Another daft question, (thanks for all the screwfix shop replies - works
a treat!), but the incoming mains to our house is a black semi-flexible
pipe of about an inch in external diameter. This has what looks like an
odd coupling that looks like some sort of compression joint to 15mm pipe
where I fitted a stop cock some years back... (works fine).

Our water pressure is high (8 bar), but flow rate low (under 10 litres
a minute) I think due to some external restriction in the pipe work -
which I'm not prepared to dig up at this point in time.

I'd like to remove the join to the 15mm pipe, fit a coupler to 22mm pipe,
a quarter turn full-bore "stop cock" to make it fool-proof for wifey,
then fit a pressure reducer to 3.5 bar, and then run 22mm pipe from
there - hoping to get a better flow rate at a pressure that'll reduce
the possibility of burst pipes (not a plesant sight round here when it
happens - as it did to our neighbours recently)

Googling finds various names for plastic pipe - mostly seem to refer to
blue alcathene or MDPE pipe, but I'm not sure that's what I have. It's
black!

So can some kind soul tell me the name/official size of the pipe and
suggest a coupling device?

Thanks,

Gordon

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Gordon Henderson
saying something like:

Googling finds various names for plastic pipe - mostly seem to refer to
blue alcathene or MDPE pipe, but I'm not sure that's what I have. It's
black!

So can some kind soul tell me the name/official size of the pipe and
suggest a coupling device?

It will probably be black alkathene - is it thick-walled, ie, 1/2" bore
in a 3/4" outer diameter, or metric equiv? The thin-walled stuff is
commonly used by farmers for shed and field cold water supply.
If thick-walled, you can simply treat it like copper pipe and use a
normal compression fitting on it, tightened well. I have a 150psi mains
supply with a compression fitting on it that's survived a decade like
that.

"Gordon Henderson" wrote in message

Another daft question, (thanks for all the screwfix shop replies - works
a treat!), but the incoming mains to our house is a black semi-flexible
pipe of about an inch in external diameter. This has what looks like an
odd coupling that looks like some sort of compression joint to 15mm pipe
where I fitted a stop cock some years back... (works fine).

Our water pressure is high (8 bar), but flow rate low (under 10 litres
a minute) I think due to some external restriction in the pipe work -
which I'm not prepared to dig up at this point in time.

I'd like to remove the join to the 15mm pipe, fit a coupler to 22mm pipe,
a quarter turn full-bore "stop cock" to make it fool-proof for wifey,
then fit a pressure reducer to 3.5 bar, and then run 22mm pipe from
there - hoping to get a better flow rate at a pressure that'll reduce
the possibility of burst pipes (not a plesant sight round here when it
happens - as it did to our neighbours recently)

Googling finds various names for plastic pipe - mostly seem to refer to
blue alcathene or MDPE pipe, but I'm not sure that's what I have. It's
black!

So can some kind soul tell me the name/official size of the pipe and
suggest a coupling device?

Thanks,

Gordon


Is the pipe plastic, or are you looking at an old lead pipe? Lead can feel,
look and act like plastic in some cases, and the coupling you talk about
could be a lead to copper fitting which was used when the solder wipe joint
was outlawed back in the eighties, early ninties.

So look at the black pipe again and gently scrape the outside of it with a
small blade to make absolutely sure that it is what you think it is.

...

In article ,
BigWallop wrote:

So look at the black pipe again and gently scrape the outside of it with a
small blade to make absolutely sure that it is what you think it is.

So... Thanks for the replies...

Proper investigation has found the following:

It's plastic and black. Not lead - it bends easy and feels
plasticy. Scraping the surface reveals more black plastic!

Outside diameter is very close to 20.5mm. Wall thickness hard to determine
without cutting it, but it's fairly stiff to try to bend. (but it also
has 8 bar inside it)

It could very probably be dated to the early 60's for initial installation.

So shouldn't be hard to get the right fitting now.

Cheers,

Gordon

Gordon Henderson wrote:
In article ,
BigWallop wrote:

So look at the black pipe again and gently scrape the outside of it with a
small blade to make absolutely sure that it is what you think it is.

So... Thanks for the replies...

