The National Transportation Safety Board began three days of hearings yesterday on last September's natural gas pipeline disaster in San Bruno. Highlights of the first day's testimony center on PG&E's admission that after a 2006 review of automatic and remotely operated pipeline-shutoff valves, it decided that the devices wouldn't do much to protect life or property and that it didn't need to install them.
That judgment came in a memo from PG&E senior consulting engineer Chih-Hung Lee, who was setting out proposed guidelines for the utility in response to a federal law (CFR 49 Section 192.935) that directed pipeline operators to "take additional measures beyond those already required ... to prevent a pipeline failure and to mitigate the consequences of a pipeline failure in a high-consequence area." (High-consequence area? Essentially, that's anywhere a pipeline might pose a risk to human life or important infrastructure. The San Bruno neighborhood where PG&E Line 132 exploded and burned was a high-consequence area.)
More specifically, Section 192.935, Paragraph (c) reads:
"Automatic shut-off valves (ASV) or Remote control valves (RCV). If an operator determines, based on a risk analysis, that an ASV or RCV would be an efficient means of adding protection to a high consequence area in the event of a gas release, an operator must install the ASV or RCV. In making that determination, an operator must, at least, consider the following factors—swiftness of leak detection and pipe shutdown capabilities, the type of gas being transported, operating pressure, the rate of potential release, pipeline profile, the potential for ignition, and location of nearest response personnel. "
Lee's findings were based on a review of seven industry reports on the issue of the cost and effectiveness of automated or remote shutoff valves.
Based on his reading, Lee reported that most damage from a pipeline rupture "occurs immediately (within 30 seconds) from the initial loss of containment." That led him to write that "the duration of fire [following a pipeline failure] has little or nothing to do with human safety and property damage."
Lee concluded by repeating that statement and suggesting the company's policy should be to prevent pipeline failures through better design and construction methods and a more thorough and vigilant safety campaign.