Flammability testing combustion products

Fire extinguishment can be attained with certain products by using a sprinkler system that discharges a low expansion foam or AFFF agent, typically at concentrations of 1%, 3%, or 6% with water. Foam-water sprinkler systems have been successfully tested with ordinary products and containerized storage of flammable and combustible liquids. The cooling capabilities of foam-water... 

The substitution of more benign solvents in many formulations will have global ramifications. For example, water-reducible coatings are products where the solvent system used to disperse and suspend solids is primarily water. The remainder of the solvent system may contain liquids that are classified as flammable or combustible liquids. Inherent limitations in these systems relate to product viscosity, accuracy in predicting overall fire hazard, abihty to assess physical changes of state when a product is tested, and test method rehabihty and ease of use (Scheffey and Tabar, 1996). 

The purpose of bench-scale reaction-to-fire tests is to measure the flammability characteristics of materials, i.e., ease of ignition, flame spread propensity, heat release, and production of smoke and toxic combustion products. Some tests are designed to measure only one of these characteristics. Other tests are more sophisticated and can be used to measure several characteristics at the same time. 

Many current flammability tests are based on perceived hazards and often involve flames applied to products or materials. Such tests use flames of different type, size, and duration, and test specimens of different size, shape, and orientation, although considerable rationalization has taken place recently. For historical reasons, they are often industry and or product based. The majority of these tests essentially determine whether a product will sustain combustion away from the ignition. source. When assessed in terms of fire hazard analysis, the effective differences between these flames may be minor compared to the actual fire scenario. 

The above discussion shows that a definitive toxicity specification for combustion gases is much more uncertain than that for the strictly defined flammability or smoke production, in spite of the great number and variety of toxicity test results. Even the test procedures are less established — only one of them has been standardized so far (DIN 53 436). The Technical Committee 92 of the International Standard Organization (ISO) has reached only a Technical Report, ISO/TR 6543-1979, surveying the published test methods without any appraisal. 

Moves to harmonise fire safety assessment for building products in Europe has sparked a major shake-up in the flammability testing and classification of polymer materials [2]. As far back as 1998, over 30 tests were in use and more have been developed since then. The most radical change will be the introduction of the Single Burning Item for class B, C and D materials of intermediate combustibility, including most plastics. 

The ignition, combustion, and fire propagation behaviors of polymer are examined in various flammability test standards, where polymers are intentionally degraded, and the degradation products are ignited and burned under controlled exposure and environmental conditions. Various countries and agencies promulgate these types of flammability test standards ... 

Cone calorimetry according to the ASTM E1354138 or ISO 5660139 standards are commonly used in the laboratory to screen flammability of materials by measuring heat release characteristics of the compound.116140 This device is similar to FPA but does not have the versatility of FPA. The cone calorimeter can determine the ignitability, heat release rates, effective heat of combustion, visible smoke, and C02 and CO development of cable materials. This test has been used extensively for wire and cable material evaluation. The microscale combustion calorimeter (MCC), also known as pyrolysis combustion flow calorimeter (PCFC), was recently introduced to the industry for screening heat release characteristics of FR materials.141142 This device only requires milligram quantities of test specimen to measure the heat release capacity (maximum heat release potential). Cone calorimetry and MCC have been used in product development for flammability screening of wire and cable compounds.118... 

A micro-scale combustion calorimetric method test has been developed by Walter and Lyon, which involves pyrolysis and combustion calorimetry of the volatile products [12]. Using this technique, the heat release capacity can be obtained. The heat release capacity is a material parameter and has been used to correlate polymer structures with flammability [13]. 

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