Commercial gas work uses its own set of documents, and the codes are not interchangeable with the domestic landlord record. A business premises with a commercial kitchen, a warm air heater or a boiler above domestic output needs an engineer registered for commercial work and the certificate that matches the installation.
What the commercial codes cover
CP42 is commonly used for the commercial catering or commercial appliance safety record, and CP17 for a gas installation safety report on non domestic pipework and plant. The scope differs by installation, so the engineer should say which document the premises needs before quoting.
Why the engineer is different
Commercial registration is a separate qualification from domestic. A registered domestic engineer is not qualified to certify a commercial catering installation, and the register records which categories each engineer holds.
What moves the price
The number and size of appliances, the interlock and ventilation arrangements in a commercial kitchen, the complexity of the pipework, and whether the visit includes gas tightness testing and a full installation report as well as the appliance checks.
Who needs one
Any business with gas appliances used at work: restaurants and takeaways, care homes, schools, workshops and offices with commercial plant. It is a health and safety duty as well as a gas one, and insurers routinely ask for the current certificate.
Questions people ask about cp42 gas certificate
Is a CP42 the same as a CP12?
No. CP12 is the domestic landlord record. CP42 is a commercial appliance safety record and requires an engineer registered for commercial work.
How often is a commercial gas certificate needed?
Annually is the normal cycle and is what most insurers and local authorities expect, with more frequent checks where the appliance or the risk justifies it.
Does a commercial kitchen need anything else?
Usually a gas interlock with the ventilation system, and the certificate should confirm it works. It is the item most often found defective in catering inspections.