INTRODUCTION : Unlike any other pollutants viz, air and water, Noise pollution is not physically seen, thus, we are not much bothered about the harmful effects of Noise pollution that effects us just like slow poison.
Noise can be defined as 'Clamour', 'Din', 'Loud outlay'. Noise (sound) is a physical disturbance that is capable of being detected by human ear. It is due to any manmade (i.e. Industrial, Commercial industrial/or Domestic activity) or natural activity. Depending upon the noise levels and duration of exposures, various impacts on human beings can be enumerated.
Short duration exposures to high noise levels may cause discomfort, irritation and problems in speech communications, where as, long duration exposures to high noise levels may cause mental problems, permanent or temporary disorders, efficiency loss, nervous disorders and gastric disorders. Sudden generation of very high noise levels may cause diversion of concentration, which may lead to accidents resulting loss of money, machine and even life.
Air borne noise levels have been limited in different areas as per notification dated 26th" December-1989 under schedule-III by Ministry of Environment & Forests (MOEF) Govt. of India (Table-1) . TABLE-1 NOISE POLLUTION STANDARD (Ministry of Environment & Forests (MOEF) Govt. of India) Note., Silence zone has been identified as area up to 100 m around Hospitals, Education Institutes, Courts etc. Area of Category Noise level in dB (A) Noise level in dB (A) 6 A.M.-9 P.M. 9 P.M.-6A.M. Industrial area 75 70 Commercial area 65 55 Residential area 55 45 Silence zone 50 40
DEFNITION OF NOISE POLLUTION As per the definition in Encyclopedia Americana, Noise by definition is unwanted sound , what is pleasant to some ears it may be extremely unpleasant to other, depending on a number of physiological factors like: the sweetest music , if it disturbs person who is trying to concentrate or sleep, is a noise to him. Just as the sound of pneumatic reverting hammer is noise to nearly everyone.
<ul><li>GENERAL SOURCES OF NOISE POLLUTION </li></ul><ul><li>The sources of noise pollution can be divided in two categories. </li></ul><ul><li>INDUSTRIAL </li></ul><ul><li>Industrial noise is due to big machines, cutting, grinding, packaging, transportation of materials etc. </li></ul><ul><li>2. NON-INDUSTRIAL SOURCES </li></ul><ul><li>Non-industrial sources can be mainly loudspeakers, automobiles, trains, aircrafts, construction work, radio, cassettes, CD players etc. </li></ul>
EFFECTS OF NOISE POLLUTION: Noise not only impairs sensibility to hearing, but, studies have proved that a loud noise during peak hours creates tiredness, irritation and impairs brain activities, so as to reduce thinking and working abilities.
The general effects of noise on human being is that it causes disturbances in sleep which lead to other side effects. The effects of noise pollution can be categorized in to following (A) PHYSIOLOGICAL EFFECTS: This form of pollution has implications for health as serious as air or water pollution. Noise can change mans physiological state by speeding up pulse and respiratory rates . it can impair hearing either permanently or temporarily Millions of industrial workers are threatened with hearing damage.
Medical evidence suggests that noise can cause heart attacks, hypertension, deafness etc. Empirical research conducted on pregnant female mice reveals that air craft taking off which bring 120 to 160 db caused miscarriages in them.
(B) PSYCHOLOGICAL EFFECTS: The effects of this categories includes, annoyance, tensions in muscles, nervous irritability and strain. (C) BEHAVIORAL EFFECTS: It has been reported that performance of school going children is poor where, schools are in the busy/ traffic prone area. Noise can cause irritation, which results in learning disabilities . Physiological and environmental consequences of noise could be serious to the survival of wild life also.
(D) PERSONOLOGICAL EFFECTS: If the effects of noise tend to persist for longer duration, they may cause disturbance in individual ‘s total personality make-up, Insomnia, fatigue, hypertension, blood pressure, deafness etc. (E) NOISE POLLUTION EFFECTS ON WILDLIFE: It has been reported that noise pollution has serious adverse effects on wildlife too. There is decline in migratory birds to a habitat if it becomes noisy. Dears, lions etc. also get affected from the traffic noise as observed in some Zoo.
(F) EFFECTS OF NOISE ON NON-LIVING THINGS: The high intensity of noise such as vibrations emanating from heavy machinery cause shattering of window glasses, loosing the plaster of house walls, cracks in walls , cracks in household crockery and breaking down the hangings in the house.
