Electric Fire Install - Gas pipe consideration

[Charlie_Don't_Surf]

Disclaimer - this isn't directly related to electrical matters. Rather it's a question about a situation which has cropped up during my going to quote an electrical job, and is basically me looking for any hints as to how to make certain (or as certain as possible) that I'm not going to drill through a gas pipe. As such hopefully its still not off topic here, after all these are the kinds of things us domestic electricians (in my case fairly inexperienced compared to most, and still in the process of getting fully qualified, but still) come across on a regular basis. Also, as per Dan's recent circular about posting more frequently, I thought there can't be any harm in at least asking for any advice or suggestions.

I've recently started doing my own jobs (domestic) having now nearly 2 years experience working with a local domestic firm. Level 2 diploma and 18th Edition qualified.

I have recently quoted a job scheduled for later this week which involves mounting an electric fire (on a plug top) to a lounge wall. The location previously had a gas fire installed there, and the old gas pipe can be seen protruding slightly into the room out of the wall, having been capped off. The customer is wanting the new electric fire mounted just above where the pipe sticks out. Directly above the gas pipe (maybe 30cm) there is an uneven area of plaster where the customer has filled in the flue from the gas fire. They said they didn't see any gas pipes in the process of filling that in.

Basically, they've ordered one of those long LED electric fires you might often see recessed into a media wall. I've installed a few in the past, but this one they are wanting it just bolted to the flat wall. The unit states on amazon that it is wall mount-able, and it does come with brackets for this purpose. I have advised the customer this isn't typically how they are situated, and it might look a bit odd, but they've now been able to look at the fire and they say they are happy with this method of mounting. So hey, fair enough.

As stated above, I'm concerned that when it comes to SDS-ing into the wall (it's an exterior wall, plaster and double skin brick) that I don't go into the gas pipe, or rather I mean whatever pipe feeds the bit sticking out of the wall. I've looked on the outside/exterior face of the wall, and there's no sign of anything there. Used a stud finder in the vague hope it might pick something up, but it didn't. Admittedly what I could have done when quoting, but didn't think of at the time, was to check under the floorboards in the room (not even sure if there are floorboards or its a concrete floor, but I would hazard a guess it's floorboards given the age and situation of the house). and, maybe I should have checked what is in the room above I suppose, in case there's a gas boiler above it or something. Aspects I plan to check when I go back before I start the job.

For the sake of completeness (and some actual electrical content here), in terms of the socket for the new fire, the customer hasn't decided yet whether they're happy to have the cable dangling from the mounted fire across the floor to a socket behind the TV (the flex is long enough, that has been checked), or, I offered them that for extra cost, I could drill out the back of an existing single socket which is elsewhere on the same wall, and run 2.5mm T&E in conduit on the exterior of the wall (there's nothing on the outside to obstruct this) and then have that come back in to a surface mounted single socket which would be located just below the mounted fire. I could then chop off the fire's plug top and excess flex length, and put a new plug top on it so that it just neatly plugs in beneath the fire, without the dangling cable running across the floor. I would of course check whether that single socket was a spur off a ring, or part of a radial, and follow regs in respect of what is permissible.

I'm aware (or I've been told at least) that there are no zones for gas pipes, unlike with us, where we have to stick to zones. So theoretically the pipes could go anywhere. I'm wondering if anyone has any advice about how they would approach this situation.

The fire weighs 16kg, so I'm going to be wanting to sink a masonry bit nice and deep into the brick to get good strong fixings. So I might penetrate through the first skin completely, I would think.

Short of having one of those posh devices which can give like an x ray readout of whats behind the plaster, I don't know how I can be sure of whether where I'm drilling will be a safe location. I have decided that I will drill a fair distance to either side of a vertical and horizontal line where the protruding gas pipe is located, that seems sensible, but outside of that, I'm kinda racking my brains as to how to further minimise the risk of a bad outcome.

Having overheard conversations on previous jobs where someone did cut a gas pipe and a gas certified engineer was called in, I would be minded to make sure I know before drilling, where the gas shut off valve/gas meter is located, and once the fire is mounted, to then make sure all gas appliances in the home are turned off, and go and watch the gas meter for a few minutes to try and give myself some peace of mind that I haven't caused a leak.

