PaintPRO , Vol. 7, No. 5
September/October 2005
PaintPRO, Vol 7 No 5

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Related Readings:
Regulations for Coatings
Gel Stains
Low VOC Paints
New VOC Regs in the Northeast
Other articles in this issue:
Premium Interior Finishes
Keep Fire at Bay
Removing Graffiti
Tools for Paperhanging
School's Open!
Contractor Profile: Murals & More
Manufacturer Profile: Insl-x
Paint Industry News
Product News
Product Profiles
Toolbox: Ladders & Accessories
Painting Tips

Fire Retardent Paints

Fire Retardent Paints
Fire Retardent Paints
Steel coated with Contego PFB is protected when the coating expands and reflects thermal energy, keeping the steel below the critical temperatures at which it loses structural integrity.
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PaintPRO Archives
Fire Retardent Paints



Intumescent Paint

Fire Retardent Paints. Flame-retardant intumescent coatings provide precious time in the event of a fire. When exposed to flame or extremely high heat, the coating layer expands and produces a char, which insulates the surface and helps keep oxygen -- necessary for combustion -- away from the substrate.
by Susan Brimo-Cox

When a building catches fire, every second counts. These extra seconds can mean life or death, and in some instances, can determine whether a structure is savable or a total loss.

Intumescents — Growing Up In Difficult Times
by Anne Truesdale

On Sept. 11, 2001, the World Trade Center came tumbling down. The collapse was due to an intense fire that heated the structural steel to the point that it lost structural integrity and allowed the enormous mass of the upper stories to crush everything below. The structural steel was coated with fireproofing material, but it was an old technology that wasn’t bonded to the steel and fell off on impact. The fires were fueled by enormous volumes of jet fuel from the planes that crashed into the towers. There were sprinkler systems, but they either failed or, in some cases, only served to disperse the jet fuel, making the fire even worse. What we learned that day was that the time had come for improved technology that would remain in place in the event of a fire and respond passively — unlike sprinkler systems that can fail if supply lines rupture, sprinkler heads fail to operate properly or water pressure drops. Passive intumescent systems are also advantageous because they have no way of intensifying a petrochemical fire as does water.

As described earlier, intumescent coatings expand when exposed to intense heat or direct flame, forming a hard char barrier that acts in one of two ways. According to Tony Scott of Contego International, an Indianapolis-based intumescent manufacturer, the char barrier either separates fire from the fuel that it needs (in the case of combustibles like wood, drywall, or spray foam) or it sets up a thermal barrier to reduce the temperature increase on structural steel to either avoid or delay the time it takes for steel to heat up to the point that it loses structural integrity. Scott shares interesting statistics. “Fire doubles every 60 seconds. Most residential fires occur at night when you are asleep, disoriented, and less able to respond. By the time you realize there’s a fire, the level of smoke and toxic fumes that can kill are already in place. Your sense of smell is extremely diminished while sleeping. Fires kill more people than all other naturally occurring disasters combined.” That’s why the drive is on for intumescent technology.

While intumescent coatings may seem like the “hot” topic in construction, they’ve been around for nearly three decades. However, like any technology, it has taken a great deal of time and money to perfect the products that are available today. Earlier products and even some that are currently available can be thick, lumpy and difficult to apply. Some do not bond well to various substrates. Others are toxic and carcinogenic. Still others require special primers and, if you choose, special topcoats.

Brent Parsley of Cal-Con Fire Solutions in Sacramento, Calif., has focused 100 percent of his energy toward educating the architectural community about the vast improvements in intumescent technology and how it can significantly reduce the cost of meeting fire code while doing a better job of protecting lives and property. According to Parsley, “Fire code officials see the level of risk we face and codes are getting tougher. The byproduct of more stringent codes is often either increased cost of construction or an incentive to find shortcuts that can prove disastrous. Intumescents allow the architectural world to offer a better level of protection for less.”

The total number of fires is on the decline, according to the most recent statistics from the NFPA. However, fires in high-density housing, apartments, school dormitories and condominiums are on the rise. Gregg Wood of Long Item Development (Carmel, Ind.) provides intumescent coatings to W.D. Armstrong, a national chain that supplies the high-density market. “High-density fires are not only on the rise, they are more destructive and the level of collateral damage is higher than ever,” says Wood. “The insurance industry is taking note of that and leading companies are looking to reduce risk by providing incentives in the high-density market to buy and apply intumescent coatings.”

