Can one get square waste pipe?

I have a clearance problem running a waste pipe between where I want to put a washing machine and the adjacent wall. I need an extra couple of cm compared with the existing 40mm waste pipe that's there.

Can one get rectangular waste pipe with adapters to and from 40mm? It would be a perfect solution for me. It's not a waste pipe that needs a lot of capacity, it just runs from a cloakroom wash basin.

I can't really chase the pipe into the wall as access is very difficult.

Reply to
tinnews
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There's square mini guttering downpipe, but I forget what the size is. May be easier to just stay with a lower size of round though, unless you really have to get your square section up. If you do, a calculation showing the square downpipe has enough cross section area should make it allowable as an alternative method of achieving the same result.

NT

Reply to
meow2222

This is a waste pipe from a washbasin, not an outside pipe. A round pipe that would fit in the clearance I have would be tiny, around

20mm, that would have 1/4 the cross section of a 40mm pipe. On the other hand a 20mm x 40mm rectangular pipe would be 2/3 the cross section of a 40mm one (approximately, by my sums).
Reply to
tinnews

Bit of a botch, but could you perhaps take the pipe out and heat up the middle section enough to crush it into more of an oval shape - yet leaving the ends round where they connect to fittings?

Reply to
Harry Bloomfield

I feel sure that there are uPVC extrusions that you could use. Perhaps not ones that are specifically made for drainage purposes, but that doesn't mean they would be unsuitable. You would just have to engineer some connections.

For example, the legs to my uPVC patio set are rectangular section.

No, they are NOT available! ;-)

Reply to
Bruce

Sounds like the best option to me. One _could_ use 22mm waste with access points if prepared to rod it now and then and put up with slow drainage, ie it would function, but squashed 40 would be a lot better.

NT

Reply to
meow2222

I was going to suggest that too. I've done that and it works. I used boiling water to heat the pipe up.

Reply to
Matty F

In the past I've squashed waste pipe flat to get it through narrow spaces by carefully heating it with a heat gun, putting it in a vice and waiting for it to cool.

Reply to
Huge

Yes, I have wondered what else one might try, as you say it wouldn't be too difficult to make the connections, I can do it as one straight length with two side connections of 40mm. A bit of imperfection (in terms of places where water might stay) won't matter, it's "beyond the trap" and is used regularly enough to keep it reasonably fresh.

Reply to
tinnews

Now *that's* not a half bad idea. It makes the 'engineering' relatively easy and also means the waste will be reasonably smooth inside still. I'v got a few lengths of pristine 40mm so I can experiment a bit and mistakes wont really matter too much.

Reply to
tinnews

Yes, I think it's the best option, cue lots of boiling water! Thanks for the ideas everyone.

Reply to
tinnews

For a long pipe the heat gun may be safer than boiling water. I was just bending a short piece of pipe so that it would fit into a square pipe, funnily enough.

Reply to
Matty F

It should be simple enough to arrange some shaped "benching" within the bottom of the rectangular section to ensure that water doesn't linger. You could use silicone sealant.

I think your idea is perfectly practical and look forward to hearing from you when you have done it. ;-)

Reply to
Bruce

Bear in mind that a squashed 40mm pipe will have only a fraction of the cross sectional area of a circular one, and therefore a much lower water carrying capacity.

Reply to
Bruce

ISTR that the areas don't differ much if the ellipse isn't too pronounced, but after some searching I haven't found anything on this :-(

The [rough] formula for tha cross-sectional area an ellipse is:

pi * r1 * r2 where r1 is the verticle radius and r2 is the horizontal radius

(this is simplified and the notation probably isn't standard, but it's near enough for the purpose here).

Now, it's easy enough to calculate empirically, but when a pipe is squashed the circumference will stay the same(if it doesn't you've got problems!) but I don't know what happens to the radii.

Reply to
PeterC

No, I don't know either. But I do know that a pipe squashed flat has zero cross sectional area for carrying water. ;-)

Reply to
Bruce

That's more an eclipse!

Reply to
PeterC

I don't think it is simplified you know. A quick google suggests that the formula is exact (for a perfect ellipse of course).

To a first approximation, their sum stays constant. (That isn't quite right. For a given circumference C, a circle has r1 =3D r2 =3D C/2pi =3D>

r1+r2 =3D C/pi. A complete flattened tube has r1 =3D 0, r2 =3D C/4.

Now C/pi is not the same as C/4 - but it's not a million miles away either!

:-)

Reply to
Martin Bonner

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