Who may do gas work, the materials allowed in buildings, the precautions while work is under way, and what must not be done to premises.
Parts A and B of the Gas Safety (Installation and Use) Regulations apply to gas work of every kind: who may do it, and the precautions that go with it.
Who may do the work
- Competence applies to everyone. No person may carry out work on a gas fitting unless competent to do it (regulation 3(1)). That includes a householder working on their own home.
- Registration applies to business work. An employer's staff and self-employed people may do gas work only if they belong to the class of persons approved by HSE, which is Gas Safe registration (3(3)).
- Two named exemptions from registration, not from competence: replacing a hose or regulator on a portable or mobile space heater, and replacing a hose that connects a refillable cylinder to installation pipework (3(4)).
- Registration is category-specific. ACS certificates are evidence of competence for the categories held, not authority for a business to do gas work. If a job falls outside your registered scope, decline it and refer it to someone registered for that work; a simple-looking job, customer pressure or goodwill does not change that.
Materials
- Every part of a gas fitting must be of sound material and construction, adequate strength and size, and suited to the gas it carries.
- No lead or lead-alloy gas pipe may be installed in a building (5(2)).
- Non-metallic pipe, such as polyethylene, may be used inside a building only to connect a readily movable appliance designed for use without a flue, or where a pipe enters the building and the section inside runs in a metallic sheath built to stop gas escaping into the building if the pipe fails (5(2)). Polyethylene softens and fails in a fire; the sheath contains the gas if it does.
While the work is going on
- A fitting may not be left unattended with an open gasway. Seal every incomplete gasway with the appropriate fitting, such as a cap or plug made for the pipe, unless the fitting is otherwise safe. Anyone who disconnects a fitting seals every outlet of every pipe it was connected to (6(2) and 6(3)).
- No smoking or other ignition source where gasways are exposed, and no ignition source at all when searching for an escape.
- After work that might affect tightness, test the installation for gas tightness immediately afterwards, at least as far as the nearest valves upstream and downstream of the work (6(6)).
- Where needed to prevent danger, a suitable bond keeps electrical continuity across a break in metal pipework until permanent continuity is restored.
Where gas equipment may not go, and alterations
- No gas storage vessel, and no LPG appliance with automatic ignition or a pilot light, may be installed in a cellar or basement.
- No one may alter premises in a way that would leave an existing gas fitting in a condition that would break the regulations had it been installed after the alteration (8(1)). The duty falls on whoever makes the alteration, builders included. A conservatory that encloses a room-sealed flue terminal would discharge products of combustion into an occupied space, so the plan changes or a registered engineer re-routes the flue first.
Emergency controls
Gas may not be supplied to premises for the first time without an appropriately sited, accessible emergency control. Its lever lies parallel to the pipe when open, its open and shut positions are marked, and unless it is beside a primary meter a permanent notice near it says what to do if gas escapes.
Common mistakes
- Leaving an open end taped, behind a closed valve, or with a note to the occupier: each leaves an open gasway that can be opened or leak.
- Testing only the new joints or the new section: disturbed joints that were not remade can fail just as easily. Testing the whole installation meets the minimum and is often the practical choice.