A Small Drop on the Gauge

On 1 October 2026 a new edition of the industry standard for testing gas pipework in homes and small buildings became mandatory. It's called IGEM/UP/1B Edition 4, and it replaces Edition 3, which was withdrawn on 30 September. Most people will never hear of it. The first they'll know is when an engineer tells them a test has failed on a job that would have passed the week before.

What's actually different

A tightness test is simple in principle. The engineer shuts the gas in, watches a gauge, and sees whether the pressure drops. Two things have changed.

How much drop is allowed. The limit used to be tied to the size of the meter. Now it depends on how much pipework there is in the property — the engineer works out the “installation volume” and the limit follows from that. For natural gas the allowed drop runs from 8 mbar on the smallest installations down to 1 mbar on the larger ones.

A second step. If the gauge moves at all, even within the allowed drop, the engineer isolates the appliances and tests the pipework on its own. This time no movement the gauge can show is allowed. If the appliances can't reasonably be isolated, they're tested with the appliances connected, under the same no-movement rule. Any movement is a fail.

A fail doesn't mean “try again tomorrow”. The engineer has to trace and repair the leak, or disconnect and make the installation safe. In practice that often means the supply is capped until it's put right.

Why it catches people out

A slow weep at a joint that sat comfortably inside the old tolerance can fail now, especially on pipework that's been in the wall for decades. The engineer isn't being awkward — under the new standard they can't leave it. The test usually comes at a moment of change: a new meter, a new boiler or fire, work on the pipework. That's often when someone is least expecting a problem.

One thing I couldn't pin down: how much a repair costs. It depends entirely on where the leak is. A joint behind a fire is a different job from a pipe under a floor. I've heard talk of big bills, but I haven't found a figure I can stand behind, so I won't quote one.

If you let a home

Under Regulation 36 of the Gas Safety (Installation and Use) Regulations 1998, a landlord has to keep the gas appliances they provide, and the installation pipework, in a safe condition. The annual check covers appliances and flues. Pipework is a separate duty, which is usually met by a tightness test and a look at the pipework during the annual visit. Section 11 of the Landlord and Tenant Act 1985 adds that the gas installation must be kept in repair and proper working order.

So when pipework fails and the supply is capped, the fix normally falls to you, and the clock is running. If the heating or hot water has gone, a tenant needs something in the meantime, such as electric heaters. A recent Housing Ombudsman case shows how this goes wrong: a landlord capped a supply after failed gas checks, then let it drag on for around ten months. The Ombudsman found severe maladministration and ordered £2,425 compensation. That case wasn't about the new standard, but it shows how seriously slow repairs are treated.

Two practical things to ask your engineer at the next visit: that the pipework test result is written down on the record, and whether any older appliance without its own isolation valve should have one fitted. That's my suggestion rather than a rule, but it gives the engineer the option of testing the pipework on its own.

If you rent a home

An appliance you own — a freestanding fire you bought yourself, say — is yours to look after. The pipework in the home is generally the landlord's. If the supply is capped, tell your landlord in writing straight away, keep a copy, and don't try to reconnect or use anything an engineer has disconnected. If you smell gas, don't wait for anyone: call the National Gas Emergency Service on 0800 111 999. If a repair drags on, the Health and Safety Executive and your local council's housing team are the usual routes to push things along.

If it's a shop, café or other commercial unit

Regulation 36 is about residential lettings, so it doesn't apply to a commercial let. Who sorts out the pipework comes down to your lease — the repairing clause, who maintains the installations, and what the service charge covers — along with general health and safety duties. The new standard covers small installations, which takes in plenty of small shops, cafés and flats. Bigger systems fall under a different standard. It's worth reading what your lease says now, rather than after the gauge has moved.

Worth checking before you assume

If you're told the pipework needs replacing, it's fair to ask what the readings were and where the engineer found the loss, and to get a second Gas Safe opinion before agreeing to anything big. This isn't legal advice, and standards get tweaked. Treat it as a prompt to check your own position.