I'm guessing more experienced sparks (i.e. the vast majority of you!) might be able to detect if a masonry bit starts hitting metal instead of brick. I've not had that happen before, so I'm not sure how easy that is to detect.

To be honest at this point I'm not 100% sure I will go ahead with the job. I have a couple of colleagues who I will quiz tomorrow about this, and dependent on what feedback I get from them, and hopefully on here, I'll take a view on it. I'd rather be safe than sorry, and am not willing to take cavalier risks for the sake of making some money. But on the other hand, if I want to get more experienced and competent, I will have to take some risks, and frankly I've drilled into that many walls now, with only an educated guess of what was behind the plaster (and witnessed many colleagues doing the same), and so far nothing I've personally done has gone wrong. In fact, I've even witnessed a guy I used to work with, about to sink a metre long masonry bit into the upper end of the underside of a staircase, going "Please don't be pipes! Please don't be pipes!" Which I found slightly amusing at the time, but now it seems less funny in retrospect, and appears that it's my turn to hold that sentiment.

For anyone still awake after this minor dissertation, thanks for reading, and any feedback would be gratefully received.

 

[davesparks]

You do your best to work out where the gas pipe is and avoid it.

If you damage the gas pipe then you call on one of the gas plumbers you have befriended during your apprenticeship/time in the trade and they'll come and fix it, either in repayment for a favour you have done them or next time they damage a cable you will go and fix it.

Ultimately if all else fails despite your best efforts your insurance will cover it, that's why we have insurance.

There is absolutely no need to drill all the way through the brick and compromise the cavity for something as lightweight as 16Kg, A single red rawl plug in a brick wall has a weight capacity of over 50Kg and that needs a hole only half the depth of the brick.

And it is a plug, not a plug-top!

 

[littlespark]

Jump up and down in the middle of a big room will tell you if it’s floorboards or concrete….

Or look outside. Air bricks below floor level suggest a void under the floor = floorboards.

Or pull up corner of carpet in a cupboard or under the stairs. Possibly find a hatch too.

Or, if it’s a thin, well trodden carpet… you’ll see if it’s boards.

 

[Charlie_Don't_Surf]

Thank you both for your responses. Helpful and encouraging. That a single red rawl plug has a weight capacity of 50kg is news to me and something worth remembering for future.

I spark I work with today suggested that I use a screwdriver in the location of my intended fixing, to make a small hole in the plaster (ideally low down, not one of the upper fixings) and see whether it is brick behind the plaster, and if so, go for it. Otherwise, lower the intended mounting position a bit and hopefully find brick there to drill in to. Which I thought was a good tip too.

He echoed Davesparks' comment that there's no need to penetrate into the cavity as single brick fixings should hold it.

I'm very grateful for others sharing their knowledge about such things. It feels a little bit like flying by the seat of my pants starting out on my own jobs, and knowing there's a knowledgebase here and people kind enough to bother sharing their experience and wisdom is a really reassuring thing to have at this point in time. I look forward to one day being able to pass on some accumulated sparky wisdom to other fledgling sparks. Sorry if that comes across a bit gooey, but yeah just really feeling grateful today.

 

[brianmoooore]

Doesn't your stud detector have a metal detecting function? A metal detector should be able to trace the pipe up to a couple of inches into the wall.
Watch the swarf while drilling. After the surface plaster, red swarf is good. It means you are drilling virgin brick and not a plastered filled chase.
A good reason for not drilling into the cavity is that if you were to nick a gas pipe, then block the outer part of the hole with a wallplug and screw, gas will leak into the cavity, and a gas/air mix filling the cavity of a house can have spectacular results, to say the least.
Did a full rewire on a house once, and soon discovered that the walls were riddled with old lead gas pipes buried into the plaster, that once fed multiple wall lights. All were capped off where the fittings had once been, but all were also still connected to the gas supply. Fortunately they all connected back to a short piece of lead pipe near the gas meter, which was easily replaced with copper.

 

[davesparks]

That a single red rawl plug has a weight capacity of 50kg is news to me and something worth remembering for future.

It seems odd to me that anyone would use fixings without knowing what they can hold, but then part of the work I do involves installing fixings with designed, tested and certified safe working loads so I am perhaps more aware of these things.

