Immediately Dangerous (ID) means a gas appliance or installation that is an immediate danger to life or property, in use or left connected to the gas supply. At Risk (AR) means one or more recognised faults are present that could become a danger to life if the appliance keeps running. Both classifications come from the Gas Industry Unsafe Situations Procedure, and both end with the same "Danger Do Not Use" label on the appliance. The difference between them is urgency. This page covers rented homes in England, where gas safety duties sit in the Gas Safety (Installation and Use) Regulations 1998 as amended.
What does Immediately Dangerous mean on a gas safety check?
Immediately Dangerous (ID) is the classification a Gas Safe registered engineer gives an appliance that is an immediate danger to life or property. It applies to an appliance in use and to one simply left connected to the gas supply. During a gas safety check the engineer disconnects it, caps the supply where that is needed and attaches a "Danger Do Not Use" label.
The classification comes from the Gas Industry Unsafe Situations Procedure (GIUSP). GIUSP is the industry procedure registered engineers follow when they find an unsafe gas installation, and HSE sets it out in its operational guidance. An ID finding is not one engineer's view of an old boiler. It is a defined category with a defined response.
How is At Risk different from Immediately Dangerous?
At Risk (AR) means one or more recognised faults are present that could be a danger to life if the appliance keeps running. The danger is not immediate. The fault is real, and it is recorded on the gas safety record.
Immediately Dangerous sits a step above At Risk in urgency, not in paperwork. Both categories end with the same warning label on the appliance. Looking at the label alone, you cannot tell which of the two was recorded, so read the wording on the record itself.
Neither classification leaves you with an appliance anyone may use. HSE is clear that it is against the law to use a gas appliance when you know or suspect it is unsafe. In England those duties sit in the Gas Safety (Installation and Use) Regulations 1998 as amended. Only a Gas Safe registered engineer can put a failed appliance back into service.
Which faults make an appliance fail, and what might you notice first?
Appliances are classed ID or AR for reasons such as blocked ventilation, a blocked or damaged flue, poor combustion or unsafe installation work. A Gas Safe registered engineer finds most of those by testing, not by looking. Some signs are visible to you or a tenant between annual checks.
- Yellow or orange flames where the flame should be clear and blue
- Soot or yellow-brown staining on or around a boiler, gas fire or water heater
- More condensation than usual on the inside of windows in the room with the appliance
- Air vents that have been blocked, boxed in or covered over, when rooms with gas appliances need enough ventilation
- A flue or chimney route that has been built over or obstructed
- Pipework, appliances and flues that have gone years without maintenance
Early carbon monoxide symptoms are easily mistaken for food poisoning, a viral infection, flu or ordinary tiredness. If you or a tenant smell gas or suspect a leak, call the National Gas Emergency freephone line on 0800 111 999 and leave the appliance alone. In England, landlords must also fit a carbon monoxide alarm in every room with a fixed combustion appliance other than a gas cooker, under the Smoke and Carbon Monoxide Alarm (England) Regulations 2015 as amended in 2022 — see carbon monoxide alarm rules for rented homes.
Can an engineer cut off the gas, and can the appliance still be used?
A Gas Safe registered engineer may only turn off or isolate an appliance with the customer's permission, and HSE states that plainly. If permission is given and the appliance is turned off, it was turned off because it is unsafe. It should not be switched back on or used by anyone in the property.
Using an appliance you suspect to be unsafe is against the law and puts your tenant at risk. Leave the appliance and its warning label as the engineer left them. If permission to disconnect is refused, the unsafe situation is unchanged, and the fault and the advice given still go on the record.
Does a failed appliance stop you getting a Landlord Gas Safety Record?
No. A Landlord Gas Safety Record is still issued when a defect is found, and HSE describes the record as a living document. It must show each safety defect identified and any remedial action taken. Follow-up work is added to the record as it happens, and issuing should not be delayed because a fault was found.
In England the landlord duty sits in regulation 36 of the Gas Safety (Installation and Use) Regulations 1998 as amended. A check on every gas appliance and flue is due within 12 months of installing a new appliance or flue, then annually. Keep the record for two years, give existing tenants a copy within 28 days of the check, and give new tenants a copy before they move in. There is more on the duties in landlord gas safety in England.
Is a dangerous gas fitting reported to HSE?
Yes, in defined cases. A Gas Safe registered engineer who judges a gas fitting, flue or ventilation dangerous enough to risk death, unconsciousness or hospital treatment must report it to HSE. In practice that covers situations classed as Immediately Dangerous. The report is submitted through HSE's "Report of a Dangerous Gas Fitting" form.
The reporting duty sits with the engineer, not with you as landlord. It applies in England under the Reporting of Injuries, Diseases and Dangerous Occurrences Regulations 2013 (RIDDOR) and the Gas Safety (Management) Regulations 1996 as amended. A report records an unsafe situation so it can be acted on.
What can you check yourself before calling a Gas Safe registered engineer?
Four things are safe for you or a tenant to check, and none of them touch gas: boiler pressure, the thermostat and programmer, the reset button and bleeding radiators. Anything involving gas, the flue, seals or the inside of the boiler casing is work for a Gas Safe registered engineer.
- Boiler pressure: manufacturers put a cold boiler at around 1 bar, and roughly 1 to 2 bar while heating. Below 1 bar, the filling loop is used to top it up as your manual describes.
- Repeated top-ups: a system losing pressure every month points to a leak or a faulty pressure relief valve, which is engineer work.
- Thermostat and programmer: check the temperature setting and the time programme before assuming the appliance itself has failed.
- Reset button: a lockout is a protection feature, so read the fault code and the manual first. The button sits near the display on most models and is a dial on some.
- Radiators: manufacturers list bleeding a radiator as a very minor fix a householder can do.
None of these checks clears an ID or AR classification. That takes a Gas Safe registered engineer, not a reset. Your boiler has stopped: what to check goes through the same four checks in more detail.
FM Power is Gas Safe registered and covers London and the surrounding counties, and you can arrange the annual check on the landlord gas safety certificate (CP12) page.
Sources
- HSE — OC 440/37: Dangerous Gas Fittings (Gas Industry Unsafe Situations Procedure)
- HSE — Gas safety: Home owners
- HSE — Domestic gas: frequently asked questions
- HSE — Carbon monoxide awareness frequently asked questions
- HSE — Notifying and reporting gas incidents under RIDDOR and GSMR
- HSE — Landlords' responsibility for gas safety
- HSE — Gas safety check records and what to keep
- legislation.gov.uk — Gas Safety (Installation and Use) Regulations 1998
- legislation.gov.uk — Smoke and Carbon Monoxide Alarm (Amendment) Regulations 2022
- Worcester Bosch — What to do if your boiler loses pressure
- Vaillant — How to reset a boiler