Excessive or disruptive noise reduces efficiency and can damage health. The best method of controlling noise is to eliminate or reduce the noise. However it has been proved that a certain level of background noise is desirable and certain sound sources improve performance and efficiency.. Music etc..
In surveys it has been proved that on many occasions it is not the level of noise which is the problem it is the source of the sound and its frequency. Other peoples conversation, persistent click or the sounds of insects can be very disturbing when people need to concentrate.
Peak noise levels dB(A) in Industry
| Noise Source | dB(A) value |
| Pneumatic Chisel Hammer | 115-120 |
| Rocking Sieve, Chain Saw, Compressed Air Riveter electric cutter | 105-115 |
| Milling /Weaving machine,Crosscut saw, Stamping Machine | 100-105 |
| Electric Motor, Rotary Press, Wire Drawing Machine Sawmill, Bottle filling Machine | 90-95 |
| Toolmaking machine -lightly loaded | 80 |
Human Noise Levels at 1 m (dB
| Noise Source | dB(A) value< |
| Quiet Conversation | 60-65 |
| Dictation | 65-70 |
| Speaker at Conferences | 65-75 |
| Delivery of a lecture | 70-80 |
| Loud Shouting | 80-85 |
Desirable Noise Ranges in Open Plan Office
| Noise measure | dB(A) value |
| Equivalent Noise Leq | 54-59 |
| Mean Noise level L50 | 50-55 |
| Peak Noise level L50 | 60-65 |
The noise level Leq relates to the average noise levels
The noise level L50 means that the indicated noise level may be exceeded for 50% of the time.
The noise level L1 means that the indicated noise level may be exceeded for 1% of the time.
Sound Deadening Effects of building items
| Item | Damping in dB(A) value |
| Normal Single Doors | 21-29 |
| Normal double Doors | 30-39 |
| Heavy Special Doors | 40-46 |
| Window - Single Glazed | 20-24 |
| Window - Double Glazed | 24-28 |
| Double Glazing with Felt Backing | 30-34 |
| Dividing Wall 6-12cm brick | 37-42 |
| Dividing Wall 25-38cm brick | 50-55 |
| Double Wall 2 x 12 cm brick | 60-65 |
Noise Protection
Ear plugs properly used -conical plugs of synthetic material - can reduce noise levels by up to 30 dB..
Protective Ear Caps (ear muffs)- can reduce noise levels by 40-50dB..
It is suggested that ear plugs be used for noise levels of 85-100 dB(A) and ear muffs be used for noise levels above 100 dB(A).
