Newer power tools in the owner’s manual manufactures are starting to include decibel or db ratings for the tool running with no load and under load. Ok. That is nice information, but what is a decibel and how does that relate to the amount of noise in the wood shop?
The decibel is used to measure the sound level being emitted by the power tool. The decibel is a logarithmic unit used to describe the ratio of sound pressure. Decibels describe very big ratios in modestly increasing number range. Logarithmic scales, in case you have forgotten, grow a exponential rates the further out on the X axis you go.
Some examples to refresh / demonstrating dBA scale
Suppose you measure the sound of two power tools running at full speed under load called Tool1 and Tool2.
If Tool2 is twice as loud as Tool1 the difference in dBA is:
10 log (Tool2/Tool1) = 10 log 2 = 3 dBA
If Tool2 is ten times as loud as Tool1 the difference in dBA is:
10 log (Tool2/Tool1) = 10 log 10 = 10 dBA
As you can see a three decibel increase is equal to Tool2 being twice as loud as Tool1.
How do you know what is a safe decibel level? What are some good guidelines to follow? The next post will answer these questions and more.
