What do the NRR and SNR of earplugs and earmuffs mean?

What do the NRR and SNR of earplugs and earmuffs mean?
NRR and SNR are the noise reduction values of current anti noise earplugs or anti noise earmuffs. The noise reduction values correspond to two international standards, of which NRR is the American Standard and SNR is the international standard.
Single Number Rating (SNR) is the single-value noise reduction value detected according to the international standard ISO 4969-2. Single value noise reduction rate is a standard for evaluating the anti noise performance of hearing protection products by reducing the three frequency noise of HML.
Noise Reduction Rating (NRR) is a single-value noise reduction value detected according to the American Standard ANSI s3.19-1974. The noise reduction assessment number is the difference between the C sound level of the noise in the working environment and the a sound level of the noise exposed by the wearer of the ear protector in the working environment.
Compared with NRR, SNR of the same anti noise earplug is about 3 dB higher than NRR. The higher the noise reduction value of earplugs and earmuffs, the better the anti noise effect.
How to select earplugs and earmuffs according to noise level
Appropriate anti noise earplugs and earmuffs shall be selected according to the noise level. During selection, attention shall be paid to: earplugs are divided into different models, and users shall use them according to the size of their own ear canal; The anti noise cap is also numbered by size, and the wearer shall select it according to his own head shape.
1. Selected according to A-level noise
According to the requirements issued by the state, hearing protectors can be selected according to the La monitoring results of A-level noise in the workplace. It is required that the SNR value of hearing protectors multiplied by 0.6 should be greater than the noise exceeding the standard value.
For example, the noise level of a workplace for 8h is 95dB, while the national standard is 85dB, exceeding 10dB. Use the following formula to calculate the minimum SNR value of hearing protectors. Minimum SNR value of anti noise products = (95db-85db) ÷ 0.6=17db
According to the experience, the noise value actually exposed by the employees is the best between 75 and 80dB, so the hearing protector with SNR value of 22 to 27db can be selected.
2. Sound selection based on C-level noise
According to another standard, hearing protectors can be selected according to the on-site C-level Noise LC monitoring results, that is, the SNR value of hearing protectors subtracted from LC should be greater than 85dB of the occupational health standard, and it is required that the optimal range of noise exposure after using hearing protectors is 75 ~ 80dB.
For example, the 8h noise level of a workplace is 98dB, and the C-level noise is 100dB. Therefore, it is more appropriate to choose a hearing protector of 20 ~ 25dB.
When using earplug earmuffs, they must be close to the ear canal (earplugs) and the outer edge of the ear shell (earplugs), so as to have a good protective effect.
Changzhou Sunnergy Energy Technology Co., Ltd. produces noise reduction earplugs and earmuffs with different materials and noise reduction decibels. Welcome to our company for inquiry!