MINDEN, NVSIERRA Safety technology has written another chapter in the contamination control industry's cleanroom fire-safety saga.
In May, on the heels of a collaboratively drafted and worldwide-accepted fire-safety test for cleanroom materials, Ansul Inc. (Marinette, WI) began distributing Sierra's DCR1 flame detector, a device that meets the Factory Mutual Research's (Norwood, MA) Approval Standard 3260 for “Flame Radiation Detectors” for use in wet bench applications and cleanrooms.
Sierra's DCR1 is controlled by a microprocessor that detects flames using a combination of ultraviolet and infrared technology. The device, says Ansul's Robert Langer, is programmed with fire algorithms, which recognize specific flame signatures, while rejecting such false sources as sunlight, fluorescent and incandescent lights, flashlights and infrared heaters.
A group training in FSI’s ISO Class 5 (Class 100) manufacturing area.
“It's a relatively new technology for wet benches,” says Langer, manager of technical services for Ansul. “The flame-detection has been used in other industries, such as petrochemical, and it was repackaged for the cleanroom industry. Without having a fire-detection and -suppression system, the room would burn. With these systems, you still will have smoke damage, but you will minimize the loss.”
The issue of fire-safe cleanrooms has sparked heated debate over the years. Although tension has subsided, the subject continues to receive an increasing amount of attention. [See “Final fire-safety test imminent,” CleanRooms, December 1999, p. 1]
“As computer chips get smaller and faster, and the manufacturing practice gets more complex, even the slightest delay in production can mean millions in lost revenue,” says Steven Zenofsky, media liaison for Factory Mutual Research. “Contamination from a fire, no matter how small, could potentially put a chip maker out of business for weeks, if not permanently. Flame detectors for cleanrooms and new fire-safe cleanroom materials are some of the new alternatives for reducing those hazards.”
Factory Mutual Research, Zenofsky says, is one of only a few laboratories internationally offering performance-based certifications for flame detectors, spark detection and extinguishing equipment. Because cleanrooms in semiconductor fabs represent special hazards, Zenofsky says Factory Mutual Research recognized the need for detection and signaling equipment that could help protect these special hazard facilities.
Ansul, an affiliate of Tyco Fire & Security Services (Marinette, WI), offers the DCR1 as part of an integrated detection and fire suppression package. According to the company, one or more of the DCR1 detectors are connected to an electronic control unit that sounds alarms, operates auxiliary equipment relays, performs time delay functions and triggers the carbon dioxide suppression system. The CO2-system discharge nozzles are coated with corrosion-resistant material that is not affected by an acidic environment of a typical wet bench.
The detector's sealed, flame-retardant polypropylene housing is designed to the International Electrotechnical Commission's 529 IP67 rating for the protection from a wide variety of acids and solvents that are commonly found in cleanrooms. The DCR1's surfaces are smooth, non-shedding and scuff-resistant and can be wiped down. The device is also rated over a wide operating temperature range for applications where drying or heating elements are used.
According to Zenofsky, the 1994 version of Approval Standard 3260 is being updated. Sections slated for revision include wet bench applications; product-related information based on Factory Mutual Research experience and property loss-prevention data sheets; and false-alarm criteria.