How to Identify What's in a Pipe - Unidentified Capped 15mm Copper Pipe Information, help and advice on many gas related subjects from gas fires to domestic appliances

[Lima7]

Hi,

I'm doing some work on my kitchen, and want to install a gas hob.

Very close to where I want the gas hob, there is an unidentified 15mm copper pipe that pops out of the floor and is capped with a compression end-stop. Does anyone know how I can safely identify what's in it? The pipe is miles away from the sink and any hot/cold running water, it's also nowhere near any of the known routes for the water supply. There's only one pipe, so it's probably not the location of a long-gone, capped-off radiator. Also the temperature of the pipe is always at room temperature - again, this suggests it's nothing to do with the heating.

My current plan is to loosen the compression cap, and the moment I smell gas, tighten it back up again. If my guess is correct, then this will prove it's a gas pipe. If my guess is incorrect, then my fear is I'll be left with open pipe gushing gallons of water all over the house. Is there a better way of identifying what's in it?

If this pipe is NOT a gas pipe, then I'll need to get an engineer to tap into the supply to the gas boiler (on the opposite side of the kitchen), and run a pipe around three walls of the kitchen - this will involve removing ALL the kitchen units - something I'm anxious to avoid.

Thanks

[proptech]

Hi Lima7

yes, it's probably gas, but DO NOT LOOSEN IT. Please get a registered Gas Safe engineer to check it out. DIY gas can be very dangerous, and you will not be able to carry out the required testing.

[Lima7]

Thanks proptech,

Good advice, but how can a Gas Safe Engineer determine it's contents without opening it?

How can I make sure HE doesn't end up flooding the house instead of me? If he pops the end off and water gushes out, then it's going to be very hard switching it off if there a no glues about where it comes from? It could be mains water, hot water, or radiator water (or nothing!)

Cheers

[proptech]

Simple answer - An experienced engineer will not have the problems, and would know exactly what to do. He may well open it, but he can do so safely, and test the installation afterwards.

[htg engineer]

As it is a 'dead leg' the temperature wont change when the heating or hot water are used as there's no flow. It could be a gas pipe, or could be an old redundant pipe that has leaked in the past and been capped off elsewhere.

You're right there's no way of a Gas Safe Registered engineer identifying the content of the pipe, other than cracking the joint to see what's there - but they will be able to test afterwards to ensure they haven't disturbed a joint in the floor and the blank joint has been re-made correctly.