Acoustic Enclosures For noise reduction in the Power Generation and Power Transmission industries

Acoustic Enclosures are designed to reduce industrial and intrusive noise. In the power generation and power transmission industries, they normally enclose transformers within sub-stations to reduce noise ‘leakage’ into the outside world. This is for reasons of environmental protection, by planning conditions, noise abatement orders and to protect the workforce from excessive noise.

To design and manufacture an acoustic enclosure, you need to work with acoustic engineers. They need to fully understand noise reduction in an industrial setting and have specialist technical knowledge. In order to achieve optimum noise control and ensure compliance with regulations and standards, they need industry specific expertise. Within the power generation and power transmission industries there are the additional requirements for expertise in working within high voltage sites and all of the associated risks this presents too.

Regulatory requirements govern Industrial noise reduction. Any project that does not meet regulation can put staff at risk and the business at risk of legal action. Therefore, every project needs to undergo a thorough evaluation in order to ensure the current Control of Noise at Work Regulations are met. To be able to deliver on these standards, any industrial acoustic engineering business needs to be able to recommend the most appropriate industry-specific noise reduction solutions based on both experience and the performance it will deliver.

Any team that designs acoustic enclosures need to be highly qualified in the design and manufacture of acoustic solutions for the power generation industry. They should work closely with customers throughout each individual project to evaluate the specific noise factors and the environmental conditions they face.

Many of the biggest noise reduction challenges within power generation and power transmission are within substations associated with wind farms. By definition, these will normally be located in quite isolated, hostile environments with wind, rain and ice frequently prevalent on site. They will also often be in marine environments.

Reducing business interruption

For any business in any industry, downtime costs money. In the power generation and power transmission industries, the cost of downtime can be enormous. Taking a grid asset out of operation has to be planned to ensure supplies are not interrupted. This is no different within a factory environment either as interruptions to production have to be planned.

Before any project begins, the engineers perform a comprehensive assessment of operating site conditions and employee exposure to noise levels to enable the correct identification of appropriate noise protection, that fully complies with the latest Control of Noise at Work Regulations.

So, before any design proposals are prepared, the practicalities of installing noise control equipment are also considered to ensure it does not adversely affect the smooth running of the business and down-time is kept to an absolute minimum. It must also give consideration to the machinery itself. If there is an optimum operating temperature for the machinery, this must also be adhered to and ventilation designed to order to prevent catastrophic machine failure and more down time and costs.

The machinery the acoustic enclosure contains, in any industry will always need both planned and preventative maintenance. An example of this is with a large CHP (combined heat and Power) system, installed within a hospital environment. These will normally be located within a basement, near or on the roof or in a standalone building on site. Whichever location it lives in, the entire unit may need removal for major refurbishment work at infrequent but regular intervals. The design of the acoustic enclosure system needs to prepare for this and make future access both sensible and swift to reduce the business interruption.

The installation of acoustic enclosures can be scheduled to accommodate your individual production and scheduled downtime programmes to minimise business interruption and availability of a team to complete the work for you. As an alternative, you could always arrange for the supply of general arrangement drawings and instructions, which allows your own in-house team, if you have one and they are suitably qualified, to complete the installation, with or without on-site assistance from an external contractor or certifying body.

Manufacture of and installation of Acoustic Enclosures

There is always a cheap solution to any noise reduction challenge. An acoustic enclosure may, on the surface, look like a simple device to contain noise. In its simplest form, that’s just what it is. But, in the same way a bin bag will, in theory, keep you dry from the outside, but make you sweat from the inside, a poorly designed enclosure will do nothing other than risk the enclosed machinery. If there is poor ventilation, there is a real risk of the machinery overheating and conversely, poorly designed ventilation will have the effect of undermining all of the hard work in enclosing the noise. It’s a lose lose. It’s bad for the machinery and doesn’t contain the noise.

Quality of the design, materials and manufacturing are therefore critical. There needs to be an assurance that any noise suppression products are manufactured to the highest specification. This can only come from a highly skilled and experienced team working to precise and agreed standards that meet and even exceed requirements. We would recommend, that all products and services work to internationally recognised quality assurance procedures and ensure all projects are completed to the most exacting standards.

