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.

--
Chris Green

wrote:
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.

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

wrote:
wrote:
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.

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.

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).

--
Chris Green

After serious thinking wrote :
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.

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?

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

wrote:

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).


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! ;-)

Harry Bloomfield wrote:

After serious thinking wrote :
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.

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?

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

On Feb 27, 10:56 am, Harry Bloomfield
wrote:
After serious thinking wrote :

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.

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?

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

Bruce wrote:
wrote:

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).


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! ;-)

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.

--
Chris Green

Harry Bloomfield wrote:
After serious thinking wrote :
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.

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?

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.

--
Chris Green

Matty F wrote:
On Feb 27, 10:56 am, Harry Bloomfield
wrote:
After serious thinking wrote :

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.

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?

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

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

--
Chris Green

On Feb 27, 10:23 pm, wrote:
Matty F wrote:
On Feb 27, 10:56 am, Harry Bloomfield
wrote:
After serious thinking wrote :

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.

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?

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

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

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.

wrote:

Bruce wrote:
wrote:

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).


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! ;-)

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.


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. ;-)

wrote:

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.


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.

On Fri, 27 Feb 2009 11:40:46 +0000, Bruce wrote:

wrote:

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.

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.

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.
--
Peter.
You don't understand Newton's Third Law of Motion?
It's not rocket science, you know.

PeterC wrote:

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.


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

On Fri, 27 Feb 2009 15:44:10 +0000, Bruce wrote:

PeterC wrote:

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.

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

That's more an eclipse!
--
Peter.
You don't understand Newton's Third Law of Motion?
It's not rocket science, you know.

On Feb 27, 1:53*pm, PeterC wrote:
On Fri, 27 Feb 2009 11:40:46 +0000, Bruce wrote:
wrote:

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.

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.

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).

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

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.

To a first approximation, their sum stays constant. (That isn't quite
right. For a given circumference C, a circle has r1 = r2 = C/2pi =
r1+r2 = C/pi. A complete flattened tube has r1 = 0, r2 = C/4.

Now C/pi is not the same as C/4 - but it's not a million miles away
either!
--
Peter.
You don't understand Newton's Third Law of Motion?
It's not rocket science, you know.
:-)