2015-06-12 / Letters

How about some extra credit?

To the editor:

In the June 5 edition of the Sentry, there was a letter from Stephen Demetriou, who claimed one could easily convert cubic feet of gas to gallons of liquefied gas. Mr. Demetriou is missing the facts on two accounts.

First, when the liquefied petroleum gas vaporizes into a gaseous form that is not under pressure, it will actually expand far greater than the simple conversion that Mr. Demetriou has stated. LPG expands 270 times its original liquid volume as it vaporizes into a true gas. One gallon (0.133) of liquid LPG boils off to become 270 gallons (36 cubic feet) of gas. Mr. Demetriou has ignored the contributions of specific gravity and ideal gas laws to the conversion process. The water that Mr. Demetriou is discussing always remains water. It might be interesting (and worth extra credit from the high school) if Mr. Demetriou calculated what volume that 360,000 gallons of water would occupy if it was turned into water vapor.

Second, building codes and fire codes recognize that materials impose very different hazards when they are in liquid or gas form. Liquefied petroleum gas is a very different hazard than the same product in the gaseous form. Using the International Building Code, which is the law in Maine, a business could store 1,000 CF of gaseous propane in a building (with great difficulty) without sprinklers before additional code requirements are placed on the building. That same building could store 150 gallons of liquefied propane before special requirements kick in. That 150 gallons is equivalent to 5,400 cubic of propane gas when vaporized into gas. If you had a choice between storing propane at your house in gas or liquid, take the liquid.

Pat Doucette’s job should be safe.

Jim Landau South Portland

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