ACS Domestic Gas Safety 
Sector Gas
Certification NICEIC Certification will issue a Certificate of Competence to successful candidates and notify the Gas Safe Register of the successful completion of assessments.
Expiry 5 years
Assessment Information: Engineers who have the necessary pre-requisites to be admitted onto the ACS Scheme run by one of our approved centres to enable registration with Gas Safe.
These engineers are classified into 2 categories:
Category 1 – Experienced practicing gas fitting operative
Category 2 – Applicant with relevant mechanical engineering/fitting qualifications/ experience
Domestic Gas Safety Core
Code Description
CCN1 Core Domestic Natural Gas Safety
CPA1 formed part of the CCN1 assessment in April 2012
Domestic Gas Safety Changeover Core
Code Description
CoCDN1 Changeover from Commercial Natural Gas to Domestic Natural Gas
Domestic Gas Appliances
Code Description
CENWAT Domestic Natural Gas And LPG Central Heating/Hot Water Boilers &
Circulators, Combination Boilers, Storage Water Heaters & Instantaneous
Water Heaters
CKR1 Domestic Natural Gas & LPG Domestic Cooking Appliances
CKHB1 Domestic Natural Gas & LPG Combustion Performance
CMDDA1 Domestic Carbon Monoxide/Carbon Dioxide Atmosphere & Appliance Testing  for 1st, 2nd & 3rd Family Gases
DAH1 Domestic Natural Gas & LPG Ducted Air Heaters
DFDA1 Domestic Natural Gas & LPG Forced Draught Gas Burners
HTR1 Domestic Natural Gas & LPG Gas Fires And Wall Heaters
LAU1 Domestic Natural Gas & LPG Domestic Laundry Appliances
LEI 1 Domestic Natural Gas & LPG Leisure/Miscellaneous Appliances
MET1 Domestic Natural Gas Meters
WAT1 Domestic Instantaneous Water Heaters
Successful completion of the Core Domestic Gas Safety qualification is a pre-requisite before gas engineers can undertake additional assessment on natural gas fuelled installations and
Contents: Course Content – Core Domestic Gas
·       Gas safety legislation and Standards.
·       Gas emergency actions and procedures.
·       Products and characteristics of combustion
·       Ventilation.
·        Installation of pipework and fittings.
·       Tightness testing and purging.
·       Checking and/or setting meter regulators.
·       Unsafe situations, emergency notices and warning labels.
·       Operation and positioning of emergency isolation controls and valves.
·       Checking and setting appliance burner pressures and gas rates.
·       Operation and checking of appliance gas safety devices and controls.
·       Chimney Standards.
·       Chimney inspection and testing.
·       Installation of open, balanced and fan assisted chimneys.
·       Re-establish existing gas supply and relight appliances.
·       Inspect, test, commission and maintain gas appliances (Re-assessment only).
Course Content – Domestic Gas Appliances
·       Gas safety regulations, Building Regulations, British Standards and other related legislation
·       Unsafe situations and emergency actions
·       Gas pipework (Specific to appliance category)
·       Flues and ventilation (Specific to appliance category)
·       Combustion (Specific to appliance category)
·       Combustion Performance Analysis (Flue gas testing)
·       Appliance controls (Specific to appliance category)
·       Commissioning, service, maintenance and basic gas safety related fault finding
Note: Training is not a pre-requisite to assessment
Pre- requisites: Please refer to the following links for a list of suitable entry level qualifications (Cat 1 &2)
Domestic Gas Safety Core;
Domestic Gas Appliances;
CCN1 (inc. CPA1, valid from 1st April 2012)
Re-Assessment On expiry of certificate, candidates are eligible to take reassessment.
Previous certificates must be presented to the assessment centre as evidence of holding the initial qualification.
Re-Assessment can be taken up to 6 months prior to the expiry of assessments allowing learners to take advantage of the MOT style Certification
Useful information
Guidance Note 8
Scheme Rules

Candidates wishing to find a centre near to them can use the Find my Nearest Centre facility on this site.

Centres wishing to apply for approval to run the scheme should refer to the  Our Assessment Centre section of the site.