Environmental noise causes people to worry about interference in conversation, thinking, sleep and rest. The special residential area in China's environmental noise standard refers to residential areas that need special quiet, such as recuperation areas, high-grade hotel areas, etc.; residents, cultural and educational areas refer to pure residential areas, cultural and educational, and institutional areas;
A type of mixed area refers to a mixed area of ​​general commercial and residential;
The second type of mixed area refers to the mixed area of ​​industry, commerce, a small amount of transportation and residents; the commercial central area refers to the prosperous area where the business is concentrated; the industrial concentration area refers to the industrial area designated by the local government; the traffic trunk line refers to the traffic flow of more than 100 vehicles per hour. On both sides of the road. The standard values ​​listed in Table 6 are outdoor allowable noise levels, and the measurement points are selected 1 m outside the window of the residential building affected by noise and 1.2 m above the ground. Frequent noise at night, the peak is not more than 10 decibels above the standard value. Occasional noise at night, the peak is not more than 15 decibels.
Outdoor noise standard
The city 5 environmental noise standard values ​​are as follows:
Category nighttime
0 class 50 decibels 40 decibels
Class 1 55 decibels 45 decibels
2 classes 60 decibels 50 decibels
3 categories 65 decibels 55 decibels
4 categories 70 decibels 55 decibels
Applicable areas of various types of standard
(1) Class 0 standard is applicable to areas that are particularly quiet, such as health resorts, high-end villas, and high-end hotel areas. This type of area located in the suburbs and villages is executed at a rate of 5 decibels in accordance with Category 0.
(2) Class 1 standard is applicable to areas where residence, cultural and educational institutions are the mainstay. The rural living environment can refer to the implementation of this type of standard.
(3) Class 2 standard is applicable to residential, commercial and industrial mixed areas.
(4) Class 3 standard is applicable to industrial areas.
(5) Class 4 standard is applicable to both sides of the road traffic trunk road in the city, crossing the two sides of the inland waterway of the urban area. This type of standard is also implemented for the background noise of the main and secondary lines of the railway passing through the urban area (referring to the noise level when the train is not passing).
Indoor standard
Indoor noise standards can be divided into residential and non-residential. The indoor noise standard of residential buildings is based on the requirements of quiet living and the environmental noise of the area. According to the conditions of residential windows, it should not be lower than the environmental noise standard of 20 decibels in the area. The standard for indoor housing in China is 10 dB below the ambient noise level in the region, as there are more small factories in China that are close to the home. Non-residential indoor environmental noise standards are specified according to the use of the room.
Cleanroom
According to the relevant national standard, the clean room noise of the standard Huaihua should meet the following requirements:
1. During dynamic testing, the noise level in the clean room should not exceed 70 decibels.
Second, when the air state test, the noise level of the turbulent clean room should not be greater than 60 decibels; the noise level of the laminar clean room should not be greater than 65 decibels A.
Note:
1. When the technical and economic conditions are limited, or the noise is greater than 70 decibels, the noise level may be appropriately relaxed, but not more than 75 decibels;
Second, the above noise level refers to the measured value of the human ear position (person leaving) at each working point in the room. For varying noise, take the equivalent continuous sound pressure level at the same position within a normal working day.
The noise spectrum of the clean room should be limited to the octave sound pressure level;
The flat and cross-sectional layout of the clean room should consider the requirements of noise control. The surrounding structure should have good sound insulation performance, and the sound insulation of each part should be close to each other.
Low noise products should be used for all equipment in the clean room. For equipment with radiated noise exceeding the allowable value of the clean room, special sound insulation facilities (such as soundproof rooms, sound insulation enclosures, etc.) should be provided.
When the noise of the clean room air conditioning system exceeds the allowable value, control measures such as sound insulation, noise elimination, and vibration isolation shall be adopted. In addition to accidents, the air exhaust system in the clean room should be designed for noise reduction.
Purification air conditioning system, according to the requirements of indoor noise level, the wind speed in the air duct should be selected according to the following regulations:
First, the total air duct is 6 ~ 10 m / s;
Second, the air duct with no delivery or return air outlet is 6-8 m / s;
Third, the air duct with the air return and return air inlet is 3-6 m / s.
The noise control design of the clean room must consider the air cleanliness requirements of the production environment, and must not affect the clean room cleaning conditions due to control noise.
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