Heat release tests

The Ohio State University (OSU) calorimeter (12) differs from the Cone calorimeter ia that it is a tme adiabatic instmment which measures heat released dufing burning of polymers by measurement of the temperature of the exhaust gases. This test has been adopted by the Federal Aeronautics Administration (FAA) to test total and peak heat release of materials used ia the iateriors of commercial aircraft. The other principal heat release test ia use is the Factory Mutual flammabiHty apparatus (13,14). Unlike the Cone or OSU calorimeters this test allows the measurement of flame spread as weU as heat release and smoke. A unique feature is that it uses oxygen concentrations higher than ambient to simulate back radiation from the flames of a large-scale fire. 

This secondary effect of materials is illustrated by the difficulties encountered, in a recent study [54], when attempts were made to correlate CO concentrations measured in small scale and full scale fire tests. The same small scale equipment (typically the cone calorimeter rate of heat release test) could predict adequately a number of very important full scale fire properties, including ignitability, rate of heat release, amount of heat release and smoke obscuration. It could not, however, be used to... 

In an ideal situation the parameters used to define furniture should be ignition resistance and the rate of generation of heat, smoke and toxic gases. Tests to do this with actual or mock-up full sized furniture are not yet available as final specifications but the Nordtest (28) and NBS furniture calorimeters (29) represent scientific methods while room/ corridor rigs, typically UK DOE PSA FR5 and 6 of 1976 (5) (6) were originally used but are less satisfactory from a scientific point of view. The Californian (30) and Boston tests (31) for public area furniture are essentially simple room tests and are similar in principle to DOE, PSA, FR5 and 6 although the latter do not have pass/fail criteria. Bench scale rate of heat release tests include the NBS cone (29) which, with a code of practice represent a possible alternative but the rate of burning of... 

Boric acid in conjunction with APP was reported in epoxy intumescent coating.30-31 Boric acid and its derivatives were used in phenolics to impart thermal stability and tire retardancy. For example, Nisshin steel claims the use of boric acid and aluminum trihydroxide (ATH) in phenolics for sandwich panel.32 It was also reported that the small amounts of boric acid (around 0.25% by weight) in polyether imide (PEI) and glass-filled and PEI can reduce peak HRR by almost 50% in the OSU Heat Release test for the aircraft industry.33 In applications where high modulus and high strengths are needed, boric acid can be added without the softening effects of other additives such as siloxanes. 

The recent development of rate of heat release tests in a form that can be routinely used by test houses represents a major step forward. Probably the best known instrument is the cone calorimeter (ISO 5660-1), which determines the rate of heat release using the oxygen consumption technique. The OSU calorimeter (ASTM E906) uses a direct heat measuring system and is used in regulations by the FAA. 

ISO 5660-1 [92] defines the cone calorimeter, which is probably the most widely used ol the rate of heat release test methods see Fig, 17. A horizontal 100 mm square specimen is exposed to a radiant heat flux of 10 to 100 kW m with a spark ignition. system. The effluent is drawn through a duct fitted with sensors for determining temperature, gas flow rate, and oxygen concentration. These data enable the rate of heat release to be determined using the oxygen consumption method. For most plastics, rubbers, and natural materials, the amount of heat produced per unit mass of oxygen consumed is approximately the... 

Modified Flammability Tests. A number of smoke tests exist in which the smoke produced by a flammability or heat release test is determined using photocell light systems positioned in the smoke streams. 

There are various standard methods available to assess the heat release rate. Widely used bench scale methods include the cone calorimeter which is based on oxygen consumption principle, such as ISO 5660 and ASTM E1354, and the Ohio State University (OSU) heat release apparatus (accepted for ASTM E906 Test Method for Heat and Visible Smoke Release Rates for Materials and Products) which measures heat release rate by the sensible enthalpy rise method. The large scale heat release tests using... 

All the standards of polymer combustibility can be subdivided into five major types 1. Ignitability tests 2. Flame spread tests 3. Oxygen index 4. Heat release tests 5. Smoke tests. 

Flame Spread and Smoke Development from Tunnel Test Rate of Heat Release Test... 

Rate of Heat Release Test for Aircraft Cabin Materials. The Federal Aviation Administration requires (14 CFR 25.853) that large areas including interior ceiling and wall panels, partitions, galley structures, cabinets, and stowage compartments of commercial transport aircraft pass a rate of heat release test in addition to flammability and smoke tests. The rate of heat release apparatus (see Fig. 26) is a modified version of the ASTM E906, Standard Test Method For Heat And Visible Smoke Release Rates of Materials and Products (configuration A). 

Section 18.8 discusses ASTM D 2863 LOI testing as well as procedures of UL94 (ASTM D 3801), D 635 horizontal testing, D 1354 cone calorimeter procedures, the E 906 heat release test, E 84 Steiner tunnel large-scale tests, E 662 NBS smoke testing, and the D 5485 corrosive gas and E 1678 toxic gas tests. These arc the procedures most prevalent in the United States. There are literally scores of similar tests and also many of a special purpose nature, required by individual regulatory bodies. There is considerable effort under way to rationalize and correlate test procedures throughout the world. 

FAA regulations on the flammability of materials cover the following burning behavior heat release (OSU Heat Release Test), smoke generation (NBS Smoke... 

OSU Heat Release Test 2 minutes Peak Rate kw-min/m kw/m FAA Requirements 65 65 Transparent OSU Resin <55 <55... 

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