What is the explosive power of compressed natural gas in a 42-inch pipeline?
(Evans Comment #20060426-00099) The absence of oxygen and an ignition source in the pipeline prevents explosion. Pipe construction and installation below ground prevent air from combining with the gas in an explosive mixture. If a pipeline is ruptured, then shutoff valves limit the amount of natural gas released. The spacing of isolation valves along a section of pipe will meet or exceed minimum federal safety standards. 49 C.F.R. § 192.179. Any gas released from a rupture between shutoff valves will quickly rise and dissipate because it is lighter than air at ambient temperatures. A leak or rupture is unlikely to ignite or explode. Unconfined natural gas in the air is in a flammable range only very briefly and must meet a source of ignition within this narrow range. But when unconfined, natural gas is not in an explosive concentration. Will the EIS include an analysis of the risk of terrorist attack on the pipeline? (Ga. Sierra Comments # 20060424-05053; Wilkes-Washington Trans., p. 6
