Can someone recommend a good book / guide to underground drainage?

[kingandy2nd]

Hi all,

Not sure if there is such a book as googling reveals limited results. I have also found the paving expert website which is helpful.

Basically I'm looking for a book so I can read-up on how to lay all the sewerage pipes and new manholes for my extension.

Thanks
Andy

 

[Notch7]

There probably isnt one.....

Its worth downloading document H of building regs, although it doesnt provide much in the wsy of construction datail.

Also a manufacturers catalogue might be useful as it will give details on using the products.

 

[23vc]

Document H, or Ian H.

 

[^woody^]

Construction handbook by Chudley and Greeno

 

[JohnD]

If you have a public library that hasn't been closed down yet, they will have a shelf of Building Technology books, and Architecture, and access to many more. Especially if there is a local college doing courses in such things.

 

[kingandy2nd]

Many thanks to all for the input. I've downloaded the part H document and ordered myself a copy of the book @^woody^ recommended.

I've also found a number of useful videos on the Drainage Sales website.

 

[Ian H]

It’s all very easy. Are you using plastic manholes or building brick ones?

If it’s the plastic ones I dig 150mm deeper, fill it with concrete then knock the manhole down onto it with a piece of timber. Check both ways with a level, some manholes have the correct fall built in so the risers should sit level.

The pipes, I put a bag of gravel under each joint to I can sit a level on and get a steady fall. Then surround them in 10mm pea gravel and ‘chop’ the gravel in with the edge of my spade until I can bounce up and down on them and they don’t move.

 

[kingandy2nd]

Thanks Ian. I'm planning on buying a load of plastic stuff, but there are so many choices (from example 250, 300 and 450mm inspection chambers) that I want to make sure I buy the right stuff.

Also the existing manholes are nasty 70's concrete ringed versions, which are incased in about 2 foot of concrete. Also the pipes are clay and incased in concrete. I guess concrete was cheap back in the day!

I'm hoping that I can cut the existing clay pipes and connect the plastic to them by way of a drain connector.

 

[Ian H]

There are a few clay to plastics, the best ones are the rubber band seals. I use AC4000’s but always think a tighter one would line the joint up a bit better.

For the plastic manholes i’d say the bigger the better, some of the very small lids look odd when in the ground.

 

[kingandy2nd]

Thanks Ian. Yeah, I was thinking there’s next to no price difference in the manholes, so better to go big - but I wasn’t sure if there was any reason/reg to use a size.

In respect of the clay pipe, the are surrounded by solid concrete...so need to use one of the adaptors that goes inside the existing pipe.

 

[Ian H]

You would be better off chipping the concrete off for a few inches rather than using the internal connections if your on a horizontal pipe. Sometimes it comes away quite easy.

 

[kingandy2nd]

I have already tried with a bit that I was looking to remove - think they’ve used enough concrete for the pipe to survive a bunker-buster bomb.

 

[noseall]

need to use one of the adaptors that goes inside the existing pipe.

Noooooo!

 

[noseall]

As Ian said, we always use the Fernco rubber/jubilee type connector as it lines up the pipes better. Avoid the universal rubber type connectors as they produce a 'baggy' finished result and can mean a misalignment of the pipes.

Look at your starting depth then consider your furthest drainage item away from the start point and work on an ideal fall of around 25mm per metre (1:40). Less fall is acceptable, especially with carefully laid plastic pipe.

Some of the plastic preformed chamber bottoms have the through channel set at the lowest point, with the 45 degree and 90 degree inlets set higher. So factor this in when you are gauging your falls into the side inlets as they will afford you less fall than say the through channel and could mess with your original falls calculations - i.e. you will have less than you thought.

If falls are an issue and you need to be cute with the amount of fall on the pipes, then you need to be super-diligent when setting the pipes in gravel. Less fall means that any dips or humps in the pipe will be all the more problematic in the future.

Rest bends (set at the bottom of SVP's) require a decent amount of depth in order to ensure that the orange part of the pipe remains below the paving or finished ground level. Factor this in to your dig, especially if you are entering into one of the higher side inlets on the chamber.

 

[kingandy2nd]

Noooooo!

Thanks for the tips - all very helpful.

On doing research about connecting to clay pipes encased in concrete I could only find the Mac-alpine DCL-B1 as the solution for such a connection.

My only alternative would be digging out all the way to the manhole and fitting a new pipe in there, but as the existing manholes are concrete ring style, which are encased in 2ft of concrete (no exaggeration), I think that would not really be viable.