Gas Safe Certificates Explained: Every Form a UK Engineer Needs
Gas Safe work generates a lot of paperwork. Different jobs require different certificates, and issuing the wrong one — or missing one — creates problems for you, your customers, and potentially the HSE. Here’s a plain-English guide to the forms you’ll use most often.
The Core Documents
CP12 — Landlord Gas Safety Record
The most common form for engineers working in the rental sector. Issued after a landlord gas safety inspection. Required annually for all rented residential properties with gas appliances.
See our full CP12 guide for detailed requirements.
CP6 — Gas Appliance Service Record
The CP6 is a service record for a gas appliance. Unlike the CP12, it’s not a legal requirement — but it’s what you issue to homeowners after servicing a boiler or fire. It provides a record of the work done and any observations, and it supports warranty claims.
Insurers and boiler manufacturers increasingly ask for annual service records. A homeowner without them may find a warranty void.
Gas Safety Warning Notice
Issued when you identify an unsafe situation and the customer declines to have the work done or the appliance disconnected. You must:
- Warn the customer verbally
- Issue a written warning notice stating the nature of the risk
- Keep a copy
The notice creates a legal record that you identified and communicated the danger. Without it, if something goes wrong later, there is no evidence you raised the concern.
CP7 — Commercial Gas Safety Record
The CP7 is the commercial equivalent of the CP12, used for non-domestic properties — offices, pubs, restaurants, hotels. The legal framework differs: commercial landlords have duties under the Gas Safety (Installation and Use) Regulations and the Health and Safety at Work Act.
Frequency and specific requirements vary by property type, risk assessment, and tenancy agreement.
Commissioning Certificate
Issued when a new appliance is installed and commissioned. The certificate confirms:
- The appliance type, model, and serial number
- Gas rate and working pressure readings
- Flue flow test results
- Ventilation check
- That the appliance was tested to the manufacturer’s specification
Building control may require this for boiler replacements in England and Wales under Part J of the Building Regulations.
Benchmark Completion Certificate
Part of the Benchmark scheme (run by the Heating and Hotwater Industry Council), the Benchmark certificate is included in most boiler manufacturer documentation packs. Filling it in and leaving it with the appliance is a condition of many manufacturer warranties.
It covers the same ground as a commissioning certificate but in the manufacturer’s format. Some engineers treat them as interchangeable — technically they’re separate documents, though the information overlaps significantly.
Warning Notice vs. Unsafe Situation Report
There’s sometimes confusion between these two:
- A warning notice goes to the customer when they refuse to allow you to make a situation safe. It’s a record of their informed refusal.
- An unsafe situation report (filed with the National Gas Emergency Service or Gas Safe Register in serious cases) is what you use when you believe the customer cannot make an informed decision, or the risk is severe enough that it needs to go beyond the immediate customer relationship.
IGEM/G/11 sets out the industry procedure for unsafe situations in detail.
Keeping Records
As a Gas Safe registered engineer, you are required to keep records of all gas safety inspections you carry out. Gas Safe Register can audit these at any time. Records should be kept for a minimum of two years.
If you’re using paper, that means filing folders and manual searching when a landlord calls asking for last year’s certificate. If you’re using Heatflow, every certificate is stored against the job and the customer — searchable, accessible, and ready to resend in seconds.