关于I类和II类湿式喷水灭火系统的防回流保护程度，存在很多争论。争议主要集中在如果发生回流事故，湿管消防喷淋系统的水质是否会对健康造成危害。防止回流的潜在要求引起了消防行业的关注，因为改造现有的I类和II类湿管系统可能会出现水力问题。为了解决这一问题，开展了一项研究，以评估I类和II类湿地的水质- 管道自动喷水灭火系统，以确定是否存在公共卫生危害，并确定在这种情况下有效保护公众的方法。本文总结了一项为期18个月的研究结果，该研究由26名美国和4名加拿大水资源供应商参与。该项目专门确定了由黑钢（黑铁）管道材料建造的I类和II类湿式喷水灭火系统的水质。

There has been much debate on the degree of backflow protection on Class I and II wet-pipe fire sprinkler systems. Much of the controversy centers on whether the water quality in wet-pipe fire sprinkler systems would pose a health hazard if a backflow incident were to occur. The potential requirement for backflow prevention has caused concern in the fire protection industry because of possible hydraulic problems associated with retrofitting existing Class I and II wet-pipe systems. To address this issue, a study was conducted to evaluate the water quality in Class I and II wet-pipe fire sprinkler systems to determine if a public health hazard exists, and to identify methods to effectively safeguard the public in such a case. This paper presents a summary of the results of an 18 month study that was performed with the participation of 26 American and 4 Canadian water purveyors. The project specifically determined the quality of water within Class I and II wet-pipe fire sprinkler systems constructed of black steel (black iron) pipe materials.