Overview
ISO 18172-2:2007 - "Gas cylinders - Refillable welded stainless steel cylinders - Part 2: Test pressure greater than 6 MPa" specifies minimum requirements for the design, materials, manufacture and testing of refillable, transportable welded stainless steel gas cylinders. It applies to cylinders with water capacities from 0.5 L to 150 L, manufactured from stainless steels with maximum tensile strength below 1 100 MPa, and having a test pressure greater than 6 MPa (60 bar). The standard supports safe use for compressed and liquefied gases and is written for regulatory conformity and transport safety.
Key topics and technical requirements
- Materials and heat treatment: requirements for stainless steel categories, solution annealing, cryoforming and heat-treatment controls.
- Design: calculation of cylindrical shell wall thickness, design of convex or other end shapes, bungs, openings and minimum permitted thicknesses; use of a design stress factor (F) and related symbols.
- Construction and workmanship: welding qualifications, cryoforming and cold-forming procedures, welded joints, valve protection, neck threads and visual examination.
- Testing regime:
- New design tests and certification requirements for prototype designs.
- Batch tests: tensile, bend, impact, hardness, macroscopic examination of weld cross-sections, plus acceptance criteria.
- Tests on every cylinder: hydraulic/pressure testing, leakage and hardness checks.
- Non-destructive testing: radiographic and visual testing of welds (annexes and references specify techniques and acceptance).
- Marking and certification: mandated markings and documentation for conformity with transport regulations.
Practical applications
- Ensures safety and reliability of refillable welded stainless steel cylinders used in industry, medical gas supply, specialty gases, and laboratory settings.
- Guides manufacturers through material selection, welding procedures, production controls and quality assurance for cylinders intended for high-pressure service (>60 bar).
- Provides the technical basis for type approval, batch certification and conformity assessment, and for demonstrating compliance with transport of dangerous goods rules.
Who uses this standard
- Cylinder manufacturers and designers
- Welding and quality-control engineers
- Testing and inspection laboratories
- Regulatory authorities, certification bodies and transport safety organizations
- Purchasers and specifiers of high-pressure gas cylinders
Related standards
Commonly used with other ISO documents referenced in the standard, e.g.:
Keywords: ISO 18172-2, gas cylinders, refillable welded stainless steel cylinders, test pressure greater than 6 MPa, high-pressure cylinders, cylinder design, welding, batch tests, pressure testing.
Open preview (PDF)Gas cylinders — Refillable welded stainless steel cylinders — Part 2: Test pressure greater than 6 MPa