Approved document J: combustion appliances and fuel storage guide

Approved Document J sets out the statutory guidance under the building regulations for England covering combustion appliances, flues, fuel storage and carbon monoxide detection. It explains the applicable requirements, relevant British Standards and the effect of the 2022 amendments on every new or replacement appliance installation included in your certification.

What Approved Document J covers

Approved Document J, formally the 2010 edition incorporating the 2010, 2013 and 2022 amendments, is the principal route to compliance for fixed combustion appliance installations in England. The Approved Document J guide addresses air supply, the discharge of combustion products, protection of the building and fuel storage as one connected system.

Scope in England

The document applies to building work carried out under the building regulations in England. It also applies to excepted energy buildings in Wales, as defined by the Welsh Ministers (Transfer of Functions) (No. 2) Order 2009. Separate national rules govern Wales, Scotland and Northern Ireland, so your installation must be checked against the relevant jurisdiction before work starts.

• England primary scope: All building work involving fixed combustion appliances and fuel storage in England falls under Approved Document J without exception.
• Wales exception: Excepted energy buildings in Wales are also subject to this document; other Welsh building work follows separate Welsh Government guidance.
• Scotland and Northern Ireland: Distinct national frameworks apply, and neither jurisdiction uses Approved Document J as its regulatory basis.
• Gas appliances: Non-domestic gas work is additionally regulated under the Gas Safety Regulations, enforced by the HSE through the Gas Safe Register.

Approved Document J regulates the installation as a complete system. Hearths, fireplaces, fluepipes, chimneys, ventilation routes and fuel storage arrangements sit within its scope alongside the appliance itself. A defect in one component can make the entire installation non-compliant.

Core requirements J1 to J5

Requirements J1 to J5 establish the technical baseline for fixed heat-producing appliances. J1 requires a sufficient air supply for combustion, prevention of overheating and effective flue operation, an increasingly important consideration as homes become more airtight. J2 covers the discharge of combustion products to outside air through a correctly specified and constructed route.

The log burner fitting regulations under J4 require reasonable protection against burns and fire from appliances, fluepipes, fireplaces and chimneys.

Carbon-monoxide alarm rules

Requirement J3 mandates suitable carbon monoxide alarms where a fixed combustion appliance is installed in a dwelling. Since 1 October 2022, the obligation has covered new and replacement fixed solid fuel, gas and oil appliances, including boilers, log burners and oil-fired units, but it excludes gas appliances used solely for cooking. The alarm must comply with BS EN 50291 and be fitted in the same room as the appliance, 1 m to 3 m horizontally from it.

A ceiling-mounted unit must be at least 300 mm from any wall. For wall mounting, position the alarm as high as possible, above doors and windows, but at least 150 mm below the ceiling. Sealed-for-life battery units are recommended; mains-powered alarms require fixed wiring and a sensor-failure warning device. Portable equipment does not satisfy this requirement.

Flues, chimneys and installation records

Flues and chimneys must be designed, installed and commissioned in accordance with BS EN 15287-1:2007+A1:2010 for non-roomsealed appliances, or BS EN 15287-2:2008 for roomsealed appliance installations. Requirement J2 addresses the discharge of combustion products to outside air through a correctly specified and constructed route. Requirement J4 then extends protection obligations, against burns and fire, across the full run of the flue system, not only at the appliance collar. The specification must also account for the relationship between the flue termination and any adjacent pitched roof, as set out in the technical guidance.

Requirement J5 creates a mandatory information duty. Where a hearth, fireplace, flue or chimney is provided or extended, a durable notice stating its performance capabilities must be fixed in a suitable location within the building. This allows future installers to select a compatible appliance safely and provides a permanent record for building control. The installer responsible for the notifiable work must affix the notice, while building control retains enforcement powers if the obligation is not met.

Frequently asked questions

What does Approved Document J cover beyond the appliance itself?

Approved Document J covers the complete installation, not just the appliance body. Its scope includes air supply, the discharge of combustion products, fireplaces, chimneys, hearths, ventilation and the storage of fuel. For fixed oil storage tanks above 90 litres and LPG installations above 150 litres, J6 addresses the protection of liquid fuel against fire risk from adjacent buildings.

Requirement J7 applies specifically to liquid fuel storage systems of 3,500 litres or less serving private dwellings. It covers construction and separation, and requires a prominent, durable notice on oil tanks explaining how to respond to any escape.

Do the 2022 amendments to Approved Document J apply to existing homes?

Yes. The 2022 amendments came into force on 1 October 2022 and require carbon monoxide alarms whenever a new or replacement fixed combustion appliance is installed in an existing dwelling, not only in a new build. The specified threshold sizes are: solid fuel appliances up to 50 kW, gas appliances up to 70 kW and oil appliances up to 45 kW.

Transitional provisions protect work for which a building notice, initial notice or full plans were deposited before 1 October 2022, provided the work began within three months of that date. The 2013 amendments and earlier versions did not impose this alarm requirement for replacements in existing dwellings. It is therefore a material change for installers registered with Gas Safe or an approved competent person scheme.

How does self-certification work for carbon monoxide alarm installations under Approved Document J?

Installing a carbon monoxide alarm alongside a new or replacement fixed combustion appliance does not require a building notice, initial notice or full plans to be deposited with the local authority. Compliance is self-certified under regulation 20 of the Building Regulations 2010, so building control will not normally be directly involved.

Local authorities nevertheless retain enforcement powers under sections 35 and 36 of the Building Act 1984. They must consider whether those powers are appropriate if non-compliant work comes to light. Registered installers under Gas Safe or any approved competent person scheme remain responsible for certification and must confirm that fuel storage, alarm placement, appliance specification and any protection of liquid fuel meet the current requirements of the approved document before signing off the installation.