Gas

At Risk and Immediately Dangerous: GIUSP

When you find an unsafe gas appliance, the Gas Industry Unsafe Situations Procedure tells you how to classify it and what to do — and getting Immediately Dangerous and At Risk right is what keeps people safe and you covered.

Updated 20 Aug 20268 min read

Not every gas defect is the same, and the Gas Industry Unsafe Situations Procedure (GIUSP) is the framework every registered engineer uses to classify what they find and act on it consistently. It sorts unsafe situations into Immediately Dangerous (ID), At Risk (AR) and Not to Current Standards (NCS), and sets out the action — making safe, warning the customer, and the paperwork — for each.

This guide explains the three classifications, the Warning/Advice Notice you leave, the customer's permission to disconnect, and where RIDDOR reporting comes in. It's guidance for engineers; all gas work and any decision to disconnect must be made by a Gas Safe registered engineer applying the current GIUSP.

Key takeaways

GIUSP defines three classifications: Immediately Dangerous (ID), At Risk (AR) and Not to Current Standards (NCS).
Immediately Dangerous means injury or danger is likely now — the appliance/installation should be disconnected and made safe (with permission) before you leave.
At Risk means a defect exists that could cause danger — the appliance is turned off and not used, with the customer's permission, pending remedial work.
Not to Current Standards isn't dangerous — it doesn't meet today's standards but is safe to use; you advise the customer, you don't disconnect it.
You need the customer's permission to disconnect; if refused, you still warn them in writing and leave the Warning/Advice Notice, and report where RIDDOR/RGI reporting requirements apply.

What GIUSP is

The Gas Industry Unsafe Situations Procedure is the recognised industry procedure for identifying, classifying and dealing with unsafe gas situations. It gives every engineer the same definitions and the same steps, so an unsafe appliance is treated consistently whoever finds it and whatever the job — a service, a landlord check, a breakdown or a commercial inspection.

It exists because 'unsafe' isn't a single thing: some defects put someone in danger right now, others create a risk that hasn't yet materialised, and others are simply below today's standard but safe. GIUSP separates those and tells you what to do with each — which protects the public and gives you a defensible, documented basis for your decision.

Immediately Dangerous (ID)

Immediately Dangerous means an appliance or installation is, or if used would be, an immediate danger to life or property — the danger exists now. Examples are the serious ones: products of combustion spilling into the room, a dangerous CO situation, exposed live/hot parts, a serious gas escape, or a flue that isn't clearing combustion products.

The action is to make it safe: with the customer's permission, disconnect and turn off the appliance or installation so it can't be used, label it, and warn the responsible person clearly. An ID appliance must not be left available for use — the whole point of the classification is that continued use risks injury or worse.

ID means danger now

Immediately Dangerous is the top of the scale — the risk is present, not hypothetical. Make it safe and take it out of use (with permission) before you leave, label it, and warn the customer in writing.

At Risk (AR)

At Risk means one or more recognised faults exist that could constitute a danger — the situation isn't an immediate danger like an ID, but a real risk is present that warrants taking the appliance out of use until it's put right. A concealed flue that can't be inspected, inadequate ventilation, or a defect that could develop into a danger typically classifies At Risk.

With the customer's permission the At Risk appliance is turned off and not used, and the customer is advised it must not be used until the fault is remedied. The distinction from ID is timing and severity: At Risk is a genuine risk that hasn't yet become an immediate danger, so it's taken out of use pending repair rather than being an emergency.

ID vs AR — the test

Is it dangerous now (ID) or does it carry a real risk that isn't yet an immediate danger (AR)? Both come out of use with permission. NCS, by contrast, is safe to use — you advise, you don't disconnect.

Not to Current Standards (NCS)

Not to Current Standards covers an installation that was fine when installed but doesn't meet the current standards, yet is not At Risk or Immediately Dangerous — it's safe to continue using. Standards change over time, so plenty of older but sound installations fall here.

Because it's safe, you don't disconnect an NCS situation. You advise the customer of it — what falls short and that they may wish to have it brought up to standard — and record it, but the appliance stays in use. Reaching for a disconnection on an NCS finding is as wrong as failing to disconnect a genuine ID; matching the action to the classification is the whole discipline.

The Warning/Advice Notice, permission and RIDDOR

Whatever the classification, you document it and inform the customer with a Warning/Advice Notice (the Gas Warning/Advice Notice), which records what was found, the classification, the action taken and the advice given, with a copy to the responsible person. This is your evidence you identified the situation and acted on it, and the customer's record of what must be done.

Disconnection needs the customer's permission — you can't lawfully turn off and cap someone's supply without it. If permission to make safe or disconnect is refused on an ID or AR situation, you still warn the responsible person of the danger in writing, leave the notice, and follow the procedure's reporting route. Certain dangerous situations and gas incidents carry a duty to report (for example to the gas emergency service, and under RIDDOR / the reporting obligations placed on registered engineers where the relevant criteria are met). The message is consistent: classify correctly, act to the classification, document it, and report where required.

No permission, still warn

You need permission to disconnect — but if it's refused on an ID or AR, you don't just walk away. Warn the responsible person in writing, leave the Warning/Advice Notice, and follow the procedure's reporting route (including RIDDOR where it applies).

Frequently asked questions

What's the difference between Immediately Dangerous and At Risk?

Immediately Dangerous (ID) means the danger exists now — the appliance is, or would be if used, an immediate danger, so it's made safe and taken out of use. At Risk (AR) means a fault exists that could cause danger but isn't yet an immediate danger — it's turned off pending repair. Both come out of use with the customer's permission.

Do I disconnect a Not to Current Standards situation?

No. Not to Current Standards (NCS) means the installation doesn't meet today's standards but is safe to continue using. You advise the customer and record it, but you don't disconnect — disconnecting an NCS finding is as wrong as failing to disconnect a genuine ID.

Can I turn off a customer's appliance without their permission?

No — disconnection requires the customer's (responsible person's) permission. If they refuse on an Immediately Dangerous or At Risk situation, you still warn them of the danger in writing, leave the Warning/Advice Notice, and follow the procedure's reporting route.

When does RIDDOR come into it?

Certain dangerous gas situations and gas incidents carry statutory reporting duties, including under RIDDOR and the reporting obligations placed on registered engineers, where the relevant criteria are met. The Warning/Advice Notice documents the finding and action; reporting is the separate step where those criteria apply.

From guidance to action

Gas Warning/Advice NoticeRecord the classification, the action taken and the advice given, signed on site.Domestic gas safety certificateLog unsafe findings and their classification on the gas safety record.