1.1 本火灾试验响应标准涵盖了一种方法，用于确定暴露在50 kW/m辐射热通量下时点燃的材料或产品产生的烟雾的致命毒性 2. 持续15分钟。 1.2 该试验方法仅限于厚度不大于51 mm（2 in.）、不大于76 mm乘127 mm（3 in.乘5 in.）的试样。样品旨在代表成品材料或产品，包括复合材料和组合系统。 1.3 与30分钟暴露相关的致命毒性效力值是使用燃烧气氛分析数据进行计算预测的，这些数据包括一氧化碳、二氧化碳、氧气（失效）以及氰化氢、氯化氢和溴化氢（如果存在）。 因此，预测方程仅限于那些烟雾毒性可归因于这些毒物的材料和产品。动物检查确定了额外的毒物对烟雾致命毒性的影响程度。 1.4 以国际单位制表示的数值应视为标准。SI单位后括号中给出的值仅供参考，不被视为标准值。 1.5 本标准测量并描述了材料、产品或组件在受控条件下对热量的响应，但其本身并未包含在实际火灾条件下对材料、产品和组件进行火灾危险性评估所需的所有因素。 1.6 本标准并不旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性（尤其是与实验动物的护理和使用有关的限制）。 有关具体危害说明，请参阅第节 7. 和 注X1.1 . 1.7 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。 ====意义和用途====== 5.1 该测试方法旨在为火灾危险性的数学建模提供数据，作为评估材料和产品的手段，并协助其研发。 5.1.1 试验方法 E1678 在功能上等同于NFPA 269-2017。 5.2 该试验方法用于预测并随后确认材料或产品暴露于特定火灾试验条件下产生的烟雾的致命毒性。确认确定某些主要气体毒物是否解释了观察到的毒性作用和致命毒性效力。如果预测的致命毒性效价没有得到充分证实，表明可能存在异常或无法解释的毒性，则需要使用其他方法来研究致命毒性效价，例如进行LC的实验测定 50 使用所描述的设备。看见 X1.3.1和 X1.3.2 .) 5.3 该试验方法产生的致命毒性效价值适用于闪络前和闪络后火灾的建模。在美国，大多数因吸入烟雾而导致的火灾死亡发生在火灾发生房间以外的区域，并且是由火灾发生房间之外的火灾引起的。假设这些是闪络火灾。因此，重点放在评估这些条件下的毒性危害上。在闪络后火灾中，大量一氧化碳的产生是由于向火羽的空气供应减少和其他房间规模因素造成的。台架试验不具备模拟这些现象的能力。 该试验方法中确定的致命毒性效价值是从更能代表闪络前而非闪络后条件的燃料/空气比中获得的。在火灾危险建模中需要预闪络火灾表示的情况下，这些LC 50 值是适当的。本试验方法中确定的致命毒性和一氧化碳产量值需要进行调整，以用于对闪络后条件下的危害进行建模。看见 X1.4.1 .) 5.4 当用于预测实际规模的毒性时，本试验方法中确定的致命毒性值的准确性存在一定程度的不确定性。看见 X1.4.2 .) 5.4.1 工作台的准确性- 闪络前火灾的规模数据尚未通过实验确定。装置中的燃烧条件与实际的闪络前火灾非常相似，尽管质量燃烧率在50kW/m时可能更高 2. 试验方法的辐照度。 5.4.2 毒物产量与LC的比较 50 使用该方法获得的（后闪络）值已在有限的试验中显示 ( 1. ) 以复制LC 50 从实际规模、闪络后火灾到精度约为三倍以内的值。因此，LC 50 （后闪络）值相差不到三分之一，彼此无法区分。看见 X1.4.2 .) 5.5 本试验方法不试图解决真实火灾中可能发生的颗粒物和气溶胶尺寸、烟雾传输、分布或沉积变化或任何烟雾成分浓度随时间变化的毒理学意义。 5.6 只有在老鼠作为一个生物系统与人类相关的情况下，才能推断出任何材料产生的烟雾在火灾情况下对人类产生相同影响的倾向。 5.7 此测试方法不评估丧失能力。丧失能力必须根据致命毒性效价推断。 5.8 本试验方法未涉及感官刺激的影响。

1.1 This fire-test-response standard covers a means for determining the lethal toxic potency of smoke produced from a material or product ignited while exposed to a radiant heat flux of 50 kW/m 2 for 15 min. 1.2 This test method is limited to test specimens no larger than 76 mm by 127 mm (3 in. by 5 in.), with a thickness no greater than 51 mm (2 in.). Specimens are intended to be representative of finished materials or products, including composite and combination systems. 1.3 Lethal toxic potency values associated with 30-min exposures are predicted using calculations that use combustion atmosphere analytical data for carbon monoxide, carbon dioxide, oxygen (vitiation) and, if present, hydrogen cyanide, hydrogen chloride, and hydrogen bromide. The predictive equations are therefore limited to those materials and products whose smoke toxicity can be attributed to these toxicants. An animal check determines the extent to which additional toxicants contribute to the lethal toxic potency of the smoke. 1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard. 1.5 This standard measures and describes the response of materials, products, or assemblies in response to heat under controlled conditions, but does not by itself incorporate all factors required for fire hazard of fire risk assessment of the materials, products, or assemblies under actual fire conditions. 1.6 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 (particularly with regard to the care and use of experimental animals) prior to use. For specific hazards statements, see Section 7 and Note X1.1 . 1.7 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. ====== Significance And Use ====== 5.1 This test method has been designed to provide data for the mathematical modeling of fire hazard as a means for the evaluation of materials and products and to assist in their research and development. 