ISO 21172-1:2015

Overview

ISO 21172-1:2015 - "Gas cylinders - Welded steel pressure drums up to 3 000 litres capacity for the transport of gases - Design and construction - Part 1: Capacities up to 1 000 litres" specifies minimum requirements for the material, design, fabrication, construction, inspection and testing at manufacture of refillable welded steel pressure drums. It applies to cylindrical and spherical drums with volumes from 150 L to 1 000 L and test pressures up to 300 bar, for both compressed and liquefied gases.

Key technical topics and requirements

ISO 21172-1:2015 sets out detailed engineering and manufacturing controls including:

• Materials and heat treatment
  • Selection of steels for the pressure envelope and weld consumables, and heat-treatment rules to ensure mechanical properties and toughness.
• Design calculations
  • Design stress and temperature limits, plus thickness calculations for cylindrical shells, spherical shells and dished ends.
• Fabrication and welding
  • Welding procedures, joint preparation, assembly, temporary attachments, and construction/workmanship tolerances.
• Fittings and attachments
  • Requirements for screwed and bolted fittings, protection of valves and openings, lifting attachments and rolling bands.
• Inspection, testing and NDE
  • Mechanical tests (tensile, bend, impact), radiography/radioscopy, macro examination, proof pressure and leak/tightness tests.
• Type approval and manufacturing tests
  • Prototype testing, per-drum manufacturing checks (volume, tare weight, proof pressure), marking and certification.
• Quality control
  • Acceptance/rejection criteria for manufacturing defects and record-keeping for certification.

Practical applications and target users

ISO 21172-1 is essential for anyone involved in the lifecycle of welded steel gas drums intended for transport:

• Manufacturers and fabricators designing and producing welded pressure drums (150–1 000 L)
• Welding engineers and production supervisors implementing welding procedures and heat treatment
• Quality and inspection teams performing mechanical tests and non-destructive examination (NDE)
• Certification bodies and test laboratories responsible for type approval and manufacturing conformance
• Gas suppliers, transport companies and fleet operators ensuring drums meet regulatory safety and marking requirements
• Regulatory authorities and auditors verifying compliance with international transport safety standards

Use cases include designing new drum models, establishing factory test regimes, approving repaired drums, and preparing documentation for export or transport certification.

Related standards and compliance context

ISO 21172-1:2015 is Part 1 of the ISO 21172 series (Part 1 covers capacities up to 1 000 L). It is typically used alongside other national and international transport regulations and standards (transport of dangerous goods regulations, certification rules and complementary cylinder standards) when addressing safe manufacture, testing and marking of gas transport containers.

Keywords: ISO 21172-1:2015, welded steel pressure drums, gas cylinders, design and construction, 150–1000 L, 300 bar, manufacturing, testing, inspection, type approval.