What is BS EN 1488 about?
BS EN 1488 discusses expansion tanks with a focus on tests and requirements. BS EN 1488 specifies the dimensions, materials and performance requirements (including methods of the test) for expansion groups. The sizes for these are from DN 15 to DN 25, and working pressures are from 0,1 MPa (1 bar) to 1,0 MPa (10 bar).
Expansion groups are fitted to the cold potable water supply only for expansion purposes, e.g., of storage water heaters, having a maximum distribution temperature of 95 °C. Expansion groups limit pressure in the water heater to which they are fitted, prevent the backflow of water into the supply pipe, and prevent the discharged water from coming in contact with the water in the water heater. Expansion groups do not control temperature and alone do not constitute the protection required for storage water heaters.
Note 1: The use of the device specified in BS EN 1488 does not override the need to use controls (e.g., thermostats and thermal cut-outs) which act directly on the power sources of water heaters.
Who is BS EN 1488?
BS EN 1488 on building valves — expansion groups —tests and requirements is applicable to:
- Manufacturers of expansion tanks and valves
- Water heater manufacturers
- Design engineers
- Builders / Architects
Why should you use BS EN 1488?
Expansion tanks enhance the safety of heaters. Expansion tanks are pressure safety components; and help reduce stress on valve stems, safety valves, and ball seals. BS EN 1488 helps you to select materials for your expansion tank. BS EN 1488 provides you with a test that will help you to verify the resistance of the material, to cracking under stress. BS EN 1488 provides a corrosion resistance test to qualify all used materials of an expansion group. BS EN 1488 provides multiple tests which will help in the reliability, durability, efficiency, safety, and protection of the expansion tank. BS EN 1488 helps you to enhance safety for the end-user.
What’s changed since the last update?
BS EN 1488:2021 supersedes BS EN 1488:2000, which is withdrawn. BS EN 1488:2021 includes some technical and editorial changes with respect to BS EN 1488:2000. These include:
- The chapter on materials was completely revised and testing with disinfectant was introduced
- Torque test was added and testing for safety valve was changed and optimized
- The coating test procedure was revised
- Normative references were updated and editorial changes have been made throughout the entire document

