Search This Blog

Noise

Noise is primarily annoying or harmful sound....

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 SourcedB(A) value
Pneumatic Chisel Hammer115-120
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 loaded80


Human Noise Levels at 1 m (dB

Noise SourcedB(A) value<
Quiet Conversation60-65
Dictation65-70
Speaker at Conferences65-75
Delivery of a lecture70-80
Loud Shouting80-85


Desirable Noise Ranges in Open Plan Office

Noise measuredB(A) value
Equivalent Noise Leq54-59
Mean Noise level L5050-55
Peak Noise level L5060-65


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

ItemDamping in dB(A) value
Normal Single Doors21-29
Normal double Doors30-39
Heavy Special Doors40-46
Window - Single Glazed20-24
Window - Double Glazed24-28
Double Glazing with Felt Backing30-34
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).