Sound Attenuation for Diesel Generators – How Does It Work?

sound attenuation diesel generator noise reduction

If you asked someone who has worked in construction or civil engineering for the last 30-40 years what has changed the most about your work environment, they might say noise levels. This might be surprising, but it is true. You see, builders and civil engineers often rely on diesel gensets for steady, inexpensive electrical power while they work, both to run the electrical equipment that makes modern construction possible and to power the signs, lights and safety equipment that has turned construction from one of Britain’s deadliest industries to what it is today. None of that would be possible without the humble portable diesel genset, and those gensets have themselves changed much over the years. Not only are the engines themselves miles quieter and more efficient, recent advances in sound attenuation housings and design have made them a lot more pleasant to work around.
The most commonly used systems rely on isolating the diesel genset from workers and the public alike with a ‘sound attenuated enclosure’ - a housing which allows the generator to get the air it needs to run and to carry off its filtered exhaust, yet deadens the vast majority of the sound the genset makes in operation. The huge, roaring diesel gensets of the 60s and 70s are now clean caravan-like shapes which many passers-by don’t even realise house a multi-kilowatt generator set!

How is the sound attenuated?

The key is in the sound-absorbing materials that line the inside of the housing. Most are of a soft yet very dense material, and feature an open-pore surface that is superefficient at directing sound waves deep into the interior of the muffling material where the kinetic energy of the sound pressure waves can be transformed into heat, which radiates off harmlessly (and noiselessly).
Different muffling materials have differing levels of effectiveness at absorbing sound in this way. This is called the material’s ‘sound absorption coefficient’, which is a number between 0 and 1. A material with a coefficient of 0 would transmit sound perfectly – even better than air. A material with a coefficient of 1 would block all sound absolutely. Alas, we haven’t been able to develop anything quite that effective yet.
Modern sound attenuation housings use a layered approach, with the sound first moving through a porous muffling material, a perforated lining which is ‘tuned’ to absorb and reflect back the particular frequencies of sound a particular genset produces at peak efficiency, and then a hard, weatherproof shell on the outside to protect the muffling material and of course the genset itself. In addition to simple sound muffling, many attenuation housings also use active and reactive silencing systems to further eliminate harmful or unpleasant levels of noise that the genset may produce.

A sound attenuation housing should be tuned to a particular type of genset

One important thing to understand is that each genset has a unique sound. One type might be higher while another has a lower overall pitch. Most are complex mixes of different pitches. A modern sound attenuation system will be carefully tuned to be most effective against the sound profile of a particular model of genset, and will not be nearly as effective if used with another type.

Diesel Generators

Add up these numbers, and you begin to see how much a single day without reliable, steady power actually costs your business, and how much not having a reliable backup power generator hurts your bottom line. Most organisations will find that an emergency power supply quickly pays for itself, and then goes on to make them more profitable.

But there is more to the equation than simple power cuts. Another advantage enjoyed by those organisations that install backup power supplies is that they provide protection against severe voltage fluctuations in mains power, which can easily damage sensitive computers or expensive capital equipment. A good diesel generator puts the safety of your equipment (and employees) back in your own control.

As an added bonus, you have a hedge you can use against a sometimes volatile energy market. Especially if your business uses large amounts of electrical power, a backup power supply can become your primary power supply when the price of mains electricity exceeds that of diesel fuel on a per-kilowatt hour basis.

Diesel Generators

Are you in the market for a new sound-attenuation system?

If so, talk to us right away. We can advise you on selecting the right system for your existing diesel genset, or provide the perfect pairing of a new, much quieter genset paired with an attenuation housing that is tuned specifically to its sound profile. Your workers, and the general public, will thank you!

Diesel Generators

Latest posts