Generator Noise Levels and How to Reduce Them

What the numbers mean

• 85 dB(A) is loud: continuous exposure at that level damages hearing over a working day.
• 75 dB(A) is roughly the noise of a busy street; 70 dB(A) is close to a normal conversation.
• Every 10 dB increase is perceived as roughly twice as loud.

Why silent type is only about 10 dB quieter but feels much quieter

• An open frame set at 85 dB(A) next to a building sounds intrusive; a 75 dB(A) set a few metres away is tolerated.
• 10 dB is a large subjective difference, which is why hotels and clinics always order silent type.

Distance is your cheapest tool

• Sound drops about 6 dB every time you double the distance.
• Moving a set from 3 metres to 12 metres away cuts the perceived noise to about a quarter.

Practical noise reduction

• Place the set so that a wall is between it and the people affected.
• Point the exhaust away from buildings and from enclosed courtyards.
• Use anti-vibration mounts and place the set on a solid pad, not on a hollow wooden deck.
• Keep the canopy panels and seals in good condition; a missing panel can raise noise by several dB.