BS ISO 23555-3:2024

Gas pressure safety and control devices for use in gas transmission, distribution and installations for inlet pressures up to and including 10 MPa. Safety shut-off devices | Status: Current

1 Scope This document specifies safety, constructional, performance, testing and documentation requirements of gas safety shut-off devices (SSDs). This document is applicable to SSDs with operating pressures greater than 500 kPa (5 bar1) up to 10 MPa (100 bar) of nominal connection sizes up to and including DN 400 for use with fuel gases such as natural gas, manufactured gas, biomethane or liquefied petroleum gas (LPG) in commercial industrial installations, including fuel gas infrastructures. This document is applicable to SSDs for an operating temperature range from −20 °C to +60 °C; This document is applicable to:

• — test methods which are intended for product type tests, routine tests and batch surveillance tests;
• — SSDs which use the pipeline gas as a source of control energy unassisted by any external power source;
• — SSDs integrating on the same body a second SSD, conforming to the requirements in this document;
• — SSDs integrating a gas pressure regulator conforming to ISO 23555‑2;
• — SSDs incorporating a creep (venting) relief device and/or a vent limiter conforming to the requirements in this document;

This document does not apply to:

• — SSDs upstream from/on/in domestic gas-consuming appliances which are installed downstream of domestic gas meters;
• — SSDs designed to be incorporated into pressure control systems used in service lines (pipework from the main pipework in a gas infrastructure to the point of delivery of the gas) with declared volumetric flow rate ≤ 200 m3/h (n);
• — industrial process control valves on/off type (see IEC 60534 for information on the design, classification and tests for this type of valve);

  NOTE Such valves cannot be declared conformant to this document.

• — SSDs used in sour gas environments (gas environments containing water and H2S are considered sour) or corrosive conditions;
• — SSDs in service conditions with waste gases (e.g. biogas etc.), if additional information is not provided (e.g. contaminant, liquid etc.).