CP15 and CP16 Commercial Gas Certificates London
Arrange the correct commercial gas installation record for testing, purging or commissioning work in London. This guide helps facilities managers, contractors, commercial landlords and business occupiers identify the information an engineer needs before a CP15 or CP16 request can be scoped safely.
CP15 and CP16 are commonly used labels for specialist commercial gas paperwork, but the code is not enough to define the job. Send the exact requester wording and installation scope. Pipework volume, pressure, fuel, recent work and whether the task is testing, purging or commissioning determine the suitable procedure and competence.
Identify the engineering task, not only the form code
An email may simply say “CP15” or “CP16”, while the actual need is a tightness test after pipework alterations, a controlled purge, plant commissioning or evidence for a handover. Forward the original wording and explain what work has happened. This lets the enquiry be checked before labour, instruments and site controls are arranged.
- Exact wording from the contractor, landlord, insurer or project team.
- What was installed, altered, isolated, repaired or taken out of service.
- Natural gas or LPG, operating pressure, pipe sizes and drawings if available.
- Site contact, permits, occupied areas, shutdown window and deadline.
Testing, purging and commissioning answer different questions
These activities are related, but they are not interchangeable. The engineer needs to know which question the project or dutyholder is asking before selecting the applicable procedure and record.
Strength testing
Used for relevant new pipework or extensions to demonstrate that the installation can withstand the specified test pressure. The test medium, pressure, duration and preparation come from the applicable procedure and design information.
Tightness testing
Checks the defined installation for leakage under controlled conditions. It can be relevant after installation work, an alteration, suspected leakage, loss of pressure or before a purge, depending on the system and procedure.
Commissioning purge
Replaces air in a proven installation with fuel gas in a controlled way before use. Planning must address purge volume, flow, endpoint, discharge location, ventilation, ignition sources and site access.
Decommissioning purge
Removes fuel gas when pipework or plant is being taken out of service. Isolation, the replacement medium, safe discharge and confirmation of the endpoint need to be planned for the installation.
Plant commissioning
Concerns the safe set-up and proving of the plant, controls and operating conditions after installation or significant work. This is different from simply testing the distribution pipework for tightness.
Handover evidence
Records should identify the installation and completed task, not merely carry a familiar code. Project teams may also need drawings, calculations, commissioning sheets, remedial evidence and operating information.
The applicable standard depends on the installation
IGEM publishes separate procedures for industrial and commercial strength testing, tightness testing, direct purging, installation pipework and gas-fired plant commissioning. The correct procedure is selected from technical limits and the work being undertaken, not from the trading name of the premises.
Useful scoping information includes fuel type, maximum operating pressure, supply pressure, pipework volume, nominal bore, meter arrangement, whether the system is new or existing, and whether appliances or plant remain connected. Larger, higher-pressure or unusual installations may require additional planning, calculations, permits or specialist resources.
Why a photograph is not always enough
Images help identify meters, valves and plant, but they rarely establish pressure, internal pipe volume, hidden branches or the full work history. Send drawings, schedules, previous records and the contractor’s scope where available. A survey may be needed before a final quotation or method can be confirmed.
When testing, purging or commissioning evidence may be requested
The dutyholder or project team should define the required evidence. Common triggers include the following, but the engineer must still confirm what is technically appropriate for the installation.
Read the record by its scope and result
A useful record should make clear which installation or section was addressed, the work completed, the applicable procedure, test or purge information, the result, the engineer and business details, the date, and any limitations or observations. Project documents may also include drawings, calculations, commissioning sheets, permits and remedial evidence.
Do not file the document by its CP number alone. Check that the address, installation description and work scope match what the landlord, contractor, insurer or facilities team actually asked for.
A pass does not cover excluded equipment
A pipework test or purge record does not prove that every connected appliance has been serviced or safety checked. Note isolated sections, inaccessible areas, disconnected appliances and any work outside the agreed scope, then arrange the separate service or certificate route where needed.
Plan access, isolation and business disruption before attendance
Testing and purging can affect more than the plant room. Agree who controls the installation, who can authorise isolation, which tenants or departments are affected, and whether other contractors need to attend.
- Confirm the responsible site contact, access time, keys, induction and permit-to-work process.
- Provide current drawings, pipe sizes, meter information, plant schedules and previous records where available.
- Explain recent installation, alteration, repair, isolation or pressure-loss events.
