Connecting waste pipes to plastic barrels.

[matthelliwell]

I'm trying to put together a plan for a new filter for my pond and am getting confused about different pipe diameters. Basically it's going to be two plastic barrels like these

together near the top with a piece of pipe and an outflow from one of the barrels to the pond.

What I'm not sure about is the cheapest way to connect the pipes to the barrels. I can order different sized tank connectors, such as here

But if I want to use at least a 3" pipe then I seem to be stuck with buying expensive pipes from the same place.

The connectors aren't took expensive but as I'll be using several meters of pipe and a few elbows does anyone have any cheaper suggestions as to what pipes would be suitable. Ideally something I can solvent weld or at least be sure won't leak.

Thanks

Matt

[Bob Minchin]

connected together near the top with a piece of pipe and an outflow

Do you really need such a large diameter pipe? 3" will support a huge flow rate. If you can live with domestic waste pipes of 32 & 40 mm, there are loads of cheap fitting both solvent weld and compression types which will allow disconnection for cleaning/modification etc.

I think there is some 50mm waste pipe too but less popular and possibly only push fit too.

Bob

[nightjar]

Class C is the cheap stuff. However, it is a standard plumbing material and, if you shop around you should be able to get it a bit cheaper than they sell it at.

Colin Bignell

[Tim S]

Bob Minchin coughed up some electrons that declared:

Nope, solvent weld is available too. Surprisingly B&Q sell it (at bigger stores at least) as do BES. Made by both Floplast and Marley.

I know - I've just used loads :)

OT: Made a homemade 50mm u-trap out of bends and tees with 2 access plugs, for clearing - partly as an excercise in wibbling.

However, this u-trap, under garden tests with hosepipe and bucket can cope with in excess of 50 l/min without backing up. The idea was to have a single u-trap serving two machine standpipes, partly to have the trap on the other side of the wall (under the stairs for easier access) and partly to avoid problems relating to if a machine was not present and having the associated trap dry out and pong.

Whoever it was how recommended 50mm for my kitchen (sink + 2 appliances max) - thanks. Under tests it does perform extremely well, despite a 3.5m run to the 110 stack.

Cheers

Tim

[matthelliwell]

these

> connected together near the top with a piece of pipe and an outflow

I've currently got two 40mm outflows from the current filter that are just about ok but i'm pondering a bigger flow for the new filter. I didn't realise you could get 50mm pipe easily, two of those should give the same area as a 3" outlet, if I can squeeze them in.

Matt

[matthelliwell]

Is class C some sort of special pressure pipe or does that just been bog standard waste type pipe? Either way, at least I know what to search for now!

I am however, getting confused with pipe sizes. Are the quoted sizes (50mm or whatever) internal or external diameter? I assume they are internal diameter and the external diameters vary between manufacturers?

Thanks

Matt

[nightjar]

2 x 50mm pipes would give you a 56% increase in area. 1 x 2½ inch pipe would give you a 26% increase 1 x 3 inch would give an increase of 81%

Colin Bignell

[Tim S]

matthelliwell coughed up some electrons that declared:

Internal I think.

But - the pipes are generally made to one of two BS's - one for push fit and the other for solvent weld.

Solvent weld comes in ABS (usually for dia 50mm.

I'm not sure if you can solvent weld ABS to uPVC - but at that interface it's usually been a rubber joint for me (32/40/50mm to 110mm adaptors).

Come to think of it - I did weld ABS to uPVC last week, but it was only dry ducting for a water pipe, so not very important. Seemed to be firm though...

Cheers

Tim

[Tim S]

Tim S coughed up some electrons that declared:

What I started out to say, was that pipes to the same BS are compatible between makes, though you do noticed that sometimes one combination is tighter than another...

[YAPH]

Plastic rainwater pipe can be solvent welded and has a small range of bends and couplings. And is cheap as chips.

[Tim S]

YAPH coughed up some electrons that declared:

Would you take any special precautions when burying it?

(I normally stick a bit of shingle around 110 and 82mm, but this is weaker pipe - so sand maybe?)

Cheers

Tim

[matthelliwell]

It is but will I be able to solvent weld the stuff to the tank adaptors, does it even have a standard diameter?

The problem I've having now is working out exactly what pipe sizes can be connected to

a 90mm pipe going to weld onto it ok? or 3"? It all seems to be a wierd mixture of metric and imperial.

Matt

[Tim S]

matthelliwell coughed up some electrons that declared:

Try these guys:

have an odd range of pipes - I had to use them as no-one else in the entire universe seemed to stock solvent weld 82mm 135 degree bends for my soil vent pipe...

I noticed they seem to have a lot of pipes for interconnecting big tanks.

Cheers

Tim

[Andy Dingley]

Wickes. They have a range of guttering diverters, barrel taps, barrel linking kits. Very cheap too.

[nightjar]

British Standard PVC pipe comes in three grades - Class C, Class D an Class E. Others are theoritically possible, but not made. Class C have the lowest pressure rating and the thinnest wall. Class E has the thickest wall and is the standard for industrial installations.

Dimensions given in inches are the internal diameter of a wrought iron (up to 2½") or cast iron pipe (3" and above). The external diameter of pipe in those materials sets the external diameter of a BS pipe of the same size, as it is necessary to be able to cut a BS Pipe thread on them.. The internal diameter of BS pipes therefore varies according to the material and pressure rating. Confusingly, some retailers nowadays refer to these pipes by their nominal OD in millimetres.

White plastic waste pipe sizes are the notional internal diameter in millimetres. However, they can vary in size according to manufacturer and according to whether they are push-fit or solvent weld. Whereas BS pipe and fittings of the same material can be freely mixed, with waste pipe, it is important always to use the same make and type of pipe and fittings, or to check that the bits you have mix properly.

Copper pipe is measured by its external diameter in millimetres.

Simple really :-)

Colin Bignell

[nightjar]

I find that identical items that fit together freely one day may be tight on another. Talking to my pipe and fitting suppliers, I think it is a result of different density PVC being used for different elements of the system and having slightly different thermal expansion rates.

Colin Bignell

[Tim S]

nightjar coughed up some electrons that declared:

Wonder how we got here... For most practical purposes, pipes are best known by their OD seeing as that is the bit that has to marry the fitting.

[matthelliwell]

Thanks for that explanation, it is all making sense now. Now wonder I was confused. My conclusion is I can't easily get all the fitting in the sizes I want so I'll have to do some more. At least I know what I'm looking for now and have some vague chance of getting bits which fit together.

[nightjar]

For most practical purposes, you want to know what the capacity of the pipe is, which why the bore was always the important measurement. Mind you, I find a lot of plumbers don't know how to measure pipes. If I get an order for a fly screen to fit, say, a 2½" pipe, unless I know the customer, I have to check whether they really mean a 2½" pipe, or a 2" pipe, which has an OD of near enough 2½"

Bignell

[Tim S]

nightjar coughed up some electrons that declared:

I think this is perhaps the difference in the markets... In domestic land, I feel fairly safe in believing that most people want to know if pipe X connects to fitting Y. No-one's that fussed over a couple of mm (or a few on bigger pipe) differences in ID.

But in industrial work, I take your point - especially WRT to factories, chemical plants and the like.

Cheers

Tim