Cylinder Testing

Gas cylinders contain large amounts of stored energy. It is vital that they are made to appropriate standards and are then regularly maintained to ensure the safety of those who transport, fill and use them.

All gas cylinders used for the transport of gases by road in the UK are subject to Statutory Regulation. Specifically The Carriage of Dangerous Goods and Use of Transportable Pressure Equipment Regulations which implements the Agreement concerning the International Transport of Dangerous Goods by Road (ADR).  

ADR requires that gas cylinders are inspected and tested on a periodic basis. This provides assurance that each cylinder is fit for purpose. The test periodicity is laid down in ADR, Packing Instruction P200. ADR allows an option to extend the period between inspection and test of certain cylinders to 15 years. This extension has to have the agreement of the National Competent Authority. In the UK this is the responsibility of the Vehicle Certification Agency (VCA), who are an Executive Agency of the UK Department for Transport (DfT).  The VCA have published guidance  to gain approval for (1) LPG cylinders, and (2) for certain aluminium alloy and seamless steel cylinders, as well as an Application Form and an Annual Returns Form.  These are available on their website.  Additional information is available within BCGA GN 36

Inspections

An inspection is a formal examination of the gas cylinder and its valve. This may or may not be carried out at the same time. For example:

  • A pressure test
  • A visual examination (internal at time of manufacture and at periodic inspection and testing)
  • A check of the marking and labelling
  • The correct operation of the valve (or an integrated regulator).

Each cylinder is given an initial inspection and test at the time of manufacture, a pre-fill inspection is carried out prior to each fill and a periodic inspection and test is carried out at set frequencies or when the pre-fill inspection determines a need.

Initial and periodic inspection and testing can only be carried out by an Inspection Body authorised by the National Competent Authority. In the UK the Competent Authority is the Secretary of State for Transport, within the Department for Transport (DfT). DfT has set up a scheme to appointment Inspection Bodies in order to meet these obligations. The scheme is operated by the Vehicle Certification Agency (VCA) Dangerous Goods Office. DfT has appointed the United Kingdom Accreditation Service (UKAS) as the delegated ‘accreditation’ body. Appointments are made by VCA following an assessment and, if appropriate, recommendation for the appointment by UKAS; successful applicants are issued an approval by the VCA defined by their individual Schedule of Accreditation.

Information on the Inspection Bodies who have been appointed to undertake various functions in connection with the inspection of tanks and/or pressure equipment can be found on the VCA website. Further information on appointments can be obtained from VCA.

An initial inspection and test is carried out at the time of manufacture by the manufacturer in accordance with the applicable design standards with supervision from an Inspection Body selected by the manufacturer. The degree of supervision is dependent upon the choice of the manufacturer and the capability of the manufacturer’s Quality Management System.

Pre-fill inspections are carried out at specially equipped filling centres, with qualified staff using appropriate procedures. Pre-fill inspections are required to conform to standards, such as:

  • BS EN ISO 24431, Gas cylinders. Seamless, welded and composite cylinders for compressed and liquefied gases (excluding acetylene). Inspection at time of filling.

For further information on filling refer to BCGA CP 43, The safe filling of gas cylinders. Note that cylinders are only allowed to be filled and transported if they are in date for their periodic inspection and test, however, you are allowed to transport an out-of-date cylinder provided you are returning it to a place where it will be tested.

A periodic inspection and test is carried out by an inspection body. The relevant standards describing the periodic inspection and testing requirements for cylinders include:

  • BS EN 1802, Transportable gas cylinders. Periodic inspection and testing of seamless aluminium alloy gas cylinders.
  • BS EN 1803, Transportable gas cylinders. Periodic inspection and testing of welded carbon steel gas cylinders.
  • BS EN 1968, Transportable gas cylinders. Periodic inspection and testing of seamless steel gas cylinders.
  • BS EN ISO 10460, Gas cylinders. Welded aluminium-alloy, carbon and stainless steel gas cylinders. Periodic inspection and testing.
  • BS EN ISO 10462, Gas cylinders. Acetylene cylinders. Periodic inspection and maintenance.
  • BS EN ISO 11623, Transportable gas cylinders. Periodic inspection and testing of composite gas cylinders.
  • BS EN ISO 18119, Gas cylinders. Seamless steel and seamless aluminium-alloy gas cylinders and tubes. Periodic inspection and testing.

