Optimum Soil Pipe Fall?

[jmhill]

Hi,

I believe the regulation fall for a horizontal run is 18-90mm per metre.

Is there an optimum or standard fall?

Thanks

Jon

 

[denso13]

1:40 is a normal fall, or 25mm/metre.

 

[Nige F]

2.1/2 degrees on a horizontal soil pipe - 1:40 for underground drain - but can go as low as 1:80 in plastic

 

[jmhill]

Many thanks!

Jon

 

[muggles]

2½ degrees, which is 44mm per metre. If you look at branch tees and swept bends you'll see they're set at 87.5º rather than 90º to give the optimum fall (the difference being 2.5º), although they are of course a bit slack so you can get a bit more or a bit less out of them

 

[newbuildinstaller]

optimal would be vertical

 

[Agile]

They used to have a glass pipe in Brunel Uni to demonstrate how solids were not washed away if the slope was too steep!