1、 Equipment name: Semi anechoic chamber
2、 Number of devices: one set
3、 Equipment function
This product is a semi anechoic chamber, and its purpose is based on; GB/T 6882-2016 "Acoustics - Determination of sound power level and sound energy level of noise sources - Precision method for anechoic and semi anechoic chambers" ISO 3745 Acoustics --Determination of sound power levels of noise sources using sound pressure --& nbsp; Precision methods for anechoic and hemi-anechoic rooms According to the requirements of relevant standards, accurately measure and analyze the noise characteristics of the product to determine its noise level, and take corresponding measures to reduce product noise and improve product quality.
4、 The design basis for the semi anechoic chamber is mainly based on the following standards:
ISO 3745 "Acoustics - Determination of Sound Power Levels of Noise Sources - Precision Methods for Fully and Semi anechoic Chambers"& nbsp; GB 6882-2016 "Acoustics - Determination of Sound Power Levels and Sound Energy Levels of Noise Sources - Precision Method for Anechoic and Semi anechoic Chambers"& nbsp; JJF 1147-7.2006 "Calibration Specification for Acoustic Characteristics of Anechoic and Semi anechoic Chambers"
5、 Identification method for anechoic chamber:
According to the international standard ISO 3745 "Acoustics Determination of sound power levels of noise sources - Precision methods for anechoic and semi anechoic rooms" and the national standard GB6882-2016 "Determination of sound power levels of noise sources and sound energy levels by acoustic pressure method - Precision methods for anechoic and semi anechoic rooms"; Test the free field identification method of the anechoic chamber. Using a single frequency signal with a center frequency interval of 1/3 octave below 125Hz and above 4KHz, and a single frequency signal with a center frequency interval of 1/1 octave between 125Hz and 4KHz, the difference between the measured sound pressure level and the theoretical sound pressure level is measured. Based on this, according to the maximum allowable difference specified in ISO 3745, GB6882-2016, and JJF 1147, the allowable measurement radius and the free sound field space area that meets the standard can be determined.
ISO3745 、 GB6882 The maximum allowable difference between the measured sound level and the theoretical sound level specified in the regulations
Test room type | 1/3 Center frequency of octave band (Hz) | Allowable difference dB |
Anechoic chamber | ≤630 800～5000 ≥6300 | ±1.5 ±1.0 ±1.5 |
Semi anechoic chamber | ≤630 | ±2.5 |
800~5000 ≥6300 | ±2.0 ±3.0 |
6、 Main technical requirements for anechoic chamber
Our company is a high-tech enterprise and has passed the; ISO9001，ISO14001 Quality system certification, this anechoic chamber product is also a high-tech product, ensuring that the product is at a high level of technology.
1. Using imported environmentally friendly sound-absorbing materials, it is required that the raw materials are formaldehyde free environmentally friendly sound-absorbing materials made of non glass wool fibers, and an import customs declaration form should be provided.
2. The laboratory sound-absorbing body adopts a detachable structure, 100% detachable, which is convenient for future relocation
3. The acoustic absorption structure is a flat plate type sound body, ensuring the customer's ground load-bearing capacity and acoustic indicators.
4. The main structure of the soundproof chamber is a customized civil engineering structure& nbsp;
5. All materials are environmentally friendly and pollution-free, and all materials are flame-retardant.
The acoustic technical indicators are as follows:
Half anechoic chamber footprint size: around 8900L x 7500W x 5000H (mm) (including top civil engineering ring beam)
After the completion of the semi anechoic chamber, the internal net volume is about 7600L × 6200W × 4500H (mm).
Cut off frequency: ≤ 100Hz
Free field radius: Length direction radius ≥ 3.2; Meter, with a width direction radius greater than; 2.4 rice
Background noise: Under normal laboratory working conditions; 65dB Left and right, that is, in the absence of any other abnormal noise or vibration interference around, the background noise; Below 30dB (A) (with air conditioning and ventilation turned off).
7、 Design principles
The design process is advanced, reliable, and mature. After the completion of the anechoic chamber, various technical indicators such as background noise and cutoff frequency meet the design requirements.
Flexible design processing system, simple equipment operation, and easy maintenance;
The engineering cost is reasonable.
8、 Design conditions
The semi anechoic chamber is placed in the workshop, and according to the customer's description, the environmental noise frequency characteristics are low and medium frequency, with a size of; 60dB (A) -70dB (A), with peak values mainly concentrated in the range of; 100－1000Hz And there are some noise frequency characteristic distributions; 10KHz；
The environmental noise around and near the semi anechoic chamber should be considered as follows:& nbsp;
Considering the relatively quiet surrounding environment and cost considerations, our company suggests using civil structure soundproof walls.