So, whilst there may always be a cheap solution to an acoustic issue, it will more than likely cause you much bigger problems in the long run.

This was summed up perfectly by Benjamin Franklin in his now infamous quote “The bitterness of poor quality remains long after the sweetness of low price is forgotten.”

Installation is everything

Any job in any industry can be made or broken by the quality of the installation. When it comes to an acoustic enclosure this is particularly critical for both performance and reduction of ongoing maintenance.

You therefore need to give serious consideration to who is performing the installation on your behalf and ensure they have a track record and the required certification to install to the standards the industry sector requires.

Within the power industry all of the team need to be fully qualified. The team should ALL have completed the training course for suitably experienced persons being considered for the duties of person working with high voltage electrical or competent person (high voltage electrical) with respect to HV distribution systems. Without this, the installation and the working party themselves would be at serious risk.

With the UK nuclear industry, formal training is also vital to understand the risks and procedures for operation. Where he nuclear industry is different to others is there are many more formal and informal groups of peers from different organisations, who cooperate and share best practice to help each other.

Beyond this, there are also various skills councils and the National Skills Academy for Nuclear, as well as Women in Nuclear and the Young Generation Network, all of whom aim to raise the standards of training within the industry. According to Thomas Thor, the recruitment specialist in this industry, “Formal training is excellent, but the value that people in the UK nuclear industry get from interacting with their peers is a clear differentiator from other industries.”

With the growth of acoustic enclosures within industrial environments, there is a parallel growth in the demand for re-installation services for acoustic enclosure products. As with the hospital example above, we often find that where occasional access is needed, such as for a CHP removal and refurbishment, some of the enclosure may need to be dismantled in order to improve access and allow removal.

There are acoustic engineering teams available who are happy to both remove and reinstall acoustic enclosure products. With the change in operating standards, it can also offer the opportunity to upgrade the acoustic enclosure for greater noise reduction, or improved ventilation at the same time, with minimal business interruption.

What are the acoustic enclosure options available?

1. Acoustic Enclosures

As described above, a full acoustic enclosure is designed to reduce noise levels at source on new or existing machinery. These are common in industrial manufacturing, power generation or power transmission environments.

An acoustic enclosure will help to meet specific noise reduction requirements to answer noise abatement orders within factories or can be used to reduce noise pollution and ensure compliance with the Control of Noise at Work Regulations. They reduce incidence of noise within areas that surround operational machinery. These are often large scale CHP’s or industrial stamping, pressing and rolling machinery etc.

Acoustic enclosures are normally modular in construction. Because of the varying needs for sound reduction, ventilation and specifics of the enclosed equipment, they are predominantly custom-designed. They can also be supplied with access doors built into the structure and often panels designed for easy removal for servicing or access to some working parts.

As the enclosures can be deployed both internally and externally, they are also designed with varying degrees of weatherproofing. When you are looking to brief or specify an enclosure, it’s important to ensure that you select an appropriate rated enclosure to provide the level of durability that will provide your equipment with the right level of protection from the extremes of weather.

2. Acoustic Screens and Barriers

An acoustic screen is a more cost-effective solution to a full acoustic enclosure, because, as the name implies, it does not fully enclose the electrical switchgear or transformer, but rather contain noise on one or more sides.

Whilst an acoustic enclosure is the best way to contain noise, it can be more cost effective and allow for easier maintenance access to erect acoustic screens to surround the equipment.

These screens are constructed from either metals, timber or plastics and filled with materials that have exceptional sound stopping or absorption properties. An acoustic barrier can be constructed to any length, from as little as a few metres to well several kilometres long. They can also be installed in a ‘U’ shape to enclose three sides, in a single straight run, extending far enough to prevent noise ‘leakage’ on one side of the installation, or in rare cases, enclose all four sides.

They can also be designed and constructed to almost any height and should always be completely weatherproof and designed to last at least 20 years, although often 40 years is sought.

