Clean room requirements for indoor noise and detection methods
Clean room is not only on the indoor air cleanliness has strict requirements for the operation of the environmental noise also has certain national standards parameters, because the clean room workshop is a relatively closed, more depressing environment, if the noise is not properly controlled, it is easy to cause the workshop staff and the deterioration of the production environment.
①Noise measurement method:
When the room area is not greater than 50m2, only the center of the room to determine a point. When the room area is larger, each additional 50m2 increase a measurement point. The measurement point is 1.0m from the ground. when there are conditions, it is desirable to measure the noise and background noise of the static condition of the room.
②Qualified standards:
Should meet the design requirements, according to the requirements of the (clean plant design specifications), clean room air condition, non-unidirectional flow clean room noise should not be greater than 60dB (A). Unidirectional flow and mixed flow clean room noise should not be greater than 65dB (A).
How to control the noise of the clean room
The noise standard of the clean room is generally more stringent than the standard for the protection of health, the purpose is to ensure that the operation is carried out normally, to meet the necessary conversations and contacts and a safe and comfortable working environment. Therefore, the main indicators to measure the clean room noise is:
①Trouble effect
Because of the noise, make people feel uneasy and trouble emotions, generally divided into very quiet, very quiet, quieter, a little noisy, more noisy and extremely noisy 7 trouble level. Where the response level belongs to the very noisy and extremely noisy people, that is, high worry, high worry in the total number of people in the percentage of high worry rate.
②The effect on work efficiency
This mainly depends on three aspects of the response level, which are: concentration, accuracy of movement, work speed;
③The interference with the integrated communication
This is mainly divided into: clear or satisfactory, slightly difficult, difficult, impossible
The three aspects of the above indexes are used in the evaluation of the A sound level. In the 50's had proposed to use a spectral curve as an evaluation standard that the center frequency of each frequency band sound pressure level shall not exceed the curve. Later, it was realized that the brush A level to measure the noise and the noise of voice interference and annoyance degree is more suitable, can replace the octave band sound pressure level as the evaluation standard index.
According to the Chinese Academy of Building Research Institute of Building Physics in 1981 for the preparation of "clean plant design specifications" and the measurement of information, in the 65dB (A) below, only 30% of the people feel high annoyance. In 65-70dB (A), its impact on the efficiency of the three responses to show a low level; in 60dB (A) below the speech clear and satisfactory. 60-75dB (A) when there is a certain degree of difficulty, the dog in 75dB is very difficult. Therefore, it is considered that the clean room noise level to 65d) is appropriate, at this time can make the high worry rate of less than 30%; to ensure that the general call; the impact on work efficiency is very small.
Clean room noise control
Noise control can take a variety of management measures, such as the use of acoustic isolation, acoustic absorption, muffling, vibration isolation and other technical measures on the sound source, the transmission pathway for the effective control of the air shower room; clean room, due to the surface of the decorative material is smooth, solid, noise attenuation is reduced, the noise level is very difficult to reduce the noise control measures, it is desirable to take the muffling approach, that is, the purification of air conditioning system Set muffler, and try to reduce the wind speed in the return air duct.
(1) clean plant noise control methods
①Source noise control
-Select advanced low-noise production equipment and power equipment;
-Regular maintenance and repair of equipment, replacement of worn out, loose parts;
-Low-speed machines as much as possible;
-Feasible measures of damping Noise reduction measures;
-Apply air intake or exhaust muffler at the air intake or exhaust port of the equipment.
②Noise control in the propagation path
-use of acoustic enclosures to close the sound source;
-use of sound insulation for large sound sources, to protect the health of the operator;
-purification of air conditioning systems, exhaust systems to set up the muffler, and try to reduce the speed of air flow in the duct;
-use of a single-layer or composite structure to form a local sound insulation barrier outside the source of sound insulation panels Acoustic panels to form a local acoustic barrier;
- Power station walls, ceiling acoustic treatment, space clean shed can be suspended acoustic body; on the main sound-generating equipment can be added around the acoustic screen.
③Protection of operators
-Shorten the continuous working time of operators in the strong noise environment:
-Adopt personal protective equipment, such as earplugs, caps and helmets, etc.;
-Apply the method of acoustic isolation to the centralized control room, lounge and so on.
The above is provided by Anhui Renhe purification, hope to adopt!