<ul><li>International & National Legislations : </li></ul><ul><li>Noise limit levels vary from country to country. </li></ul><ul><li>The ILO code of practice indicates that in the light of present knowledge , the following values may be recommended : </li></ul><ul><li>Warning Limit Value : 85dB </li></ul><ul><li>Danger Limit Value : 95dB </li></ul><ul><li>Further it adds that: </li></ul>
<ul><li>International & National Legislations: </li></ul><ul><li>(a) No matter for how short a time, a worker should not enter an area where the noise level is 115dB or more without appropriate ear protection. </li></ul><ul><li>If these are single isolated bursts of noise which can go about 130dB , PPE should be used. </li></ul><ul><li>No worker should enter an area where the noise level exceeds 140dB </li></ul>
International & National Legislations: Guidelines suggested by occupational safety and health administration (OSHA) for industrial noise exposure are
GUIDELINES SUGGESTED BY OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION (OSHA) FOR INDUSTRIAL NOISE EXPOSURE 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
Legislation On Noise In India In India the government had included “ Noise hearing loss” as a notifiable disease under the Factories Act. 1948. Under section 89 of the Act. Any Medical practioner who detects noise included hearing losses in worker has to report the case to the chief inspector of the factories.
NOISE POLLUTION RULES 2000: In India, ambient noise level has increased in public places from various sources. The Ministry of Environment and forests considered it necessary to regulate and control noise-producing sources with the objective of maintaining the ambient air quality standards. This notification called as “ the Noise Pollution (regulation and control) rules 2000”.
<ul><li>MONITORING OF SOUND ---- WHY MEASURE SOUND? </li></ul><ul><li>Accurate measurement of sound is essential in establishing </li></ul><ul><li>the existence of a noise problem, </li></ul><ul><li>its character & severity , </li></ul><ul><li>its potential to harm people , </li></ul><ul><li>violation of law, or for its effective </li></ul><ul><li>control. </li></ul><ul><li>It may also be measured for checking conformance to pre-agreed specifications for a range of domestic or industrial products. </li></ul>
<ul><li>The R & D people may measure sound while developing a quieter vehicle, a more effective industrial silencer or quieter air conditioner </li></ul><ul><li>The maintenance personnel may measure sound to identify trouble prone machines. </li></ul><ul><li>The government may measures sound to ensure conformance to law eg. The Factories act , the motor vehicles act and soon the act for air and noise pollution </li></ul>
Industrial Noise is largely produced by the industrial machines. The survey recently conducted by the Oto-Rhino-Laryngology, Madras, revealed that industrial noise pollution has damaged the hearing ability of nearly 20% workers. The main sources of noise in the petroleum industry are:
<ul><li>Oil & Gas developmental activities can generate noise during all phases of development including : </li></ul><ul><li>Seismic Operations </li></ul><ul><li>Construction Activities </li></ul><ul><li>Drilling & Production </li></ul><ul><li>Areial Surveys </li></ul><ul><li>Transportation </li></ul>
(1) “Seismic Operations” The sound & vibration propagation arising from seismic operations may result in impacts to human populations or to wild life. In planning seismic surveys, the following should be considered to minimize impacts: 1. Minimize seismic activities in the vicinity of local population wherever possible. 2. Minimize simultaneous operations on closely spaced survey lines. 3. Use the lowest practicable vibrator power levels 4. Reduce operations times, to the extent practical
“ Seismic Operations” (5) When shot hole methods are employed, charge size and hole depth should be appropriately selected to reduce noise levels. Proper back – fill or plugging of holes will help to reduce noise dispersion. (6) Identify areas and time periods sensitive to wildlife such as feeding & breathing locations and seasons and avoid them when possible. (7) If sensitive wildlife species are located in the area, monitoring should be done throughout the seismic program, for their presence before the onset of noise creating activities.
“ Seismic Operations” (8) Noise from offshore activities (especially from seismic operations) can temporarily affect fish & marine populations. Recommended measures to reduce the risk of noise impact to marine species include : (a) Identifying areas sensitive for marine life such as feeding, breeding, calving(giving birth to calf) areas. (b) Planning seismic surveys & offshore construction activities to avoid sensitive times of the year.
(c) Identifying fishing areas and reducing disturbance by planning seismic surveys and construction activities at less productive times of the year, where possible. (d) Maximize the efficiency of seismic surveys to reduce operation times, where possible. (e) If sensitive species are anticipated in the area, monitor their presence before the onset of noise creating activities throughout the seismic program.
