Heat release tests. Cone calorimeter

ISO 5660-1 Reaction-to-Fire Tests—I leal Release, Smoke Production and Mass Loss Rate—Part 1 Heat Release Rate (Cone Calorimeter Method). International Organization for Standardization, Geneva, Switzerland. ISO 5660-2 Reaction-to-Fire Tests—I Ieat Release, Smoke Production and Mass Loss Rate—Part 2 Smoke Production Rate (Dynamic Measurement). International Organization for Standardization, Geneva, Switzerland. ISO 9705 Fire Tests—Reaction-to-Fire—Room Fire Test. International Organization for Standardization, Geneva, Switzerland. 

ISO 5660 Reaction-To-Fire Tests—Heat Release, Smoke Production And Mass Loss Rate—Part 1 Heat Release Rate (Cone Calorimeter Method), ISO, Geneva, Switzerland, 2002. 

ASTM E1354-04 (standard test method for heat and visible smoke release rates for materials and products using an oxygen consumption calorimeter) and ISO 5660-1 2002 (reaction-to-fire tests-heat release, smoke production, and mass loss rate - part 1 heat release rate, cone calorimeter method) for heat release and oxygen consumption. 

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... 

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... 

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... 

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... 

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. 

The Cone calorimeter yields smoke results which have been shown to correlate with those from full scale fires [10, 15-18]. The concept of a combined heat and smoke release measurement variable for small scale tests has been put into mathematical terms for the cone calorimeter smoke parameter (SmkPar) [10]. It is the product of the maximum rate of heat release and the average specific extinction area (a measure of smoke obscuration). The correlation between this smoke parameter and the smoke obscuration in full scale tests has been found to be excellent [10]. The corresponding equation is ... 

This parameter, the smoke parameter, is based on continuous mass loss measurements, since the specific extinction area is a function of the mass loss rate. A normal OSU calorimeter cannot, thus, be used to measure smoke parameter. An alternative approach is to determine similar properties, based on the same concept, but using variables which can be measured in isolation from the sample mass. The product of the specific extinction area by the mass loss rate per unit area is the rate of smoke release. A smoke factor (SmkFct) can thus be defined as the product of the total smoke released (time integral of the rate of smoke release) by the maximum rate of heat release [19], In order to test the validity of this magnitude, it is important to verify its correlation with the smoke parameter measured in the Cone calorimeter. 

The same hazard concept could, potentially, be used for full scale tests, multiplying the total heat released, per unit surface exposed, by the maximum smoke obscuration. This is the basis for the magnitude smoke hazard (Smoke Haz.), shown in Table II. It is of interest that smoke hazard results yield the same ranking as mass of soot formed. Cone calorimeter tests are being planned with the same materials used in the full scale tests to investigate the usefulness of this concept. 

ISO DIS 5660 Fire Test—Reaction to Fire—Rate of Heat Release from Building Products 1990 STD. BSIDD 246-ENGL 1999 Recommendations for use of the Cone Calorimeter. 

The time to ignition as a function of incident radiant heat flux can also be measured in the ISO ignit-ability test apparatus. This apparatus and its use are described in ISO 5657. Bench-scale heat release calorimeters such as the Cone Calorimeter (Section 14.3.3.2.1) and the Fire Propagation Apparatus (Section 14.3.3.2.3) can also be used to obtain this kind of data. 

Of the several approaches that have been used to calculate fuel generation rates from solid materials in CFD-based fire growth calculations, the simplest are empirical models. Instead of attempting to model the physical processes that lead to gaseous fuel production inside decomposing solids, empirical data that can be measured (transient heat release or mass loss rate) or inferred (heat of gasification) from common bench-scale fire tests such as the Cone Calorimeter are used to characterize fuel generation processes. 

Other test methods can also be used to assess ignitability, together with other properties. Some important ones are the cone calorimeter (ASTM E 1354,71 Figure 21.7, which has the assessment of heat and smoke release as its primary purpose) the OSU calorimeter (ASTM E 906,38 Figure 21.8, which also... 

In the early 1980s, Vytenis Babrauskas, at the NIST (then NBS), developed a more advanced test method to measure RHR the cone calorimeter (ASTM E 1354).71164 This fire test instrument can also be used to assess other fire properties, the most important of which are the ignitability (as discussed earlier), mass loss, and smoke released. Moreover, results from this instrument correlate with those from full-scale fires.165-170 To obtain the best overall understanding of the fire performance of the materials, it is important to test the materials under a variety of conditions. Therefore, tests are often conducted at a variety of incident heat fluxes. The peak rates of heat release (and total heat released) of the same materials shown in Table 21.15 at each incident flux, are shown in Table 21.16.147... 

ASTM E 84 Steiner tunnel test, thus generating more useful results. Figure 21.13 shows a room-comer test layout. The cone calorimeter fire-performance index (with tests conducted at 50kW/m2)179 was shown to be a good predictor of time to flashover in FAA full aircraft fires170 180 and in the ISO 9705 room-corner test.181 In addition, the same cone calorimeter tests, but using only heat release criteria, have been shown to have almost perfect predictability of ISO 9705 room-comer test rankings.181... 

Subsequently, the ignition temperature and the HRC parameter can be determined and used to compare PCFC data with data from other test methods. The HRC is defined as the ratio of the heat release rate and the heating rate. The peak heat release rates determined in cone calorimeter experiments correlate well with peak HRC data from PCFC experiments. In terms of other tests, results from the LOI (ASTM D 2863) test method exhibit a reciprocal correlation with HRC values, while HRC can also be a rough indicator for UL 94 ratings. In approximate terms, it has been said that HRC results can classify materials into three ranges of material flammability, as follows ... 

ASTM E 1354, Standard Test Method for Heat and Visible Smoke Release Rates for Materials and Products Using an Oxygen Consumption Calorimeter (cone calorimeter), Annual Book ASTM Standards, American Society for Testing and Materials, West Conshohocken, PA. 

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