标准133提供了在实验室条件下测试直接蒸发冷却装置以获得额定值信息的推荐做法和准确测量程序。2015年版标准对2008年版标准进行了重大修改，将密度校正简化为饱和有效性。其他改进包括更新参考资料和澄清强制性语言。

Standard 133 provides recommended practices and accurate measurement procedures for testing direct evaporative cooling devices under laboratory conditions to obtain rating information.The 2015 edition of the standard makes a key change to the 2008 edition by simplifying the density correction to saturation effectiveness. Other improvements include updates to references and clarifications of mandatory language.