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How to Design an Acoustic Enclosure

8 steps to consider when creating a custom soundproof enclosure...

8 steps to consider when creating a custom soundproof enclosure

An acoustic enclosure (also known as a soundproof enclosure) encloses noisy equipment in an acoustically treated room.

However, simply enclosing noisy equipment will not reduce the amount of noise emitted; which is why the incorrect design of an enclosure may result in enhancing unwanted sound.

For optimal acoustic performance, the exterior of the enclosure must be constructed of dense and solid material such as galvanised steel. By contrast, the interior must be covered by absorbent material such as acoustic wool (glass wool or Rockwool).

Noise can then be prevented from escaping through the ventilation system via the air inlets and outlets with the installation of silencers.

Here are eight factors to consider when designing the ideal acoustic enclosure for your facility.


1) What sound reduction do you need?

An acoustic engineer best measures the sound produced by machinery with a sound level meter. Ideally, the acoustic enclosure must reduce noise levels below 85 dB (A) (decibels), which is the legal limit for an 8-hour shift.

For example, for a machine producing a noise level of 120 dB (A), the enclosure’s sound reduction should be 35 dB (120 dB (A) – 35 dB (A) = 85 dB (A))[1].

The desired level of soundproofing will determine the type of engineered noise control solution. For an acoustic reduction of only 5 to 10 dB, an acoustic barrier (one or several walls) will often be sufficient.

For a higher acoustic reduction, a partial or complete enclosure is recommended. An enclosure has the option for vibration-dampening systems to achieve a cut of 35 to 55 dB. A noise reduction of 70 dB may result by using multiple-layer walls.

[1] This calculation is simplified for the explanation. In reality, the forecast is much more complicated due to the consideration of the octave bands (high and low-pitched sounds/ high and low frequency).


2) What are the required dimensions of the sound enclosure?

Determining the uses of the enclosure will establish the interior and exterior dimensions:

  • Will the sound enclosure be close to the machinery?
  • Will any operators be working inside?
  • Is it a complete or partial enclosure?

Avoid contact between the machinery and the enclosure to maintain optimum acoustic performance. Depending on the type of equipment in the enclosure, vibration and/or sound can be transferred to the enclosure, which in some instances can reduce the overall efficiency (in terms of sound reduction outcomes).

If you have space restrictions around the machinery, acoustic sliding doors can be a practical solution to allow proper access to the equipment.

Where it is not possible to enclose the machinery, a control room (or any other type of soundproof chamber) may be used to isolate the employee from the noise, rather than confining the machine.


3) What openings are available?

When designing the soundproof enclosure, it is crucial that every opening is considered and acoustically insulated to prevent noise from escaping.

Examples of potential penetrations include:

  • Access for maintenance
  • Ventilation (fresh air compensation, heat, humidity, condensation)
  • Utilities and fluids (compressed air, electricity)
  • Discharge of waste and pollutants (dust, oil mist, gas)
  • Inlet and outlet for entry and exit of the product


4) What type of access to the equipment is required? Is access necessary daily or only for significant maintenance?

Do you need access to all machinery or only to individual sections? A custom engineered enclosure will allow you to design the noise control solution according to your specific needs.

Acoustic enclosures allow optional partial or complete disassembly if required. Different types of access panels are available for maintenance, from a simple removable panel to an oversized motorised door.

Options include:

  • Liftable hood or roof
  • Fully liftable enclosure
  • Oversized doors
  • Sliding doors
  • Removable panels


5) How many doors, windows and removable panels are required? What is their size, and where will they be located?

Restricting access to machinery is the negative side to an acoustic enclosure. This makes it essential to include the doors, windows and any other access penetrations necessary to operate, monitor and maintain the equipment when designing the enclosure.

You may choose any doors from a single door to an automatic sliding door. With acoustic windows, several options are possible without compromising the acoustic performance of the enclosure.


6) Do you need ventilation inside the noise enclosure?

The engine and other systems of a machine produce a variable amount of heat. In many cases, this warmth must be removed from the enclosure to avoid overheating.

When designing the ventilation system, the amount of heat generated inside must be taken into account, including equipment (watt), but also the number of people working inside, computers, lights and any other element that produces heat.

Additionally, certain types of equipment require stringent control of temperature and humidity.

Talk to an expert about the ventilation system options available.


7) Is lighting required inside the soundproof enclosure?

The type of work carried out inside the enclosure will determine lighting requirements. At times it may be necessary for light to allow operators to run the machine, or to supervise the machinery from the outside. All types of lighting are possible inside an acoustic enclosure, including fluorescent or LED lighting.


8) Do you need to protect the soundproof enclosure from other elements?

In several plants, noise is not the only harmful element present. For example, the paper and mining industries often struggle with high levels of humidity and dust, intense heat, and chemical exposure, as well as debris flying over the enclosure. These hazards are damaging to buildings that are not sufficiently sturdy.

A tailor-made acoustic enclosure will allow you to adapt the engineering and choose the ideal materials for the environment, which will increase the longevity up to and above 25 years.


Contact Flexshield for information about acoustic enclosures

It is vital to involve operators and equipment maintenance managers when defining the design criteria for the enclosure, as they may raise essential factors you may not have considered.

For more information on an acoustic enclosure, visit our product page or call Flexshield on 1300 799 969.