9、 Design points:
The semi anechoic chamber has been awarded as a high-tech product, and our company has applied it in multiple fields such as automobiles, communications, home appliances, aerospace, etc., contributing to numerous global projects; 500 Strong enterprises provide acoustic solutions.
Sound insulation index of anechoic chamber:
To ensure the background noise of the anechoic chamber; Lp≤30dB（A）， Require the sound insulation enclosure structure of the anechoic chamber to have a sound insulation capacity △ Lp ≥; 40dB. Suggest adopting 250mm The mixed brick soundproof wall is equipped with flat sound-absorbing materials inside, and its theoretical sound insulation capacity is greater than that of the design; 51dB.
External power lines and other circuits are introduced into the soundproof chamber through wire holes, and sealing materials with good sealing performance are used to seal the wire holes to ensure that the sound insulation of the wall will not be reduced due to pores and other reasons.
Based on the above on-site conditions and handling situation, ensure that the technical specifications are met.
1. The required dimensions for the soundproof room are:
The anechoic chamber adopts civil structural walls, and our company provides design drawings and on-site guidance; All sound absorbers are modular structures& nbsp; It can be installed on site with screws, and its cut-off frequency is designed to be; 100Hz.
2. The door of the soundproof room is a double-layer sealed sound gate, which has superior performance, easy opening, and beautiful appearance.
3. Lighting and distribution system
Install energy-saving lamps for lighting in soundproof rooms to ensure indoor illumination; Energy saving lamps do not produce electromagnetic noise;
Power distribution system: Provide indoor power distribution installation according to the power distribution requirements of the soundproof room, and introduce external power lines and other circuits into the soundproof room through conduit holes.
10、 Design proposal:
The overall plan is as follows:
1. The overall structure adopts civil engineering, and the outer house adopts 240mm Solid mixed brick wall; Top adopts 200mm Reinforced concrete civil structure soundproof wall has the technical characteristics of low degree and high sound insulation, meeting the technical requirements of external noisy office environments The overall theoretical sound insulation is; 51dB. Set up on the wall; 350mm Flat sound-absorbing body& nbsp; Ensure the reasonable allocation of sound insulation in each frequency range of the overall structure, approaching the standard curve of sound insulation index evaluation, and appropriately increasing it in the low frequency range to ensure that the background noise of the anechoic chamber meets technical requirements.
Internally, flat sound-absorbing panels are installed to meet the cutoff frequency requirements, which can meet the performance requirements.
Internally adopted; 350mm Flat sound-absorbing body, thin plate resonant structure, internal sound-absorbing cotton made of imported sound-absorbing cotton (not glass wool material), flame retardant grade; B1 Grade; The outer surface of the sound-absorbing structure is equipped with metal perforated steel plates, with a flame retardant rating; A1 Grade, perforated steel plate thickness not less than; 1.5mm, perforation rate reaches; More than 42%. Can prevent mechanical collisions, ensure sound transmission, and ensure usability during use; 20 Not deformed within the year.
Due to the use of non glass wool material for the flat sound-absorbing body and the metal perforated surface, it has a protective function against oil mist, dust, etc. If cleaning is needed, simply wipe the surface with a cloth.
Our flat sound-absorbing body has the following advantages:
A. environment protection
The overall design adopts our patented technology, which can be installed on site with only screws. It is easy to disassemble, has a beautiful appearance, and has high sound insulation; A staggered combination of steel plates, sound-absorbing damping, soundproof panels, and different density soundproof cotton; All materials are made of environmentally friendly and formaldehyde free materials, which comply with and are provided domestically; The environmental requirements of GB18883.
B. Efficient:
The thickness of the sound-absorbing structure is only; 350mm, relative to the sharp edge; 800mm height, saving a lot of space
C.100% detachable:
All structures are modular, easy to install and disassemble, and 100% reusable. It can be disassembled and assembled multiple times to prepare for customers' future relocation.
D. Long lifespan:
The flat structure is protected by steel plates, which are resistant to mechanical impact; Acoustic materials after system acceptance; 20 Not falling off or remaining unchanged within the year
Shape and service life can be as long as; 10-20 years or more.
E. Light:
The internal light reflects well, greatly improving the working environment.
2. Suspension damping structure
Due to the low requirement for background noise, considering the cost-effectiveness of the customer, we do not adopt a suspended damping structure. The condition is excellent.
