![decibel scale safety decibel scale safety](https://www.cdc.gov/niosh/topics/noise/infographics/images/7_noise_level_by_decibles600.jpg)
This 3dB rule is important to remember when you come to measure noise as well as analyse and predict individual exposure. If the pin dropping has a sound level of 10dB (decibels) then two pins would have a level of 13dB. In a work context, this means that a small increase in the number of decibels results in a huge change in the amount of noise and, as such, the potential to cause damage to your hearing. When this sound is doubled this is equated to a rise of 3dB (decibels), using a logarithmic scale*. It can, however, distinguish the significant multiplying of the energy of the sound. 3dB rule and the doubling of sound energyĪlthough the human ear can distinguish the rise in level between one or two pins dropping, it cannot distinguish between 10,000,000,000,000 pins and 10,000,000,000,001 pins or even 10,100,000,000,000 because it is not a linear device. This is something that we cover at length during our noise awareness training courses with our safety professionals. It would take 10,000,000,000,000 pins dropping simultaneously to measure the same sound level as the jet engine. Therefore it can hear the sound of a pin dropping close-by as well as the roar of a jet engine. It has a mechanism that reduces its sensitivity as the sound level rises and it also has the remarkable ability to handle an enormous range of sound levels. We say this often in this blog but, truly, the ear is an extremely versatile and an amazing hearing device. Here, we have tried to explain in simple terms how it works. At first, the 3dB rule can appear a challenging concept but, once you are used to it, it should cause you little difficulty.
![decibel scale safety decibel scale safety](https://2.bp.blogspot.com/-Gt8cRfLS2e4/U1EKTzDWYdI/AAAAAAAAAWE/K8I9LeFC_Os/s1600/DECIBEL+SCALE.jpg)
This is because changes in noise levels can have a significant impact on how you manage it and keep within the legal limits of exposure. If your work involves controlling noise in the workplace, especially if you are responsible for monitoring noise exposure levels, you will need to understand the 3dB rule.
![decibel scale safety decibel scale safety](https://www.enoisecontrol.com/wp-content/uploads/2015/11/Decibel-Chart.jpg)
What is the 3dB rule and how to understand it?