The San Bruno pipeline explosion and fire in September killed eight people and destroyed 38 homes.
Posted on 03/08/2011 10:28:51 AM PST by SmithL
A "screwed-up" repair project at a Pacific Gas and Electric Co. control station in Milpitas caused pressure levels to rise on all the natural gas transmission lines serving the Peninsula just 50 minutes before the San Bruno pipeline exploded, newly released federal documents show.
The repair project set in motion a chain of unforeseen problems and blunders leading up to the Sept. 9 explosion that killed eight people and destroyed 38 homes, records released by the National Transportation Safety Board show.
Electricity was cut off to equipment that controls gas pressure in the Peninsula pipelines, two backup power supplies failed to work and critical communications between PG&E's gas control center in San Francisco and the Milpitas control station were lost, the records show.
When the power was cut to the control station in Milpitas, a system set up by PG&E automatically increased pressure on all three Peninsula pipelines, including the one coursing through San Bruno, according to PG&E employees interviewed by the safety board. The federal agency is investigating what caused the explosion.
Through it all, operators in the San Francisco control room proved powerless to fix the problem.
"We're screwed, we're screwed," one operator said minutes before the 30-inch gas transmission line exploded.
(Excerpt) Read more at sfgate.com ...
Ping.
How did this happen under all the California Regulations.
Time to fire some people and for them to financially pay for it to those who were affected.
Affirmative Action?
Union affirmative action.
Umm, just a naive question.
Why aren’t there safety precautions in place that can prevent this from happening?
I’ve designed Hydraulic testers for a living, every one of them had EMERGENCY precautions to prevent this sort of thing from happening, yet these testers dealt with very high pressures and flow rates. Yes, if left without safety bypass valves - this was a very dangerous piece of equipment.
There is an Operational Range of pressure - then there is the HOLY S**T range where automatic safeguards SHOULD have kicked in, shut down the pumps, and bled off the pressure before something like this happened.
What happened to very basic safety design reviews?
An interesting fail-safe response.
Now the media often screws up this kind of reporting but will be interesting to see follow up info.
Another instance of the Pepsi Syndrome?
Looks like they need mooooore regulation /s
Nepotism is RAMPANT there. You know.
This is what happens when a repair crew isolates the pressure gauges to the regulators, which thinks the pressure is dropping when in fact it is increasing. Bad data = bad results.
But, you spilled a Coke.
Why no failsafe built into the system? If electrical power is a critical component, the absense of it should trigger a failsafe to avoid such a catastrophe.
Or am I missing something?
Union workers, probably on break.
I work for a company that does control systems for these type of operations and this is inexusable. There should have been multiple fail-safes and some method of shutting down the lines in such an emergency. It also appears a pressure sensor or sensors were reading wrong. I’d love to know who manufactured that sensor.
I agree, every safety device I have used was fully automatic. Never used a computer to respond to an emergency (computers can lock-up), never made a signal’s absense allow flow (wires get cut).
The default condition was zero flow. Things had to be perfect before flow was allowed - any failure shut the system down. The simple trick, is to make the safety system easy enough to understand, quick enough to matter, and robust enough to withstand an emergency.
ping
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.