rainwater drain and blg regs

[dada]

am building an extension and need to connect up a rainwater drain to the existing rainwater piping sytem. prob is cant get much of a fall on the pipe so was planning to do away with the u bend bit that would make me sink the pipe further down and thereby further limit the angle. is this ok to have no u bend as far as blg regs go. its rainwater piping, not connected to foul.

 

[Shytalkz]

You don't have to have a trap on it.

 

[Alastairreid]

if you are not putting a trap in i would install a rodding eye to the bottom of your r.w.p.

 

[noseall]

Shy is right in saying no trap.

I am a firm believer in using bottle gullies to collect rainwater, as they collect all the crud that gets washed off the roof.

Occasionally they will block-up, but this shows that the gully is doing its job. Simply remove the insert and clean out the crud.

I have lost count the number of times i have seen a failed rainwater system simply because the pipes are filled with crud.

Ironically, it is during periods of dry weather that the problem compounds. Any silt that has accrued within the pipe system, dries up and crusts. New crud is laid on top, and the process begins again.

This problem sometimes comes to light with foul drains also, typically when folks go on a summer holiday. The drains dry up. Poorly laid drains can have some 'material' left within, hence a dried out dump can cause a blockage!

 

[^woody^]

I can't understand how not having a trap will give a greater fall

With a normal P trap the outlet will be near the surface and thus give a greater fall than if a rest bend was used