3. Machine rooms and packaged plant

Packaged plant rooms were developed to deliver a transportable method for delivering an off-site pre-constructed generator enclosure (or other equipment enclosure) fitted out ready to ‘plug and play. These containers, which are mainly bespoke built, are used to contain large generators, CHP’s and boiler plant etc. and at the same time, minimise the noise pollution into the surrounding area.

These units are generally a ‘plant room in a box’ and lifted into place by crane to be an almost plug and play solution for site power. It’s an ideal solution for both new build and refurbishment projects. The packaged solution enables a quick and easy replacement of existing plant for newer, more efficient and low carbon technologies such as CHP or biomass.

4. Acoustic Louvres and Attenuators for ventilation

An acoustic enclosure is only an effective tool if it allows the machinery it contains to function as normal. What this means is that they must not only be exceptional at their role in noise suppression but also be fully ventilated to allow enough air to flow to cool the machinery.

Part of the discovery and design process is in understanding and delivering the required air flow rates through the acoustic enclosure, whilst maintaining the agreed nose reduction levels. This means that the use of attenuators and suitably sized acoustic louvres is essential and correctly deployed. As they are often exposed to the elements too, they also need to be designed for performance into the long-term and perhaps galvanised and/or powder coated to ensure minimal maintenance and degradation.

One common method for cooling utilises the stack effect. This relies on cool air being drawn in low down in the acoustic enclosure housing, passing over the transformer or machine and then relying on a stack effect, as warm air rises, passing out of the enclosure via a higher level attenuated vent. This keeps a steady flow of cool air passing through the unit and adds an extra level of cooling without any moving parts to break or wear out. The vents themselves are designed to allow as little noise as possible to escape, whilst encouraging maximum airflow.

5. Soundproof doors – Sliding and hinged

These differ from a more normal residential door in almost every way. Whilst they can be designed to be hinged or sliding doors, they are predominantly of a metal construction and filled with dense soundproofing material. They will also have a far superior sealing system to give an almost airtight seal.

The actual design depends on their purpose and specification of their noise reduction requirement. They vary in scale and complexity and are manufactured both with and without a viewing window.

They can be deployed to replace aged or damaged existing doors, or be specified as part of a new acoustic noise reduction project.

6. Acoustic Panels and Acoustic Baffles

A sound absorbing baffle can often be seen suspended from a ceiling to offer a simple and low-cost noise control solution. These are especially useful in noise reduction in packaging rooms, press shops and large production facilities. They are non-intrusive but can be designed to be part of the aesthetic design of the whole workspace. They are practical, affordable and often a good looking solution. Their effect in noise reduction can be limited but they can significantly improve the intelligibility of a space by improving its acoustics and reducing reverberation.

Equally simple, yet just as effective is the use of drop-over acoustic hoods and canopies as noise absorbers, which can often provide the perfect solution to reducing noise levels on a smaller scale. In an industrial setting they can reduce the level of direct noise radiating from the source or be designed to reduce reverberation noise level experienced by staff working close by.

With any industrial or office refurbishment, steps can be taken to reduce noise intrusion throughout the space. These range from wall and ceiling surfaces to flooring and there is a whole range of technically advanced solutions to reduce the reflection of unacceptable noise.

7. Noise Havens

Acoustic Noise Havens for industrial markets are a popular solution to reduce noise in automated plant areas. Where it is impractical to reduce the noise of machinery directly, it is another option is to create a quiet space for staff to supervise the machinery or to be able to meet.

Noise havens are designed and built to provide a quiet environment where employees can work and communicate without noise intrusion. Again they can be a solution to meeting the Control of Noise at Work Regulations within a factory setting. They are normally designed and manufactured to include access doors, double or triple glazed viewing windows and include lighting, ventilation and air conditioning for the comfort of staff on the shop floor.

Summary

There is an engineering solution to any noise, vibration or acoustic problem with some that are far more complicated than others. The list above is not exhaustive, but if you need any help in this area, then please fill in the form below or call one of the Kimpton Acoustic Engineering team on 0151 343 1963.