By the First Gas & Renewable Energy team, commercial plant room specialists based in Gillingham, Kent, serving London and the South East. Last updated August 2026.
Quick answer: what is a commercial gas safety certificate?
A commercial gas safety certificate, usually issued on a form called a CP17 (the Non-Domestic or Commercial Gas Installation Safety Report), is the document a Gas Safe registered engineer gives you after inspecting the gas appliances, pipework and safety devices in a business or commercial building. It confirms the installation has been checked and is safe to use under the Gas Safety (Installation and Use) Regulations 1998. A CP17 is valid for 12 months, so a fresh check is carried out every year, and only a Gas Safe registered engineer holding the correct commercial qualifications can issue one. For most commercial buildings in the South East, a full check costs somewhere between £150 and £500 plus VAT, depending on how many appliances you have, the size of the site and its location.
If you own or manage a commercial building with gas boilers, water heaters or catering equipment, this guide explains exactly what a CP17 is, who is legally responsible for getting one, what the engineer checks, how much it costs, and how it differs from the domestic CP12 you may have heard of.
What is a CP17 and why does the certificate matter?
CP17 is the industry reference for the Non-Domestic Gas Installation Safety Report. It is the commercial equivalent of the domestic gas safety record, and it is the paperwork that proves your gas system was inspected by a qualified engineer and found safe.
The certificate matters for three reasons. First, safety: unsafe gas appliances cause carbon monoxide poisoning, fires and explosions, and a proper inspection catches the faults that lead to them. Second, compliance: the Gas Safety (Installation and Use) Regulations 1998 place a legal duty on the people in control of gas installations in commercial premises to keep them maintained in a safe condition, and a CP17 is the recognised way to show you have done that. Third, insurance and warranty: most commercial building insurers and boiler manufacturers require evidence of an annual gas safety check, and without it a claim or a warranty can be refused.
The gas system usually lives in your plant room, the space that houses your boilers, pumps and controls, so a CP17 inspection and your wider plant room servicing tend to go hand in hand.
Who needs a commercial gas safety certificate?
If you have gas appliances on non-domestic premises, you need one. That covers a wide range of buildings and businesses, including:
- Offices, shops and retail units with gas heating or hot water
- Restaurants, pubs, cafes and takeaways with commercial catering equipment
- Hotels, care homes, schools and places of worship
- Warehouses, factories and industrial units
- Landlords and managing agents letting commercial premises to tenants
Responsibility usually sits with the person in control of the premises or the gas appliances. For an owner-occupied business that is the business itself. Where a building is let, the split between landlord and tenant depends on the lease, so it is worth checking who is contractually responsible for the gas installation, the appliances and the flues before an inspection is due. If you let out commercial space, you also have a duty of care to the people using the building, and handing over a valid certificate is the clean way to demonstrate it.
What does a Gas Safe engineer check on a CP17?
A commercial gas safety inspection is more thorough than a quick boiler service. Working to the relevant British Standards, the engineer will typically check:
- Every gas appliance for safe operation, correct combustion and gas soundness
- Burner pressures and heat input against the manufacturer’s data
- Ventilation and air supply, so appliances get the fresh air they need to burn gas safely
- Flues and chimneys, including a flue flow and spillage test to confirm combustion products are removed
- Gas pipework, emergency control valves and gas soundness across the installation
- Safety devices such as flame supervision and, where fitted, gas interlock systems
Ventilation is a big part of the check, because a plant room that is starved of air can produce carbon monoxide. If you want the detail on how much air a plant room needs, see our guide to commercial plant room ventilation requirements. At the end of the visit the engineer records the results on the CP17 and flags anything that is unsafe or needs attention.
How often do you need a commercial gas safety certificate?
Once a year. A CP17 is valid for 12 months, and the annual check is the standard interval expected by insurers, manufacturers and the regulations for keeping a commercial gas installation in a safe condition. Where a building is let, best practice is to carry out the new inspection between the tenth and twelfth month after the last one, so the certificate never lapses.
Busy or high-risk sites often need more than the yearly safety check. A restaurant kitchen running catering equipment hard, or a care home that cannot afford heating downtime, benefits from more frequent servicing on top of the annual CP17. That is where a planned maintenance arrangement earns its keep. Our guide to commercial plant room maintenance contracts explains how the yearly gas safety check fits into a wider servicing schedule.
How much does a commercial gas safety certificate cost?
For a straightforward commercial property with one or two gas appliances, expect to pay roughly £150 to £300 plus VAT. Larger sites, or buildings with several appliances, complex pipework or commercial catering equipment, commonly run to £500 plus VAT or more. There is no fixed national price because the cost depends on how many appliances and how much pipework the engineer has to test, the size and layout of the building, and where you are in the country.
