"Which gas certificate do we need?" is one of the questions we're asked most often by Preston businesses. The confusion is understandable. Commercial gas paperwork uses form numbers rather than plain names, and the same numbers get described differently from one website to the next.This guide explains what each of the common commercial certificates records, when it is issued, and how they fit together. SMR Gas Maintenance Ltd are industrial and commercial gas engineers at Higher Walton, Preston, Gas Safe registered (562186), and we issue all four.
The Gas Safety (Installation and Use) Regulations 1998 require employers to make sure gas appliances, installation pipework and flues at a place of work are maintained in a safe condition. The law does not name a particular form. The CP numbers come from industry-standard record forms that Gas Safe registered engineers use to document their work. They are how you show your insurer, an auditor or an inspector that the plant has been checked and is safe.
A CP15 records the commissioning or servicing of an individual commercial gas appliance, such as a boiler, a process burner or a warm air heater. It sets out the combustion readings, the gas pressure and heat input, and the checks made on the safety devices.When you get one: when new plant is commissioned, and each time an appliance is serviced.
A CP16 records that installation pipework has been tested for gas tightness (and, on new work, for strength) and then purged, so that air is removed from the pipework and gas is introduced safely. Commercial and industrial testing follows the IGEM/UP/1 series of standards, with the method depending on the size and pressure of the installation.When you get one: after new pipework is installed, after alterations or extensions, when a supply has been disconnected and is being reinstated, and whenever a tightness test is carried out as part of other work.A CP16 is not a boiler certificate or an interlock certificate. It is about the pipework.
A CP17 is a safety inspection of the gas installation as a whole. It covers each appliance and its flue, the ventilation, the meter installation, the pipework (labelling, support, isolation and sleeving) and the safety devices, and it records any remedial work needed.When you get one: usually once a year, as the annual gas safety check for a commercial or industrial site. It is the document most insurers ask for.
A CP42 is the inspection record for gas catering equipment. It has two parts: the kitchen environment (gas installation and isolation, interlocks, extract and ventilation) and the catering appliances themselves. It follows BS 6173 and IGEM/UP/19, the standard for ventilation interlocks in commercial kitchens.When you get one: where a site has a gas-fired kitchen, canteen or food preparation area, normally once a year.You may see it called a "CP42 risk assessment". The current version of the form no longer includes a risk assessment section, so that name is out of date. It is an inspection record.
If an engineer finds an unsafe situation, they follow the Gas Industry Unsafe Situations Procedure. The appliance or installation is classed as "Immediately Dangerous" or "At Risk", and you are given a warning notice (often a CP14) explaining the problem and what has been done to make it safe. Keep this with your certificates and close it out once the repair is complete.
On a typical industrial site, a year's paperwork might include a CP15 for each appliance serviced, a CP17 for the annual installation safety check, a CP16 whenever pipework is tested or altered, and a CP42 if there is a gas kitchen or canteen. Lining these up under one maintenance schedule means fewer visits and no gaps.
Most insurers ask for evidence of an annual gas safety inspection, which is usually a CP17, along with servicing records. Check the wording of your policy, as some insurers set specific conditions.
Not automatically. A CP16 is issued when pipework is tested and purged, for example after alterations. Some sites include a periodic tightness test in their maintenance plan.
Often, yes. Servicing, the annual safety inspection and any catering inspection can usually be planned for the same visit.
No. A CP42 covers catering appliances and the kitchen environment. A CP17 covers the gas installation and appliances more generally.
Send us a list of your gas appliances and your current certificates, and we will tell you what is due and when.SMR Gas Maintenance Ltd
Unit 10 Higher Walton Mill, Cann Bridge Street, Higher Walton, Preston PR5 4DJ
📞 07882 898492 (24/7 commercial emergency call-out)
📧 andy@smrgasservices.co.uk
🌐 www.smrgas.co.uk
Gas Safe Register No. 562186. Industrial and commercial work only.
