ISO/TR 28821:2012

Overview - ISO/TR 28821:2012 (Gas welding equipment, hose connections)

ISO/TR 28821:2012 is an ISO Technical Report that lists hose connections for gas welding, cutting and allied processes which are either standardized or in common use in ISO member countries. Its main purpose is to limit the proliferation of new hose fittings by directing users and national committees to existing, widely used connection types. The report provides thread type and size information (nominal diameter, pitch, left/right-hand and internal/external designations) but does not give full dimensional or performance details.

Key topics and technical scope

• Catalog of hose connections: nominal diameters and thread pitches for connections used with oxygen, inert gases and flammable gases.
• Thread designations: UNF/UN, metric (M), Whitworth/G (G) and national variants; includes LH/RH (left/right hand) and INT/EXT (internal/external) annotations.
• Country usage: mapping of specific connection types to countries or regions (e.g., US/CAN, EU members, JP, AU) to show which fittings are standardized or commonly used where.
• Limitations: the report only lists thread type and size. For complete descriptions, limitations and additional requirements (e.g., hose tail dimensions, sealing, materials, pressure ratings), users must consult the referenced national or industry standards (EN 560, CGA E-1, JIS B 6805, AS 4267, etc.).
• Standardization objective: encourages adoption of existing connections to prevent further fragmentation of fittings in industry and national practices.
• Replaces: ISO/TR 28821:2012 cancels and replaces ISO 3253:1998.

Practical applications and users

ISO/TR 28821:2012 is useful for anyone involved in the design, selection, procurement or regulation of gas welding and cutting equipment:

• Equipment manufacturers and designers - check common thread types to improve international compatibility of torches, regulators and hose assemblies.
• Standards committees and national bodies - select an existing connection from the list when developing or updating national standards to avoid proliferation.
• Procurement and supply chain - verify hose/connector compatibility when sourcing regulators, hoses and fittings for multinational operations.
• Service technicians and safety managers - identify correct thread types to reduce cross-connection risk and improve on-site safety.
• Gas suppliers and welding shops - align equipment with locally standardized connections to ensure safe, compatible installations.

Related standards (for detailed specifications)

• EN 560, CGA E-1, JIS B 6805, AS 4267 - referenced for full dimensional, material and performance requirements.
• ISO 3253:1998 - earlier document replaced by this Technical Report.

Keywords: ISO/TR 28821:2012, gas welding equipment, hose connections, thread types, thread sizes, welding and cutting, EN 560, CGA E-1, JIS B 6805, hose fittings, regulator outlets.