CertBox
Gas Engineers Create in CertBox

Chimney / Flue Commissioning Record (CP3)

A CP3 records the commissioning of a new or replacement chimney or flue for a gas appliance. It documents flue type, dimensions, termination position, and the results of spillage and flow tests. The record confirms that the flue installation meets BS 5440 requirements for safe dispersal of combustion products.

Gas Safety (Installation and Use) Regulations 1998, BS 5440 (Flues and ventilation)Valid: One-off (issued at commissioning)

No credit card required. Set up in 30 seconds.

Sample CP3 certificate

Sample Chimney / Flue Commissioning Record (CP3) certificate created with CertBox, showing the professional PDF layout with flue type, material, and dimensions, termination position and clearance distances, spillage test results

Sample CP3 with fictional data. All personal details shown are fake.

What it covers

  • Flue type, material, and dimensions
  • Termination position and clearance distances
  • Spillage test results
  • Flue flow test (smoke pellet or match)
  • Ventilation provision check
  • Visual inspection of flue route and joints

Who needs a CP3?

Gas engineers
Chimney installers
HETAS engineers
Homeowners

Create your CP3 with CertBox

1

Fill in the form

Pick CP3 from the list, fill in the fields on your phone.

2

Compliance checks run

Built-in validation catches missing fields and out-of-range readings.

3

PDF generated instantly

Professional PDF ready to share via secure link or download.

Frequently asked questions about CP3

When is a CP3 required?
A CP3 is required whenever a new chimney or flue is installed for a gas appliance, or when an existing flue is significantly modified. This includes liner installations, flue extensions, and changes to termination position. It forms part of the commissioning handover documentation.
Does a flue liner replacement need a CP3?
Yes. Installing a new flue liner counts as a new flue installation and should be commissioned with a CP3. The engineer must verify the liner is the correct type and size for the appliance, and that spillage and flow tests pass.

Related certificates

Gas Engineers

CP12

A CP12 is the annual gas safety check every UK landlord needs. Learn what it covers, who can issue one, and create compliant CP12s digitally with CertBox.

Gas Engineers

Gas Service Record

Create gas service records on your phone. Covers FAGS checks, BS 7967 combustion analysis, and pressure readings. PDF ready in minutes, no paperwork.

Gas Engineers

CP43

Create CP43 flue in void risk assessments digitally. TB 008 compliant, risk classification, remedial recommendations. PDF on site with CertBox.

Gas Engineers

Chimney Sweep Certificate

Create chimney sweeping certificates on your phone. Flue condition assessment, smoke draw test, CO alarm check. For accredited chimney sweeps.

Ready to create your CP3?

Free forever. Set up in 30 seconds, no card required.

No credit cardCancel anytimeSet up in 30 seconds

Create your CP3 in minutes