This Nordtest Method specifies a method of measuring in the laboratory, the noise emission (sound power level) from a radiator valve coupled to a specified reference radiator when a flow of water is forced through the valve at specified reference operating conditions.
The method can be used to rank valves of different makes with respect to their noise emission with reference to the same operating conditions. The sound pressure level in a room with a specified room absorption may be calculated from the sound power level of a tested valveand- radiator assembly (see e.g. IS0 3741:88, Clause 8.2.2).
It is permitted to use a custom radiator in place of the reference radiator, and to measure at other operating conditions.
In this case however, it is required for the reference to this method, to measure and declare the results using the reference radiator and the reference operating conditions as well unless they are unfeasible with respect to the intended use of the valve. The purpose of this requirement is to facilitate comparisons between different makes of valve. A noise emission of a valve connected to a specified radiator is valid for this radiator-and-valve assembly only.