To expand on the 50Kg loading that is subject to many factors and not every fixing using a red plug will be able to hold that load. Factors include the strength and condition of the brick, size and strength of the screw, direction of fixing and application of the load (horizontal, vertical etc)

He echoed Davesparks' comment that there's no need to penetrate into the cavity as single brick fixings should hold it.

Unless you are bolting all the way through with a spreader plate on the other side of the brick I can't really think of any time you would want to drill fixings all the way through a wall.

 

[littlespark]

Use the fixings that come with the product….



Nah… neither would I.

 

[DPG]

It's one of those things you get used to I suppose. I wouldn't particularly look at the data for fastenings unless it was something unusual or critical.

I would also take note of whether it is mainly a sheer force, like something heavy but fastened close to a wall, or whether there is significant leverage.

 

[Charlie_Don't_Surf]

Thanks all for your comments, advice and suggestions. The following is probably pretty boring for most, and is simply a summary of how the job went in the end, followed by my musings on the subject of gas pipe locations and associated danger. To recap, the job I did was a relatively tiny job, mounting an electric fire to a wall (and running a spur out the back of an existing socket, capped across outside of wall, to a new socket directly underneath the fireplace, to make it look tidy) but for me it was a pretty big deal as I've only recently started doing my own jobs, and so these first few weeks of undertaking my own works, essentially with no safety net, have felt like a leap into new territory. Hence I've been extremely careful about what I've done.

As it turned out, the job went well (aside the fact I probably under-quoted it by a significant margin, still learning about quoting and attempting to win jobs / create repeat custom so it's a work in progress / lost leader type situation I suppose). In terms of my concerns about the gas pipe, I established there was no other existing gas appliances above the room, or any indication that there would potentially be a reason for gas pipes to be present in that location other than for the purposes of supplying the gas fire which was previously there. As per advice from a colleague, I used a screwdriver to pierce a hole in the plaster, in an attempt to see if I could reach red brick behind where I was intending to drill. Turns out there was no red brick at any of my fixing points, and when (carefully) SDS-ing the fixing holes (the percussion of the SDS barely even activated, so soft was the wall), the bit went into the wall as though it was made out of, well, something very soft. The swarf was grey, and so I assume the inner skin of the wall must be made out of breeze block (the property is probably about 20 years old or less, it's like an older new-build). I went in about 4 inches, or to the full depth of a typical 5.5mm SDS bit. Anyhow, I used 2 x red plugs for each hole, so that there was some certainty a red plug would be pressing against whatever was behind the plaster, and used 4 inch screws to secure the mounting plate for the fire. I Put 5 fixings in altogether.

Given the fire was 16kg in weight, and I tested the resistance of the mounting plate beforehand, I was pretty sure it was going to hold the weight of the fire. And so far so good. I've been back to the property since and the fire is still where it ought to be. In terms of the gas pipe, at no point did I detect any resistance when drilling which could be considered to be indicative of a metal pipe, there was no odour of gas (I know the odour as added to the gas on purpose, but you know what I mean) and I avoided drilling particularly close to the location of the capped off pipe spur protruding from the wall. So for me, that was enough certainty to be reassured that I have not drilled into a gas pipe. I would hope that seems like a reasonable conclusion to reach.

I was talking to another colleague this week whilst we were drilling fixing points for sockets, and asked him 'have you ever drilled into a gas pipe'? He answered 'No, and you don't want to be drilling into a gas pipe, because there is a reasonable chance you might cause an explosion [if you're using a circular saw, or something which might cause sparks]'. which obviously makes sense. I then expressed my slight incredulity that as electricians (and I guess for many other trades too) we are often drilling into walls with only an educated guess as to what we are drilling into, and that obviously the consequences of drilling into a gas pipe could be horrific, that there isn't somehow more safeguarding against this outcome. What form that safeguarding would take I'm not sure, the only thing which springs to mind is that surely it would be helpful if gas engineers had zones which they have to abide to, so that at least there could be more certainty about the location of modern gas pipes, to aid in the avoidance of puncturing them. For arguments sake, if they had to follow roughly the same rules that we do, inasmuch as that gas pipes were required to run either vertically or horizontally from any given appliance or visible indication of pipework, then surely this would be preferable to pure guesswork. I'm no expert, but presumably as it stands, gas pipes could run diagonally across a wall, behind plaster, or take any number of routes preferable to the installer. I wonder if anyone has any thoughts of reflections about that.

Once again thanks all for your replies and advice.