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Noise Isolation Enclosures

Some will prefer to call them acoustic enclosures, acoustic chambers, acoustic barriers/screens etc. All these are a type of noise mitigation measure, made from acoustical materials to provide the basic functions:

Sound isolation
Sound absorption
Vibration
Isolation
Vibration absorption

These enclosures work by preventing noise radiation that comes from a noise source to the outside area. They also work the other way round, by blocking external noise from getting into interior spaces. Acoustic enclosure designs can be customised based on its use. For example, some enclosures are designed to attenuate sound of frequencies that are in range with human hearing sensitivity, while some are made to counter for noise at frequencies that interfere with manufacturing or industrial processes.

Acoustic enclosures are usually made of heavy materials in double-leaf constructions, such as sheet metal, timber, masonry or loaded vinyl, which can effectively stop huge amounts of sound. Sound absorbing materials will be filled inside protective faces made of perforated metal or vinyl.

Applications

Noise isolation enclosures can be used for a variety of applications. They are often used for sound dampening with manufacturing or power generation equipment, air conditioning and cooling/refrigeration system. Enclosures can also be used for noise attenuation if applied with compressors, blowers or fans. It is very important to implement such noise control measures to ensure the hearing protection for employees and also for high-precision equipment. In some cases, acoustic enclosures are also used as in-plant offices, metrology spaces and test chambers.

Testing the noise reduction performance of noise-isolating enclosures

There are international and local standards available as reference for the testing of noise reduction of sound-isolating enclosures. The commonly used ones include the ISO 15667:2000 Acoustics – Guidelines for noise control by enclosures and cabins, and the ASTM E596-96 (Reapproved 2006) Standard Test Method for Laboratory Measurement of Noise Reduction of Sound-Isolating Enclosures.

There is no right or wrong in which standard one should use, as long as it is being recognised by the country/organisation. Of course, different standards have their own precision requirements to be followed. Regardless which standard being used, the goal is to find out the acoustic performance of enclosures.

Ultimately, it is strongly advisable to carry out acoustic performance tests for your enclosures to make sure that their functionalities are always working well.