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Know your fabrics, fabrication and flammability

December 2nd, 2012 / By: / Feature

No matter where you are in the supply chain, a thorough knowledge of flame retardancy leads to well-informed customers—and safer environments

1212_f2_1If a fabric is going into a commercial space—whether used for a trade show banner, theater drapery or restaurant awning—it needs to be flame retardant (FR). Call the material fireproof, flameproof or flame resistant, but the goal is still the same: to stop or significantly slow the spread of fire and ultimately provide additional time for people to evacuate the premises. There is a variety of different methods to make a fabric flame retardant, as well as a variety of common industry flammability standards and testing methods—all of which should be known to fabrication professionals.

FR, IFR and performance

Photo: Firetect
Photo: Firetect

Flammability can be achieved in two fundamental ways: through inherently fire-retardant (IFR) fibers and by applying fireproof coatings. Manufacturers produce IFR fabrics by adding flame-retardant polymers to the yarn before it is woven or knitted into the fabric, says Pedro Vega of Sun Valley, Calif.-based Dazian, a distributor of FR fabrics in the special event and entertainment industries. In the last few years, the company has moved more toward IFR fabrics for practical purposes. “Most theater fabric, for example, requires a long life span,” Vega explains. “When you use an IFR yarn, your flame retardancy is for the life of the fabric. You can wash IFR products repeatedly and expose them to flame, and they will retain their FR properties.”

Although IFR fabrics tend to cost more than their non-IFR counterparts, Vega finds that customers are willing to pay a premium for a fabric that will retain its flame-retardant characteristics.

Glen Raven Inc. in Glen Raven, N.C., produces Firesist®, its latest incarnation of fire-resistant commercial awning fabric made of a proprietary FR material. The company has used FR polyesters and FR acrylics in past products, says Benji Bagwell, director of research and development. He also notes that IFR fabrics can be made from recycled materials, and that Firesist (which also has a water-barrier coating) can be recycled as part of the company’s Sunbrella® recycling program.

Some situations, however, call for the re-treatment of IFR fabrics, says Kathleen Newman, CEO of Canyon Country, Calif.-based Firetect, a manufacturer, supplier and certified applicator of FR coatings and saturants for various surfaces. “You don’t always know why some IFR fabrics lose their flame resistance,” she says. “There may have been a flood, atmospheric conditions may have changed the flame-spread rating, or other situations may have occurred.”

As an example, a school sought Firetect’s help to clean and re-treat its IFR draperies because they did not pass NFPA 705 field flame testing. After the drapes were cleaned, there was a different shade along the bottom five feet. “It turned out that the janitors had been cleaning the bottom of the drape with degreaser, which changed the color and properties of the drape,” Newman says.

Coatings and applications

Photo: The Govmark Organization
Photo: The Govmark Organization

More commonly, fabrics receive their FR properties through backcoatings, immersions or sometimes a combination of both, says Bud Styles, director of sales at TSG Finishing LLC in Hickory, N.C. “The art of applying a backcoating to a fabric is akin to spreading butter on bread, while immersion processing is representative of dunking a doughnut,” he explains.

A fireproof coating serves as a protective layer that prevents the underlying fabric from catching fire. It can be applied in different steps of the supply chain—some mills will add an FR coating before selling the fabric; in other instances, distributors, fabricators, installers or end users may decide on an aftermarket treatment.

In some applications, FR coatings can be included with other treatments (such as those providing mold and mildew resistance or antimicrobial functionality), but the process must be a careful one. “When we provide a flame-resistant fabric, we modify our coating formula to include flame resistance,” says Alan Prelutsky, vice president, Textile Group, at MarChem CFI in New Haven, Mo. “This is not as simple as just adding flame resistance to the original formula, as we have to compensate for a variety of factors the flame-resistant chemicals affect, like weight and water repellency, among others.”

Firetect has found a way to successfully add a stain retardant after applying an FR coating to the material without inhibiting the FR performance. “The problem is that with so many chemicals on the market, a manufacturer cannot say that their product will work with all stain retardants,” Newman says. “The two products have to be tested in a certified laboratory as a system to ensure flame-spread results.”

Safety plays an important role in the coatings themselves. The FR treatment process is nontoxic and does not create hazardous waste. The industry also continually strives to improve the composition of the FR solutions, and organizations like the Environmental Protection Agency (EPA) monitor and sometimes ban certain chemical formulations.

Know your standards

Although flammability regulations may vary from municipality to municipality, some flame specifications are common to most locations in the marketplace. These include:

  • ASTM E84: 12b Standard Test Method for Surface Burning Characteristics of Building Materials
  • NFPA 701: Standard Methods of Fire Tests for Flame Propagation of Textiles and Films (a voluntary industry specification)
  • CAN/ULC S-109: Flame Tests of Flame Resistant Fabrics and Films (Canada)
  • California State Fire Marshal (CSFM) Title 19: California Code of Regulations. The specialty fabrics industry often tries to meet the high standards set forth by this document, even if the textiles aren’t slated for use in California, because of the specification’s thoroughness.

When it comes to standards relating to re-treating fabrics, the decision is in the hands of a municipality’s fire marshal. A fire inspector may order a flammability re-test (and re-treatment, if necessary) of a fabric, but currently, neither the office of the California State Fire Marshal nor the National Fire Protection Association has regulations on re-treatment.

Such guidelines would promote safer environments, Newman believes. “I think there should be maintenance procedures in place to ensure fire safety and to maintain the FR properties,” she says. For instance, one drape may have gone untouched for a decade and be just fine, while another fabric has been exposed to dirt, dust, grease and moisture—all of which can increase flame spread.

“Fire authorities have expressed their desire for maintenance guidelines in the fire code so they know that a soft good has been properly maintained and that the surface meets compliance,” adds Newman, who sits on the technical committee for updating the fire-retardant regulations of California’s Title 19 and the California Bureau of Home Furnishings.

Another challenge: There’s no good way to guarantee the life span of a flame retardant for soft goods, Newman notes. “If you indicate your coating is guaranteed for one year and put a warranty on that, does that mean that even one week after application and certification of a surface that the flame retardant is still in compliance, even though there is no way to verify what conditions that surface may have encountered?” she asks.

Testing … testing …

Many manufacturers, suppliers and end users rely on third-party independent testing labs to verify that a flame retardant is working properly. Salvatore Messina, CEO of The Govmark Organization Inc., an independent fire testing laboratory in Farmingdale, N.Y., says that it takes an average of three to five days to complete an FR test. “You can’t just test a flame-resistant product,” Messina says. “You have to know which standard the manufacturer or supplier is trying to achieve.”

For example, in the case of Title 19, California Code of Regulations, end products need to be tested at a testing laboratory approved by the state fire marshal. The responsibility typically falls to manufacturers, who then send an application with the test report, appropriate fee and fabric or chemical samples to the CSFM for review, evaluation and approval. The CSFM may conduct testing to verify the result and, if passed, the office will assign a registered number that can be placed on a CSFM certificate of flame resistance.

The many varied and fragmented flame retardant standards fall into two categories: vertical tests and horizontal tests, according to Styles. “The most difficult aspect in working with FRs is the combination of the flame testing variability coupled with the different end uses and fiber contents,” he says. “So while one of our treatments might work on one fabric for one application, a change in the flame test code or end use may require an entirely different treatment for the exact same piece of fabric.”

He also reminds customers that the local fire marshal on the job site makes the ultimate call for the proper flame test code.

Holly O’Dell is a freelance writer based in Pine City, Minn.