【国外标准】 Standard Test Method of Small-Scale Evaluation of Fire-Retardant Paints (2-Foot Tunnel Method)

3.1 A number of laboratory procedures are used to evaluate the effectiveness of fire-retardant and fire-resistant treatments and coatings. In general, these methods measure the three stages of fire development: (1) ignition; (2) flame spread (rate of growth of the fire); and (3) conflagration extent. While all three are of extreme importance, flame spread has been recognized as the main factor associated with testing fire-retardant coatings.3.2 Flame spread ratings based upon Test Method E84 have acquired common acceptance by regulatory agencies, but such large-scale tests are seldom practical during the development or modification of a fire-retardant coating.3.3 This test method provides the relative flame spread of experimental coatings using small test specimens under the conditions established in the 2-foot tunnel. By experimentally calibrating the 2-foot tunnel with similar Test Method E84-rated fire-retardant paint, results obtained by this test method can be used to screen coatings for suitability for testing in the Test Method E84 tunnel.3.3.1 This test method is intended as an experimental tool in evaluating experimental coatings for further development. No direct correlation of results from this test method and the Test Method E84 tunnel have been made or are implied.3.3.2 The results obtained by this test method do not in themselves act as an accurate predictor of performance in Test Method E84 and shall not be used for the purpose of certification to any class of flame spread performance.1.1 This test method determines the protection a coating affords its substrate, and the comparative burning characteristics of coatings by evaluating the flame spread over the surface when ignited under controlled conditions in a small tunnel. This establishes a basis for comparing surface-burning characteristics of different coatings without specific consideration of all the end-use parameters that might affect surface-burning characteristics under actual fire conditions.1.2 In addition to the experimental flame spread rate, the weight of panel consumed, time of afterflaming and afterglow, char dimensions and index, and height of intumescence can be measured in this test. However, a relationship should not be presumed among these measurements.1.3 This standard is used to determine certain fire-test responses of materials, products, or assemblies to heat and flame under controlled conditions by using results obtained from fire-test response standards. The results obtained from using this standard do not by themselves constitute measures of fire hazard or fire risk.1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.5 This standard is used to measure and describe the response of materials, products, or assemblies to heat and flame 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.1.6  Fire testing is inherently hazardous. Adequate safeguards for personnel and property shall be employed in conducting these tests.1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.