5.1.1 Test Method E1678 is functionally equivalent to NFPA 269-2017. 5.2 This test method is used to predict, and subsequently confirm, the lethal toxic potency of smoke produced upon the exposure of a material or product to specific fire test conditions. Confirmation determines whether certain major gaseous toxicants account for the observed toxic effects and lethal toxic potency. If a predicted lethal toxic potency value is not confirmed adequately, indicating a potential for unusual or unexplained toxicity, the lethal toxic potency will need to be investigated using other methodology, such as conducting an experimental determination of the LC 50 using the apparatus described. (See X1.3.1 and X1.3.2 .) 5.3 This test method produces lethal toxic potency values that are appropriate for use in the modeling of both pre-flashover and post-flashover fires. Most fire deaths due to smoke inhalation in the U.S. occur in areas other than the room of fire origin and are caused by fires that have proceeded beyond the room of fire origin. It is assumed that these are flashover fires. Therefore, the principal emphasis is placed on evaluating toxic hazard under these conditions. In post-flashover fires, large concentrations of carbon monoxide results from reduced air supply to the fire plume and other room-scale factors. Bench-scale tests do not have the capacity to simulate these phenomena. The lethal toxic potency values determined in this test method are obtained from fuel/air ratios more representative of pre-flashover, rather than post-flashover conditions. In cases where a pre-flashover fire representation is desired in fire hazard modeling, these LC 50 values are appropriate. Lethal toxic potency and carbon monoxide yield values determined in this test method require adjustment for use in modeling of the hazard from post-flashover conditions. (See X1.4.1 .) 5.4 The lethal toxic potency values determined in this test method have a level of uncertainty in their accuracy when used to predict real-scale toxic potencies. (See X1.4.2 .) 5.4.1 The accuracy of the bench-scale data for pre-flashover fires has not been established experimentally. The combustion conditions in the apparatus are quite similar to real pre-flashover fires, although the mass burning rate may be higher at the 50 kW/m 2 irradiance of the test method. 5.4.2 Comparison of the toxicant yields and LC 50 (post-flashover) values obtained using this method have been shown in limited tests ( 1 ) to reproduce the LC 50 values from real-scale, post-flashover fires to within an accuracy of approximately a factor of three. Therefore, LC 50 (post-flashover) values differing by less than a factor of three are indistinguishable from each other. (See X1.4.2 .) 5.5 This test method does not attempt to address the toxicological significance of changes in particulate and aerosol size, smoke transport, distribution, or deposition or changes in the concentration of any smoke constituent as a function of time as may occur in a real fire. 5.6 The propensity for smoke from any material to have the same effects on humans in fire situations can be inferred only to the extent that the rat is correlated with humans as a biological system. 5.7 This test method does not assess incapacitation. Incapacitation must be inferred from lethal toxic potency values. 5.8 The effects of sensory irritation are not addressed by this test method.