排水管道
To prevent water damage, the valve must be properly connected to a discharge line which terminates at an adequate drain. 为了防止水的破坏，这些阀门必须与排水管道连接，以便能够将水排到适当的排水口。
Drains which pass under a house must be of cast iron, the most expsive material for pipe drains. 穿过房屋下面的排水管道，必须使用铸铁管，这是排水管所用的最昂贵的材料。
