Overview

EN ISO 20475:2020 / ISO 20475:2018 specifies requirements for the periodic inspection and testing of cylinder bundles containing compressed, liquefied and dissolved gases. Prepared by ISO/TC 58 and adopted by CEN, the standard sets out general principles for maintenance, inspection procedures and documentation needed to return bundles to service safely. It is applicable to most industrial and transportable cylinder bundles, with specific exclusions (see Key points).

Key topics and technical requirements

The standard describes the full periodic inspection and testing process for gas cylinder bundles (assembly of cylinders interconnected by a manifold and carried as a unit), including:

Scope and applicability
- Applicable to bundles carrying compressed, liquefied and dissolved gases.
- Not applicable to solvent-free acetylene cylinders; additional acetylene requirements are in Annex A.
- Excludes bundles that are part of a battery vehicle; some applications (e.g., offshore) may require extra provisions.
Inspection procedures
- Identification and preparation of cylinders and bundles before inspection.
- Depressurization of manifolds and individual cylinders prior to disassembly.
- Disassembly of manifolds and fittings where required.
- Periodic inspection and testing of individual cylinders in the bundle in line with retest obligations.
- Inspection of frame, manifold, valves and fittings for structural integrity, corrosion, leaks and correct operation.
Reassembly, testing and marking
- Bundle reassembly procedures and leak/pressure testing prior to return to service.
- Stamp marking and documentation requirements to record the inspection outcome and traceability.
Safety and maintenance principles
- Emphasis on safe procedures (e.g., depressurization) and consulting manufacturers’ recommendations where doubts exist.
- Alignment with transport regulations and the UN Model Regulations where applicable.

Applications and users

EN ISO 20475 is intended for organizations and professionals involved with cylinder bundles, including:

Cylinder and bundle manufacturers
Inspection and testing bodies / third‑party inspectors
Gas suppliers and distributors
Plant maintenance and safety engineers
Transport and logistics operators handling packaged gases
Regulatory and compliance teams

Use cases include routine maintenance scheduling, pre‑transport safety checks, compliance with regional/national transport rules, and asset lifecycle management.

Related standards

Relevant normative references cited by EN ISO 20475 include (but are not limited to):

ISO 10286 (terminology)
ISO 10961 (design, manufacture, testing and inspection of cylinder bundles)
ISO 10460 / ISO 18119 (periodic inspection and testing of welded/seamless cylinders)
ISO 22434 (inspection and maintenance of cylinder valves)

Keywords: EN ISO 20475:2020, ISO 20475:2018, cylinder bundles, gas cylinders, periodic inspection, testing, manifold, valves, acetylene, bundle maintenance.

Overview

Key topics and technical requirements

The standard describes the full periodic inspection and testing process for gas cylinder bundles (assembly of cylinders interconnected by a manifold and carried as a unit), including:

Scope and applicability
- Applicable to bundles carrying compressed, liquefied and dissolved gases.
- Not applicable to solvent-free acetylene cylinders; additional acetylene requirements are in Annex A.
- Excludes bundles that are part of a battery vehicle; some applications (e.g., offshore) may require extra provisions.
Inspection procedures
- Identification and preparation of cylinders and bundles before inspection.
- Depressurization of manifolds and individual cylinders prior to disassembly.
- Disassembly of manifolds and fittings where required.
- Periodic inspection and testing of individual cylinders in the bundle in line with retest obligations.
- Inspection of frame, manifold, valves and fittings for structural integrity, corrosion, leaks and correct operation.
Reassembly, testing and marking
- Bundle reassembly procedures and leak/pressure testing prior to return to service.
- Stamp marking and documentation requirements to record the inspection outcome and traceability.
Safety and maintenance principles
- Emphasis on safe procedures (e.g., depressurization) and consulting manufacturers’ recommendations where doubts exist.
- Alignment with transport regulations and the UN Model Regulations where applicable.

Applications and users

EN ISO 20475 is intended for organizations and professionals involved with cylinder bundles, including:

Cylinder and bundle manufacturers
Inspection and testing bodies / third‑party inspectors
Gas suppliers and distributors
Plant maintenance and safety engineers
Transport and logistics operators handling packaged gases
Regulatory and compliance teams

Use cases include routine maintenance scheduling, pre‑transport safety checks, compliance with regional/national transport rules, and asset lifecycle management.

Related standards

Relevant normative references cited by EN ISO 20475 include (but are not limited to):

ISO 10286 (terminology)
ISO 10961 (design, manufacture, testing and inspection of cylinder bundles)
ISO 10460 / ISO 18119 (periodic inspection and testing of welded/seamless cylinders)
ISO 22434 (inspection and maintenance of cylinder valves)

Keywords: EN ISO 20475:2020, ISO 20475:2018, cylinder bundles, gas cylinders, periodic inspection, testing, manifold, valves, acetylene, bundle maintenance.

SIST EN ISO 20475:2021 PDF

Technical details

Abstract

Overview

Key topics and technical requirements

Applications and users

Related standards

Related standards

Abstract

Overview

Key topics and technical requirements

Applications and users

Related standards

Related standards

Gas cylinders — Cylinder bundles — Periodic inspection and testing

Gas cylinders. Cylinder bundles. Periodic inspection and testing.

Gas cylinders - Vocabulary (ISO 10286:2025)

Gas cylinders - Cylinder bundles - Design, manufacture, testing and inspection (ISO 10961:2019)

Gas cylinders - Welded aluminium-alloy, carbon and stainless steel gas cylinders - Periodic inspection and te…

Gas cylinders - Seamless steel and seamless aluminium-alloy gas cylinders and tubes - Periodic inspection and…

Gas cylinders - Inspection and maintenance of valves (ISO 22434:2022)