All carpet sold in the United States must meet the federal flammability standards, but local and regional standards also exist. The local fire marshal has the authority to establish additional specific criteria, and he or she should be consulted prior to writing specifications or purchasing carpet for a particular installation.
The flammability characteristics of building materials, interior finishes and furnishings greatly affect the speed with which a fire grows and, consequently, can contribute to a potentially catastrophic fire event.
The pill test: The first standard, U.S. Department of Commerce (DOC) FF 1-70, requires all carpet and large rugs (24 square feet or larger) manufactured for sale in the United States or imported into this country to pass a small-scale ignition test or “pill test.”
The test specifies that no more than one out of eight specimens should burn a distance of three inches from the point of ignition, when tested according to the prescribed method. The pill test subjects a carpet or rug to a condition similar to a lighted cigarette, match or a fireplace ember.
Eight 9 inch x 9 inch specimens are cut from the same carpet roll, placed in an oven to remove the moisture, and allowed to cool in a moisture-free container. Each specimen is placed in a specially designed box that eliminates drafts. A methenamine (time burning) tablet is placed in the center of the carpet specimen, and then the tablet is ignited, providing a standard flame source for 2 minutes. If the burned or charred area is more than 3 inches in any direction from the center, the specimen fails. If two or more specimens fail, then the carpet roll fails and must not be sold.
The second, standard DOC FF 2-70, stipulates that small rugs less than 24 square feet must be tested, but they do not have to pass the test. If small rugs, as defined by the regulation, do not pass, they must have a permanent label stating, “Flammable; (Fails U.S. Department of Commerce Standard FF 2-70); should not be used near sources of ignition.” Details of these standards, FF 1-70 and FF 2-70, may be found in the Code of Federal Regulations under 16 CFR 1630 and 16 CFR 1631, respectively.
Flooring radiant panel test: Local building and fire codes should be reviewed for applicability of this more stringent test. Critical radiant flux limits for specific use areas where automatic sprinkler protection is not provided are as follows:
These limits are based upon known performance of traditionally used materials and the performance of flooring systems when subjected to full-scale corridor fire tests. The higher level of critical radiant flux recommended within healthcare occupancies is based on the assumption that non-ambulatory occupants (patients) require a higher level of protection than would be necessary in buildings where occupants are mobile and rapid escape is possible.
The flooring radiant panel test evaluates the tendency of a floor system to spread flame when exposed to the radiant heating of a gas-fired radiant panel. The method determines a material’s critical radiant flux (measured in watts per square centimeter) — the lowest intensity of radiant heat that will cause a floor covering to propagate flame over its surface. The flooring radiant panel apparatus involves a 39 inch x 8 inch sample that is horizontally mounted on the floor of the test chamber. The specimen receives the radiant energy exposure from an air-/gas-fueled radiant panel mounted above the specimen. The gas-fired radiant panel generates a radiant heat energy exposure along the length of the specimen, ranging from a maximum of approximately 1.1 watts per square centimeter immediately under the radiant panel to approximately 0.1 watts per square centimeter at the far end of the test specimen, remote from the panel. A gas-fired pilot burner is used to initiate the flaming of the sample. The test is continued until the flooring system ceases to burn. The distance the flooring system burns is noted. The radiant heat energy exposure is noted at the point the flooring system “self-extinguished.” This measurement is reported as the sample’s critical radiant flux. This value, critical radiant flux, is the minimum energy necessary to sustain flame propagation.
The test method also has been adopted as a standardized test by the American Society for Testing and Materials (ASTM) and the National Fire Protection Association (NFPA) and is identified as ASTM-E-648 and NFPA-253, respectively.
The Flooring Radiant Panel test is referenced in the Basic Building Code of Building Officials and Code Administrators International, Inc. (BOCA), the Standard Building Code of Southern Building Code Congress International, Inc. (SBCC), the Life Safety Code of the National Fire Protection Association (NFPA), and the Uniform Fire Code of the International Conference of Building Officials (ICBO).