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Quieter Equipment
A cost-effective way to reduce noise at a construction worksite is to buy quiet equipment. When buying equipment always ask if there is a quieter way of doing the job. All things being equal most contractors would choose a quieter machine or process. Quieter machines or processes can cost more. Manufacturing tolerances are tighter, gears mesh better, quieter cooling fans are used, etc. Because of this, when contractors buy quieter equipment the final determination often depends on whether the noise reduction justifies the extra expense. Looking at this decision another way, if the quieter machine costs $100 more and is 5 dB quieter, the extra cost of $20 per decibel reduced can be considered cheap noise control when compared to cost of establishing a hearing conservation program or medical cost associated with noise induced hearing loss.

In addition, equipment in use should be the most suitable for the job. Avoid using equipment that is over-powered and, conversely, avoid using under powered equipment. Whenever possible the quietest equipment alternative should be used. In general, electronic powered equipment is quieter than diesel powered equipment and hydraulically powered equipment is quieter than pneumatic power. Below are examples of ways quieter construction equipment can be introduced into the worksite to reduce noise levels.  In addition, the National Aeronautics and Space Administration (NASA) offers guidance in purchasing quieter equipment: NASA Buy-Quiet Process Roadmap.

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Buying Quiet Saw Blades

       
Problem:
Sound level tests on different saw blades under comparable conditions reported sound levels at the operator position between 91 and 97 dB (A).
Solutions:
Results:
Sound level tests on different saw blades under comparable conditions
Sound Level -dB(A) at Operator Position
Tooth Number and Size
Cutting lengths of aluminum

• 350mm dia. TCT blade, 84 teeth, 3.5mm wide
97

• 350mm dia. TCT blade, 108 teeth, 3.2mm wide
91
Decibel Reduction
6
Vibration Dampening
Cutting bricks

• 350mm dia. “standard” masonry blade, 20 teeth
94

• 350mm dia. “damped” masonry blade, 20 teeth
84
Decibel Reduction
10
Air Noise
“Dummy cut” (run up to 3400 rpm, run down), without cutting

• 350mm dia. TCT blade, 84 gullets, 10mm x 7mm
91

• 350mm dia. TCT blade, 108 gullets, 8mm x 4mm
84
Decibel Reduction
7

 

Note: This reduction would apply to electrical block saws.  Gas powered saws are much louder so changing to a quieter blade will not make an appreciable difference.

Reference: WorkSafe Western Australia Engineering Noise Control Reports No’s. ENC-2-93, ENC-4-93

 

Buying Quieter Diesel Generators
Problem:
Compressors and generators rank second behind trucks of all onsite construction equipment in terms of daily sound energy produced.
Newer heavy duty diesel generators are designed to emit low noise and vibration. Some units are up to 15 dB (A) quieter than older diesel-powered generators and quieter than most gasoline sets. The units are totally enclosed and damped, including cooling, exhaust and intake systems.
Built-In Solutions:
  • Improved intake / muffler system
  • Suitable enclosure with damping cladding
  • Improved cooling fan
Benefits:
Up to 15 dB (A) noise reduction

Reference: OR-OSHA, “Guide for Controlling Hazardous Noise on Construction Jobsites,” 1/03