Generator Sets – Noise Control

Generator Sets - Noise Control

Generator sets were notorious for being loud and disturbing, but the technological advancements now provide several solutions to handle such noise. 

This guide discusses why noise control is necessary, why generator sets can be noisy, and the solutions to achieve the desired acoustic control. 

Why is Noise Control of Generator Sets Important?

Noise can disrupt regular business routines, but the importance of noise control goes beyond that. Constant loud noise can cause:

Hearing Loss

Prolonged exposure to loud noises damages various structures inside your ear, causing temporary or permanent hearing loss. 

According to the American Speech-Language-Hearing Association, you may listen to sounds up to 70 dB for as long as you need without experiencing damage in your ears. 

However, a small, non-containerized 50kW diesel generator set can produce over 70 dB if you’re within close proximity to it, which can eventually cause damage. 

Psychological Distress

Loud noise is often disruptive and can cause distractions and loss of focus. For some individuals, it can even cause psychological distress in the form of anxiety and even depression. 

Physical Manifestations 

Loud noise is among the most common causes of headaches. Migraine and tension-type headaches are common manifestations of loud noise because of the sensory overload and overstimulation of your ears. 

If the noise goes beyond 140 dB, actual pain can be felt since the noise crosses the threshold of pain in the average human ear. 

What are Generator Sets Noise Level Regulations?

Noise-level regulations are rules that dictate how loud generator sets are allowed to be in a certain establishment relative to its surroundings. 

Depending on where you live, your country may impose noise level regulations on establishments that utilize generator sets to ensure quality of life for the surrounding people. 

Let’s take the UK, for example. According to the Noise Emission in the Environment by Equipment for Use Outdoors Regulations 2001, the UK has strict regulations regarding power generator sets based on their power output.

The permissible noise level is 98 dB for generator sets with a net installed power (Pel) between 2 and 10 kW.

This is only an example, as regulations vary from country to country. Noise-critical establishments like hospitals and data centers usually have even stricter noise regulations and often require sound-proofing techniques (more on that soon). 

On the other hand, industrial sites and factories typically have more leniency regarding the maximum allowed noise. According to Research Gate, industrial noise can range between 90 and 100 dB, with some manufacturing processes exceeding the 110 dB threshold. 

This is different from country to country, as some countries employ stricter noise regulation levels.

According to the HSE, if the noise threshold is not possible to meet within a work environment, workers within close proximity of the noise must be issued hearing aids by their employer. 

As such, it’s essential to check the local regulations and inquire about the generator set you are buying before purchasing. 

What are the Main Sources of Noise in Generator Sets?

Generator sets contain various mechanical components, including the engine, its housing, the alternators, the fuel tank, the exhaust system, the cooling system, the air filter, the base frame, the control panel, and more. 

However, not all generator set components and processes contribute to the loud noise they produce. Further, various generator set designs and housings can also limit or increase the noise made by certain components. 

Still, here are the three significant contributors of noise in an average generator set:

The Engine Noise

The engine is the primary source of generator set noise. The noise intensity depends on the engine’s size, current load, and RPM. 

Larger engines typically produce more noise compared to smaller ones, with the following factors contributing further to the noise produced:

  • Wear and tear of parts (especially with overlooked maintenance).
  • Premature ignition of the air/fuel mixture within the engine cylinder (mechanical knocking). 
  • Loose engine parts.

The Exhaust System Noise

The exhaust system is another primary source of generator set noise, especially if it’s malfunctioning or damaged. 

For example, a clogged or disconnected muffler may cause a loud rumbling noise. A crack in the exhaust manifold or pipe can also produce an uncomfortable, hissing sound. 

Fixing any damage within the exhaust system should reduce the produced noise to acceptable levels. 

The Cooling System Noise

Cooling fangs, along with the strong airflow they generate to control the engine’s temperature, can be pretty noisy. 

The fans themselves aren’t noisy, but the airflow they produce can cause turbulence and vibrations in nearby components (like the silencer shell) within the generator set, leading to projected noise. 

This occurs even if the fans within the cooling system are operating without issues. As such, noise related to the cooling system is often due to the poor design of the generator set. Optimizing the design from the start should alleviate this. 

Techniques for Sound-proofing of Generator Sets

Besides constant maintenance and fixing any issues within the mechanical components, here’s how the noise produced from generator sets can be controlled:

Acoustic Canopies

A soundproof acoustic canopy is an excellent solution to reduce the overall noise coming from the generator set. By enclosing the generator set within a vented acoustic canopy, you can achieve greater noise control over the generator set. 

This allows for rather loud generator sets to be utilized in environments with strict noise requirements, like hospitals. 

Acoustic canopies can be purchased separately, but getting a customized acoustic canopy with your purchase can be better for a perfect fit. 

Silencers

Generator sets’ silencers can be designed and fitted within the set’s internal systems to muffle the noise produced. Open-configuration generator sets typically don’t come with a silencer, but many manufacturers offer these silencers as accessories. 

Multiple types of silencers are available. They include:

  • Absorptive silencers: These silencers work by dampening the noise as it flows through heavy insulation. They are best used in environments with a strict noise code.
  • Reactive silencers: These silencers mute the loud noise by bouncing it around in one or more chambers. These are more suitable for low-medium acoustic soundproofing demands. 
  • Reactive/absorptive silencers: These silencers combine the two previous mechanics, offering even higher noise control for a relatively higher price.
  • Resonator silencers: These silencers aren’t commonly used for noise reduction, as they are less effective in noise control. Their primary purpose is to reduce back pressure. 

Vibration Isolators

Excessive vibration may not be a direct contributor to noise pollution; however, it can increase the noise transmission of the generator set. As such, minimizing them can help reduce the overall noise conducted by the generator’s engine. 

Elastomeric vibration isolators are typically used to isolate the engine and alternators from the rest of the base frame. The purpose is to interrupt the energy transmission between a working machine and the surrounding environment. 

In other words, these vibration isolators prevent the engine’s shaking from reaching other parts of the generator set. As such, they dampen high-frequency vibrations resulting from fast shaking and unexpected bumps. 

Keep in mind that vibration isolators are typically used for lighter components within the generator sets, as they’re not capable of working with heavier parts that utilize spring isolators instead. 

Acoustic Panels

If you have a generator set power plant, acoustic panels can be an additional means to reduce noise. 

Acoustic panels can be placed directly on the generator set’s noisiest areas (like the air intake and radiator discharge) or on the room walls to limit noise from within the room from reaching the outside perimeter. 

Note: When designing acoustic panels, static pressure should be considered. Static pressure is the air pressure pushing outwards from the generator. The soundproofing panels around the radiator must allow air to flow through without being blocked by the pressure. 

Final Words

Noise control can either prevent or allow a generator set from being utilized in a specific facility. If you own a business with a strict noise code, we advise you to explore our acoustic soundproofing solutions at Precision Industries

If you have any questions or inquiries, we’ll be happy to hear them. Contact us through:

The Head Office in Dubai 

24b St., Community 365 Al Quoz Ind. 2, Dubai, UAE

(+971 4 338 4033) , (+971 4 338 3997)

info@pi-dubai.com

Precision Integrated – Abu Dhabi

M02., Union National Building  Muroor Road, Abu Dhabi, UAE

(+971 2 448 1166) , (+971 2 448 1168)

auh@pi-dubai.com

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  • Tel: +966 13 868 1119
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