Free ACS CCN1 Exam Prep
ACS CCN1 Core Domestic Natural Gas Safety Assessment
Pass your ACS CCN1 exam without spending hundreds on expensive prep courses. Free study guides, practice questions, flashcards, and related exam resources.
Quick Facts
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ACS UK Gas Safe / ACS Gas Assessments License: Complete Roadmap
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Legislation, Tightness Testing & Gas RatingYou are here
Master GSIUR 1998 and Gas Safe duties, the let-by and tightness test (20-21 mbar, 2 minutes, 4 mbar / 2.5 mbar drops), gas rating and calorific value (~28% combined).
Pipework, Ventilation & Flueing
Study pipework sizing (1 mbar drop), bonding within 600mm of the meter, BS 5440-2 ventilation (5 cm2/kW), flue types, flue flow and spillage testing (~33%).
Combustion & CO/CO2 Analysis
Learn complete vs incomplete combustion, flue gas analysis, the 0.004 CO/CO2 ratio limit, carbon monoxide hazards and flame picture (~12%).
Emergency & Unsafe Situations, then Practice
Cover GIUSP ID/AR/NCS, warning notices, the ECV, gas escape procedures (0800 111 999) and RIDDOR, then complete the 100-question practice bank and review every miss with the AI tutor (~14%).
Can You Take the ACS CCN1 Exam?
Check if you meet the basic eligibility requirements
- •Complete an approved gas managed learning programme (new entrants) or hold relevant qualifications/experience
- •Book the CCN1 assessment at an ACS-approved centre
- •Pass open-book written theory (multiple-choice, short-written and scenario) covering core domestic gas safety
- •Pass the observed practical assessment for core domestic gas work
- •Re-assess CCN1 typically every 5 years to maintain Gas Safe registration
ACS CCN1 Quick Facts
Time to Get Licensed
4-8 weeks typical alongside a managed learning programme
From start to license in hand
Exam Provider
ACS-approved assessment centres under the Nationally Accredited Certification Scheme
Retake Policy
Candidates who do not pass a subject area can retake that component per the ACS centre's retake policy (additional fee may apply).
Total Cost Breakdown
Free ACS CCN1 Prep That Actually Works
118+ Practice Questions
More free questions than most paid courses
AI Tutor Explains Mistakes
Understand why answers are wrong, not just which ones
Updated for 2026
Content reflects latest exam changes
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What You'll Study
9 chapters covering everything you need to pass
Chapter 0: Introduction & ACS CCN1 Overview
2 sections
Chapter 1: Gas Safety Legislation & Regulations
4 sections
Chapter 2: Tightness Testing & Let-By Testing
4 sections
Chapter 3: Gas Rating, Pressure & Calorific Value
4 sections
Chapter 4: Pipework Sizing, Installation & Purging
4 sections
Chapter 5: Ventilation Requirements for Domestic Gas
4 sections
Chapter 6: Flue Types, Siting & Spillage Testing
4 sections
Chapter 7: Combustion Analysis & Carbon Monoxide Safety
4 sections
Chapter 8: Emergency & Unsafe Situations (GIUSP / RIDDOR)
4 sections
ACS CCN1 Exam Details
ACS CCN1 Core Domestic Natural Gas Safety Assessment
Administered by Gas Safe Register / ACS approved centres (e.g. LCL Awards, BPEC)
Exam Content Breakdown
Based on the official Gas Safe Register / ACS approved centres (e.g. LCL Awards, BPEC) content outline
Gas Safety (Installation and Use) Regulations 1998, Gas Safe registration, landlord duties (Regulation 36 / CP12), and operative responsibilities
Let-by test of the ECV, tightness test at 20-21 mbar over 2 minutes, stabilisation, and permissible pressure drops for U6/G4 meters per IGEM/UP/1B
Gas rating from the meter, gross calorific value (about 39.5 MJ/m3), heat-input calculation, natural gas properties, working pressure and standing pressure
Pipework materials, the 1 mbar maximum pressure drop, sleeving and protection, purging, and equipotential bonding within 600mm of the meter outlet
BS 5440-2 ventilation, the 5 cm2/kW open-flue rule above the first 7kW, adventitious air, air vents, and ventilation for flueless appliances
Open-flued (Type B), room-sealed (Type C) and flueless (Type A) appliances, flue flow tests, spillage testing under worst-case conditions, and terminal siting (BS 5440-1)
Complete vs incomplete combustion, flue gas analysis, the 0.004 CO/CO2 ratio limit, carbon monoxide hazards, CO alarms, and flame picture
GIUSP classifications ID / AR / NCS (IGEM/G/11), warning notices, the emergency control valve, gas escape procedures, 0800 111 999, and RIDDOR reporting
What's Included
9 Chapters
Complete exam coverage
Practice Quizzes
With detailed explanations
Free to Start
No credit card required
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What's Next After the ACS CCN1?
After passing the ACS CCN1, you can pursue these career paths
uk-city-guilds-6014-gas
Build underpinning gas utilisation knowledge with the City & Guilds 6014 Level 3 NVQ in Gas Utilisation
uk-acs-commercial-heating
Progress to non-domestic work with the ACS Commercial Heating gas safety assessment
uk-acs-commercial-catering
Specialise in commercial kitchens with the ACS Commercial Catering gas safety assessment
ACS CCN1 Exam FAQ
Official Gas Safe Register / ACS approved centres (e.g. LCL Awards, BPEC) Resources
Verify information with these official sources
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