US CSB warns of hazardous material in piping

15 July 2004 18:01  [Source: ICIS news]

WASHINGTON (CNI)--The US Chemical Safety and Hazard Investigation Board (CSB) on Thursday cited a recent Huntsman plant explosion in a bulletin to chemical plants warning of the dangers of hazardous material in piping.

 

The bulletin comes a half-year after CSB began investigating an explosion at a Huntsman Petrochemical plant in Port Neches, Texas in January, injuring two employees.

 

CSB said the explosion resulted from a peroxide/alcohol mixture heated above its thermal decomposition temperature and that was trapped in a process pipe. As steam heated the trapped peroxide, it over-pressurized and ruptured the pipe.

 

In the Huntsman case, the agency said plant employees incorrectly believed that a nitrogen gas purge had released the liquid and pressure from the pipe. CSB said the company revised procedures to use inert gas instead of water flushing to remove trapped liquids, but “inert gas or steam does not necessarily remove trapped liquid,” CSB said.

 

“Opening chemical process piping and equipment can be extremely hazardous,” CSB said in today’s bulletin. “It should never be considered routine work.”

 

In a list of “lessons learned,” the agency suggested that facilities should, among other things, perform a complete examination of all piping and components and identify all connections and valves. CSB also said chemical companies should prepare a specific written procedure for removing hazardous material from a piping system.

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