Geoff Fale, of Lake Oswego, Ore., has been in construction for 35 years but sees intumescent technology as one of the most exciting developments ever. “Now that the better grade intumescent coatings have matured, there’s a solution for a host of problems that have plagued us over the years. But you have to do your homework,” he cautions. “You have to disregard manufacturer claims that go beyond what their test data and track record can support.”

There are many materials and coatings that can slow a fire. Kenjay Williams of PPG Industries, which makes a variety of fire protective coatings, points to cementitious and subliming coatings; dry insulation, such as rock wool or gypsum board; and intumescent coatings as examples. For our discussion, it’s the intumescent coatings we’ll concentrate on.

How do intumescent coatings work? A chemical reaction takes place in the coating when it is exposed to flame or extremely high heat. The coating layer expands and produces a char, which insulates the surface (helping to keep it cooler) and helps keep oxygen — necessary for combustion — away from the substrate.

This chemical reaction can offer minutes of extra time in the event of a fire. Intumescent coatings are available in different formulations from a variety of manufacturers.

Exterior intumescent coatings are typically epoxy-based, Williams says, offering good corrosion resistance and less weight than cementitious coatings. Epoxy intumescents are used in the petrochemical industry for exterior applications on refineries and offshore platforms. Because they are known for their impact strength, adhesion and resistance to humidity, they are also being looked at for some interior applications, such as swimming pools, clean rooms and high-rise structures, Williams adds.

Epoxy-based intumescent coatings require a thick-film application, usually by licensed applicators. They are typically applied at 100-500 mil thickness, typically use fabric or steel mesh reinforcement for longer ratings and have a more textured surface finish than thin films, Williams says.

Interior thin-film intumescents can be vinyl- or water-based and provide a paintlike finish. Some are designed to be used on exposed interior structural steel where a paintlike finish is desired. Others are designed to protect interior wood, drywall and other substrates. You’ll find these used in many commercial environments, such as office buildings, health care facilities, multifamily housing units (such as apartments and condominiums), hotels and restaurants, and schools.

Thin-film intumescents can be spray-applied using airless equipment. The specific coating thickness depends on the product being used and the specified fire rating.

According to Jim Raby, who’s in charge of technical service sales at Flame Control Coatings LLC, different localities set their own minimum requirements for fire ratings. A municipality can’t set a rating lesser than the state-mandated rating, he says, but if it meets or exceeds the state regulations, a municipality is free to set its own.

Much testing has been done relating to fire and flame spread, and there are a variety of laboratory tests that flame retardant coatings must pass in order to be rated. ASTM, Underwriters Laboratory and other industry-specific agencies generally conduct the testing.

Fire retardant coatings aren’t used very often in single-family homes, but it wouldn’t be a bad idea.

Jake Clark, owner and president of Armstrong-Clark Co., a California-based exterior stain manufacturer, has developed an exterior flame-retardant stain he has confidence in, but he faces a challenge. “There is no test criteria for the aftermarket in California for exterior products,” he says. So he has created his own tests, using roof shakes, wood siding, wood fences and a wood deck, with the goal of having burning embers burn out in place without spreading.

Bill Hendricks, owner of Safer Building Solutions, does a lot of work concerning wildland-urban interface and agrees that there are no fire retardant testing parameters for exterior paints and stains. He says the problem with using interior flame retardant products on the exterior of a home is that they don’t hold up to weather. (As far as he knows, no interior flame retardant product has passed the accelerated weatherization test.) Some possible remedies are to use an oil-based product or encapsulate it; still, “a product may be flame retardant, but how long it will last is the uncertainty,” he says.

Beyond thin-film fire retardants are products that provide fire resistance. More than a matter of semantics, fire resistance relates to penetration of flame versus spread.

Steve Beck, president of International Fire Resistant Systems Inc., explains the difference: At the lower end of the scale, flame retardants generally need to pass a flame spread test. At the high end they pass what is referred to as the room corner tests, where they also test for flashover and smoke. But, not only do flame resistant products need to pass the room corner tests, they need to pass a fire penetration test, too. The added protection of preventing fire penetration for up to two hours preserves the structural integrity of a building, he says. Beck already offers an interior fire resistant product that applies like paint, and he is working on an exterior-use version.

The important thing to remember when selecting a fire retardant or fire-resistant product is to make sure you are getting one that does what it promises. Ask the product manufacturer for the testing certification documentation. If they won’t provide it, look elsewhere. And make sure the tests passed measure up to the fire rating standards you need to meet. “There is a lot of misconception out there,” Hendricks says. “You really need to look at how the testing is done.”


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