1.1 本规程涵盖了在建筑设计和系统评估中计算和解释净效益（NB）和净节约（NS）方法的推荐程序。 1.2 以英寸-磅为单位的数值应视为标准值。括号中给出的值是到国际单位制的数学转换，仅供参考，不被视为标准值。 1.3 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。 1.4 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 NB（NS）方法提供了一种衡量投资经济表现的方法，考虑了投资者研究期间与该投资相关的所有相关货币价值。考虑到货币的时间价值，NB（NS）度量可以用现值或等效年价值表示。 5.2 NB（NS）方法用于确定给定项目是否具有成本效益，以及在不存在预算约束的情况下，对于给定目的，哪种规模或设计最具成本效益。 5.3 NB（NS）方法也可用于确定有限预算下最具成本效益的项目组合；也就是说，具有最大总NB（NS）且符合预算约束的项目的组合。 5.4 当重点是效益而不是项目成本时，使用NB方法。 5.5 当关注项目节约（即降低项目成本）时，使用NS方法。

1.1 This practice covers a recommended procedure for calculating and interpreting the net benefits (NB) and net savings (NS) methods in the evaluation of building designs and systems. 1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.3 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. 1.4 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 The NB (NS) method provides a measure of the economic performance of an investment, taking into account all relevant monetary values associated with that investment over the investor’s study period. The NB (NS) measure can be expressed in either present value or equivalent annual value terms, taking into account the time value of money. 5.2 The NB (NS) method is used to decide if a given project is cost effective and which size or design for a given purpose is most cost effective when no budget constraint exists. 5.3 The NB (NS) method can also be used to determine the most cost effective combination of projects for a limited budget; that is, the combination of projects having the greatest aggregate NB (NS) and fitting within the budget constraint. 5.4 Use the NB method when the focus is on the benefits rather than project costs. 5.5 Use the NS method when the focus in on project savings (that is, reductions in project costs).