AC Transit Hydrogen Incident

From the Oakland Tribune:

Wrong valve cause of fire at AC Transit hydrogen station By Denis Cuff Contra Costa Times Posted:   07/24/2012 04:45:27 PM PDT 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 Advertisement 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.