BCGA GN 25 provides guidance on assessing the competency of personnel who are required to undertake periodic inspection and testing of gas cylinders.

Cylinder Stamp Marks

After successful completion of the initial inspection and test, and any subsequent periodic inspection and test, cylinders are permanently marked with mandatory stamp marks. The stamp mark will consist of the date of the inspection and the identity mark of the Inspection Body. In addition, it is good practice to identify the next periodic inspection and test date by the use of a cylinder test ring. Cylinder test rings provide a quick, visual reference. They consist of a plastic disc, fitted between the cylinder and the valve, colour coded and shaped to indicate the year when the next periodic inspection and test is due. This ring may also give an indication of the month. Some companies use two separate plastic rings to indicate the month and year.

It is not acceptable to disfigure or remove these stampmarks, for example by grinding. Where cylinder test rings are fitted they shall always be whole. If there is evidence of deliberate damage to stamp marks or cylinder test rings, for example, split rings, the cylinder is to undergo inspection and test before further filling or use is allowed.

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Cylinder testing providers

Several members of the BCGA have been appointed and offer the services of an Inspection Body.

A selection of these companies providing out cylinder testing and/or a range of associated services are listed below. See the full list here.

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Links

Additional information regarding cylinder testing can be found via the agency website links below:

Committees

Within BCGA cylinder testing is the responsibility of Technical Sub-Committee (TSC) 2. Members can access information on TSC2 via the Meetings page.

Publications

Publications

CP32 The safe filling of food gas cylinders for beverage dispense. Revision 3: 2019

1713 Codes of Practice CP32

This Code of Practice addresses the safety, quality and operational issues necessary for the filling of gas cylinders with food gases for beverage dispense. The document covers safe filling practices, cylinder identification, handling, corrosion prevention and product quality.

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CP43 The safe filling of gas cylinders. 2018

1762 Codes of Practice CP43

The filling of gas cylinders is hazardous and subject to statutory controls. Cylinders have to be checked to ensure their integrity and that they are safe to fill. Filling has to be carried out at specially-equipped centres, with qualified staff using appropriate procedures.

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GN6 Avoidance and detection of internal corrosion of gas cylinders. Revision 3: 2021

1783 Guidance Notes GN6

Describes methods to prevent and detect internal corrosion of gas cylinders. Includes measures to prevent contamination by customer processes, and methods of moisture and corrosion detection.

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GN8 Catalogue of gas container marks used by BCGA members and their inspection bodies. Revision 6: 2018

1815 Guidance Notes GN8

This document provides a list of the recognised gas container test marks used by BCGA members and their inspection bodies during an inspection and test.

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GN25 Guidance on assessing the competency of personnel undertaking periodic inspection and testing of gas cylinders. Revision 1: 2021

1893 Guidance Notes GN25

Provides guidance on assessing the competency of personnel who are required to undertake periodic inspection and testing of gas cylinders. It explains the regulatory background and then provides extensive information on conducting an appropriate assessment.

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GN36 Guidance for the use, inspection and transport of cylinders with various design codes. 2017

1937 Guidance Notes GN36

Provides guidance on the range of gas cylinders which may be encountered in the UK and the associated regulations that control their use.

Readers are advised to check the information in GN36 against current legislation. Changes brought about following Brexit will be incorporated in due course.

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TIS6 Gas cylinder identification. Label and colour coding requirements. Revision 3: 2018

1931 Technical Information Sheets TIS6

An explanation of the content of a typical gas cylinder label and a guide to the colour coding system used on gas cylinders.

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