Various Sources of Noise
Ambient Level of Noise in Industries
Effects
Control of Noise in Industries
Noise pollution is not physically seen likeany other pollutants air and water, thus, weare not much bothered about the harmfuleffects of Noise pollution that effects us justlike slow poison.
GENERAL SOURCES OF NOISE POLLUTION
The sources of noise pollution can be divided in twocategories.
1.INDUSTRIAL SOURCES
Industrial noise is due to big machines, cutting,grinding, packaging, transportation of materials etc.
2. NON-INDUSTRIAL SOURCES
Non-industrial sources can be mainly loudspeakers,automobiles, trains, aircrafts, construction work,radio, cassettes, CD players etc.
Rotors Stators Gears Fans Vibrating panels Turbulent fluid flow Impact processes Electrical machines Internal combustion
engines etc.
WHEN Production fabrication Production assembly Power generation Processing Self-propelled working
machines In-plant conveying
systems Transport vehicles
The major noise sources are flow of oil, waterand gas through pipes, valves etc.
The noise level close to valves is in between80 - 90 dB(A).
The noise level close 40 mts. from the flare isaround 70dB(A).
The general noise level ranges between 70 – 90dB(A)
Iron and steel industry
Saw mills
Textile mills
Airports and aircraft maintenance shops
Crushing mills
Among many others
Area code Category of area/ zone
Limits in dB(A) Leq
Day time Night time
(A) Industrial area
75 70
(B) Commercial area
65 55
(C) Residential area
55 45
(D) Silence zone 50 40
Level Exposure Duration
(Hrs.)
Maximum Allowable
Level dB (A)
8 90
6 92
4 95
3 97
2 100
1.5 102
1 105
0.5 110
< 0.25 115
GUIDELINES SUGGESTED BY OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION (OSHA)
FOR INDUSTRIAL NOISE EXPOSURE
S. No Range in decibel Effects
01 Below 65 db Tolerable
02 80 db Annoying / irritating
03 88 db Hearing Disorder if
prolonged exposure
04 110 db Discomfort & may cause
hearing loss
05 135 db and above Painful
Noise limit levels vary from country tocountry so generally the following valuesmay be recommended for all type ofindustries
Warning Limit Value : 85dBDanger Limit Value : 95dB
International & National Legislations:
(a) No matter for how short a time, a workershould not enter an area where the noiselevel is 115dB or more without appropriateear protection.
(b) If these are single isolated bursts of noisewhich can go about 130dB
(c) No worker should enter an area where thenoise level exceeds 140dB
There are various options available to controlthe noise pollution.
The options of noise pollution can be selectedas per the particular needs.
1. Isolate noise at source
2. Noise control in path
3. Noise control at the receiver end
The first and simple way to control the noise pollutionis insulation. By insulation noise can be reduced atsource.
Choosing a quieter manufacturing process. E.g. DC Engines, bush bearing etc.
By reducing practicable rotational speeds, reducing flow speeds, reducing pressure of gases in stages etc.
Damping vibration of the crucial parts through the use of the correct fabrication material
Putting major noise sources at one place & separating itfrom quieter area.
Using acoustic barriers, sound absorbing linings & soundinsulating partitions.
Complete or partial enclosure of noisy equipment
Providing silencers on the intake as well as exhaust side offlow machines, like, blowers, fans etc.
Insertion of damping material between machine bases andfoundations and use of anti vibration mountings.
Wherever it is not possible to reduce noise exposure to the permissible limit at the source or in the path, the workers exposed to high should be provided with suitable ear protector.
Receivers can protect himself by:
1. Making use of ear muffs, ear plugs etc.
1. Using acoustically closed cabin.
Music Monitor and Controller
Desk Noise Meter
Monitoring office noise levels. Hospital Ward Noise Levels
Hearing Problems
Health Issues
Sleeping Disorder
Cardiovascular Issues
Trouble Communicating
Effect on Wildlife
Administrative remedies
Judicial Remedies
Legislative Remedies
Public Co-operation
International Co-operation
The first category (mobilesources) includes:
Vessel traffic within port;
Road and Rail traffic,
Including that which flowsinto urban roads.
The second category(stationary sources)includes:
Ships at dock;
Industrial areas,
Recreational areas;
Activities of handling,loading/unloading goods;
Shipbuilding processes.
• Marine life can be susceptible to noise or soundpollution from sources such as passing ships, oilexploration seismic surveys, and naval low-frequencyactive sonar
• Sound travels more rapidly and over larger distancesin the sea than in the atmosphere.
• Marine animals, such as cetaceans often have weakeyesight, and live in a world largely defined byacoustic information. This applies also to many deepersea fish, who live in a world of darkness.
A 10 decibel increase in sound represents a 10 times increase in volume
If 20 decibel increase in sound represents a 100 times increase in volume
A 30 decibel increase in sound represents a 1000 times increase in volume.
Sound also travels faster and further in water than in air. High intensity sound in the oceans may not dissipate for thousands of miles. Humpback whales are particularly sensitive to oceanic noise pollution.
Reduce the sea transport in interior to protect aqua life
Reduce unwanted sirens inside the ocean and near coastal lines
Make signals is better than the sirens
Control night time loading and unloading