1.1 本规程涵盖了计算调整系数的程序，这些调整系数考虑了阻燃处理对木材设计性能的影响。根据本规程计算的调整系数将应用于未处理木材的设计值，以确定在环境温度[工作温度高达100°F（38°C）]和作为屋顶系统框架使用的阻燃处理木材的设计值。 注1: 该分析侧重于在受控暴露于高温和高湿度的特定条件下，与环境条件平衡后，测试的经处理和未经处理材料的相对性能。 未处理木材设计中通常考虑的高温、水分、负荷持续时间和其他因素也必须在阻燃处理木材的设计中加以考虑，但不在本规程下制定的处理调整范围内。 1.2 弯曲、平行于晶粒的张力、平行于晶粒的压缩、水平剪切、，弹性模量基于在标称室温[72°F（22°C）]下处理后的匹配处理和未处理的小型透明木材样本以及在150°F（66°C）下暴露后的其他类似样本的强度测试结果。 试验数据根据试验方法编制 D5664 . 为确定垂直于颗粒的压缩特性和连接设计值的调整系数提供了指南。 1.3 屋顶框架应用的处理调整系数基于美国采暖、制冷和空调工程师协会（ASHRAE）气象带定义的各种气候条件下使用的正常木质屋顶结构的热负荷曲线。 2. 选择了计算机模型中使用的太阳负荷、湿度条件、通风率和其他参数来代表典型的斜屋顶设计。 本规程中的热负荷适用于3/12或更陡的屋顶坡度，适用于设计有符合国家实践标准的通风区域和通风位置的屋顶，以及屋顶覆板底侧暴露于通风空气的设计。对于没有一个或多个这些基线特征的设计，用户需要记录本实践的适用性。 1.4 本规程的程序与实践中给出的程序类似 D6305 . 实践中的一般参考文献和评论 D6305 也适用于本实践。 1.5 以英寸-磅为单位的数值应视为标准值。括号中列出的国际单位仅供参考，不被视为标准单位。 1.6 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户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。 1.7 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）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》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 阻燃处理用于降低木材的阻燃特性。众所周知，处理中使用的化学品和复烤条件会改变正在处理的木制品的强度特性。本规程规定了确定调整系数的程序，这些调整系数解释了阻燃处理对木材设计性能的单独影响。这些影响是相对于未处理木材的性能确定的。 5.2 阻燃处理对屋顶框架应用中使用的木材强度的影响与时间有关。 在该实践中，所有温度箱对年度热负荷强度的累积影响增加了50倍，以确定阻燃处理木材屋顶框架的处理调整系数。 5.3 试验方法程序 D5664 采用旨在在短时间内产生强度损失的高温。虽然暴露比实际屋顶系统中发生的暴露严重得多，但实验室试验中发生的化学反应被认为与现场长时间发生的化学反应相同。 5.4 根据本规程制定的处理调整系数适用于按照阻燃化学品制造商建议的施工规程安装的木材，其中包括避免直接润湿、沉淀或频繁冷凝。本规程的应用仅限于设计符合以下要求的屋顶应用: 1.3 .

1.1 This practice covers procedures for calculating adjustment factors that account for the effects of fire-retardant treatment on design properties of lumber. The adjustment factors calculated in accordance with this practice are to be applied to design values for untreated lumber in order to determine design values for fire-retardant-treated lumber used at ambient temperatures [service temperatures up to 100 °F (38 °C)] and as framing in roof systems. Note 1: This analysis focuses on the relative performance of treated and untreated materials tested after equilibrating to ambient conditions following a controlled exposure to specified conditions of high temperature and humidity. Elevated temperature, moisture, load duration, and other factors typically accounted for in the design of untreated lumber must also be considered in the design of fire-retardant-treated lumber, but are outside the scope of the treatment adjustments developed under this practice. 1.2 These adjustment factors for the design properties in bending, tension parallel to grain, compression parallel to grain, horizontal shear, and modulus of elasticity are based on the results of strength tests of matched treated and untreated small clear wood specimens after conditioning at nominal room temperatures [72 °F (22 °C)] and of other similar specimens after exposure at 150 °F (66 °C). The test data are developed in accordance with Test Method D5664 . Guidelines are provided for establishing adjustment factors for the property of compression perpendicular to grain and for connection design values. 1.3 Treatment adjustment factors for roof framing applications are based on thermal load profiles for normal wood roof construction used in a variety of climates as defined by weather tapes of the American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. (ASHRAE). 2 The solar loads, moisture conditions, ventilation rates, and other parameters used in the computer model were selected to represent typical sloped roof designs. The thermal loads in this practice are applicable to roof slopes of 3 in 12 or steeper, to roofs designed with vent areas and vent locations conforming to national standards of practice and to designs in which the bottom side of the roof sheathing is exposed to ventilation air. For designs that do not have one or more of these base-line features, the applicability of this practice needs to be documented by the user. 1.4 The procedures of this practice parallel those given in Practice D6305 . General references and commentary in Practice D6305 are also applicable to this practice. 1.5 The values stated in inch-pound units are to be regarded as standard. The SI units listed in parentheses are provided for information only and are not considered standard. 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 prior to use. 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 Fire-retardant-treatments are used to reduce the flame-spread characteristics of wood. Chemicals and redrying conditions employed in treatments are known to modify the strength properties of the wood product being treated. This practice establishes the procedures for determining adjustment factors that account for the isolated effects of fire-retardant treatment on design properties of lumber. These effects are established relative to performance of untreated lumber. 5.2 The effect of fire-retardant treatments on the strength of lumber used in roof framing applications is time related. In this practice, the cumulative effect on strength of annual thermal loads from all temperature bins is increased 50 times to establish treatment adjustment factors for fire-retardant treated lumber roof framing. 5.3 The procedures of Test Method D5664 employ an elevated temperature intended to produce strength losses in a short period of time. Although the exposure is much more severe than that which occurs in an actual roof system, the chemical reactions that occur in the laboratory test are considered to be the same as those occurring over long periods of time in the field. 5.4 Treatment adjustment factors developed under this practice apply to lumber installed in accordance with construction practices recommended by the fire-retardant chemical manufacturer which include avoidance of direct wetting, precipitation or frequent condensation. Application of this practice is limited to roof applications with design consistent with 1.3 .