Ämnesområden

This document specifies dimensions, materials and performance requirements, including test methods, for combined temperature and pressure relief valves, of nominal sizes from DN 15 to DN 40, having working pressures ) from 0,3 MPa (3 bar) to 1,0 MPa (10 bar). Combined temperature and pressure relief valves control and limit the temperature and pressure of the water contained in a hot water heater to the valves rating pressure and a temperature not exceeding 100 °C and will prevent water to steam formation when other temperature controls fail. Combined temperature and pressure relief valves are classified having a maximum opening temperature range from 90 °C to 95 °C for class A and 75 °C to 80 °C for class B. They are not intended to act as an expansion valve and do not control cold water flow. Alone it does not constitute the control functions for a water heater. A combined temperature and pressure relief valve is an independently mechanically operating device, therefore operating without an external energy source. NOTE The use of the device specified in this document does not override the need to use controls (e.g. thermostats and cut-outs) which act directly on the power sources of water heaters (for more information, see Annex B).

This document specifies the minimum requirements for the material, design construction and workmanship, manufacturing processes, examination and testing at time of manufacture of an assembly of permanently mounted composite tube(s) in a frame with associated components.

Tubes covered by the requirements of this document are:

a) of composite construction, permanently mounted in a transport frame and suitable for specified service conditions, designated as:

Type 3 — a fully wrapped tube with a seamless metallic liner and composite reinforcement on both the cylindrical part and the dome ends; or

Type 4 — a fully wrapped tube with a non-load sharing liner and composite reinforcement on both the cylindrical part and the dome ends.

b) with water capacities from 450 l up to and including 10 000 l;

c) containing compressed gases but excluding:

liquefied gases,

dissolved gases, and

gases and gas mixtures which are classified for transport as toxic or oxidizing;

d) with working pressure up to 1 000 bar.

This document does not address tubes with working pressure times water capacity (p × V) more than 3 000 000 bar∙l.