1.1 本规范涵盖用作外部住宅铺板的聚烯烃基塑料木材产品。 1.2 塑料木材产品目前主要由回收的聚烯烃塑料（特别是高密度聚乙烯）制成，其中产品的横截面或多或少不均匀。然而，本规范也可能适用于由其他具有非均匀横截面的塑料和塑料复合材料制成的类似制造的塑料产品。 1.3 本规范详细说明了计算支撑托梁间距的建议跨度长度的程序。该程序是使用主要由回收高密度聚乙烯制成的典型无增强塑料木材的实验数据开发的。其他类型和组成的塑料木材的跨度长度开发方法详见 附录X1 符合本标准。 1.4 数值以英寸表示- 磅单位，因为这些是目前建筑行业最常用的单位。括号中显示了等效的国际单位制。然而，耐候性部分中规定的辐照度暴露单位( 6.3 )采用国际单位制，因为这些单位通常用于此类测试。 1.5 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。 注1: 没有类似或等效的ISO标准。 1.6 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。

1.1 This specification covers polyolefin-based plastic lumber products for use as exterior residential decking boards. 1.2 Plastic lumber products are currently made predominantly with recycled polyolefin plastics (in particular high-density polyethylene) where the products are more or less non-homogenous in the cross-section. However, this specification is also potentially applicable to similar manufactured plastic products made from other plastic and plastic composite materials that have non-homogenous cross-sections. 1.3 This specification details a procedure to calculate recommended span lengths for spacing of support joists. This procedure was developed using experimental data from a typical unreinforced plastic lumber made predominantly from recycled high-density polyethylene. The methodology to develop span lengths for other types and compositions of plastic lumber is detailed in Appendix X1 of this standard. 1.4 The values are stated in inch-pound units, as these are currently the most common units used by the construction industry. Equivalent SI units are indicated in parentheses. However, the units stated for irradiance exposure in the weatherability section ( 6.3 ) are in SI units as these are the units commonly used for testing of this type. 1.5 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. Note 1: There is no similar or equivalent ISO Standard. 1.6 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.