A vendors view of methane in groundwater. Methane gas has been a problem in Northeastern Pennsylvania. The gas is typically associated with wetlands, bogs, landfills, coal-producing formations, natural saline seeps, some glacial deposits, and gas storage areas. Because of the development of the Marcellus Shale, the presence of methane gas and the potential for methane gas migration is a growing concern. Methane is a colorless, odorless gas that is lighter than air. Natural gas is mostly methane (70 to 90 percent CH4), carbon dioxide (0 to 8 percent CO2), plus other gases. The other gases may include ethane (C2H6), propane (C3H8), butane (C4H10), and hydrogen sulfide (H2S) as well as small amounts of helium.
Methane gas is highly flammable between a lower explosion limit (LEL) of 5.53 percent by volume in air and an upper explosion limit (UEL) of 15 percent. These percentages are equivalent to a methane concentration of 50,000 and 150,000 parts per million (ppm) in air. The minimum concentration level at which the gas has the potential to explode is called the lower explosive limit (LEL), below the LEL level there is not enough gas to cause an explosion. Above the UEL, there is inadequate oxygen to fuel combustion, but if the space is vented and the gas concentration drops below the UEL, the gas can become diluted enough to explode (it would require an ignition source). Methane is not considered toxic, but it is an asphyxiant at a concentration of over 50 percent in air (it displaces oxygen). Therefore, the primary risks for methane would be asphyxiation in a confined or poorly vented area or a potential explosion hazard. As a safety measure, the natural gas industry adds mercaptans to the produced methane gas that enters the pipeline and your home. The mercaptans produce a very pungent odor so that gas leaks will be noticed, but unprocessed methane gas tends to have NO ODOR.
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Managed & Built by I2M Consulting, LLC | © 2010-
Managed & Built by I2M Consulting, LLC | © 2010-