Acceptable bends for waste water which doesnt need rodding

[shabbaranks]

Hi guys

Happy New Year...!! The building project is almost at an end. We're still dealing with the waste from the bathroom and our builder was on about bringing the waste water out to an inspection chamber which is fine. The only problem is when the utility and bathroom grey waste (shower sink etc) come down to it. I was under the impression at every change in direction this needs to be roddable but he said only if its 90 degrees??

A quick Google tells me anything over 30 degrees needs to be roddable/easily inspected - am I right?

Thanks

 

[John D v2.0]

All runs need to be accessible for cleaning either from one end or the other. But for sink waste runs you could use one of those drain snake things, you wouldn't really "rod" then in the same way as 4 inch underground drainage or soil pipes.

 

[Hugh Jaleak]

All underground pipework needs to be accessible for rodding should need arise. Underground should be done in 110mm pipework, and same rules still apply even if it's only for grey water. Builder is talking out his backside, only exception to the rule I am aware of is bends are allowed, provided they are immediately outside of a chamber.

 

[^woody^]

The concept is that where a drain changes direction, it creates a potential blockage point and so each bend (however gradual) should be either accessible via a chamber or roddable via an access point.

Most inspectors or designers will take a pragmatic view on the risk of a blockage occurring in the first place, so for instance waste from a toilet or a kitchen sink has more risk of blockage than that from a basin or a shower.

However the future maintenance of the drains is down to you, so you need to ensure that the design of these runs is agreed by the inspector or the designer who have no vested interest in the work, and not by the builder who may want to just save time and money. And if you want an access point, instruct the builder to put one in.

 

[oldbutnotdead]

All underground pipework needs to be accessible for rodding should need arise. Underground should be done in 110mm pipework, and same rules still apply even if it's only for grey water. Builder is talking out his backside, only exception to the rule I am aware of is bends are allowed, provided they are immediately outside of a chamber.

Yeah this. And not much of a bend either- up to 10 degrees or so is usually ok, greater than that is poor design and at the discretion of your bco.

 

[Hugh Jaleak]

Yeah this. And not much of a bend either- up to 10 degrees or so is usually ok, greater than that is poor design and at the discretion of your bco.

Its commonly accepted practice now to use a 45 either end of the main channel when using a plastic chamber to turn a 90º corner, allows for better flow through the chamber and less risk of the detritus fouling the opposite unused channels. Having seen what some Groundworkers deem acceptable now on housing jobs, I honestly despair.

 

[oldbutnotdead]

Its commonly accepted practice now to use a 45 either end of the main channel when using a plastic chamber to turn a 90º corner, allows for better flow through the chamber and less risk of the detritus fouling the opposite unused channels. Having seen what some Groundworkers deem acceptable now on housing jobs, I honestly despair.

Is it now- makes sense from a flow point of view but I know my cheapo rods would struggle round a 45° bend.

 

[Hugh Jaleak]

Is it now- makes sense from a flow point of view but I know my cheapo rods would struggle round a 45° bend.

Totally agree, Steel Kane rods used to be the weapon of choice on the Council for clearing blockages, and they definitely paid for themselves, many times over, but I think it is assumed people will use a Jetter to clear any blockages these days, and rods are old school. However, I know of at least one job where the Water Co had thrown it back as a collapse, as their van pack wouldn't touch it, and we cleared it with steel rods!

 

[russellsmiler]

as important as any use of bends is to remember that bends usually means cutting pipes to fit....just make sure that the inside of the pipe is de-burred.... burring can play havoc with the smooth flow of foul debris down a shallow gradient pipe, regarding using bends... 2 x 45s either side of a chamber is standard stuff, a bend to change direction mid run I think is acceptable in some cases..