Landlord compliance

Commercial Gas Safety Certificate (CP42)

Non-domestic gas safety certification for restaurants, shops and commercial premises.

From £30 (inc VAT) Certificate issued within 24 hours 12-month workmanship guarantee

Book this service 07426 409342

Starting from

£30inc VAT

meter only · appliance tiers from £169.99

Gas Safe engineers registered in the correct commercial categories

Gas interlock and ventilation assessed, not just appliance operation

Meter-only certification available for premises with no live appliances

Out-of-hours attendance so kitchens are certified without losing service

Book online

Overview

What is a Commercial Gas (CP42) certificate?

The CP42 is the commercial equivalent of the domestic CP12, covering gas installations in non-domestic premises: restaurant and takeaway kitchens, pubs, offices, shops, care settings and industrial units. Commercial gas work requires different engineer qualifications from domestic — catering appliances, larger plant and commercial pipework each have their own competencies — and the check is correspondingly more involved, covering gas interlocks, extract ventilation and emergency control valve arrangements alongside appliance safety.

Why it matters

Why it's worth getting right

A commercial kitchen concentrates every gas risk in one room: multiple high-output burners, heavy extract ventilation that can pull combustion products the wrong way, and staff working beside open flame for hours at a time. The consequences of a failure extend well past the premises — to employees, customers and adjoining buildings. It is also the certificate most likely to be demanded at short notice, by an insurer at renewal, an environmental health officer during an inspection, or a landlord at lease assignment.

Your duty in non-domestic premises

The Gas Safety (Installation and Use) Regulations 1998 apply to commercial premises as well as domestic, and require that gas appliances and installations are maintained in a safe condition. Where the premises is a workplace, the Health and Safety at Work etc. Act 1974 and the Management of Health and Safety at Work Regulations 1999 add duties to employees and to anyone else affected. Only an engineer registered with Gas Safe in the specific commercial categories relevant to the appliances present may lawfully carry out the work — domestic qualification is not sufficient for commercial catering equipment. Most commercial leases and virtually all insurers require an annual certificate.

Regulations & standards

The rules this work is carried out to

Every inspection we do is measured against a published standard — here are the ones that apply to this service.

GSIUR 1998

Gas Safety (Installation and Use) Regulations 1998

Applies to commercial as well as domestic gas installations.

BS 6173

Installation of gas-fired catering appliances

Ventilation, interlock and installation standards for commercial kitchens.

IGEM/UP/1

Strength and tightness testing of commercial installations

Defines commercial pipework testing and purging procedures.

In detail

Understanding your Commercial Gas (CP42)

The technical detail behind the certificate — what gets checked, what the results mean, and the decisions that actually affect your property.

Gas interlock systems in commercial kitchens

A gas interlock links the kitchen's gas supply to its mechanical ventilation, so that gas cannot flow unless the extract and supply fans are proved to be running. It is one of the most important safety devices in a commercial kitchen and one of the most commonly defeated — we regularly find interlocks bypassed by staff frustrated at the gas cutting out. BS 6173 requires an interlock on new and substantially altered commercial kitchen installations, and testing that it actually operates is a core part of the CP42. An interlock found bridged or disabled is an immediate fail, because it means the burners can run into a kitchen with no extraction at all.

Why ventilation is the dominant risk in commercial kitchens

Commercial catering appliances have far higher heat inputs than domestic ones, which means far greater air demand and far greater production of combustion products. Two failure modes recur. Under-ventilation starves the burners, producing carbon monoxide from equipment that appears to be working normally. Over-extraction is the subtler one: a powerful canopy extract with insufficient make-up air creates negative pressure that can pull combustion products back down an open flue into the room. Both are calculated rather than judged by eye, and the calculation depends on total appliance heat input — which is why adding a single extra fryer can invalidate a ventilation design that was correct the week before.

Why pricing starts at meter-only

Not every commercial premises has gas appliances. Offices, shops and units with a capped or unused supply still frequently need certification — for a lease assignment, an insurance renewal, or simply to prove the installation is sound and safely isolated. The meter-only check covers the emergency control valve, the meter installation, and a tightness test on the pipework, and is priced accordingly at £30. From there, pricing rises by the number of appliances because each one requires its own combustion, ventilation and flue assessment.

Landlord, tenant, or both?

Responsibility in commercial property is set by the lease, and it splits more often than people expect. Typically the landlord retains the incoming supply, meter and any plant serving the building as a whole, while the tenant is responsible for appliances they installed and the pipework beyond the emergency control valve. Disputes surface at the worst moments — after an incident, or during dilapidations at lease end. Our advice is straightforward: read the lease before you need to, and if the split is ambiguous, certify the whole installation and apportion the cost. A £250 certificate is cheaper than a dilapidations argument.