Proper investigation has found the following:

It's plastic and black. Not lead - it bends easy and feels
plasticy. Scraping the surface reveals more black plastic!

Outside diameter is very close to 20.5mm. Wall thickness hard to determine
without cutting it, but it's fairly stiff to try to bend. (but it also
has 8 bar inside it)

Are you sure it's not just standard black MDPE pipe for use above
ground? It's identical (in dimensions) with the more common blue
stuff but for use above ground.

--
Chris Green

Gordon Henderson coughed up some electrons that declared:

Another daft question, (thanks for all the screwfix shop replies - works
a treat!), but the incoming mains to our house is a black semi-flexible
pipe of about an inch in external diameter. This has what looks like an
odd coupling that looks like some sort of compression joint to 15mm pipe
where I fitted a stop cock some years back... (works fine).

Not daft - been there done that.

Mine was 1/2" black alkathene (phone call to water board who took a stab at
identifying by description). As other's have said, yours is almost
certainly the same.


Our water pressure is high (8 bar), but flow rate low (under 10 litres
a minute) I think due to some external restriction in the pipe work -
which I'm not prepared to dig up at this point in time.

I would say you have a restriction. I have 12-13m of that pipe at 7 bar and
I can get 50+l/min out of it.

I'd like to remove the join to the 15mm pipe, fit a coupler to 22mm pipe,
a quarter turn full-bore "stop cock" to make it fool-proof for wifey,
then fit a pressure reducer to 3.5 bar, and then run 22mm pipe from
there - hoping to get a better flow rate at a pressure that'll reduce
the possibility of burst pipes (not a plesant sight round here when it
happens - as it did to our neighbours recently)

http://photos.dionic.net/v/public/bu..._0019.jpg.html

http://photos.dionic.net/v/public/bu..._0016.jpg.html

I went via blue MDPE - not sure if that's your intention. Or do you want to
go direct from 1/2" to copper 22mm?


If the former, I used

http://www.bes.co.uk/products/168.asp (part 11330) to go from 25mm MDPE to
copper (don;t forget the pipe insert).

and 13544 on the same page to go from 1/2" to 25mm MDPE.

If going from 1/2" to copper I suspect you could just use the latter as it's
rated for 22mm copper.

1/2" alkathene can be made off with a compression joint similar to 11330
above, but I'm not sure where you'd get one with the correct olive and
insert.


Peglar 1/4 turn full bore valves are good - and for the pressure reducer I
recommend

http://www.hav.co.uk/products/shw-de...13086&cid=1051

It doesn't mess with the flow at all. I still get 50+ l/min through it at
any pressure setting.

You'll need some gas PTFE (or a *lot* of water PTFE or some other potable
threadlok type stuff) to seal the pressure dial on. For some sick reason
they used parallel BSP threads and there's no seat to seal against - and if
there were, you'd not get the dial in the right place.

Cheers

Tim

coughed up some electrons that declared:

Gordon Henderson wrote:
In article ,
BigWallop wrote:

So look at the black pipe again and gently scrape the outside of it with
a small blade to make absolutely sure that it is what you think it is.

So... Thanks for the replies...

Proper investigation has found the following:

It's plastic and black. Not lead - it bends easy and feels
plasticy. Scraping the surface reveals more black plastic!

Outside diameter is very close to 20.5mm. Wall thickness hard to
determine without cutting it, but it's fairly stiff to try to bend. (but
it also has 8 bar inside it)

Are you sure it's not just standard black MDPE pipe for use above
ground? It's identical (in dimensions) with the more common blue
stuff but for use above ground.


That's a point. My alkathene stuff has concentric rings on it - very faint
but it's not smooth. If someone could confirm if black MDPE is as smooth as
blue, then that would be one possible indicator.

Cheers

Tim

In article ,
wrote:
Gordon Henderson wrote:
In article ,
BigWallop wrote:

So look at the black pipe again and gently scrape the outside of it with a
small blade to make absolutely sure that it is what you think it is.

So... Thanks for the replies...

Proper investigation has found the following:

It's plastic and black. Not lead - it bends easy and feels
plasticy. Scraping the surface reveals more black plastic!

