The impact of noise on auditory organs is a process of transition from physiology to pathology, and pathological hearing damage must reach a certain intensity and contact time. The change of hearing damage caused by harmful noise generally develops from a temporary hearing width displacement to a hearing width displacement. The harm of noise to the human body is systemic, which can cause changes in the auditory system and affect the non-auditory system. In addition, noise in the workplace can also interfere with language communication, affect work efficiency, and even cause accidents.
In production and life, the interference of noise is everywhere. In order to ensure people's living environment, relevant departments have standardized the corresponding standards to stipulate the environmental noise emission limits and measurement methods of industrial enterprises and fixed equipment factories. So what should we pay attention to in noise monitoring?
1. Monitoring factors
Generally Ld (equivalent continuous A sound level between eggs), Ln (equivalent continuous A sound level at night), when there is sudden noise or occasional noise, Lmax (larger A sound level) should be measured at the same time at night [Lmax must be written on the preceding qualifiers]
2. Monitoring distribution plan
The general rule is to choose outside noise-sensitive buildings, 1m away from walls or windows, and 1.2m above the ground.
3. Monitoring time and frequency
The environmental noise monitoring of sensitive buildings should be measured under the normal working conditions of the surrounding environmental noise sources. According to the operating conditions of the noise sources, it should be carried out continuously in two periods of day and night. The measurement period can be optimized according to the characteristics of the ambient noise source. Divided into fixed sound source, traffic noise source (mobile sound source).
(1) Influence of fixed sound source
Monitoring time: the equivalent sound level of steady-state noise measurement for 1min, such as Ld is obtained by measuring 1min in the daytime, and Ln is obtained by measuring 1min at night. Non-steady-state noise measures the equivalent sound level for the entire operating time (or a representative period).
Monitoring frequency: generally no less than 2 consecutive days of monitoring, 2 times in day and night, that is, 1 time monitoring between stars every day and 1 time monitoring at night.
(2) Traffic noise source (mobile sound source)
Monitoring time:
For road traffic, the day and night measurements shall not be lower than the 20min equivalent sound level Leq of the average operating density.
For railways, urban rail transit (ground section), and inland waterways, the day and night measurements shall not be lower than the 1-h equivalent sound level Leq of the average operating density. If the urban rail transit (ground section) is densely operated, the measurement time can be shortened to 20min.
Monitoring frequency:
Generally, it is not less than 2 consecutive days of continuous monitoring, 2 times in the day and night, that is, 1 time during the day and 1 time at night.
In noise monitoring, noise sensor is particularly important. Noise sensor is the basis of noise monitoring. The accuracy of noise data monitoring is also determined by noise sensor.
How Noise Sensors Work
