Your home or building may be susceptible to sewage backups if the lowest drain is less than 24" above the nearest upstream manhole. Most building codes require owners to install a backflow prevention valve to minimize the chance of flooding at properties with drains that meet the specification mentioned above. * |9 x: U' u! q+ v# s0 }& L8 s% b8 I2 T- z! {
backflow prevention valvesHow does it work? A backwater valve can be installed in the basement at the exit point from the home or building, or in the sewer lateral outside of the building. 3 A0 t. c# t5 c, H, ~+ G0 J" F
! @8 t" ^3 m& f4 wThe "lateral" is the underground pipe that carries sewage from private property to the city’s sewer main. The backflow valve is installed downstream and prevents sewage from backing up into the lateral beyond ("above") this valve
还是不太明白,继续请教。, ~( k- k/ A' k. I, N$ _' G# ]
我想backflow prevention应该是需要在排污管下游安装一个单向阀(check valve),但我目前清理土后露出来的东西:一截环状混凝土围墙+末端封好口的水管怎么实现这个功能?是否这个阀门还没有显露出来?