Overview
EN ISO 11363-2:2017 (ISO 11363-2:2017) defines the types, dimensions and principles of use of inspection gauges for the 17E and 25E taper threads used to connect valves to gas cylinders. It is Part 2 of the ISO 11363 series and is intended to be used together with ISO 11363-1, which specifies the nominal thread forms. The standard includes examples for calculating thread gauge dimensions on the large end diameter (Annex A) and discusses limitations of the gauging system (Annex B).
Key topics and requirements
- Scope and purpose: Specifies gauges for routine gauging of cylinder neck (internal) and valve stem (external) taper threads for 17E and 25E connections.
- Types of gauges:
- Inspection gauges: single-part and two-part, plain or threaded.
- Check gauges: for verifying dimensional conformity of inspection gauges (not for direct gauging of cylinder/valve threads).
- Plug gauges (for internal/cylinder threads) and ring gauges (for external/valve threads).
- Gauge configurations:
- Single-part gauges: full-form gauges long enough to contact the full taper length.
- Two-part gauges: separate small-end and large-end gauges used together.
- Materials: Gauges must be manufactured from materials of suitable strength, stability and hardness.
- Thread profile: Threaded inspection and check gauges use a British Standard Whitworth (BSW) form with a 55° thread angle (as specified in the document).
- Use, verification and identification: The standard outlines practical use (plain and threaded gauges), accept/reject criteria for plug and ring gauges, procedures for gauge verification and the identification/marking of inspection and check gauges.
- Informative annexes:
- Annex A: worked examples for calculating large-end thread gauge dimensions.
- Annex B: limitations of the gauging system to be considered by users.
Applications and who uses it
EN ISO 11363-2:2017 is essential for:
- Gas cylinder manufacturers and fabricators who need to ensure neck threads comply with 17E/25E requirements.
- Valve manufacturers and assembly vendors validating valve stem threads.
- Inspection and calibration laboratories that produce or verify plug and ring gauges.
- Quality, compliance and maintenance teams in gas supply, transportable cylinder management, and safety/regulatory bodies.
- Service technicians and fitters performing routine cylinder/valve assembly checks.
Related standards
- ISO 11363-1 - Specifications for 17E and 25E taper threads (normative reference).
- Other cylinder and fitting standards maintained by ISO/TC 58 (Gas cylinders) may be relevant for complete conformity and safety programs.
Keywords: EN ISO 11363-2:2017, ISO 11363-2, 17E taper thread, 25E taper thread, gas cylinder inspection gauges, plug gauges, ring gauges, BSW 55° thread, gauge verification.
