1n order to select a hearing protector, we should first determine the required SNR value, and then select a specific type of hearing protector according to the characteristics of operation and user needs. At present, there are two methods to select the SNR value of hearing protectors according to the noise level at the scene, which are “code for hearing protection of workers in industrial enterprises” and “GB / t23466-2009” selection method of hearing protectors “
1, according to A-level noise
according to the requirements of” code for hearing protection of workers in industrial enterprises “issued by the Ministry of health in 1999, Hearing protectors can be selected according to the La monitoring results of A-level abusive noise in the workplace. The SNR value of hearing protectors multiplied by 0.6 should be greater than the noise exceeding the standard value. Examples are as follows
the noise level of a workplace in 8h is 95dB, and the occupational health standard is 85dB, exceeding 10dB. The minimum SNR value of hearing protectors is calculated with the following formula
minimum SNR value of hearing protector = (la-85db) / 0.6
=(95dB-85dB) / 6
= 17D
generally, the actual contact noise value of users wearing hearing protectors is between 75 dB and 80dB. 1n the above examples, the final choice is the hearing protectors with SNR value of 22 dB to 27db< According to GB / t23466-2009, hearing protectors can be selected according to the monitoring results of on-site C-level Noise LC, that is, the SNR value of hearing protectors subtracted by LC should be greater than 85dB of the occupational health standard, and the optimal range of noise exposure is 75-80db after using hearing protectors. The examples are as follows according to the following formula, the 8h noise level of the hearing protectors in the most certain workplace is 98dB, and the C-level noise is 100dB. The SNR value is used the best SNR value of hearing protectors = lc-85db + (5-10) DB = 100db-85db + (5-10) DB = (20-25) d 3. The selection of hearing protectors (earplugs or earmuffs) should consider the working conditions and the special needs of users, including the following aspects (1) wearing time: the longer the wearing time is, the more comfortable hearing protectors are needed (2) dirty hands: earmuffs or preformed earplugs are preferred to avoid slow rebound earplugs (3) glasses must be worn: ear plugs are preferred (4) safety helmet must be worn: ear plugs or neck belt earmuffs are preferred; 1f the design of safety helmet allows earmuffs, choose the earmuffs that can be hung with safety helmet (5) durable: preformed earplugs or earmuffs are preferred (6) easy to wear: earmuffs or preformed earplugs are preferred (7) lightweight and loss proof: earplugs with thread< (8) glasses and earmuffs must be worn: 5dB must be deducted from the actual noise reduction capacity of earmuffs (9) the noise reduction ability of earplug or earmuff alone is not enough: when earplug and earmuff are used at the same time, the actual noise reduction level is calculated according to the higher SNR value, plus 5dB