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Firestopping Facts

For Years, There Were Building Inspectors Who Turned a Blind Eye When It Came to Enforcing the Installation of Fire-Retardant Seals on Any Material That Penetrates a Wall. Several Fatal Fires in the U.S. and the Sept. 11 Terrorist Bombings Have Helped Reverse That Trend.

January 1, 2003  

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It’s not as sexy as faster networks, and firestopping has been a largely neglected area of cabling, but it is getting more attention lately. That is partly due to some nasty fires in the U.S. that might have been less severe had more attention been paid to firestopping.

Firestopping is placing fire-retardant seals, or firestops, where anything penetrates a wall. Building codes say any such opening should be closed with either a soft seal or some kind of mechanical collar to prevent fire from traveling through.

The responsibility for firestopping has never been clearly defined, nor have the qualifications required of the people who do it. The result is that the job often falls to contractors or cable installers who may or may not be knowledgeable about the materials and techniques they should be using.

“It’s an area that the low-voltage industry has been pretty much derelict in,” observes Mike Tobias, chief executive of Unique Firestop in Robertsdale, Ala.

Frank Walsh, national sales manager for the commercial business of London, Ont.-based 3M Canada Ltd. — a major vendor of firestop products — says things are getting better. “What’s changed has been a heightened understanding of the need to do passive firestopping,” Walsh says.

Richard Lintelman, general manager of Nelson Firestop Products, a unit of Emerson Electric Co. of St. Louis, says building codes have for years required proper firestopping, but enforcement was lax. “You have building inspectors who just don’t enforce it,” he says. “You don’t see our product. It’s buried in behind, underneath, it’s on the bottom side — it doesn’t lend itself to specific inspection.”

“It’s been part of the national code to maintain your fire separation within any given building, whether industrial, commercial or institutional,” says Bruce Richards, president of Global Firestop Services in Bedford, N.S. “But back 15 years ago, nobody paid much attention to it.”

Walsh says some fatal fires in the U.S. have created pressure to tighten building codes and enforce them more closely. Lintelman agrees, citing the 38-storey One Meridian Plaza building in Philadelphia, where three firefighters died trying to extinguish a blaze that gutted nine floors in 1991. The burned-out floors had no sprinkler systems, and firefighters were able to control the fire when it reached the 30th floor, where the tenant had installed sprinklers. According to Lintelman, there were also questions about firestopping in the building.

The terrorist attacks in New York and Washington on September 11 also heightened concerns, Walsh adds.

“We’re fortunate in Canada that we haven’t had major fires that created great loss of life like they have in the U.S.,” says Richards. Nonetheless, firestopping is gaining attention in both countries.

Lintelman says contractors who specialize in firestopping are becoming increasingly common. Firestopping is growing faster than the over-all construction industry, Lintelman says, although “I don’t think it’s hit its full stride yet.”

Firestopping around a single cable usually means filling the hole through which the cable passes with a material designed to expand when exposed to high temperatures. In case of fire, the firestop material expands to plug the hole tightly, stopping flames and smoke from passing through. This tendency to expand is called intumescence. Walsh says typical approaches involve either “pillows” filled with intumescent material that can be stuffed around a cable, or composite sheets with intumescent material sandwiched between a mesh on one side and a solid sheet on the other, which can be wrapped around cables or cable trays.

He adds that 3M is working on new products that will make it easier to open up openings when cables need to be added, without having to replace the firestop material each time.

There is some debate about the best way to firestop around cable trays. A common practice is to cut a rectangular hole large enough to run the cable tray right through the wall, and then fill around the tray with intumescent firestop material. Tobias maintains this is a poor solution, and cable installers should use mechanical devices with individual collars for every cable — which his company and a few others manufacture. Part of the problem, he contends, is a lack of clear standards for installing firestop around cable trays passing through walls.

The way intumescent materials expand to fill an opening tightly is important in holding back flames for as long as possible — giving occupants time to escape the building and firefighters time to control the fire before it spreads. However, firestops also need to slow the spread of smoke and potential toxic gases. “Most people don’t die from fire per se,” says Richards. “They die from smoke inhalation.” So even before heat from a fire causes it to expand, firestop material should provide an effective barrier to smoke and gases.

Intumescents start to expand at 275 to 300 degrees, Richards says, but building sprinkler systems are activated at lower temperatures than that, and once the sprinklers go off there will be plenty of smoke.

While twisted-pair cabling is relatively easy to firestop, Richards says, fiber-optic cable has presented some challenges because much of today’s fiber cabling has a Teflon coating. While the virtually fireproof Teflon is a good thing from a fire safety point of view, many traditional firestopping materials won’t adhere to it (this is essentially the same material frying pans are lined with to keep food from sticking, after all).

If the firestopping does not adhere to the cable, there is more risk smoke and gases can get through. So the industry has had to develop new materials that adhere to the Teflon coatings.

Richards says a wealth of new firestopping materials have been appearing, in many respects making the firestopping contractor’s job easier. For instance, new silicon intumescents are not affected by water and will not freeze or dry out, in contrast to traditional latex or acrylic materials.

“It’s evolved from a very complicated system to a user-friendly system for installation,” he says.

That does not mean just anyone can install them, though. “The products are becoming more user-friendly, but it saying that, they’ve also become built for the professional applicator,” Richards continues. “You’re better off having a professional do the installation, because it’s a life safety issue.”

With a growing number of firestop materials and techniques to choose from, and an increased concern about preventing the spread of fires, many people believe the time is coming when firestopping installers will require professional certification. And not a moment too soon, some of them say.

The Firestop Contractors International Association (FCIA), based in Wheaton, Ill., is a trade association for firestop specialists that promotes the use of certified firestopping contractors. The group worked with commercial and industrial insurer FM Global to develop FM 4991, a standard for the approval of firestop contractors. To obtain this certification, contractors have to pass examinations, submit to quality control inspections and take continuing education units.

“I’m a strong believer in the FCIA,” says Richards, adding that he believes firestop contractors will eventually be required to have FM 4991 or similar certification. “It’s not going to be in the next couple of years, but I think it’s going to be in the near future,” he says. “It’s a trade in itself, and is becoming more respected as a professional trade.”

Grant Buckler has written about information technology and telecommunications since 1980. He is now a freelance writer and editor living in Kingston, Ont.

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