Firestopping: A must in any installation

With firestopping, damage and injuries can be minimized. Without it, a structure can be reduced to a virtual smokestack.

Oct 1st, 1998
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With firestopping, damage and injuries can be minimized. Without it, a structure can be reduced to a virtual smokestack.

Mark A. DeSorbo

And unfortunately, firestopping--one of the most important steps in cabling installation--is often a part of the project that falls by the wayside. That oversight can prove to be costly now that more local fire inspectors are cracking down and enforcing firestopping regulations.

William Degnan, deputy state fire marshal for the State of New Hampshire, says his inspectors have found that floor and wall openings in buildings undergoing retrofitting for new technology, such as computer networks, are not being firestopped. "We are having to get people to address that. When you have openings where wires and cable go through, they need to be sealed," he says. "When they are not sealed they create a means for fire to travel from one area to another. Without it, you can compare that to a building acting like a chimney."

Firestopping materials, he adds, must meet local building codes, many of which are based on tests devised by Underwriters Laboratories (UL--Northbrook, IL) and the American Society for Testing and Materials (Philadelphia, PA). There are several different types of firestopping materials such as caulks, pillows, putties, and sheets. Caulks, which are usually latex- or silicon-based, are particularly useful around pipe, conduit, duct, electrical cables, and openings that are subject to movement or vibration. Firestopping pillows are intumescent materials enclosed in durable polyethylene bags that are hand-pressed into an opening. Putties are hand-pressed into place around areas such as electrical boxes. Designed primarily for temporary installation, pillows can also be removed and reused. Composite sheets are used for areas that were created for cable trays. Sheets can be easily cut and contoured to fit around cables and trays (see Product Update table, page 130).

Whatever the application, firestopping materials should be a staple in any installation. "It is a very important part of the fire-protection system in a building," Degnan adds. In fact, firestopping materials do more than just halt the spread of flames and intense heat. They also suppress the spread of smoke and toxic combustion and hold up to the jetting waters unleashed by firefighters. That`s why nearly all municipal fire codes require that firewalls and floors in commercial buildings be firestopped to contain a fire within the area in which it starts. Codes from organizations such as the International Conference of Building Officials, the Southern Building Code Congress International, and the Building Officials Code Administrators International Inc. cover firestopping materials and methods that require that every wall and ceiling penetration be sealed.

"The material also has to be rated so that it meets the fire-rating that walls are intended to be. For instance, one hour, two hours, or three hours, before the fire penetrates the firewall," Degnan adds.

An installer, however, cannot just arbitrarily stuff floor or wall openings with any kind of firestopping material. "You can`t mix competitors` items either, unless they are third-party approved, and that doesn`t usually happen because you don`t want to help your competition," says Joe O`Brien, product manager for Nelson Firestop Products. "You have to return the hole in the wall to the same integrity of the wall."

O`Brien started the company in 1965, and since then he says he has just about seen it all when it comes to firestopping. "I`ve been in utility plants where holes were stuffed with lunch bags, rags, dungarees. You go pre-1975, and there are many buildings that don`t have anything," he says with a laugh. "I was trying to sell some [firestopping material] to this guy in New York City, and he threw me off the site because he said I was trying to ruin what he called his air-conditioning system."

The type of firestopping most sought after by his customers, O`Brien says, is Nelson`s Firestop Pillows, which offer flexibility in an environment where the technology is always changing. "We are getting inundated with pillow orders from hospitals and nuclear power plants. They are always changing their cabling systems, and with pillows you can put them in and pull them out," he says, adding that Nelson`s pillows can contain fire and smoke for up to three hours.

Two other popular products, he says, are Nelson`s Multi-Cable Transit and Multi-Plug Systems. "These two devices came from the Swedish Navy and a civilian. I obtained the license for them in the 1960s. Now, every ship the U.S. Navy has built since 1965 has these," O`Brien says. The Multi-Cable Transit seals several cables that pass through wall or floor openings. Used individually or stacked multiply in tandem for high-volume installations, a frame is filled with grooved or solid Tecron modules, which are specified and arranged according to the size and number of cables passing through the opening. When exposed to heat, the intumescent Tecron modules expand to form a long-lasting, contiguous seal, even if cable jackets disintegrate. For multiple cables in a circular opening, such as a pipe sleeve, there`s the Multi-Plug System. Available in 2- to 8-inch pipe sizes, it can hold nine to 144 intumescent Tecron modules, O`Brien says, depending on the size of the radius. "These two devices can withstand an explosion, they are water-tight, and they can withstand electromagnetic interference," he adds.

Regardless of the number of products that are out there, firestopping still remains a commonly overlooked aspect of the installation process, says Mike Tobias, president of Unique Fire Stop Products. He says that you can even find firestopping violations in buildings as young as five years old.

Intumescent putties and caulks, he states, are the most commonly used firestopping materials. Putties and caulk fill a void, but do not always restore a wall or floor to its original integrity. "Caulk and putty around an opening seems to be acceptable," according to Tobias. "If someone makes a hole in a wall the size of a fist to put a thin cable or wire through, he or she thinks caulk or putty will do the job without even knowing the material`s limitations." In some states, this method is acceptable, but on the West Coast and in Florida, fire officials are cracking down on firestopping violations, which lessens the chance of an installer getting away with inadequate caulks or putties. "Low-voltage contractors out there are trying to avoid learning about firestopping," Tobias adds. "Most of the jobs they bid on do not include it as part of the bid, but an electrical contractor will include it as part of the bid. In a low-voltage bid, firestopping is one of the first thing to be disregarded."

That`s where Tobias, a cabling contractor by trade, found his niche. His company has developed the Split-Sleeve, Smooth Penetrator, and Threaded Penetrator systems. The Split-Sleeve System was designed for a retrofit to correct a violation. It uses a 12-inch section of rigid conduit that`s threaded on the outside and split down its axis. The two halves act as an outer casing around cables. A pair of slotted washers are worked over the cables and caulked to the firewall, with the slots 180o from each other. A nut is provided for each side to keep the two threaded halves together, and the washers are secured to the wall with a bead of caulk between the slotted washer and wall. After the sleeve is installed around the cables, the end is stuffed with insulation and putty is applied on the seal. Additional cables can be added, and systems are available in 1-, 2-, and 4-inch diameters for small and medium-sized cable bundles. A bulkhead plate has been developed for larger floor and wall openings. The Smooth Penetrator cuts its own hole through gypsum drywall. Large washers are then secured to the wall with sliding-lock couplings, or nuts. Plastic bushings protect the cables, and installation is completed with wool batting, caulk, or putty. The Threaded Penetrator requires holes to be pre-drilled. Large, round, flat washers are secured by threading a coupling on each side. Plastic bushings are screwed on each end to complete the system. Wool batting, caulk, or putty is the final step in the process.

"We developed the Penetrators as an afterthought to the Split-Sleeve," says Tobias. "There were no washers for conduit, so we made big, round washers that slide up and down conduit and up against the floor or wall. It took us a week to come up with the schemes. From concept to presentation, it was about two years before we could market them."

Firestopping products, such as those offered by Unique, are bound to catch on as local fire officials continue their crackdown. Tobias`s philosophy on the matter is simple: It`s better to be safe than sorry. "Pay attention to firestopping. Cost should not even be an issue," he says. "It`s a life-safety issue. If all your walls look like Swiss cheese with Category 5 candlewicks going through them, somebody is going to die if a fire breaks out."

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International Protective Coatings Corp. manufactures a host of firestopping materials, including caulking, pillows, and sealants.

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