If you have a need for a quiet hand dryer, then volume will be obviously be a key consideration and it is likely you are comparing the decibels of various models. When looking you will see the db(A) rating (which will look something like: 70-75 dB(A)) somewhere within the product description or specification. However, as a stand-alone figure this probably doesn’t carry much meaning. So, we wanted to write this article in an attempt to give some meaning to these figures and help guide your purchase.
The decibel system a logarithmic scale used to measure the intensity of sound, and is actually named after Alexander Graham Bell.
The smallest audible sound (near total silence) is 0 dB(A). A sound 10 times more powerful is 10 dB(A). A sound 100 times more powerful than near total silence is 20 dB(A). A sound 1,000 times more powerful than near total silence is 30 dB(A) etc.
To put this into some kind of real-world context:
- Near-total silence - 0 dB
- A whisper - 15 dB
- Normal conversation - 60 db
- The Mitsubishi Jet Towel - 58db
- Dryflow Elite Hand Dryer - 69db
- The Xlerator - 90db
- The Dyson Airblade ab14 - 80db
- A lawnmower - 90 dBA car horn - 110 dB
- A rock concert or a jet engine - 120 dB
- A gunshot or firecracker - 140 dB
Distance affects the intensity of sound: if you are a distance away the power is greatly diminished. All of the ratings above are taken while standing near the sound. The dB(A) rating on hand dryers is usually measured 1 meter away from the air outlet of the hand dryer (please check individual specifications).
Perceptions of increases in decibel level:
- Imperceptible Change 1dB
- Barely Perceptible Change 3dB
- Clearly Noticeable Change 5dB
- About Twice as Loud 10dB
- About Four Times as Loud 20dB
Decibel ratings and hearing loss
Any sound above 85 dB can have ill effects on hearing, the loss of hearing is related both to the power of the sound as well as the length of exposure. As a rule of thumb, you know that you are listening to an 85dB sound if you have to raise your voice to be heard by somebody else.
Continuous exposure for eight hours of 90 dB sound can cause damage to your ears and protective equipment is recommended. Any exposure to 140 dB sound causes immediate damage and immediate discomfort.
NIOSH (The National Institute for Occupational Safety and Health) set these daily permissible noise level exposure times (hours per day / sound level):
- 8 hours = 85dBA
- 6 hours = 86dBA
- 4 hours = 88dBA
- 3 hours = 89dBA
- 2 hours = 90dBA
- 1.5 hours = 92dBA
- 1 hour = 94dBA
- 0.5 hours = 97dBA
- 0.25 hours or less = 100dBA
You may also find it useful to check out our blog where you will find a comparative review of the quietest hand dryers on the market.
If you have any questions about our range of quiet hand dryers then don’t hesitate to get drop us a line on 0114 3540047 or contact us here.