The table below gives a rough guide for typical South East commercial buildings. Treat it as a starting point and get a firm quote for your site.
| Property type | Typical gas appliances | Indicative CP17 cost (ex VAT) |
|---|---|---|
| Small office or shop | 1 boiler or heater | £150 to £250 |
| Restaurant or cafe | Catering plus heating | £250 to £450 |
| Care home, hotel or school | Multiple boilers and appliances | £400 to £600+ |
| Industrial or multi-tenant site | Several appliances, complex pipework | £500+, priced per site |
One thing worth knowing: the cheapest certificate is not always the best value. A rushed inspection that misses a fault leaves you carrying the risk, so it pays to use a specialist who knows commercial plant.
CP17 vs CP12: what is the difference?
This is the question that trips people up most, because the two certificates look similar but apply to completely different buildings. A CP12 is the domestic gas safety record for residential rented homes. A CP17 is the commercial report for business and non-domestic premises. They also need different engineer qualifications: domestic tickets do not cover commercial appliances, so a domestic gas engineer cannot issue a valid CP17.
| Feature | CP12 (domestic) | CP17 (commercial) |
|---|---|---|
| Applies to | Residential rented homes | Business and non-domestic premises |
| Common name | Landlord gas safety record | Commercial gas safety certificate |
| Appliances covered | Domestic boilers, cookers, fires | Commercial boilers, heaters, catering plant |
| Engineer needed | Domestic Gas Safe qualifications | Commercial Gas Safe qualifications |
| Validity | 12 months | 12 months |
You may also come across a CP15 (commissioning report) and a CP16 (re-commissioning and purge), which are used when a commercial appliance is installed or brought back into service, and a CP42 for commercial catering. These are separate from the annual CP17 safety check and are issued for specific pieces of work.
What happens if you do not have a valid certificate?
Non-compliance is a false economy. If a gas installation in your building is found to be unsafe or unmaintained, the Health and Safety Executive can prosecute, and courts sentence gas safety offences based on the seriousness of the breach and the size of the organisation. Fines for businesses are not capped and can run to substantial sums, with imprisonment possible in the most serious cases. On top of that, an invalid or missing certificate can void your buildings insurance and your boiler warranty, which turns a small annual cost into a very large uninsured one.
The practical takeaway is simple. An annual commercial gas safety check by a Gas Safe registered commercial engineer is inexpensive compared with the cost of getting it wrong, and it is the clean way to protect your building, your people and your business.
How to get your commercial gas safety certificate sorted
Getting a CP17 is straightforward when you use the right people. Book a Gas Safe registered engineer with commercial qualifications, give them access to your plant room and appliances, and let them carry out the inspection and issue the certificate. If anything is flagged as unsafe, get it put right and re-tested before the certificate is issued as satisfactory.
First Gas are commercial plant room specialists working across Kent, London and the South East, and gas safety inspections sit right at the centre of what we do. We can carry out your annual CP17, fix anything the check turns up, and fold the whole thing into a maintenance plan so your certificate never lapses. Take a look at our commercial plant room services, or get in touch for a quote for your building.
Frequently asked questions
What is a commercial gas safety certificate?
It is the document, usually a CP17, that a Gas Safe registered engineer issues after inspecting the gas appliances, pipework and safety devices in a business or commercial building and confirming they are safe to use under the Gas Safety (Installation and Use) Regulations 1998.
How long is a CP17 valid for?
A CP17 is valid for 12 months. A commercial gas installation should be inspected every year, and where a building is let the new check is best done between the tenth and twelfth month after the previous one.
How much does a commercial gas safety certificate cost in the UK?
Most commercial buildings pay between £150 and £500 plus VAT. Small offices and shops sit at the lower end, while restaurants, care homes and larger multi-appliance sites cost more because there is more to test.
Who is responsible for getting a commercial gas safety certificate?
The person in control of the premises or the gas appliances. For an owner-occupied business that is the business itself. In a let building it depends on the lease, so check who is contractually responsible for the gas installation before the certificate is due.
Can any gas engineer issue a CP17?
No. Only a Gas Safe registered engineer holding the correct commercial or non-domestic qualifications can carry out the inspection and issue a valid CP17. Domestic gas qualifications do not cover commercial appliances.
What is the difference between a CP12 and a CP17?
A CP12 is the gas safety record for residential rented homes. A CP17 is the safety certificate for commercial and non-domestic premises. They cover different appliances and require different engineer qualifications.