- Identify occupied areas, vulnerable occupants, production processes and equipment affected by a shutdown.
- Confirm whether safe external discharge access, barriers or temporary exclusion areas may be needed.
- Arrange attendance by controls, electrical, mechanical or commissioning contractors where the work package requires it.
- State the handover, reopening or insurance deadline, while allowing time for any survey or remedial work.
Use an engineer competent for the actual installation and procedure
HSE guidance says gas work in premises such as shops, restaurants, schools and hospitals is covered by the Gas Safety (Installation and Use) Regulations, while employers must keep gas equipment safe and use competent people. Gas Safe registration should be checked together with the engineer’s relevant commercial work categories.
The site dutyholder still needs to coordinate the work: provide accurate system information, control access and permits, inform affected occupants, retain records and act on safety observations. A contractor request or certificate label does not transfer those responsibilities.
Do not wait for a certificate appointment. Avoid flames and electrical switches, move people away from danger and call the National Gas Emergency Service on 0800 111 999 for mains natural gas. For LPG, use the supplier or installation emergency number.
Check the current procedure, scope and engineer categories
Technical standards change and different limits apply to different installations. These official sources help dutyholders and project teams understand the relevant subject; the responsible engineer must still select and apply the current procedure for the work.
Request CP15 or CP16 commercial gas support
Send the exact requirement, site address, installation details, recent works, fuel and pressure information, drawings or photographs available, access constraints and deadline. We will review the scope and confirm the suitable next step by phone or email.
For urgent routine enquiries: submit the details first, then call 020 8004 7911 so the site and work scope can be found quickly.
CP15 and CP16 commercial gas certificate FAQs
What are CP15 and CP16 commercial gas certificates?
CP15 and CP16 are labels often used when a customer needs specialist commercial gas paperwork connected with installation testing, purging or commissioning. The code alone does not define the engineering task, so the requester wording and installation details must be checked before a visit is booked.
What is the difference between a strength test and a tightness test?
A strength test considers whether new or altered pipework can withstand the specified test pressure. A tightness test checks for leakage under the procedure applicable to that installation. The responsible engineer selects the method and standard from the pipework, gas, pressure, volume and work history.
What does purging a commercial gas installation mean?
Purging is the controlled replacement of air with fuel gas when commissioning, or fuel gas with air or another suitable medium when decommissioning. It is safety-critical work that needs a planned discharge route, controlled ignition risks and an engineer competent for the installation and procedure.
When might commercial pipework need testing or purging?
Examples include new pipework, an extension or alteration, work that may affect gas tightness, a complete loss of installation pressure, suspected leakage, recommissioning or taking pipework out of service. The applicable procedure still depends on the particular installation.
Do CP15 or CP16 records replace a CP17 or annual commercial gas safety check?
Not automatically. Testing, purging or commissioning evidence records a defined engineering task. A premises may separately need CP17-style non-domestic safety paperwork, appliance servicing, CP42 catering checks or another record requested by its dutyholder, insurer or managing agent.
What information is needed to quote the work?
Send the full address and postcode, exact requester wording, fuel type, new or existing installation status, pipe sizes or drawings if available, operating pressure, meters, appliances or plant served, recent works, isolation and access arrangements, and the required completion date.
Can testing or purging be completed while the premises remains open?
That depends on the work and site controls. Isolation, a safe purge route, restricted access, permits or a planned shutdown may be necessary. Tell us the trading hours, occupied areas and operational constraints so disruption and safety arrangements can be considered before attendance.
How much does CP15 or CP16 work cost?
The price depends on the installation size and complexity, test or purge procedure, fuel, pressure, pipework volume, plant served, access, records available and whether a return visit is needed. A reliable quotation requires the site and work-scope details rather than the certificate code alone.
What should I keep after the work is completed?
Keep the issued record with the project or premises gas-safety file, together with the agreed scope, drawings or calculations supplied, test or purge information, limitations, observations, remedial evidence and any commissioning or handover documents relevant to the installation.
What should I do if I smell gas before the appointment?
Do not use the routine enquiry form as an emergency route. Avoid flames and electrical switches, move people away from danger and call the National Gas Emergency Service on 0800 111 999 for mains natural gas. For LPG, contact the LPG supplier or emergency number for the installation.
Need commercial installation testing, purging or commissioning support?
Send the requester wording and technical details before booking. Clear scope at the start reduces avoidable visits and helps the correct engineer, procedure and site controls be considered.