Assessment flame spread

Two other test apparatuses are also suitable to assess flame spread of materials those in ASTM E 162,55 radiant panel (which is also used for cellular plastics, as ASTM D 3675152) and the one in ASTM E 1321,146, also known as the LIFT test. A variation of the latter is used by the marine industry (ASTM E 1317).131... 

Some of the other properties of interest for fire hazard assessment cannot be measured with RHR calorimeters. They include flame spread, limiting oxygen index (LOI, or simply oxygen index, 01 both names have been used, but the author s preferred nomenclature is the one used here) and fire endurance. 

Fire safety in a particular scenario is improved by decreasing the corresponding level of fire risk or of fire hazard. Technical studies will, more commonly, address fire hazard assessment. Fire hazard is the result of a combination of several fire properties, including ignitability, flammability, flame spread, amount of heat released, rate of heat release, smoke obscuration and smoke toxicity. 

Furthermore, it has been shown that the time period until ignition occurs, in the Cone calorimeter, is proportional to the inverse of the flame spread rate [16]. The Cone calorimeter can also be used to provide the mass loss rate information required for the simplified classification into categories of toxic hazard [1] quick toxic hazard assessment. Thus, the NBS Cone calorimeter is a very useful tool to overcome some of the disadvantages associated with measuring a single property at a time. 

Long Jr, R.T., An evaluation of the lateral ignition and flame spread test for material flammability assessment for micro-gravity environments, MS Thesis, Department of Fire Protection Engineering, University of Maryland, College Park, Maryland, 1998. 

As mentioned earlier, the fire hazard of interior finish materials is primarily due to the potential for rapid wind-aided flame spread over the surface. It is therefore not a surprise that reaction-to-fire requirements for interior finish materials in U.S. building codes are primarily based on performance in a wind-aided flame spread test. The apparatus of this test is often referred to as the Steiner tunnel. The Steiner tunnel test is described in ASTM E 84. Although the test does not measure any material properties that can be used in a model-based hazard assessment, a discussion of the test is included here due to its practical importance for the passive fire protection of buildings in the United States. 

In this test, a small sample of material (127 mm x 13 mm, or 5 in. x 0.5 in.) is exposed vertically to a small Bunsen burner-type flame from underneath (in the UL 94 V test) and the results show a rating, ranging from V-0 (best), through V-l, V-2 to B (for Burn). Materials with a B rating on the UL 94 Vertical test can also be tested in the less severe UL 94 HB (for horizontal burning), where the assessment is whether a flame spread rate of 4in./min is achieved. It is the most widely used fire-test specification for plastic materials, especially fire-retarded ones, and forms the basis of the famous Yellow Card used by ULs to list the plastic materials. The results from these tests are almost invariably found in a variety of specifications and data sheets. 

Measurement of flame spread under external heat flux is necessary where the thermal radiation is likely to impinge on the textile materials, for example, the flooring material of the building or transport vehicles whose upper surfaces are heated by flames or hot gases, or both. The French test method, NF P 92-503 Bruleur Electrique or M test involves radiant panel for testing flame spread of flexible textile materials. This test method (flame spread under external heat flux) is the basis of that used by the FAA (Federal Aviation Administration) for assessing flammability of textile composites used in thermal/acoustic insulation materials (FAR 25.856 (a)) used in aircraft and has also been included by the EU for fire test approval of floorings such as prEN ISO 9239 and BS ISO 4589-1. 

ASTM 3894 [139] is the standard that tests the flammability of the specimen arranged as two walls only, each 1220 mm x 610 mm high, or two walls plus a ceiling 1220 mm X 610 mm high, or two walls plus a ceiling 1220 mm square, which are exposed to a premixed propane flame positioned in the lower corner. A specified temperature time calibration is specified, and results are assessed in terms of flame spread. Thermocouples are positioned at specified locations on the specimen surface, and the times to maximum temperatures and the maximum temperatures are recorded. 

The formulation passes the FMVSS 302 (Federal Motor Vehicle Safety Standard) test used for the assessment of the burning behavior of materials used for vehicle interiors. A specimen of 35.5 X 10.0 X max. 13 cm is mounted horizontally and ignited for 15 sec. The rate of flame spread should not exceed 10 cm/min.]... 

Guidance for controlling combustible materials is provided in Chapter 5 of the SNL ES H Manual. Materials used in construction must meet criteria established to limit the combustibility, flame spread and smoke generation potential of the materials. Minimization of combustible materials is also achieved by good housekeeping practices to reduce unnecessary items and lower the overall fire load. Periodic assessments, which work in conjunction with housekeeping, are conducted to identify any materials or hazards that need to be removed. 

Basically the test involves mounting a corner section specimen - a vertical 1.5 m high by 1.0 m wide panel and another 1.5 m by 0.5 m at 90 degrees - under an enclosed calorimeter bood. Tbe Fire Research Station says the setup can accurately measure the rate of heat release, considered one of the most important parameters in assessing fire growth, also time to ignition, rate of lateral flame spread, time of production of flaming droplets and rate of smoke release. 

This is an assessment of the rate at which a flame travels along the length of a horizontal rectangular specimen. The assessment is not intended to be a measure of the performance of a material in actual fire conditions. An excellent rating indicates low flame spread. A very poor rating indicates considerable flame spread. 

The properties derived from ASTM E1321 provide information about the flame spread characteristics of materials and can serve as an indication of their hazardous characteristics [38]. The test results provide material fire parameters that correspond to property data required by theories of surface flame spread [38]. The analysis may be used to rank materials performance by some set of criteria applied to the correlation or the analysis may be employed in fire risk growth models to develop a more rational and complete risk assessment for wall materials [38]. 

ASTM E132 was developed as an improvement on the apparatus in ASTM E162 [38]. The specimen size for flame spread studies is 155 by 800 mm by a maximum thickness of 50 mm. This test method determines the critical flux for flame spread, the surface temperature needed for flame spread and the thermal inertia or thermal heating property (product of the thermal conductivity) test. These properties are used mainly for assessment of fire hazard and for input into fire models. A flame spread parameter is also determined, and this can be used as a direct way of comparing the responses of the specimens. It has been used for predictions of full-scale flame performance [39]. 

Flammability of polymers is assessed primarily throngh ignitability, flame spread, and heat release. Depending on the application of the polymeric material, one or more of these flammability criteria should be measured in appropriate flammability tests. Numerous flanunability tests are known and are performed either on representative samples or on an assembled product. Tests can be small, intermediate, or fiiU scale. Although similar trends in the rating of materials can be found based on small- and large-scale tests, in general there is no direct correlation between these tests. 

Underwriters Laboratories UL-94 test is designed to assess the flammability of plastic materials for parts in devices and appliances. The test measures ignitability and flame spread of polymeric materials exposed to a small flame. It is accepted for standardization in many countries and also internationally. Five... 

All important factor in assessing tlie causes and effects of fires is tlie beluivior of a fire s flmne. Knowledge of a flame s spreading rate and heat intensity can reduce fire liazard potentials and fire damage. The classifications of flame behavior are ... 

It is important to look beyond the initiating event to determine the potential for fire to spread to adjacent areas. If the fire is not detected early and quickly controlled, then the fire can escalate and involve other equipment and units. For escalation to occur, the fire must impact adjacent equipment by either radiant heat or flame impingement. In most risk assessments, escalation is taken into account by establishing a rule set. If any of the conditions within the rule set are exceeded, then escalation is assumed to occur. Typically, rule-sets may include ... 

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