Fire retardation standards

Depending on the polymer and the applicable fire retardance standards, flame retardants are chosen to interfere with one or more stages ofthe combustion process heating, decomposition, ignition, flame spread, and smoke density. Fire retardants have to inhibit or even suppress the combustion process. 

The most extensive body of tests are provided under the auspices of ASTM Standard methods. Specific ASTM test designations and descriptions are available (48). The other compendium of fire-retardant tests are contained ia Federal Test Method Standards 191A (49). 

The Fire Tests for Flame Resistant Textiles and Films, issued by the National Fire Protection Association (NFPA) ia 1989, is the method most used by iadustrial fire-retardant finishers (ca 1993) (50). It has been approved by the American National Standards Institute. 

As weU as imparting improved fire retardancy these materials may also result ia volume cost savings if they can be purchased for a lower price than the commodity phthalate. Precise knowledge of the compatibiHty between standard plasticizers and chlotinated paraffins is requited because some mixtures become iacompatible with each other and the PVC resias ia use at certain temperatures. Phthalate—chlotinated paraffin compatibiHty decreases as the molecular mass of the phthalate and the plasticizer content of the PVC formulation iacrease. Many compatibiHty graphs are available (1). 

In addition to standard grades varying in the ABS/PC ratio, fire-retarded, glass-fibre-reinforced and glass-fibre-reinforced fire-retarded grades are available. Typical properties of three grades of ABS-PC alloys are given in Table 20.9. 

Flammability. The fire hazard associated with plastics has always been difficult to assess and numerous tests have been devised which attempt to grade materials as regards flammability by standard small scale methods under controlled but necessarily artificial conditions. Descriptions of plastics as selfextinguishing, slow burning, fire retardant etc. have been employed to describe their behaviour under such standard test conditions, but could never be regarded as predictions of the performance of the material in real fire situations, the nature and scale of which can vary so much. 

The feasibility of using these elastomeric foams as fire retardant thermal insulation has been demonstrated by a Department of the Navy-National Bureau of Standards Test Program (54). 

Babrauskas, V., Harris, R. H., Gann, R. G., Levin, B. C., Lee, B. T., Peacock, R. D., Paabo, M., Twilley, W., Yoklavich, M. F. and Clark, H. M., Fire Hazard Comparison of Fire-Retarded and Non-Fire-Retarded Products. NBS Special Publ. 749, July 1988, National Bureau of Standards, Gaithersburg, MD. 

The aim was to assess the feasibility of substitution with less hazardous flame retardants. They selected red phosphorus, ammonium polyphosphate and aluminium trihydroxide as the least environmentally problematic alternatives. Red phosphorus can technically be used in a variety of polymers to meet even the toughest fire safety standards, although it may network forall applications. ... 

But flame retardants, as with so many persistent organic pollutants, are like the flu exposure is everywhere, and hiding behind a healthy diet won t guarantee your safety. They are also a leveler of socioeconomic class. Californians, in many ways the healthiest Americans, appear to harbor the highest body burden of flame retardants. This is because the state has the highest fire safety standards and people s homes are oozing with the stuff. But California has affected—or infected—us all as state standards become the norm for... 

Several tests have been developed to evaluate fire-retardant coatings on acoustical fiberboard surfaces. These tests are being reviewed and modified where there is necessity for standardization of the test. 

The present investigation was planned, therefore, to compare the behavior in large scale fires, of the former standard with that of newer formulations based upon chlorinated binders and with commercially available fire-retardant finishes. 

In the trials within the hangar deck, a general decrease in fire-retardancy was noted as the thickness of the paint films increased from 2 to 4 top coats. This was true for all the systems tried, except for No. 8 which retained its fire-retardancy even at a film thickness of 5.5 mils. This general decrease in fire-retardancy with increase in film thickness is in line with normal expectations. System 1, the standard fire-retardant... 

Certain commercial formulations approach or exceed the Navy s standard paint in regard to fire-retardancy. 

The addition of phosphorous-based plasticizers will provide a degree of fire retardancy to the polyurethane. Fryol PCF and CEF have been used in polyurethane systems. Most phosphorus-based fire retardants are thin liquids that are compatible with polyurethanes. Because of the very varied nature of fire-resistant tests, the material made must be tested to the appropriate standard. 

During the initial stages of a fire, fire-retardant-treated wood contributes less heat than does untreated wood, especially from the flammable volatiles (8,26). This means that the spread of fire to nearby combustibles is slow. The fire tends to be confined to the primary source. In the ASTM E84 test for building materials, treated specimens produce about 75 percent less heat than untreated red oak. In a total combustion test, however, such as the National Bureau of Standards potential heat method (54), both treated and untreated wood release about the same total heat. 

Studies are currently being conducted on smoke development and heat release rate from treated and untreated wood and wood products (52,56). An evaluation of the available treatment systems for wood shingles and shakes was completed using artificial weathering (11). A further development from this work was a new ASTM Standard Method D2898 (67,68) for testing durability of fire-retardant treatment of wood. 

The presence of impurities and additives such as PVC as a fire retardant in polyurethanes has also been detected by means of TG-MS analysis [144], PU foam containing the flame retardant tetrakis (2-chloroethyl) ethylenediphosphate decomposes in an oxidative atmosphere at standard pressure in one rapid reaction whereby several highly toxic species are formed the TG-MS detection limit of this flame retardant was determined [166]. The most striking fact is the very early generation of vinylchloride from the flame retardant, while HCN is produced at much higher temperatures. 

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