ISO 13347-2:2025

This document specifies determining sound power levels of fans under standardized laboratory conditions from sound pressure levels measured in a reverberant room.

This document is applicable for determination of the acoustic performance of fans. This document can additionally be applied to determine the acoustic performance of fans combined with an ancillary device, such as a roof cowl or damper or, where the fan is fitted with a silencer, the sound power resulting from the fan and silencer combination. For guidance of testing with ancillary items, see Annex C.

This document applies to fans as defined in ISO 13349-1. It is limited to the determination of airborne sound emission for the specified set-ups. Vibration is not measured, nor is the sensitivity of airborne sound emission to vibration effects determined.

This document is intended to be used in conjunction with ISO 5136, which covers the in-duct method, and ISO 10302-1 for small fans.

The size of fans which can be tested in accordance with this document is limited only by the practical aspects of the test set-up. Test fan dimensions and air performance will control the room size.

NOTE            Based on usage, small fans can be tested according to this document or to ISO 10302-1.

For reverberant field tests, the size of equipment under test is limited to less than 2 % of the room volume.

For low power fans (up to 3 kW) that can be run from a domestic power supply (single phase AC at a voltage not exceeding 250 V and a current not exceeding 16 A), reference IEC 60704-2-7[18].

The test arrangements in this document establish the laboratory conditions necessary for a successful test. It is difficult to meet these requirements in situ and this document is not intended for field measurements. In these situations, users are reminded that the acoustic environment is unlikely to meet the specified conditions and there can be additional acoustic system effects where inlet and outlet conditions at the fan are less than ideal.