Replacing old steel water main supply pipe
Pandora
includes fitting a new plumbing system.
A steel water supply pipe (พ"?) runs in a straight line from the water
meter at the boundary of the property, under a garage, up the garden
and into the house - a total distance of 35m. The depth of the pipe
under the ground is only 25-50cm. The pipe looks old and corroded,
although the water from the tap looks clear. There is no evidence of
leaking. The water pressure doesn't "feel" high but Cambridge Water
measured it at 2.8 bar (mid-morning).
Another point: I plan to install a new, unvented, mains-pressure hot
water system.
I am considering whether it is worth replacing the steel water supply
pipe with a blue polythene pipe. My options seem to be:
1. Leave the steel pipe where it is and run the new plumbing off that.
2. Replace all the steel pipe with blue MDPE pipe and hire a moling
equipment contractor to tunnel the 5.5m distance under the garage.
3. Run blue MDPE pipe from the meter and then around the perimeter of
the garage (adds three bends of 2m radius) and then straight up the
garden to the house. Total pipe length = 45m.
Option 1 might result in frozen underground pipes, greater probability
of leaks and lower pressures. Option 2 looks expensive. Option 3
introduces pipe bends and a longer run.
Which is best, do you think? Are there any other practical options
worth considering?
What's "best", 25mm or 32mm blue plastic pipe?
Supplementary question: Is it OK to tee off the supply pipe half way
up the garden to a stand pipe to be used for watering the plants? Or
should I run a pipe from the house back to garden stand pipe instead?
Thanks in advance for your advice.
Simon Avery
Hello Pandora
> P| 3. Run blue MDPE pipe from the meter and then around the
> P| perimeter of the garage (adds three bends of 2m radius) and
> P| then straight up the garden to the house. Total pipe length
> P| = 45m.
That would be my choice. Keep the bends as gradual as possible so
instead of 2 bends around the garage, one huge bend around it might be
better, if you see what I mean. But if there's a problem digging
there, probably not worth it for the minimum gain.
> P| What's "best", 25mm or 32mm blue plastic pipe?
45m... Maybe someone else can help with the math side, but I'd go
bigger unless the pipe the other side of the main stop was very small
and then the gain would be less. For long runs, bigger is best.
> P| Supplementary question: Is it OK to tee off the supply pipe
> P| half way up the garden to a stand pipe to be used for
> P| watering the plants? Or should I run a pipe from the house
> P| back to garden stand pipe instead?
Only if you can add a stop cock in such a way that it's 100% frost
proof. (Ie, underground). A mini inspection hatch with a T and the
short stop ASAP after it, all together and accessible should be ok.
--
Simon Avery, Dartmoor, UK
uk.d-i-y FAQ: http://www.diyfaq.org.uk/
Harry Bloomfield
> The pipe looks old and corroded,
> although the water from the tap looks clear. There is no evidence of
> leaking. The water pressure doesn't "feel" high but Cambridge Water
> measured it at 2.8 bar (mid-morning).
It is not just the pressure which is important, but the flow as well.
Old and rusty will also mean clogged up inside.
Your best route will be around the garage even if it does mean an extra
few yards of pipe and a little more digging. It will also need to be
buried quite deep to avoid both gardening and frost damage.
--
Regards,
Harry (M1BYT) (Lap)
http://www.ukradioamateur.org
Rick Dipper
quid worth of water from leaks.
Also consider what you need to dig up, if you are going to do a fancy surface, its probably best to do the pipe first, rather than risk it.
I would guess that the dig round the outside is cheeper, as you are going to have a mini digger on site anyway.
Rick
On 19 Jan 2004 10:03:45 -0800, no--...@pandora.be (Pandora) wrote:
> I am in the process of renovating my 150 year old house, which
> includes fitting a new plumbing system.
>
> A steel water supply pipe (¾"?) runs in a straight line from the water