Soil pipe, what fall?
- Thread starter Jack01
- Start date
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Jack01, good evening.
A 110mm foul drain taking the discharge of less than 1 l/s should be laid at a 1:40 (25mm per metre) fall. A foul drain taking the discharge from a minimum of one WC can be laid at 1:80 (12.5mm per metre).
And check out https://www.marleyplumbinganddrainage.com/media/1191/underground-brochure-july-2015.pdf
Gradients Foul water drainage systems are generally designed to run at a maximum of three quarters full bore. Pipe gradients should be established such that the velocity does not fall below 0.70 m/s to ensure adequate self-cleansing. A 110mm foul drain taking the discharge of less than 1 l/s should be laid at a 1:40 (25mm per metre) fall. A foul drain taking the discharge from a minimum of one WC can be laid at 1:80 (12.5mm per metre). Gullies incorporating in foul water or combined drainage systems must have a 50mm minimum water seal. The table below is taken from BS EN 752 and provides guidance on minimum gradients for different size drains
Ken
A 110mm foul drain taking the discharge of less than 1 l/s should be laid at a 1:40 (25mm per metre) fall. A foul drain taking the discharge from a minimum of one WC can be laid at 1:80 (12.5mm per metre).
And check out https://www.marleyplumbinganddrainage.com/media/1191/underground-brochure-july-2015.pdf
Gradients Foul water drainage systems are generally designed to run at a maximum of three quarters full bore. Pipe gradients should be established such that the velocity does not fall below 0.70 m/s to ensure adequate self-cleansing. A 110mm foul drain taking the discharge of less than 1 l/s should be laid at a 1:40 (25mm per metre) fall. A foul drain taking the discharge from a minimum of one WC can be laid at 1:80 (12.5mm per metre). Gullies incorporating in foul water or combined drainage systems must have a 50mm minimum water seal. The table below is taken from BS EN 752 and provides guidance on minimum gradients for different size drains
Ken
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i've just noticed the correction to my 16m, thanks for setting me straight.
but for my money, it still wont fly for 13m at 1:80.
i've had a rough experience pushing the falls limits for a soil pipe.
nothing to stop the DIY'er OP having a go but no way would i take on a job with risky falls.
but for my money, it still wont fly for 13m at 1:80.
i've had a rough experience pushing the falls limits for a soil pipe.
nothing to stop the DIY'er OP having a go but no way would i take on a job with risky falls.
Is this a soil pipe run or underground run? You need to be looking at Part H of the Buildings Regs I think, before doing too much. Max run is 6m for a single WC, and on too shallow a fall you are simply asking for problems.
Its underground.i've had a good look and think I will be able to squeeze between 20/25mm a mtr.if the max is only 6mtrs is there anyway to get round it like maybe putting in a inspection chamber halfway so it will run 6mtrs to chamber then to man hole
25mm a metre is 1:40, the recommended fall. Chamber needs to be fitted at any change of direction in the drain, ensure all runs are accessible for rodding if required.
If you can achieve a 1:40 fall, over a straight run, then you should be fine. (It is discharging into a manhole I will assume?) Provided the distance from crown of the trap in the WC pan to the invert of the drain doesn't exceed 1.3m then you can make a direct connection, you dont need to do anything else.
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