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