ISO 9809-2:2019

Overview

ISO 9809-2:2019 - Gas cylinders: Design, construction and testing of refillable seamless steel gas cylinders and tubes - Part 2 - specifies minimum requirements for quenched and tempered seamless steel cylinders and tubes with an actual tensile strength Rma ≥ 1 100 MPa. The third-edition 2019 standard covers cylinders and tubes with water capacities up to and including 450 L and applies to compressed, liquefied and dissolved gases. It defines material, design, manufacture, inspection and testing requirements to ensure safety, interchangeability and regulatory acceptance.

Key topics and technical requirements

• Scope limits: Applicable for cylinders/tubes with Rma ≥ 1 100 MPa. Not applicable where Rma,max > 1 300 MPa for diameters > 140 mm with guaranteed wall thickness ≥ 12 mm, or where Rma,max > 1 400 MPa for diameters ≤ 140 mm with guaranteed wall thickness ≥ 6 mm.
• Materials & heat treatment: Minimum requirements on chemical composition, controls and heat-treatment processes for quenched and tempered steel to achieve specified tensile properties.
• Design principles: Rules for cylindrical shell thickness, design of convex and concave ends, neck and neck rings, foot rings, and dimensional drawing requirements to ensure mechanical integrity.
• Manufacturing workmanship: Requirements for wall thickness tolerances, surface imperfections, out-of-roundness, straightness and stability.
• Non-destructive examination: Ultrasonic examination procedures and acceptance criteria for seamless cylinders (normative annex included).
• Type approval & prototype testing: Procedure for prototype tests including pressure cycling, flawed-cylinder burst and cycle tests, bend/flattening tests and thread verification.
• Batch & production tests: Mandatory batch tests such as tensile, impact and hydraulic burst tests, plus tests on every cylinder (proof pressure, volumetric expansion, hardness, leak test and capacity check).
• Certification & marking: Requirements for type approval certificates, acceptance certificates and mandatory cylinder marking.
• Annexes: Normative guidance on manufacturing imperfections and ultrasonic examination; informative examples for certificates and calculation methods.

Applications and users

ISO 9809-2:2019 is intended for:

• Cylinder and tube manufacturers designing and producing high-strength seamless steel refillable gas cylinders
• Quality, inspection and testing laboratories responsible for type approval and batch testing
• Gas suppliers, transporters and filling stations ensuring safe reuse and regulatory compliance
• Regulatory bodies and certification authorities referencing harmonized international requirements
• Design engineers selecting materials and specifying wall thickness, necks and end design for high-strength cylinders

Related standards

• ISO 9809 (all parts) - the wider series for refillable seamless steel gas cylinders
• UN Model Regulations - the standard is written to be suitable for reference in international transport regulations

Keywords: ISO 9809-2:2019, gas cylinders, quenched and tempered steel, tensile strength 1100 MPa, seamless steel cylinders, design construction testing, refillable gas cylinders.