Outside diameter is very close to 20.5mm. Wall thickness hard to determine
without cutting it, but it's fairly stiff to try to bend. (but it also
has 8 bar inside it)

Are you sure it's not just standard black MDPE pipe for use above
ground? It's identical (in dimensions) with the more common blue
stuff but for use above ground.

It sounds now that that's exactly what it is.

Didn't realise it came in black though which is what put me off the
scent earlier!

It (crudely IMO) comes out of the wall at ground level, is bent sharply
upwards to fit in a narrow gap where the compression fitting to 15mm is,
then the stop-cock and rest of house piping.

The plumbing in this house seems rather ... "creative" and I'm slowly
trying to sort it out..

Thanks,

Gordon

In article ,
Tim S wrote:
Gordon Henderson coughed up some electrons that declared:

Another daft question, (thanks for all the screwfix shop replies - works
a treat!), but the incoming mains to our house is a black semi-flexible
pipe of about an inch in external diameter. This has what looks like an
odd coupling that looks like some sort of compression joint to 15mm pipe
where I fitted a stop cock some years back... (works fine).

Not daft - been there done that.

Mine was 1/2" black alkathene (phone call to water board who took a stab at
identifying by description). As other's have said, yours is almost
certainly the same.

Going by other posts - it may be standard (modern) MDPE piping, but
black rather than the usual blue...

Our water pressure is high (8 bar), but flow rate low (under 10 litres
a minute) I think due to some external restriction in the pipe work -
which I'm not prepared to dig up at this point in time.

I would say you have a restriction. I have 12-13m of that pipe at 7 bar and
I can get 50+l/min out of it.

More investigations earlier this evening found a crudded up stop cock
outside the house, but on our land. We did get the waterboard to check
the street valve and connection when we moved in. I think it's this
external siezed up valve that's cusing the restriction. Don't have the
means to dig it up right now though.

I've seen the results of a leak in a neighbours house...

What I was really after was moving the system to mains fed rather than
tanks in the loft... The bath can fill quicker by gravity than the tanks
can re-fill from the mains.

Thanks for the links - good reference though. I'll pull the dishwasher
out tomorow (Which the pipe runs along the side of) and get a better
look at it and see if there is any identifying marks and I'll be better
able to size it then too.

Gordon

From the description, size and your probable date - black alkathene.

I have exactly the same stuff.

I lopped off the naff transition fittings from various bodges down the
years, and fitted an all-plastic MDPE stopcock (brilliant thing, light
to turn and shuts off to the last drop).

http://www.cityirrigation.co.uk/acat..._Stopcock.html

MDPE fittings will go straight on - no pipe insert required.

Gordon Henderson coughed up some electrons that declared:

Thanks for the links - good reference though. I'll pull the dishwasher
out tomorow (Which the pipe runs along the side of) and get a better
look at it and see if there is any identifying marks and I'll be better
able to size it then too.

Gordon

On an aside -

I found these clips (so called hospital clips) to be very good for mounting
the stopcock. They give an exceedingly solid mount and tight clamp to
copper pipe:

http://www.bes.co.uk/products/159.asp

Item 6504


When I ran my new bit of MDPE into the house, however I rotate and tighten
the fittings it always seems to develop a bit of torsional stress and these
clips hold it solid.

Cheers

Tim

"Tim S" wrote in message

Gordon Henderson coughed up some electrons that declared:

Thanks for the links - good reference though. I'll pull the dishwasher
out tomorow (Which the pipe runs along the side of) and get a better
look at it and see if there is any identifying marks and I'll be better
able to size it then too.

Gordon

On an aside -

I found these clips (so called hospital clips) to be very good for
mounting the stopcock. They give an exceedingly solid mount and tight
clamp to copper pipe:

http://www.bes.co.uk/products/159.asp

Item 6504


When I ran my new bit of MDPE into the house, however I rotate and tighten
the fittings it always seems to develop a bit of torsional stress and
these clips hold it solid.

Cheers

Tim


I think they're called hospital clips because they are fully enclosed, with
no bits to gather dirt in crevasses and nooks, so easily cleaned with a wipe
of a cloth.

(but don't quote me on it)..:-)
...