more gas down to garage

[Paul J S Green]

ok folks, with your help in the past i've now got the 32mm yellow plastic pipe the 25m from house to garage and it's in an open trench.

i've also got blue water pipe in there. i've leak tested the blue pipe by rigging it up to the house main with a teed in pressure guage. i've capped the far end and filled it to three bar, sealing it off from the mains afterwards leaving the pressure guage in and made sure it stayed at three bar for an hour. i'm happy the pipe's not damaged.

the next problem is how to test the gas pipe befor filling in the trench (putting in sand, warning tape, etc).

can i just do the same as i did for the water? if so, how do i purge the water out?

please be reassured that the gas plastic will be terminated outside the house and garage and brought in in cast iron before being joined to copper.

i'm reasonably competent at copper plumbing and using mdpe pipe - can i just get the stuff from BES and do it - they seem to have fittings that don't need any fancy tools? Again, please be assured i'll get the end result checked by a corgi.

also, i've got some 35mm and 32mm blue pipe in there as conduit to take cat5, coax, etc. but i can't get anything down there to put in draw strings. i've tried coax and 10mm single earth wire - both only get as far as a dip in the pipes in the middle of the garden and start to coil up in the pipe and go no further.

my next step (a big one actually) is to buy a 25m roll of 15mm plastic water pipe (the stuff you use for central heating if you're in a hurry) and hope that pushes down - any thoughts?

as always, thanks for reading

paul

[Lurch]

On 20 Nov 2004 09:18:31 -0800, [e-mail] (Paul J S Green) strung together this:

Not doing it properly then?

Use one of these, it'll get through anything. I've had them round allsorts of awkward corners in 20mm tube so your liitle job will be a breeze!

[Rob Morley]

Attach some string to a suitably sized piece of wadding and blow it through.

[Lurch]

On Sat, 20 Nov 2004 18:13:45 -0000, Rob Morley strung together this:

ITYM suck, with a vacuum cleaner.

[Andy Hall]

Take a piece of thinnish string the length of the pipe and tie a rag to it.

Take a length of polypropylene or similar cord (sheds have it) that is twice the length of the pipe plus a bit. Find the centre and tie the string there.

Attach a vacuum cleaner to one end of the pipe holding the hose in place and making a rough seal with your hands.

Get somebody else to introduce the rag to the other end and slowly let it be sucked through with them paying out the string slowly.

You can then grab the rag and pull the cord through.

Tape the cables to be pulled through to one free end of cord and pull that through.

This will leave you with a length of cord through the pipe for pulling future cables through.

>

[Rob Morley]

Actually I meant blow with a compressor, but sucking works too and I suppose more people have vacuum cleaners than have compressors :-)

[Paul J S Green]

rob - thanks for the response - unfortunately i may have mailed you direct by hitting the wrong button - apologies.

i took the view that life's all about balance.

this was a "cost / textbook solution / trouble / digging" balance. it also gave me a fair number of separate conduits reasonably cheaply.

additionally, there is quite a big dip in the garden and a concrete "bridge"-type obstacle we had to get under - this method saved quite a bit more digging .....if i could get the drawstring thro'!

seriously, though, do you forsee any problems of significance - other than how much harder it is to get some drawstrings down this arrangement as opposed to 4" or 6" waste.

BTW - mains is going down a separate route.

thanks again paul

[Paul J S Green]

i think i was lobotomised early today and didn't notice!

sorry - Lurch, not rob.

[Ed Sirett]

Use air. If it holds at 1 bar it will hold at 20 mbar. Also it might hold water but not gas or air.

[Lurch]

On Sat, 20 Nov 2004 19:08:22 -0000, "Paul J S Green" strung together this:

I did wonder.

It was just an observation I made, don't take it too personally.

Shouldn't be too bad, once the draw wire is through.

[Capitol]

Can you blow/suck through a piece of nylon wool, with the Hoover?

Regards Capitol

[James Salisbury]

I did hear of one case in Bangladesh, where there was a new gas main suspeneded from a bridge. The new gas main needed pressure testing, and they intended to use water, there was a progressive collapse of the main falling from it's hangers....

[Paul J S Green]

thanks ed.

is there a simple way to undertake this test with household stuff readily available?

i can easily do the water stuff but i've never tried anything with air pressure.

thanks agaqin paul

[BigWallop]

Does your gauge do air as well as water pressure? If it does, then you can do the test with a simple bicycle pump and the proper end caps and seals for the pipework. All you need buy is a non-inner tube valve that fits the bicycle pump and fit it to an end cap of the pipe. A non-inner tube valve is like a tank connector. It fits through the hole in the frame of the bicycle wheel with a nut and some seal washers, so it's easy to drill and insert in an end cap.

Once you get this setup, you can do the same sort of test you did with the water pipe, but just use the bicycle pump to pressurise the air in the pipe instead of using water.

[Paul J S Green]

thanks - i've been on the case today!

i think the gauge does air too. i'll soon find out.

i couldn't get a "non-inner tube valve" with nuts and seals, but, courtesy of my local kwik fit fitter i've got one with a rubber seal and a sort of bulbous rubber bell-end at the non-business end.

i've pulled it backwards through the 15mm nut (sans olive) on a full bore ball valve rated for water/gas/air and tightened it back on the valve. it seems to provide an airtight seal at 1st glance - again, i'll find out tomorrow.

i've got the full bore ball valve rigged up to the yellow MDPE with the gauge teed in.

tomorrow i'll go down to the garage and swap the 28mm copper stop-end i've got connected to the blue pipe (already tested) onto the yellow pipe, pump it up, close the full bore ball valve and see how it goes.

i'll keep you posted ;^)

thanks again paul