Warning signs

Commercial gas warning signs

In a commercial setting these need same-day attention:

Yellow or lazy flames on any catering burner instead of crisp blue

Sooting or heat discolouration on appliances, canopies or the ceiling

The gas interlock bypassed, taped over or disabled by staff

Extract fans that are noisy, weak, or not running when burners are lit

Staff reporting headaches, drowsiness or nausea during shifts

Air vents or make-up air grilles blocked by stock or shelving

Any smell of gas — evacuate, turn off at the emergency control valve, call 0800 111 999

Appliances added since the last ventilation assessment

The risks

What non-compliance costs a business

Commercial gas breaches escalate faster than domestic ones:

!HSE prohibition notice closing the kitchen, and with it the business

!Prosecution with unlimited fines and custodial sentences for serious breaches

!Employers' liability and public liability claims from staff and customers

!Insurance declined at renewal or claims refused for want of certification

!Environmental health intervention affecting your food hygiene rating

!Lease breach and dilapidations liability at the end of term

!Personal director liability under section 37 of the HSWA 1974

Keeping a commercial installation safe year-round

Certify annually as a minimum, and more often where equipment runs hard — many multi-site operators inspect kitchens six-monthly. Test the gas interlock regularly and treat any attempt to bypass it as a disciplinary matter, because it is the safety device most likely to be defeated in day-to-day use. Have canopy filters cleaned on a scheduled cycle, since a blocked filter reduces extraction and changes the ventilation balance. Crucially, reassess ventilation whenever appliances are added, replaced or moved: the calculation depends on total heat input, and a new fryer can put a compliant kitchen out of compliance overnight.

Why us

The benefits of booking your Commercial Gas (CP42) with us

Accredited, transparent and built around making compliance easy.

Gas Safe engineers registered in the correct commercial categories

Gas interlock and ventilation assessed, not just appliance operation

Meter-only certification available for premises with no live appliances

Out-of-hours attendance so kitchens are certified without losing service

Insurer-, EHO- and landlord-ready documentation

Multi-site portfolio pricing

What's included

Everything covered in your Commercial Gas (CP42)

One all-inclusive price — here is exactly what the engineer does on site and what you receive afterwards.

Tightness test on the commercial installation

Emergency control valve and meter installation check

Combustion analysis and operational check on each appliance

Gas interlock operation proved where fitted

Ventilation and extract adequacy assessed against total heat input

Flue and spillage testing on open-flued appliances

Certificate issued within 24 hours, insurer- and EHO-ready

Pricing

Simple, all-inclusive pricing

The price you see is the price you pay — VAT included, with no hidden call-out fees. Your final price depends on the size of your property; we'll confirm an exact, all-inclusive quote before we attend.

Commercial Gas (CP42) from

£30inc VAT

meter only · appliance tiers from £169.99

Get my exact price

All prices include VAT · 12-month workmanship guarantee

Commercial gas safety (CP42) pricing

Installation	Price (inc VAT)
Meter only	£30.00
1 Gas Appliance	£169.99
2 Gas Appliances	£209.99
3 Gas Appliances	£249.99
4 Gas Appliances	£299.99
5 Gas Appliances	£349.99

All prices include VAT. More than five appliances, or a multi-site portfolio? Send us an appliance list and we will quote the same day.

Prices are all-inclusive of VAT with no hidden call-out fees. Where they genuinely apply, parking (£5) and the London Congestion Charge (£18) are passed on at cost and always shown up front.

The process

How your appointment works

Simple, transparent and designed around you and your tenants.

Step 1

Confirm appliances and categories

Send us an appliance list so we attend with an engineer registered in the right commercial categories — and a fixed price.

Step 2

Installation and tightness testing

The emergency control valve, meter and pipework are checked and the installation tested for tightness.

Step 3

Appliance, interlock and ventilation checks

Each appliance is combustion-tested, the gas interlock is proved to operate, and ventilation is assessed against total heat input.

Step 4

Certificate within 24 hours

Your CP42 is issued with any defects classified and explained, ready for your insurer, EHO or landlord.

FAQs

Commercial Gas (CP42) — frequently asked questions

A CP12 covers domestic gas installations in residential property. A CP42 covers non-domestic and commercial installations — restaurants, pubs, shops, offices and industrial units. Commercial work needs different Gas Safe qualifications, and a domestic-only engineer cannot lawfully certify commercial catering equipment.

Because many commercial premises have a gas supply but no live appliances — an office, a shop, or a unit with a capped supply. That check covers the emergency control valve, meter installation and a tightness test, which is genuinely quicker than a full appliance inspection.

Annually as a minimum. Many multi-site operators inspect six-monthly because catering equipment runs hard and ventilation balance changes as appliances are added or moved. Your insurer or lease may also specify a shorter interval.

An interlock prevents gas flowing unless the kitchen ventilation is proved to be running. BS 6173 requires one on new and substantially altered commercial kitchen installations. If yours has been bypassed — which we find regularly — that is an immediate fail, because it allows burners to run with no extraction.

It depends on the lease. Typically the landlord retains the incoming supply and meter while the tenant covers appliances they installed and pipework beyond the emergency control valve. Where the split is unclear, certify the whole installation and apportion the cost — it is far cheaper than a dilapidations dispute later.

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Book your Commercial Gas (CP42) today

Fill in the form and we'll confirm your appointment and an all-inclusive price, usually within the hour. Prefer to talk? Call us and we'll book you in within two minutes.

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07426 409342

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