Fire retardant fabrics are textiles that are naturally more resistant to fire than others through chemical threatment or manufactured fireproof fibers.
The term fire retardant as applied to organic (i.e., containing carbon) materials, is intended to refer to reduced fire hazard, as all will burn under certain circumstances. The tests used specified in building codes, such as NFPA 701, are more correctly flame resistance tests, which test a fabric's ability to resist ignition with the flame size and duration in the test conditions. The result is a comparative test, which provides a measure of the material's resistance to propagating combustion caused by small scale ignition sources. These tests do not predict the burning characteristics of full scale hazards. In many cases, if exposed to a sufficiently large and sustained exposure fire, the fire retardant fabrics will burn vigorously.
Fabric flammability is an important textile issue, especially for stage drapery that will be used in a public space such as a school, theatre or special event venue. Federal regulations require that drapery fabrics used in such spaces be certified as flame or fire retardant. For draperies and other fabrics used in public places, this is known as the NFPA 701 Test, which follows standards developed by the National Fire Protection Association (NFPA). Although all fabrics will burn, some are naturally more resistant to fire than others. Those that are more flammable can have their fire resistance drastically improved by treatment with fire retardant chemicals.
The flammability of fabric can be drastically reduced through the use of fire retardants. Many natural fibers, including cotton, can be topically treated with a chemical that reduces the fabricís flammability to the extent that it becomes nearly non-combustible. During a fire, the chemical reacts with the gases and tars generated naturally by the fabric, converting the gases and tars to carbon char, thus drastically slowing the fabricís burning rate.
Some polyester fabrics are considered permanently fire retardant. This is because fire retardant properties are built directly into the molecular structure of the fibers. Fabrics manufactured utilizing Trevira and Avora polyester fibers are considered inherently or permanently fire retardant. Other synthetic fabrics may be considered durably fire retardant, fire retardant, or non-fire retardant. Durably fire retardant refers to a process in which polyesters are chemically treated during the manufacturing process with a non-water soluble chemical. In other cases, synthetic fabrics may be topically treated with chemicals after the manufacturing process (in the same manner as natural fibers such as cotton), or may be untreated (or untreatable) and therefore considered non-fire retardant.
Aramid, like Twaron is used in modern fabrics to withstand high temperatures in industry and fire-fighting.
When a fabric is designated as inherently fire retardant, permanently fire retardant, or durably fire retardant, the flame retardancy will last for the life of the fabric. The drapery can be laundered or dry-cleaned as recommended by the drapery manufacturer. In the case of fabrics that are designated as fire retardant, that have been topically treated with chemicals, the flame retardancy of the fabric will dissipate over time, particularly with repeated cleaning. These fabrics must be dry-cleaned with a non-liquid cleaning agent.
Typically, the flame retardancy of topically treated fabric is certified for one year, though the actual length of time in which the treatment remains effective will vary based on the number of times the drapery is dry-cleaned and the environmental conditions in the location in which the drapery is used. It is recommended that topically treated drapery be re-tested for fire retardancy on an annual basis and re-treated by a qualified professional as needed.
Source: Wikipedia (All text is available under the terms of the GNU Free Documentation License)