Foul drain - minimum fall

[dunny]

Hi all,

I have been reading about recommended falls for foul drains and as far as I can tell they are anywhere between 1 in 40 and 1 in 80. According to Wyre Council they can be anywhere between 1 in 40 and 1 in 110.

For my scheme I think I can manage around 1 in 60.

Would this be adequate?

Thanks

D

 

[AngelesPlumbing]

no further details https://www.gov.uk/government/uploa...achment_data/file/442889/BR_PDF_AD_H_2015.pdf

 

[dunny]

no further details https://www.gov.uk/government/uploa...achment_data/file/442889/BR_PDF_AD_H_2015.pdf

If I am reading this correctly my peak flow would be on average around 2.5 litres per second (according to table 5). In reality it might be a bit more as it is a fairly large house and there are 4 of us but even if I look at the next estimate up it is only 3.5 litres per second.

Then looking at Table 6 if you have a peak flow above 1 litre per second, which I will, then with 100mm pipe I can have a fall of 1 in 80.

I should be able to manage this as basically I have a septic tank about 60m away and a ground level near the house 1.2m above this level.

Thanks for the reference.

D