Principle of operation and application of noise sensor
The impact of noise on the auditory organs is a process that moves from physiology to pathology. Pathological hearing damage must reach a certain intensity and exposure time. The changes in hearing organ damage caused by harmful noise generally develop from temporary hearing width displacement to hearing width displacement. The harm of noise to the human body is systemic. It can not only cause changes in the auditory system, but also affect non-auditory systems. In addition, noise in the workplace can also interfere with language communication, affect work efficiency, and even cause accidents.
In production and life, noise interference is everywhere. In order to ensure people's living environment, relevant departments have standardized corresponding standards to stipulate environmental noise emission limits and measurement methods at the boundaries of industrial enterprises and fixed equipment factories. So what should we pay attention to in noise monitoring?
1. Monitoring factors
Generally, they are Ld (equivalent continuous A sound level between eggs) and Ln (equivalent continuous A sound level at night). When there is sudden noise or occasional noise, Lmax (larger A sound level) needs to be measured at the same time at night [Lmax must be written Previous qualifying words]
2. Monitoring point layout plan
The general rule is that it can be chosen outside noise-sensitive buildings, 1m away from walls or windows, and at least 1.2m above the ground.
3. Monitoring time and frequency
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: day and night. Depending on the characteristics of the environmental noise source, the measurement period can be optimized. It is divided into fixed sound sources and traffic noise sources (mobile sound sources).
(1) Influence of fixed sound source
Monitoring time: The equivalent sound level of steady-state noise is measured for 1 minute. For example, Ld is obtained by measuring for 1 minute during the day, and Ln is obtained by measuring for 1 minute at night. Unsteady-state noise measures the equivalent sound level over an entire operating time (or a representative period).
Frequency of monitoring: Generally, it is no less than 2 days of continuous monitoring, 2 times day and night, that is, once a day between stars and once at night.
(2) Traffic noise sources (moving sound sources)
Monitoring time:
For road traffic, the day and night measurements shall not be lower than the 20-minute 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 1h equivalent sound level Leq of the average operating density. If the urban rail transit (ground section) operates intensively, the measurement time can be shortened to 20min.
Monitoring frequency:
Generally, continuous monitoring is required for no less than 2 days, twice during the day and twice at night, that is, once during the day and once at night.
In noise monitoring, noise sensors are particularly important. Noise sensors are the basis of noise monitoring. The accuracy of noise data monitoring also depends on the noise sensors.
