Immediately Dangerous Gas Appliances in London: What ID and AR Classifications Mean

The Gas Industry Unsafe Situations Procedure: ID and AR Classifications

When a Gas Safe registered engineer in London discovers a gas appliance or installation that presents a safety risk, they are required to follow the Gas Industry Unsafe Situations Procedure, which is a standardised framework for categorising and responding to unsafe gas situations. The procedure defines two principal categories of unsafe situation: Immediately Dangerous and At Risk. These classifications carry specific obligations for the engineer and specific consequences for the property owner, landlord, or tenant.

An Immediately Dangerous classification is applied when the gas appliance or installation poses an immediate risk of injury to persons or property. Examples include a boiler with a cracked heat exchanger that is producing carbon monoxide in dangerous concentrations, an open-flued gas fire with a completely blocked flue that causes all combustion products to spill into the living space, or a gas pipe that is leaking at a rate that creates an explosive atmosphere. When an engineer determines that a situation is Immediately Dangerous, they are required to advise the responsible person that the appliance must be turned off immediately, to offer to disconnect it if consent is given, and to issue a Warning Notice recording the findings and the action taken.

What Happens When an Appliance Is Classed as Immediately Dangerous

The practical sequence when a Gas Safe engineer classes a London gas appliance as Immediately Dangerous is as follows. The engineer advises the property occupant or responsible person of the danger verbally and in writing using the standard Warning Notice form. The engineer will turn off the appliance and, where possible, physically disconnect it or prevent it from being operated by means appropriate to the type of appliance, such as capping a gas supply or securing a control valve. The appliance must not be used again until it has been repaired and re-inspected, or replaced, by a Gas Safe registered engineer who can confirm it is safe.

For London landlords, an Immediately Dangerous notice on a rental property creates an immediate legal obligation. The landlord must arrange remediation by a Gas Safe registered engineer as a matter of urgency and must not allow the tenanted property to be occupied without heating or hot water for an unreasonable period. The tenant has the right to report the situation to the local authority Environmental Health team if the landlord fails to act promptly, and the local authority has the power to issue emergency remediation notices. The costs of emergency remediation arranged by the local authority are recoverable from the landlord.

The At Risk Classification and Its Implications

An At Risk classification is applied when a gas appliance or installation is not performing correctly and, if left unaddressed, is likely to become dangerous. Examples include a boiler with a partially blocked flue that is producing elevated but not yet dangerous carbon monoxide levels, a gas fire where the draught diverter is showing intermittent spillage under certain room conditions, or a flexible gas hose on a cooker that is showing signs of deterioration. The engineer advises the responsible person of the risk, issues a Warning Notice, and recommends that the appliance is not used until it has been repaired or replaced.

For London landlords, an At Risk notice does not carry the same immediate emergency obligation as an Immediately Dangerous notice, but it does create a documented record that the landlord was informed of a specific safety risk. If the landlord fails to act on an At Risk notice and a subsequent incident occurs involving the appliance that was flagged, the documented notice will be central evidence in any legal proceedings or insurance investigation. The prudent response to any At Risk notice is to arrange prompt remediation, not to defer it indefinitely. Prestige Engineers issue detailed Warning Notices to London landlords and homeowners whenever an Immediately Dangerous or At Risk situation is identified, and can arrange urgent repairs or replacements to return the property to a safe condition.

Refusing Consent for Disconnection: What Happens

A property owner in London has the right to refuse consent for an engineer to disconnect an Immediately Dangerous appliance. In this case, the engineer cannot physically force the disconnection unless they are accompanied by an officer from the Health and Safety Executive or the gas supplier with the appropriate legal authority. However, the engineer is required to record the refusal on the Warning Notice and to report the situation to the gas transporter, Cadent Gas in the case of most London properties, which has statutory powers to disconnect the supply to premises where an unsafe situation exists and consent for remediation has been refused. The act of refusing disconnection of an Immediately Dangerous appliance does not protect the property owner from liability if a subsequent incident occurs.