Reciprocating internal combustion engine driven alternating current generating sets Part 10: Measurement of airborne noise by the enveloping surface method

2Scope / Description

This standard specifies the method of measurement of the noise of generator sets (airborne) driven by reciprocating internal combustion engines. That is: when evaluating the sum of all other noises of the exhaust system, cooling system and engine (generator set), there is a consistent or similar benchmark, so that the measurement results are comparable. However, when exhaust and cooling systems are piped to distant locations, their impact on noise is not included within the scope of this standard. The basic characteristic parameter of noise radiation is the sound power level. Depending on the acoustic measurement conditions to be observed, the accuracy of the measurement results obtained in accordance with this part can be classified as grade 2 or grade 3. Level 2 accuracy (that is, according to the engineering measurement method in IS0 3744), the measurement area is required to be a true acoustic free field on the entire reflection surface, (environmental correction factor K. K1A≤2 Db), and the background noise level can be ignored ( Noise floor correction factor K, K1A≤1.3 Db). Level 3 accuracy (measuring method according to IS0 3746) requires environmental correction factor K: K1A≤7 Db, background noise correction factor K1A≤3 Db. When the generating set is running under steady-state conditions, the A-weighted sound power level and octave or one-third octave sound power level of the corresponding accuracy class can be calculated according to this part. This standard applies to reciprocating internal combustion engine driven, fixed or mobile, rigid or elastic mounted alternator sets. This section applies only to land and marine generator sets, and does not apply to aviation and drive land vehicles and locomotive generator sets. Note 1: This part is formulated for AC generators driven by reciprocating internal combustion engines, but it is also applicable to DC generators driven by reciprocating internal combustion engines. Note 2: For generating sets used in some special occasions (such as hospitals, high-rise buildings, etc.), it is necessary to make supplementary requirements, but it should be based on the provisions of this part. Note 3: A real comparison between generating sets can only be made under the same measurement accuracy.