The natural gas that is piped to a residence or business is usually measured in units of volume called CCF. A CCF is 100 cubic feet of gas. The volume of a given quantity of gas depends on its temperature and pressure. It is essential to know these parameters when referring to a quantity of natural gas. The term "SCF" means standard cubic feet. The unit refers to a specific temperature and pressure at which the volume is measured.
Call the gas company and ask a technician what the pressure in the supply line should be in pounds per square inch (psi). Add 14.7 to this value to obtain what is called the absolute pressure in psi.
Multiply the CCF value by 100, then multiply by the absolute pressure of the gas. Divide the answer by 14.7. For example, if the pipe pressure is 2 psi, add 14.7 to get an absolute pressure of 16.7 psi. For 2 CCF, multiply 2 by 100 to get 200 cubic feet. Then multiply 200 by 16.7 and divide by 14.7. This calculation gives 227.22 cubic feet at the standard pressure of 14.7 psi.
Look carefully at your gas meter to see if it says "Temp. corrected" on the front panel. If the meter is corrected for temperature, you do not need to make any further adjustments. If the gas meter does not correct for temperature, estimate the temperature of the gas entering the meter. Take a thermometer and measure the air temperature close to the pipe in degrees F. Convert this value to absolute temperature by adding 460 to the temperature in degrees F. For example, if the air temperature is 75 F, add 460 to get a value of 535 degrees.
Correct the volume of gas calculated above for a gas temperature of 535 degrees. Multiply 226.21 cubic feet by 460, then divide by 535. The answer is 195.36 cubic feet. This is the SCF value for 2 CCF corrected for pressure and temperature.