Thinking outside the box

Lack of space inside a meter box is often an issue for gas installers. So what are the options for taking a gas supply from the meter to appliances in a house or commercial building?
When it comes to selecting piping to run from a meter to an appliance, there’s a choice of three basic materials: copper, rigid steel or corrugated stainless steel tube (CSST).
The big advantage of steel is that it’s robust and resistant to vandalism. Also, it’s not a great attraction to thieves. Its major disadvantage is that it’s hard to work with because it is difficult to bend. Therefore a fitting is needed for almost every deviation of the pipe’s route, meaning you have to cut the pipe, thread the pipe and use jointing compounds to seal the fitting, which creates a potential source of gas escape.
Copper is the most commonly-used material in plumbing, both for conveying water and gas. Unlike steel, you can bend copper, but space is at such a premium with most meter installations that additional fittings will be required, which introduces the need for solder, flux and heat.
Installers also have to be wary of getting flux on the flexible meter inlet connection because these are very susceptible to flux corrosion. An alternative would be to use compression fittings, but this again can lead to potential escape points for gas.
One of copper’s plus points is that purely in terms of cost per metre it’s relatively cheap – though prices are currently rising. However, the cost of fittings has to be added as well as the time taken to solder joints adds to the overall cost of the job. Everyone’s very familiar with using copper – having used it from the earliest days of being an apprentice or trainee. An important drawback with copper is again the need for hot works – involving flux and solder.
Tempting target
It’s also a desirable metal, and so a tempting target for thieves – both as loose lengths and, more worryingly, after being fitted to the gas supply, which clearly could have horrendous results. Metal theft is an increasing concern, especially as meters are increasingly being sited outside properties – a trend driven by the move to smart metering. This is because smart meters need to be able to receive a radio signal.
And what of the third option? CSST is a relative newcomer, which over the past decade has steadily grown in popularity in the UK. It’s more costly per length than copper or steel pipe. However, it requires fewer fittings and can be installed much more quickly.
Fixed options
Being a semi-rigid pipe, CSST may only be used to connect to a gas meter that’s fixed rigidly – for example on a meter bracket. A surface-mounted, semi-concealed or concealed meter box will usually be fixed, so CSST can be connected directly to the meter outlet connection. If you’re relocating a meter, rather than having to run a long length of copper externally, you can put in a single continuous length of CSST with just two fittings.
CSST can either be run all the way to the appliance or can be converted inside the property – which is an ideal solution where a meter is moved, but the existing pipework in the property is fine. The growing popularity of CSST for domestic installations has prompted UK market-leader Omega Flex, manufacturer of TracPipe, to add an elbow fitting to its range – primarily to facilitate the connection of CSST to the meter outlet in the confines of a meter box, with no other fitting needed.
If meters are at the boundary of a property, it may be necessary to run piping from the meter to a building. CSST has advantages here because CSST manufactured to BS 7838 can be used externally and also buried directly in the ground or screed in long, continuous lengths. Buried steel pipe has to be corrosion protected, as does copper. Again, steel and CSST are generally more resistant to damage and theft than copper.
For a domestic property, the pipe’s colour may be an issue for the householder. Fortunately, all three options can be painted to improve their cosmetic appearance. For commercial properties, gas pipework must be identified, and CSST already has the advantage of being colour-coded yellow and identified as ‘Gas’. Both steel and copper would need to be identified as carrying gas, with either paint or tape, which is an additional cost in both materials and labour.
Ultimate choice
Ultimately, each of the three pipe material options has its advocates, but many installers see the benefit in being able to choose which to use depending on the particular demands of the job.