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CCN1 brings together the safety decisions behind domestic gas work. These original practice questions mix recognition, calculations and judgement: look at the evidence in the question before choosing what to check or do next.
Practise converting a timed meter reading into a gas rate before comparing heat input. Write down the meter units, elapsed time and the gross or net basis in the question; a familiar number can hide a wrong conversion.
Gas-rate formula and worked examplesRevise the conditions behind a test result, as well as the reading itself. In an unsafe-situation question, identify the evidence and the required action before choosing a classification. Use the current procedure supplied for your training.
Review tightness-testing principlesSeparate air supply, removal of combustion products and delivery of enough gas to the appliance. For a calculation, choose the applicable rule and check the stated conditions before using a calculator.
Revise gas pipe sizing and pressure lossFor a calculation, work it through before choosing an option. For a safety scenario, explain which observation changes the decision. Revisit the matching CCN1 note after a mistake, then try again on another day. Recognising a familiar answer is different from being able to explain the principle.
Preparing for an ACS assessment or reassessment? Use the free CCN1 mock-test setup for a timed revision session, then review the safety reasoning behind each answer. Practical competence also needs hands-on training and assessment.
The free test offers 5, 10 or 25 questions from this same set, with an optional practice timer. In Test mode, answers and explanations appear after you finish. Repeated tests reuse this bank, so a higher score can reflect familiarity.
Set up a free CCN1 gas safety testCCN1 is the ACS core domestic natural gas safety assessment. It covers the gas safety knowledge and practical competence that underpin domestic gas work. Appliance assessments, such as CENWAT for boilers and water heaters, cover additional areas of work.
Yes. Start with the 25 original CCN1 practice questions above, including explanations and diagrams. They exercise gas safety reasoning for revision. A short online set does not check practical competence or cover every appliance assessment.
Answer the questions with immediate feedback first. Then use the Test setup on this page for 5, 10 or 25 questions with an optional timer and explanations at the end. Write down why you missed each answer before repeating the set; recognising a question is easier than explaining it.
ACS certificates are normally valid for five years. Check your own certificate dates and assessment-centre arrangements early, then revise the subjects you use less often alongside any changed requirements. Experienced engineers still benefit from working through calculations and safety decisions.
The core assessment and appliance elements serve different purposes. Check the categories relevant to the work you intend to do, rather than treating a CCN1 practice score as evidence for every appliance. CENWAT, CKR1 and HTR1 have separate revision areas.
All 25 questions on this page are free, with no account or card required. They are selected from the maintained CCN1 gas safety question bank. Premium opens the full bank of 355 questions, more modules and Weak-Spot Review.
A free account saves the answers you give while signed in and lets you continue across devices. Without an account, this browser can remember your place for 30 days; it does not transfer earlier guest answers into an account. Signing up keeps the same free question allowance.