The National Fire Protection Agency (NFPA) Guidelines require a confirming flow test to be conducted whenever a "main line" valve such as the shutoff valves or a backflow assembly have been operated.

美国国家 防火协会（NFPA）指导原则要求对于主管 线上运行的阀门，如关闭阀或防回流阀总成，必须进行流量测试。

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For deficiencies of its structure, the previous breather valve with fire protection is not suitable for installing on light oil storage tank at cold area.

原使用的轻质油储罐防火呼吸阀，由于结构缺陷，不宜使用于寒冷地区储油罐上。

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With good sealing performance and as an important part in water-distribution and fire protection system, this type of valve has widely been used in city's water-supply system and sewerage.

它具有较高的密封性能，广泛用于城市给排水管路，是各种水分配系统和消防系统的重要部件。

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