What is ACS Certification and How Do You Get It?
ACS certification is the qualification system that underpins Gas Safe registration in the UK – without valid ACS certificates in the right categories, you cannot legally work on gas. This guide explains what ACS certification is, which categories you need, how to get certified, and what it costs.
What is ACS Certification?
ACS stands for Accredited Certification Scheme. It is the system by which gas engineers in the UK demonstrate their competence in specific areas of gas work. ACS certification is managed by UKAS-accredited certification bodies including BPEC and City & Guilds.
ACS certificates are valid for 5 years from assessment. Renewal assessment is required to maintain Gas Safe registration after expiry.
ACS Categories: What Each One Covers
Every ACS category covers a specific type of gas work. Your Gas Safe card shows which categories you hold – you can only legally work in those categories.
| ACS Category | Covers |
|---|---|
| CCN1 | Core Domestic Combustion – gas safety principles. Mandatory for all domestic gas work. |
| CEN1 | Central heating boilers, radiators, underfloor heating |
| HTR1 | Gas fires and decorative fuel effect appliances |
| CPA1 | Gas cookers, hobs and ranges |
| CORT1 | Cooker points (bayonet connections) |
| CIGA1 | Gas meters and regulators |
| TPCP1/1A | Tightness testing and purging of pipework |
| COMCAT 1-6 | Commercial catering equipment |
Minimum for domestic gas work: CCN1 + CEN1. Adding HTR1 and CPA1 covers the full range of typical domestic jobs.
How to Get ACS Certified
ACS assessments test existing knowledge – they are not taught courses. You must prepare before attending an assessment centre.
Preparation routes:
Formal training course: Providers such as Logic4Training, Gas Training Direct, and Centre for Gas Works offer ACS preparation courses, typically 3-10 days per category.
NVQ Level 3 in Gas Engineering: An apprenticeship or Level 3 NVQ prepares you comprehensively for ACS assessments as part of the programme. See findapprenticeship.service.gov.uk for current gas engineering apprenticeships.
The assessment process: – Attend an ACS assessment centre approved by Gas Safe Register – Complete a written multiple-choice examination and a practical demonstration – Each category is assessed separately – Results typically available same day or within a few days
ACS Certification Costs
| Item | Typical cost |
|---|---|
| ACS preparation course (CCN1 + CEN1) | £400-£1,200 |
| ACS assessment fee per category | £100-£250 |
| CCN1 + CEN1 + HTR1 + CPA1 (all assessments) | £400-£900 |
See BPEC’s ACS pricing for current assessment fees.
Conclusion
The trades industry rewards those who combine excellent work with professional business practices. The guidance above covers the practical fundamentals – applying it consistently is what separates the tradespeople who stay busy and profitable from those who struggle with feast-and-famine cycles. For further guidance, visit Gas Safe Register: ACS certification.
Frequently Asked Questions
How long does ACS certification last?
ACS certificates are valid for 5 years. After expiry, re-assessment is required. Working with expired ACS certificates – even by one day – means your Gas Safe registration is technically invalid for that category.Do I need a separate ACS certificate for each type of gas appliance?
Yes. Each ACS category covers a specific type of work. You can only legally work on gas appliances in the categories shown on your Gas Safe card. CCN1 is the mandatory foundation for all other domestic categories.What happens if I fail an ACS assessment?
You can re-sit the assessment after a short waiting period or additional preparation. Most engineers pass with adequate preparation, but the assessments are rigorous. See Gas Safe Register’s new to gas guidance for preparation support.Related reading:
