ISO 5356-2:2012

Overview

ISO 5356-2:2012 specifies dimensional requirements for screw-threaded weight-bearing conical connectors used in anaesthetic and respiratory equipment. Intended for mounting heavy or fragile accessories on inhalation anaesthesia apparatus and ventilators, this part of ISO 5356 defines the geometry and thread forms for robust, hand-engageable connectors that are compatible with conical connectors in ISO 5356-1.

Keywords: ISO 5356-2, conical connectors, screw-threaded weight-bearing connectors, anaesthetic and respiratory equipment, medical device connectors.

Key Topics and Requirements

• Scope: Dimensional requirements for screw-threaded weight-bearing conical connectors used within breathing systems and at the common gas outlet. Covers:
  • 22 mm connectors
  • 22 mm/15 mm coaxial connectors
• Thread specification:
  • Male threads: M33 × 2, 6g
  • Female threads: M33 × 2, 6H
  • Threads conformant with ISO 965-2
• Mechanical and assembly features:
  • Union nut free axial movement limited to not more than 2 mm so male/female components separate when unscrewed.
  • O-ring groove recommended: 24.8 mm diameter × (2.3 +0.2/0) mm width to suit an O-ring of recommended size 22.1 mm internal diameter, 1.6 mm cross-section.
  • Provision for retaining lug/shoulder or circlip and a retaining shoulder; knurling on union nut for hand grip.
• Design goals: robustness, simplicity, ease of sterilization, ease of manual engagement/disengagement, and compatibility with lightweight connectors (ISO 5356-1).
• Limits: The standard gives dimensional and interchangeability requirements only - it does not specify application-specific performance tests or how connectors are to be used in particular devices.

Applications and Users

• Who uses this standard:
  • Manufacturers of anaesthetic machines, ventilators, and breathing system components
  • Biomedical engineers and product designers developing medical gas connectors and accessories
  • Test laboratories and regulatory bodies verifying connector interchangeability and conformity
  • Clinical engineering teams and procurement specialists specifying compatible accessories
• Practical uses:
  • Mounting heavy or fragile breathing attachments (filters, humidifiers, flow meters) to common gas outlets or within patient circuits
  • Ensuring mechanical compatibility across devices and reducing risk of inadvertent misconnection
  • Guiding design for sterilizable, hand-operable medical connectors

Related Standards

• ISO 5356-1 - Cones and sockets (compatibility basis)
• ISO 965-2 - Metric screw thread tolerances (threads M33 × 2)
• ISO 4135 - Vocabulary for anaesthetic and respiratory equipment

This concise reference supports safe, interoperable connector design for anaesthesia and respiratory devices while aiding manufacturers and clinicians in selecting compliant, weight-bearing conical connectors.