3. Soundproof door
The doors of the soundproof room and control room are both made of external pull and internal push sound insulation and absorption composite double doors; 1 Yes, external pull method; The sound insulation effect is superior to similar products and easy to use; Size 2000 * 3000mm, divided into left and right doors. The left door is usually closed, and personnel can enter and exit from the right side; When large-sized products enter, they will; 2 All doors are open; For the sound gate, the door frame is made of bent steel plate, and the panel of the door leaf is also made of steel plate. The comprehensive sound insulation capacity △ Lp of the door is ≥ 50dB. It is designed as a two-way, two-level sealed, special soundproof rotary leaf door, introducing new foreign technology, with a three-layer magnetic suction structure, making opening and closing effortless.
To ensure maximum utilization of the interior space of the soundproof room, an external opening method is adopted, and the doors have superior performance, easy opening, and beautiful appearance.
The main ways for sound waves to pass through doors are through the door frame and gap, not the door panel. Therefore, the design of high sound insulation doors should focus on these two aspects:The door frame is welded with rectangular steel pipes, and the inner cavity of the door frame is filled; 60kg/m3 Multi layer composite cotton felt;
The sound-absorbing door adopts a unique single axis design, which minimizes reflection when the door is closed (traditional sound-absorbing doors have larger frames). Installing flat sound-absorbing panels on sound-absorbing doors does not affect indoor acoustic performance; When the door is opened, both the inside and outside of the sound-absorbing door are equipped with; The handle can be opened horizontally along the door axis to achieve the maximum passing size.
4. Total Reflection Ground
The floor of the soundproof room is made of the original workshop floor, with an epoxy surface and a sound absorption rate of less than 6%. Meet the technical requirements for a semi anechoic chamber with a free sound field.
5. Lighting
Indoor configuration dedicated; LED The lighting system is low-noise and environmentally friendly (with a background noise of less than 15dBA). The lighting fixtures should not affect the sound field characteristics of the anechoic chamber. The lighting adopts a curved surface lighting design, with a surface volume smaller than 3/1000 of the indoor surface area of the anechoic chamber& nbsp; Free sound field range has no impact.
In the soundproof room, there is sufficient wiring space between acoustic materials and civil structures, and lighting fixtures can be flexibly arranged in appropriate positions.
Indoor illumination: capable of achieving indoor illumination; GB/T 13379-1992 The requirement for "homework with moderate visual requirements"& nbsp; The illumination range of the experimental area shall not be less than; 500lux (1m from the ground).
Indoor light sources require small size, low energy consumption, high brightness, low heat, sturdy and durable light sources, and a working life greater than under normal use conditions; 5 Ten thousand hours, working in harsh environments (high temperature and high humidity), with a lifespan greater than; 5000 Hour;
Emergency lighting is installed in the soundproof room for personnel evacuation. The illuminance value at the entrance should not be lower than; 0.5lx.
6. Semi anechoic chamber ventilation system, final muffler, and anechoic duct
Design ventilation system and air conditioning system for semi anechoic rooms; Indoor air ducts are constructed using acoustic materials, utilizing our patented technology and high-efficiency energy-saving mufflers. The unique vortex design enhances ventilation efficiency; Over 30% reduction in noise compared to equivalent products; 15dB above.
The air conditioner adopts a silent duct air conditioner, which is connected to the top muffler inlet and outlet through a hose.
Optional configuration 1 A ventilation fan is used to suction and exhaust exhaust exhaust or other gases inside the room. It is equipped with pipes, soundproof plugs, and a motor with overheating protection function; The total air volume shall not be less than; 15000 Cubic meters per hour.
7. Semi anechoic indoor strong and weak electrical interfaces and acoustic treatment
7.1. The semi anechoic chamber shall be equipped with a strong electrical interface box, with at least; 2 A 220V Power socket, 2 A 380V Power supply socket.
7.2. The semi anechoic chamber is equipped with a signal interface box and other wiring pipelines. All wiring pipelines are treated with vibration isolation and noise reduction to avoid the formation of sound bridges indoors and outdoors, which may affect indoor acoustic technical indicators. Reserved holes on the wall, loading holes, hydraulic pipeline holes, and testing holes, all of which are designed with our patented technology. The special wiring shielding box suppresses external noise leakage.
8. Distribution system
Provide indoor power distribution installation according to the power distribution requirements of the soundproof room, and introduce external power lines and other circuits into the soundproof room through wire holes. Seal the wire holes with sealing materials with good sealing performance to ensure that the sound insulation of the wall will not decrease due to pores and other reasons.