ISO 4871 Gearbox noise pressure levels

Table 1 lists the noise level behaviour of helical and bevel helical gearboxes in accordance with the power class of the gear. The table values are calculated and indicative, and they can be used for comparison with the noise level of the gearbox during operation.

According to the ISO 4871 standard, the emission sound pressure level is to be measured at a distance of 1 metre from the outer surface of the gearbox. Noise level variations due to accessories are not taken into account in the table.
 
One fan increases the noise level by approx. 3 dB(A). Major deviations from the values must be examined in order to establish the cause of the unusually loud noise.
 
TABLE 1. Output power / emission sound pressure levels of helical gearboxs and bevel helical gearboxes
 

Helical gearboxes		Bevel helical gearboxes
Unit output(kW)	Noise level(dBA)	Unit output(kW)	Noise level(dBA)
5	54	5	56
10	58	10	60
20	61	20	63
40	65	40	67
60	67	60	69
80	69	80	71
100	70	100	72
150	72	150	74
200	74	200	76
250	75	250	77
300	76	300	78
400	77	400	79
500	79	500	81
700	80	700	82
900	82	900	84
1200	83	1200	85
1500	84	1500	86
2000	86
2500	87
3000	88
3500	89
4000	90
4500	90
5000	91