many tractors
Sunday, January 22nd, 2006So, I’m doing a Thomas.net search for quiet/low-vibration vacuum pumps, and I come across this info on hearing safety. I’m a big fan of “many tractors” as a quantized unit of sound intensity, even if that’s not quite what they mean.
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Noise Levels
Safe noise levels are below 85 decibels (dB). Many farm machines exceed this by 2-3 times.
| Noise Levels (in dB) |
Type of Noise | Max. Hours Before Damage Without Hearing Protection |
|---|---|---|
| 60 | normal conversation |
SAFE ZONE |
| 70 | routine barn noise | |
| 90 | milkhouse vacuum pump | 8 |
| 95 | many tractors | 4 |
| 100 | 2 | |
| 110 | chainsaw | 1/2 |
| 115 | 1/4 |
