According to GBZ/T229.4-20 12 "Classification of Occupational Hazards in Workplaces-Part 4: Noise Requirements", there are sounds harmful to hearing and health or other hazards, and the equivalent sound level of noise exposure for 8h/d or 40h/ week is ≥80dB.
In the process of occupational disease identification, only workers engaged in noise operations can be diagnosed as occupational noise deafness.
According to occupational exposure limits of Hazardous Factors in the Workplace (GBZ2.2-2007), Part 2: Physical factors, the limit of steady-state noise is 85dB(A), and the limit of equivalent sound level of unsteady-state noise is 85dB (a); The working day per week is not 5d, so the equivalent sound level of 40h needs to be calculated, and the limit value is 85dB(A).
Basically, when the 8-hour equivalent continuous A sound level in the working environment of an enterprise is greater than 80dB, employees need to undergo noise-related occupational health examination, and when it is greater than 85, they need to be equipped with personal protective equipment such as earplugs.
Extended data:
Those who find mild hearing impairment in noise occupational disease inspection should strengthen protective measures, and generally do not need to be transferred from the noise working environment; For those with moderate hearing impairment, consider arranging jobs with low hearing requirements; Those with severe hearing impairment and noise deafness should be separated from the noise environment; Sensitive people should stay away from noisy working environment.
When the noise in the working environment is greater than 85 decibels, personal protective equipment such as earplugs should be equipped. Working under strong noise for a long time will cause hearing fatigue and hearing loss.
Under the repeated action of strong noise for many years, organic lesions will occur in ear organs, resulting in noise deafness. Cause neurasthenia syndrome, such as headache, dizziness, insomnia, dreaminess, memory loss, etc.
The positive detection rate of neurasthenia increases with the increase of noise intensity. In addition, noise can also cause gastric dysfunction and reduce vision.
Noise can also cause cardiovascular diseases. Noise can make sympathetic nerves nervous, which is manifested as rapid heartbeat, arrhythmia, blood pressure fluctuation and positive increase of ECG test.
To prevent occupational noise hazards, noise should be eradicated from the sound source, controlled from the transmission route, and protective measures should be taken at the receiving point.
1, sound source control
(1) Reduce the impact process and high-pressure pumping process, and replace riveting with welding, stamping with hydraulic pressure and steam with hydraulic pressure as far as possible.
(2) Choose low-noise equipment, adopt mute materials to reduce noise impact, and adopt flexible connections among equipment, pipelines, foundations and supports that generate large vibration, so as to improve the processing accuracy and assembly quality of equipment.
(3) Adopt mechanized and highly automated production technology and equipment to realize remote monitoring operation.
(4) improve the machining accuracy and assembly accuracy.
2, from the noise transmission path control
(1) Reasonable layout of the factory: separate the high-noise workshop from the low-noise workshop, and set the extremely strong sound source in the remote area of the factory. When the process conditions permit, the machinery and equipment in the same workshop should be discharged in different regions.
(2) Use barriers to prevent noise from spreading.
3. When the noise control from the sound source or propagation path still cannot meet the requirements, acoustic technical measures such as noise elimination, sound insulation, sound absorption, vibration isolation and damping can be further taken to solve it.
4. Personal protection: After taking noise control measures, if the noise in the workplace still cannot meet the standard requirements, workers should be provided with appropriate protective articles, such as earplugs and earmuffs.
References:
Baidu Encyclopedia-Noise Working Environment