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Wednesday, July 25, 2012

AC Transit Hydrogen Incident

From the Oakland Tribune:

Wrong valve cause of fire at AC Transit hydrogen station

Updated:   07/24/2012 08:57:26 PM PDT

EMERYVILLE -- The use of an incorrect valve caused a May 4 Emeryville fire that caused neighborhood 
evacuations and closed AC Transit's $10 million new hydrogen fueling station for buses, federal 
investigators have concluded.
In an apparent slip up, a pressure relief valve at the hydrogen fuel plant was made with a type of hard 
steel known to crack and fail when exposed to hydrogen, Sandia National Laboratories investigators 
said in a 33-page report released this week.
"Proper material selection would have prevented this incident," Sandia experts said in the report to be 
discussed Wednesday night by the AC Transit board. "The valve manufacturer already offers the same 
valve component using an appropriate material, therefore the correct selection (was) available."
It's unclear why the wrong valve was installed, officials said, but the result was dramatic.
Eight months after the plant opened as a model to boost hydrogen fuel cell buses, the valve failed, 
leaking hydrogen into the air that caught fire, boomed, and then burned for two hours.
No one was injured, but the fire rattled neighbors, spurred street closures and evacuation of two schools 
and several businesses, including Pixar Studios.
Meanwhile, AC Transit has temporarily suspended use of its 12 hydrogen cell fuel buses because it has 
no place to refuel them.
AC Transit spokesman Clarence Johnson said Tuesday the transit agency still hasn't sorted out


whether the wrong valve was ordered, 
or the supplier provided a valve different 
from requested. "We're still not clear on 
that," he said.
AC Transit hopes to reopen the fuel station 
in September after making a series of 
recommended equipment and procedure 
changes, including replacing the valve that 
caused the fire.
"We're not going to reopen the plant until 
we're sure we have measures in place to 
prevent a recurrence," he said.
Johnson said the firm that designed and 
engineering the hydrogen fuel plant -- 
Linde North America -- will pay for the 
repairs and changes in accordance with its agreement with AC 
Transit. There is no cost estimate yet for fire damage and repairs.
In their report, Sandia safety experts said the intensity and duration of the fire could have been reduced 
if AC Transit and Linde employees had followed procedures to promptly communicate fire and plant 
operation information to Emeryville Fire Department.
"Both AC Transit and Linde communicated well internally, but failed to communicate with each other 
or the incident command (Emeryville Fire Department)," concluded the report by Sandia.
The safety investigators also said the fire lasted longer than necessary because the plant was not 
designed well to isolate the flow of hydrogen.
The fuel cells combine hydrogen with oxygen in the air to make electricity to run the buses without pollution.

1 comment:

  1. Brian asked the City Council a while back, a very important question that has not been answered as of yet, “What would be the worst case scenario, such as an entire hydrogen tank being engulfed in flames or blown up? Or what about a biological disaster at the Novartis building?” If there is a potential for disaster, will our city notify us ahead of time and or does the need for making money come before residents? Is a broken valve a good enough reason to say “as you were, continue on”?