NORWOOD, MA – THERE was a time when the very mention of the words “cleanroom fire-safety testing requirements” was enough to spark a debate over the merits of the FM4910 protocol from Factory Mutual Research (Norwood, MA) versus standards developed by Underwriters Laboratories (Northbrook, IL).
But now, users, standards committees and insurance companies – Factory Mutual, UL, the National Fire Protection Association (NFPA; Quincy, MA) and HSB Industrial Risk Insurers (San Francisco) – are putting their heads together to establish a worldwide protocol.
“We need a protocol that al lows us to control the loss. It's a business issue,” says Peter K. Wu, a senior research scientist for Factory Mutual. More over, he adds if custo mers have to wait while a burned down fab is rebuilt, they will go elsewhere.
Mark Conroy, staff liaison for the NFPA, says the organization's technical committee has been wrestling with the 4910 and the UL standards. “We need to address plastics coming into the cleanroom, the type and the amount. That is really the root of it,” he adds. “We need to come up with the appropriate testing procedure. Some people think the 4910 goes too far and others think the UL doesn't go far enough.”
Robert Backstrom, a senior project engineer at UL, says the renowned laboratory and Factory Mutual have similar interests in fire-safety issues in the cleanroom. “We have a spirit of cooperation with Factory Mutual at the request of the semiconductor industry,” he adds. “Our concerns are very much the same. We are both concerned about fire-protection.”
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 A full-scale wet bench fire test. |
As Conroy says, using the appropriate plastic is key. Discussion began between the groups last January, and those who opposed the 4910 have changed their tune with all parties agreeing that a comprehensive fire-safety test was needed. UL agreed to test a handful of plastics to determine if the materials are fire-resistant. [See “Fire safety test provides insight,” CleanRooms, June 1999, page 1].
“There is a need to use the best plastics,” explains Robert Pearce, HSB's assistant vice president for area loss prevention. “It makes the loss potential a lot higher in cleanrooms to just use polypropylene. We are in the process of testing plastics to see how they perform under a fire-test apparatus.”
When discussing the proposed FM4910 standard [See “Cleanroom fire-safety debate heats up,” CleanRooms, April 1998, page 1], the groups agreed that sparking a test-fire was at the discretion of the test operator, and ignition should be better defined. “The 4910 test also had a method of using black carbon spread over the plastics to enhance absorptivity. We didn't like that about the test, and we wanted a test that was going to be repeatable and one that could be done worldwide,” Pearce says. “The next step will be the roundtable between Factory Mutual and UL to survey the data.” Those meetings were planned for September.
Mark A. DeSorbo