ISO 23551-5:2023

Overview

ISO 23551-5:2023 - part of the ISO 23551 series on safety and control devices for gas burners and gas‑burning appliances - specifies safety, constructional and performance requirements for manual gas valves. It applies to manual gas shut‑off valves, gas burner valves, appliance connector valves and delta C valves up to nominal connection size DN 100, designed for use with fuel gases (natural gas, manufactured gas, LPG) at inlet pressures up to and including 500 kPa. The standard excludes corrosive and waste gases and covers type testing only.

Key topics and technical requirements

The standard addresses the full lifecycle of valve design and verification with emphasis on safety and reliable operation:

• Construction and materials: housing, seals, springs, closure members, corrosion resistance and component integrity.
• Performance requirements: leak‑tightness (volumetric and pressure‑loss methods), rated flow rate, seating adequacy and resistance to torsion/bending.
• Functional requirements: operating torque and force limits, safety locks, multi‑position “on” configurations and pre‑setting devices.
• Durability and endurance: elastomer compatibility, resistance to lubricants and gases, humidity, marking and abrasion.
• Testing: type tests for endurance, flow, leakage and mechanical stresses; normative annexes provide test methods (e.g., leak‑tightness volumetric and pressure‑loss methods).
• Marking and documentation: open/closed position markings, installation and operating instructions, and required warning notices.
• Electrical/EMC: requirements where electrical components are part of the gas way.

Relevant regional requirements are included in normative annexes for Europe, North America (Canada/USA) and Japan.

Practical applications

ISO 23551-5:2023 is used to ensure that manual gas valves installed on gas burners and appliances are safe, durable and perform predictably. Typical uses:

• Product design and development - guiding engineers on constructional and functional requirements.
• Type testing and certification - for compliance assessment by testing laboratories and certification bodies.
• Manufacturer quality assurance - defining acceptance criteria for new valve designs.
• Procurement and regulatory compliance - specifying performance expectations in tendering and approval processes.
• Installation/maintenance documentation - standardizes marking and instructions to improve safety in the field.

Who should use this standard

• Valve and appliance manufacturers
• Design and test engineers
• Certification and conformity assessment bodies
• Product safety and compliance teams
• Regulators and standards committees

Related standards

• Other parts of the ISO 23551 series covering safety and control devices for gas burners and appliances (see ISO catalogue for related parts).