ASTM F3538-22

SIGNIFICANCE AND USE 5.1 This test method is intended for the determination of the cylinder heat transfer performance value of a flame-resistant material or combination of materials when exposed to a continuous and constant heat source. This is used to compare materials used in flame-resistant clothing for workers when exposed to combined convective and radiant thermal hazards. Note 3: Air movement at the face of the specimen and around the calorimeter can affect the measured heat transferred due to forced convective heat losses. Minimizing air movement around the specimen and test apparatus will aid in the repeatability of the results. 5.2 This test method maintains the specimen with and without air gaps in a static, horizontal position and does not involve movement unless the test specimen naturally changes due to the thermal exposure. 5.3 This test method specifies a standardized 84 ± 2 kW/m2 (2 ± 0.05 cal/cm2·s) exposure condition. Different exposure conditions have the potential to produce different results. Use of other exposure conditions that are representative of the expected hazard are allowed but shall be reported with the results, along with a determination of the exposure energy level stability. 5.4 This test method does not predict skin burn injury from the heat exposure. 5.5 This test method is similar to Test Method F2700 in that it uses the same energy heat source, water-cooled shutter, data acquisition, and measures the heat transfer through protective clothing materials using a copper calorimeter. This test method differs from Test Method F2700 in the usage of an eccentric instrumented cylinder mounted horizontally that allows for the thermal shrinkage of materials when tested. SCOPE 1.1 This test method measures the thermal response of a material or combination of materials using a combined convective/radiant heat transmission apparatus consisting of an eccentric cylindrical test sensor. It can be used to estimate the non-steady state thermal transfer through flame-resistant materials used in clothing when subjected to a continuous, combined convective and radiant heat exposure. The average incident heat flux is 84 kW/m2 (2 cal/cm2·s), with durations up to 30 s. 1.1.1 This test method is not applicable to materials that melt, drip, or cause falling debris during the test. Note 1: Because of the arrangement of the equipment, if materials melt, drip, or cause falling debris during the test, the test result is invalid. 1.2 Heat transmission through clothing is largely determined by its thickness, including any air gaps. The air gaps can vary considerably in different areas of the human body. This method provides a means of grading materials when tested under standard test conditions and an air gap exists between the fabric and the sensor. During the exposure, fabric temperatures can exceed 400 °C. At these temperatures some fabrics are not dimensionally stable and can shrink or stretch. The cylindrical geometry used in this test method allows such motion to occur, which will affect the time to achieve the end point of the test. These effects are not demonstrated in planar geometry test methods such as Test Method F2700. 1.3 This test method is used to measure and describe the response of materials, products, or assemblies to heat under controlled conditions, but does not by itself incorporate all factors required for fire hazard or fire risk assessment of the materials, products, or assemblies under actual fire conditions. 1.4 The measurements obtained and observations noted only apply to the particular material(s) tested using the specified heat flux, flame distribution, and duration. 1.5 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to inch-pound units or other units commonly used for thermal testing. If appropriate, round the non-SI units for convenience. 1.6 This standard does not p...