ACS Gas Assessment FAQ — CCN1, Codes & Revision Questions

ACS is the Nationally Accredited Certification Scheme for Individual Gas Fitting Operatives. It is an industry route for demonstrating Matters of Gas Safety competence in defined work areas. Candidates are assessed through approved centres and successful certificates are issued by the applicable certification body.

No. ACS assessment covers practical performance and knowledge for the selected competence areas. Written or oral questions may be used, but there is no single universal public online paper, question count, duration or percentage pass mark across every certification body. This website uses multiple-choice questions as a revision method only.

CCN1 is Core Domestic Gas Safety for natural gas. It covers core matters such as legislation, emergencies, combustion, ventilation, pipework, tightness testing and purging, pressures, unsafe situations, controls, gas rates, chimneys and recommissioning. It is used with relevant domestic appliance competencies.

The launch scope covers CENWAT, CKR1, HTR1, DAH1 and MET1. Additional categories are added only after current criteria, sources and technical review are in place.

Current CCN1 Issue 19 includes combustion-performance-analysis criteria, and some certification providers describe CPA1 as included with CCN1. Certificate and booking presentation can vary, so revise the current criteria and confirm the exact code combination with your assessment centre.

Gas safety competence certificates are generally renewed every five years. The applicable scheme rules and your certificate dates control reassessment eligibility. Gas Safe business registration is separate and renewed annually.

Treat reassessment like a focused revision project, not a first-time course. Confirm the exact core and appliance codes on your booking, revise current CCN1 and CPA1 criteria first, then refresh each appliance route you hold. Use free practice questions to find weak topics early, then timed mock exams closer to the date. Always confirm early-renewal windows and centre requirements with your assessment provider.

No. Current, relevant competence evidence supports an application for the corresponding work categories, but the business and operative must complete the separate Gas Safe registration process and maintain registration.

Entry is controlled by current Guidance Note 8 requirements. New entrants normally need recognised training and documented practical experience before initial assessment. Ask the assessment centre to confirm your category and evidence before paying.

The public SSB criteria require competence across the necessary criteria; they do not publish one universal percentage pass mark for every centre and competence code. Any threshold on this site is a practice target only.

No. They are original practice questions mapped to published competence criteria. The site does not use live, leaked, recalled or copied assessment questions.

No. A mock score shows performance on this question set and cannot demonstrate practical competence or guarantee an official result.

No. Gas Safety Revision UK is independent and is not part of, endorsed by or accredited by the SSB, IGEM, Gas Safe Register, HSE, UKAS, any certification body or any assessment centre.

Only questions explicitly tagged Northern Ireland or UK-common should be treated as applicable there. Northern Ireland has separate Gas Safety (Installation and Use) Regulations, so GB-specific legal questions are not automatically reused.

Every published question carries a criteria issue, source, jurisdiction, last-verified date and next-review date. Overdue or superseded questions are removed from scored quizzes until reviewed.

No. The platform is a revision aid, not a live-work procedure. Use current technical standards, manufacturer instructions, site-specific assessment and competent supervision.

Permitted reference materials and assessment conditions are set by your assessment centre and certification body. Ask them directly; this site does not determine what is allowed in a live assessment.