Acoustic Enclosures for Industrial Equipment
Introduction
Controlling noise is difficult at the best of times and it’s even more challenging when trying to control noise that is created by industrial plants and equipment. The environment in which they function is affected by reflections, reverberant fields and resonances that can actually lead to an increase in the level of the original source. All these factors have to be taken into account when designing noise control solutions that need to satisfy the statutory requirements, community relations, planning applications and worker health and safety.
In addition the solution must also consider the impact of incorporating ventilation, heating/cooling, lighting, weather protection, electrical/data services, feed lines, pollution control and worker access, without affecting the overall performance of the enclosure.
There are many possible approaches to noise reduction, but always remembering that the ‘best form of noise control is at source’. This may involve modifications to the machine, components or to routines that generate the noise in the first place. Other solutions involve screening the people to whom the noise poses a danger and supplying them with noise-cancelling ear defenders or acoustically controlled booths. If all else fails further measures could include shielding nearby homes or noise sensitive locations with acoustic barriers.
Often, the most effective solution is the most obvious one; an acoustic enclosure that surrounds the sound source. In principle, acoustic enclosures can be as small as an office printer or as large as a concert hall to house a gas turbine. It depends entirely on the size of the problem, but the majority are room-sized acoustic enclosures for equipment such as compressors, engines, boilers, diesel generators, pumps and turbines.
Modular Solutions
With so many different noise issues and different ways to address them, it is always advisable to involve an acoustic engineer early in a plant design or expansion plan. However, that does not mean a solution has to involve lengthy and expensive field studies or have extended development programmes. It’s worth noting that incorporating noise control at the initial design and installation stage is always more cost effective than trying to incorporate it to equipment post install and noise survey, as this usually results in a compromise at a vastly inflated cost.#
To avoid those situations, an experienced acoustic solutions company such as IAC Acoustics should be appointed. They have years of experience in developing high performing acoustic products such as Noise-Lock® panels and Moduline® acoustic enclosures that are modular in concept and can be sized to suit virtually any configuration of enclosure. Noise-Lock® Acoustic Doors and Noise-Lock® Acoustic Windows are engineered by design to interface with the panel system, maintaining acoustic performance. Additionally, IAC Acoustics Quiet-Duct® and Conic-Flow® silencers and attenuators can be incorporated into the ventilation system to ensure the acoustic integrity of the complete facility.
Modular systems are easier to adapt to changes in field conditions, design criteria, plant designs and changes in operational requirements. Their modularity makes it straightforward to adapt the enclosure in both size and shape and the IAC Acoustics Moduline® system means that the complete enclosure could be taken down, extended or modified – to suit a new piece of equipment – and re-installed without the loss of any acoustic performance.
IAC Acoustics have “standard” acoustic panels that range in performance from 40dB to 70dB noise reduction. Walls can be single or double construction with engineered acoustic doors, acoustic windows and acoustic louvres, completing the envelope while maintaining the certified acoustic performance characteristics. IAC Acoustics also offers a bespoke service where tailor made panels and products of higher than standard acoustic performance can be engineered, for specialist applications. With design, configuration and Solidworks/AutoCAD modelling available, deployment times are minimised, which in turn minimises the overall cost and time to install on sites that are already operational.
Noise Shelters
Even when enclosing the noise source is the ‘best’ approach, there are occasions when the only practical solution is to enclose the operators or personnel. Modern examples are data centres, where a CPU fan, clicking and whirring disk array, whining generators and howling cooling vents contribute to the overall noise pollution challenge and where the noise solution cannot be applied at source. It is in such circumstances that personnel need to be protected to comply with the Noise at work Regulations – 8 hour shifts at a level not exceeding 80dB Lepd (the statutory limit).
Other examples could include; an individual machinery operator who is exposed to direct noise, may need a small control booth to prevent long-term hearing damage; collective employees or managers may need a larger acoustically shielded space for respite or factory noise control room functions. As with other IAC Acoustics products, Noise Shelters or Sound Havens are modular in construction and compliance-ready with fire and H&S regulations, helping to minimise any on-site inspection, testing and assessment.
Laboratory Tested Performance Ratings
The IAC Acoustics Moduline® panel system and components used in the construction of acoustic enclosures have been laboratory tested and certified to guarantee the published performance. Laboratory tests include Transmission Loss (TL) and Sound Transmission Class (STC) which relate to the sound reducing capability of the panels. Further tests include Sound Absorption Coefficients (α) and Noise Reduction Coefficients (NRC) that demonstrate the sound absorption qualities of the product. The laboratory tests give enormous comfort to architects, engineers and specifiers, alongside the end-user, with on site performance guarantees delivering the noise mitigation and functionality as intended.
Professional Solutions
Accommodating the customer’s service, access, maintenance requirements into the enclosure design prior to fabrication results in a superior acoustically controlled enclosure, as opposed to those modified on site. Additionally acoustic enclosures can be supplied in a range of materials and finishes, including full polyester powder coat with customer specific design or branding options on request. While most customer’s noise problems are unique, beginning with proven and tested materials such as the IAC Acoustics Moduline® panel system makes it far easier to achieve the right solution, when combined with a wealth of project experience and proven acoustic performance.
Scott Simmons
+44 (0) 1962 873018
