This International Standard describes a method of measuring the vibrational characteristics of fans of all types, except those designed solely for air circulation, for example, ceiling fans and table fans. However, it is limited to fans of all types installed with a power of less than 300 kW. For fans of greater power than this, the methods described in ISO 10816-1 and the applicable limits given in ISO 10816-3 may be used. This International Standard gives a general method only and does not give criteria for interpretation of data (see ISO 14694). This International Standard specifies the measurement of vibration that may be recorded as overall rootmean- square r.m.s. velocity, acceleration or displacement, or in terms of a frequency spectrum, within the appropriate frequency range. Methods of testing when suspended on elastic ropes or when installed on resilient mountings are included. It is recognized that the oscillatory forces at mounting points can be a useful measurement for analysing the effects on support structures; but such measurements are outside the scope of this International Standard. Annexes are given for information. Annex B gives secondary measurement methods which, whilst not recommended for accurate measurements, may be used for assessing the balance of series-produced fans or for comparative site measurements.