Diagnose and rectify faults in gas storage vessels and supply systems

Business Sectors (Suites): LPG Installation and Maintenance
Developed by: Energy & Utility Skills
Approved on: 30 Mar 2020


This standard is about the diagnosis and rectification of faults that occur outside of, or in addition to, servicing and commissioning of gas storage and supply systems.  This could also apply to bulk supply vessels for single or multiple dwellings or for cylinders. Gas storage vessels and supply systems can be for any type of fuel gas.  

This standard includes preparing the work area, obtaining information on condition and malfunctions, establishing the nature of malfunctions, rectifying faults and complying with legislative requirements.

This standard is for anyone who diagnoses and rectifies faults in gas storage vessels and supply systems. 

Performance criteria

You must be able to:

1. make sure work area is safe and clean prior to working 
2. ensure storage vessel and valve connections are free from grease, oil and dirt
3. carry out visual inspections to establish the current condition and potential areas of malfunction of gas storage vessels and supply systems
4. obtain information about servicing, previous operation and any changes to gas storage vessels and supply systems from appropriate sources
5. conduct fault finding tests in the correct sequence in accordance with manufacturers’ instructions 
6. use fault finding tests to identify any defects of storage or supply systems
7. update customers and other site users on progress and timescales at appropriate times 
8. work in line with relevant statutory regulations, industry codes of practice and standards at all times
9. locate and repair any gas leaks, ensuring that any escaped gas disperses in line with safety requirements
10. conduct repairs in line with job specification timelines without compromising safety 
11. suggest required alternative action to appropriate people when repairs cannot be achieved, 
12. carry out tests in line with industry approved codes of practice to ensure that gas storage and supply systems can be returned to full working order
13. restore gas supply systems to normal operation when it is safe to do so
14. record clear and accurate results of tests and repairs in accordance with organisational procedures
15. send records of work carried out to relevant people and organisations
16. report and record accurate information about incidents to appropriate bodies without delay

Knowledge and Understanding

You need to know and understand:

1. relevant statutory regulations, building regulations and standards, industry codes of practice, British and European standards and manufacturers' instructions, working procedures, safe working practices
2. gas storage and supply systems, their components and their characteristics
3. risk assessment procedures
4. how to access manufacturers’ instructions
5. commonly occurring faults and their symptoms in gas systems in relation to system faults, gas availability and supply faults
6. how to clean storage vessel and valve connections
7. analysis methods and techniques used in problem solving
8. standard testing procedures and sequential checks to conduct in order to identify and isolate faults and return to normal working order
9. how to carry out tests on valves and fittings
10. information required and their sources in relation to faults
11. fault finding techniques for components and storage vessels 
12. repair techniques and procedures for different types of fault including component repairs and storage vessel structural repairs
13. environmental, health and safety factors to take into account when diagnosing  and rectifying faults
14. bodies to whom incidents should be reported including RIDDOR and HSE
15. how appropriate communication  can help to minimise disruption
16. how to communicate with customers and other site users and when it is appropriate to do so including before commencement, during and after 
17. organisational recording systems and procedures 


Scope Performance

Scope Knowledge





Links To Other NOS

External Links

Version Number


Indicative Review Date

30 Mar 2025





Originating Organisation

Energy & Utility Skills

Original URN


Relevant Occupations

Engineering, Engineering and Manufacturing Technologies, Engineering Professionals, Professional Occupations

SOC Code



Codes of practice, safe working, problem solving, solutions; gas storage vessel; gas supply system; bulk supply vessel; multiple dwellings; cylinder; diagnose; faults; malfunction;