Hearing Protection: Measuring Sound

Loudness is measured in decibels (dB). As decibels rise, loudness quickly increases. A 10-dB rise is a 10-time leap in loudness. That means an 80-dB sound (a vacuum cleaner) is 10 times louder than a 70-dB sound (a telephone ringing) and 100 times louder than a 60-dB sound (normal conversation).

When you need protection

At the workplace, your employer measures noise with sound level meters and dosimeters. If the average noise exposure over an 8-hour work shift is 85 dB or higher, you need protection. OSHA requires your employer to have a hearing conservation program. From 85 dB to 125 dB, you can lose hearing painlessly. Over 125 dB, you may feel pain. As loudness and pitch rise, you may get acoustic trauma. That means a single exposure can cause permanent hearing loss.

Barely audible

• 0–9 dB

  • Weakest sounds you can hear

• 10–19 dB

  • Rustle of leaves

Soft sounds

• 20–29 dB

  • Quiet bedroom at night

• 30–39 dB

  • Whispered conversation; milk poured on dry cereal

• 40–49 dB

  • Soft music; average suburban home during day

• 50–59 dB

  • Large business office; light freeway traffic

Daily sounds

• 60–69 dB

  • Normal conversation; household washing machine

• 70–79 dB

  • Ringing telephone; alarm clock; noisy restaurant; moderate freeway traffic; light assembly plant

Harsh sounds

• 80–89 dB

  • Vacuum cleaner; shouted conversation; busy city streets; welding equipment

• 90–99 dB

  • Small woodworking shop; portable sander; automatic screw machine; drill press; subway train; 20-ton truck; newspaper printing press

Intense sounds

• 100–109 dB

  • Lawn mower; outboard motor; snowmobile; bulldozer; chain saw; circular saw; weaving room; riveting machine; helicopter

• 110–139 dB

  • Motorcycle; loud music; 120-watt stereo system at high volume; car horn; thunderclap; ship engine room; punch press; sand blaster; turbine generator; .357 magnum gun

Deafening sounds

• 140–149 dB

  • Jet engine at takeoff; high-powered shotgun blast

• 150+ dB

  • Intense explosion; rocket liftoff