1.1 本规程涵盖了在评估建筑设计、系统和设备时计算和解释内部收益率（IRR）和调整后的内部收益率（AIRR）措施的程序。 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 内部收益率法在金融和经济学中传统上用于衡量投资收益率百分比。 5.1.1 IRR方法在大多数情况下适用于评估给定建筑或建筑系统是否具有经济效益，即其时间调整后的效益是否会在决策关注期内超过其时间调整后的成本- 制造商然而，它的不足之处限制了它在竞争有限预算的项目中的有用性。 5.2 AIRR方法是衡量投资者在指定研究期内可以从投资中预期的总体回报率。它既适用于评估给定建筑或建筑系统是否具有经济效益，也适用于在竞争有限预算的备选方案中进行选择。 5.2.1 AIRR方法克服了IRR的一些（但不是全部）缺陷。在竞争项目之间分配有限资金时，特别建议采用AIRR而不是IRR。

1.1 This practice covers a procedure for calculating and interpreting the internal rate of return (IRR) and adjusted internal rate of return (AIRR) measures in the evaluation of building designs, systems, and equipment. 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 IRR method has been used traditionally in finance and economics to measure the percentage yield on investment. 5.1.1 The IRR method is appropriate in most cases for evaluating whether a given building or building system will be economically efficient, that is, whether its time-adjusted benefits will exceed its time-adjusted costs over the period of concern to the decision-maker. However, it has deficiencies that limit its usefulness in choosing among projects competing for a limited budget. 5.2 The AIRR method is a measure of the overall rate of return that an investor can expect from an investment over a designated study period. It is appropriate both for evaluating whether a given building or building system will be economically efficient and for choosing among alternatives competing for a limited budget. 5.2.1 The AIRR method overcomes some, but not all, of the deficiencies of the IRR. The AIRR is particularly recommended over the IRR for allocating limited funding among competing projects.