Posted by Mike Williams in Arroyo Grande on March 16, 2008 at 05:57:34:
"Service Restoration Time for Major Earthquakes" Northridge 120,000 12 days Loma Prieta 156,355 9 days Whittier 20,600 10 days *Does not include customers affected by the additional time needed to reconstruct gas distribution facilities or structures Also: "The risk of a gas-related fire in residential structures following earthquakes is generally very low because of the numerous conditions necessary for gas ignition (see, for example, Williamson and Groner, 2000). The ignition of leaking gas requires an ignitable mixture of gas and oxygen between the approximate range of lower (5%) and upper (15%) explosive limits and an ignition source. This can occur in the presence of a pilot light or when a light switch is turned on or off. For natural gas that is lighter than air and tends to disperse, the rate of gas leakage capable of igniting is related to the air exchange rate in the area of the leak. The likelihood of ignition is higher in conditions where poor air mixing allows formation of pockets of higher concentrations of gas. . . . . Post-earthquake restoration of gas service by non-qualified personnel increases the potential risk of injury or death from the accumulation and ignition of unidentified gas leaks and carbon monoxide in damaged gas appliance vents. Lengthy service interruptions may lead to nonqualified personnel re-establishing service without taking the necessary precautions." From the California Seismic Safety Commission's "Improving Natural Gas Safety in Earthquakes." Link below. Mike Williams
Follow Ups:
● makes good sense - John Vidale 17:17:33 - 3/16/2008 (73515) (0)
|