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Fire Retardants and Fire Test Standards
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Fire Retardants and Fire Test Standards

By Barry Badders, P.E . | Fire Protection Engineering

Fire is a powerful phenomenon that is useful and necessary for life, yet destructive. Fire was used by early man to provide warmth from the cold, to bring light into the dark, prepare food for consumption, and in other ways that not only made life possible, but improved the quality of life. In contrast, fire is destructive and can quickly take life. When we can control it, we can use it. The problems occur when we do not have control. Our ways to control unwanted fire have been to prevent it from happening, to contain it, and/or extinguish it. To accomplish this, we have discovered and developed materials and assemblies, fire test standards and methods, and regulations. Fire retardants have played a role in our history of attempting to control unwanted fire.

There are no fire test standards or methods specifically for fire retardants. Fire retardants are added to materials to improve fire performance. They are a means to an end, allowing materials to meet fire performance requirements.

The first known use of fire retardants dates back to early China and Egypt. The early Chinese used vinegar and alum to treat wood prior to encasing it in clay to prevent the spread of fire. The Egyptians soaked reeds used for roofing materials in sea-water, which resulted in mineral salts crystalizing during the drying. The crystalized mineral salts acted as a fire retardant. Later in history, as described by Aulus Gellius, the ancient Romans fire protected wood by soaking it in alum. Through the course of history, alum continued to be used and by the 16th century, English theater owners were using alum to protect stage curtain fabrics. In Britain, Obadiah Wilde had the first flame retarded canvas patent in 1735.

By the 19th century, our understanding of chemistry was growing. Many of the inorganic chemicals used today were identified in the early 19th century. In 1821, Frenchman Joseph Louis Gay-Lussac had come up with two fire retardants, ammonium phosphates and borax. Later in 1912, William Perkins added stannic oxide, which would bind fire retardants to fabric, which allowed for up to two years of washing.

The development of fire test methods for protection of life and property as we know them today appear to only go back several centuries; however, the first fire tests have dated as far back as the known use of fire. The fire retardants discovered by the Chinese and Egyptians would have been tested in fire and determined to be beneficial before their regular use. Fire as a weapon surely necessitated performance trials prior to deployment in battle to assess its effectiveness. Fire testing as we know it today was not able to advance until mathematics was developed, followed by greater understanding of physics and chemistry. Much of our understanding of the fundamental sciences came from the 16th century through the 18th century. Then, as measuring techniques were developed and refined, researchers were able to combine the knowledge and put it to task to produce fire test methods. Almost all of the methods available today have been fine-tuned over the last 50 years with the discovery of solid-state electronics followed by the rapid development and advancement of computers and software capabilities. Computers became small and affordable, and were thus readily available. This led to the improvement of measurement techniques with more accurate and repeatable results. Major changes in fire safety have historically come on the heels of large fires. Some fires destroyed significant portions of cities such as the fire in New York City on December 16, 1835, Chicago on October 8 and 9, 1871, Boston on November 9, 1872, Baltimore on Februar y 7, 1904, and San Francisco on April 18, 1906. The National Fire Protection Association (NFPA) was established in 1896 and American Society for Testing and Materials (ASTM) in 1898. As a result of the Baltimore fire, ASTM formed Committee P, which later became E05 on fire standards. In 1896, the state of New York required the first fire test by law for floor arches and in 1899, the New York City made it a part of its building code.

Interior finishes and furnishings have been known to have an important role in causes of fire for quite some time. As mentioned earlier, flame retardants were used in curtains as early as the 16th century. As plastics were developed, their use in interior finishes and furniture was an immediate application. The fire hazards were evident by the large fires occurring in the 1920s. A.J. Steiner developed an apparatus to measure the effectiveness of fire retardant paint in 1922. Then in 1942, the Coconut Grove night club fire in Boston lead to the introduction of ASMT E84 into the model building code to eliminate the use of materials with high flame spread potential in public buildings. The ASTM E84 method was based on Steiner’s apparatus, which is why the apparatus is known today as the Steiner Tunnel.

Following World War II, carpet became popular and by the mid-1960s, the need to address the flame spread hazard of carpet was evident. By 1970, the first fire test for carpet, known as the "Pill Test,” was established.

A growing number of fires where furniture was a contributing factor lead to the development of test methods aimed to mitigate fire hazards. Regulations intended to reduce furniture flammability have been around for nearly 40 years. Furniture ignition was addressed by two types of generalized ignition scenarios. One was a smoldering ignition, such as what could be expected from a lit cigarette, and the second was open flame, such as what could be expected from a candle, heating apparatus, or cooking appliance. The cigarette ignition and open flame test was first addressed in California, in 1975, by Technical Bulletin 117 (TB 117), Requirements, Test Procedures and Apparatus for Testing the Flame Retardance of Resilient Filling Materials Used in Upholstered Furniture; however, work to mitigate the hazard was underway in other organizations.

The Flammable Fabrics Act was created to address clothing, but in 1967 was amended to include residential textiles. In 1968, the National Bureau of Standards (NBS) began research on the development of a test method for residential textiles. The Act became the responsibility of the Consumer Product Safety Commission (CPSC) when it was created in 1973, but the work continued with NBS for development of a test method. NBS submitted a cigarette-ignition resistance draft method to CPSC in 1976. CPSC modified the draft and recommended it for publication in 1978. The NFPA Fire Test Committee took the NSB’s work and published NFPA 260, Standard Methods of Tests and Classification Systems for Cigarette Ignition Resistance of Components of Upholstered Furniture, and NFPA 261, Standard Method of Test for Determining Resistance of Mock-up Upholstered Furniture Materials Assemblies to Ignition by Smoldering Cigarettes in 1983. ASTM, later in 1990, published its own versions as ASTM E1352, Standard Test Method for Cigarette Ignition Resistance of Mock-Up Upholstered Furniture Assemblies, and ASTM E1353, Standard Test Methods for Cigarette Ignition Resistance of Components of Upholstered Furniture.

Fire retardants were used in furniture polyurethane foam filling materials to meet the requirements of TB 117. CPSC concluded in 1997 that TB 117 would not ensure a substantial reduction in open flame ignitions because the tests of components did not accurately predict performance of mock-ups or actual size furniture.

California has now removed the small open flame ignition test from TB 117, not because of CPSC’s conclusions, but to eliminate the need for fire retardants in furniture due to concerns of their toxic hazards, although a definitive link to any potential hazard has not been established. TB 117 was the only test that demanded the use of fire retardants for upholstered furniture.

To provide a consensus open flame test standard in absence of one previously provided for in TB117, NFPA has initiated a project to write such a standard. The NFPA Fire Test Standards Committee initiated the project and formed a task group. At the time this article was written, the committee had not yet put forth a draft.

Over the last 100 years, increased use of fire retardants has been closely linked to the evolution of fire test standards and fire safety code requirements. The development of fire test standards and fire safety standards drove the increase in development and use of fire retardants. Now the desire to eliminate the use of fire retardants is driving a reduction in fire test standards and requirements.

Barry Badders is with Intertek Building Products.

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