这是火灾报警系统烟雾探测器的统一UL和ULC两国标准。本标准规定了烟雾探测器和附件的要求，包括在普通室内位置使用的机械防护装置，符合以下要求:在美国:NFPA 72，加拿大国家火灾报警和信号代码:CAN/ULC-S524，火灾报警系统安装标准；加拿大国家建筑规范；以及加拿大国家消防法规。

This is a harmonized UL and ULC binational Standard for Smoke Detectors for Fire Alarm Systems. This Standard sets forth requirements for smoke dectectors and accessories, including mechanical guards to be employed in ordinary indoor locations in accordance with the following:In the United States: NFPA 72, National Fire Alarm and Signaling CodeIn Canada: CAN/ULC-S524, Standard for Installation of Fire Alarm Systems; National Building Code of Canada; and National Fire Code of Canada.