The Gas Safe ID Card Categories

What do the ID categories mean?

If you’re looking for an engineer to undertake gas work at your property, it can be tempting to go for the first name you find, but it’s essential to make sure they’re qualified for the type of work they’re going to be doing.

Anyone carrying out gas work is legally required to be on the Gas Safe Register - and to be on the Gas Safe Register, all gas engineers need certain ‘core’ qualifications. Without these, we can’t issue them with their Gas Safe card to confirm they’re working safely and legally.

Once an engineer has a core qualification, they can choose to take additional qualifications. There are many different types of gas work a business can offer, so if an engineer is qualified to do additional gas work outside of their ‘core’ qualifications, then their Gas Safe ID card will show this via certain Gas Safe categories.

What are the Gas Safe ID categories?

Found on the back of your Gas Safe registered engineer’s Gas Safe card, these categories confirm an engineer’s qualification to carry out a specific type of gas work on a certain appliance. You can also check the gas services a business can offer via our web search.

You’ll find all the information you need on the different categories, as well as a glossary of gas work terms, in our two guides.


Domestic Work Categories

Commercial Work Categories 


Some useful definitions

Domestic work relates to gas appliances designed for use in a domestic property, and gas pipework up to 35mm in diameter, again in domestic property. In larger domestic properties, non-domestic appliances and larger pipework are sometimes required; in these cases, appropriate non-domestic work categories may be necessary.

Commercial work categories refer to the size of pipework, appliance type and gas consumption in addition to property type. It’s worth noting that property type isn’t the sole criteria. For example, a ‘domestic’ gas boiler installed in a church may still be considered a domestic appliance, despite installed in a non-domestic property.

If you’re unsure if your engineer is qualified to work on an appliance, please email us at