pcf

Copper: 560pcf

Corn: 45 pcf

Crushed Stone: 100 pcf

Fresh Snow: 8 pcf

Glass: 162 pcf

Lead: 710 pcf

Paper 58 pcf

Steel: 480 pcf

Water: 62 pcf

Wood: 25-45 pcf

I’m also considering other useful facts to add into the phone app. For example, the various values of energy and power listed below are occasionally useful. Do you have any other ones you would add?

Energy (work done, think kw-hrs or BTUs)

Gasoline (mid grade) 1 gallon = 125,000 BTUs

#1 Kerosene 1 gallon = 135,000 BTUs

#2 Fuel Oil 1 gallon = 138,000 BTUs

#6 Fuel Oil 1 gallon = 150,000 BTUs

Ethanol 1 gallon = 76,000 BTUs

Propane 1 gallon = 91,600 BTUs

Propane 1 cubic foot = 2,500 BTUs

Natural gas 1 cubic foot = 1,030 BTUs

Wood (air dried) 1 cord = 20,000,000 BTUs (chord = 4’ x 8’ x 4’)

Wood (air dried) 1 pound = 8,000 BTUs

1,000,000 BTUs of Energy =

10 therms or 1,000 cubic feet of Natural Gas

46 pounds or 11 gallons of Propane Gas

8 gallons of Gasoline

7 gallons of No. 2 Fuel Oil (diesel fuel)

293 KW of electricity

125 pounds of air dried wood

71 pounds of coal

Power (capacity, think KW or HP or BTUs/hr)

1 Kilowatt = 3,413 Btu/hour

1 ton of air conditioning = 12,000 Btu/hour

1 person in a room adds about 250 Btu/hour or the equivalent of a 75 watt light bulb

1 HP (motor) = 746 watts (operating energy)

A Formula One racecar is 1000 HP and would use 20 gal/hour of gasoline (if it used gasoline)

A Ford Pinto is 88 HP and uses 2 gal/hour of gasoline

If you can think of any other useful facts that belong in a phone app for converting construction units, please post a comment and let me know.


  1. Some metric conversions please.

  2. Great idea JCAHILL, I’ll include the metric equivalents. By the way, all the conversion tables have full English and metric units.

    I like the idea that these useful facts will also now have both. I appreciate the feedback!

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