(f) When marine mammals are observed congregating(gathering into a crowd) close to the area of planned activities, seismic start up should begin at least 500 m away. (g) If marine mammals are sighted within 500m of the proposed seismic array, start up of seismic activities should be postponed until they have moved away, allowing adequate time after the last sighting.
<ul><li>(h) Soft – start procedures, also called ramp-up or slow buildup, should be used in areas of known marine mammal activity. This involves a gradual increase in sound pressure to full operational levels.. </li></ul><ul><li>The lowest practicable power levels should be used throughout the seismic surveys, and their use should be documented. </li></ul><ul><li>(j) Methods to reduce unnecessary high frequency noise produced by air guns or other acoustic energy sources should be used, where possible. </li></ul>
(2) Drilling & Production Operations: The gigantic electrical Mechanical equipment used for the total drilling drilling and production operations are the sources of considerably high level of noise. A drilling rig is the unique noise source. It can be categorized as stationary or mobile source. A mechanical rig is generally more noisy than an electrical rig. Average noise level at the Electrical Rig is about 5 dB lower than Mechanical Rig. Average Noise levels of some of the important noise sources are:
Important Noise Sources S.No Mechanical Rig Noise Level(dB) at distance of 3- 5 mts. Electrical Rig Noise Level(dB) at distance of 3- 5 mts. 1 Draw works with Control system & Diesel Engines (450HP ×3) 2 operating 100 Draw Works with control system & DC motors (900 HP×2) 70 -80 2 Compressors (60HP×3) 2 operating 90 - 95 Compressors (60HP×4) 2 operating 80 -90
Important Noise Sources S.No Mechanical Rig Noise Level(dB) at distance of 3- 5 mts. Electrical Rig Noise Level(dB) at distance of 3- 5 mts. 3 Mud Pumps (750 HP×3) 2 operating with diesel engines 93 -97 Mud Pumps (750 HP×3) 2 operating with DC Motors 80 - 85 4 Diesel Generator (350HP×2) 92 - 97 Generator (1250HP×4) 2 operating 90 -92
Important Noise Sources S.No Mechanical Rig Noise Level(dB) at distance of 3- 5 mts. Electrical Rig Noise Level(dB) at distance of 3- 5 mts. 5 Mud Processing System 85 Mud Processing System 80
(3) Noise Sources at Production Installations : The major noise sources are flow of oil, water and gas through pipes, valves etc. The noise level close to valves is in between 80 - 90 dBA. The noise level close 40 mts. from the flare is around 70dBA . The general noise level ranges between 70 – 90 dBA
(4) “ Field Related Vehicle traffic” should be reduced as far as possible . Flight access routes and low flight altitudes should be selected & scheduled to reduce noise impacts without compromising aircraft and security.
Impacts of Noise from E& P Cos.: Noise from drilling rig or from any other sources attenuates considerably over a distance of few hundred meters. Noise of original level of about 95 dBA is reduced to 40 -45 dBA within a distance of 1 km. Thus, no significant impact due to noise on general public residing beyond 1 km. from the actual E & P site.
Noise impacts should be estimated by the use of baseline noise assessments for developments close to local human populations.
CONTROL TECHNOLGIES AVAILABLE FOR NOISE POLLUTION: There are various options available to control the noise pollution. The options of noise pollution can be selected as per the particular needs. 1. T0 ISOLATE NOISE AT SOURCE: The first and simple way to control the noise pollution is insulation. By insulation noise can be reduced at source.
Department for the Maintenance should have a routine checkup to observe the noise generated by every machine of the plant and restrict to its original noise level by replacing bearings, tightening of all loose parts that can vibrate. Machines should be placed on vibration isolators or mounts. Since these mounts are relatively inexpensive square pads of felts, cork and rubber.
<ul><li>Noise Control at the Source </li></ul>
<ul><li>The best way of controlling noise is at the source itself. This may be achieved by adopting one or more of the followings: </li></ul><ul><li>Taking the operator off or switching the machines off at least for some time. For this, at times, operator’s work may be rescheduled. </li></ul><ul><li>Choosing a quieter manufacturing process. E.g. DC Engines, bush bearing etc. </li></ul><ul><li>By reducing practicable rotational speeds, reducing flow speeds, reducing pressure of gases in stages etc. </li></ul>
4. Damping vibration of the crucial parts through the use of the correct fabrication material.
<ul><li>In many cases, noise control at source is very difficult or quite uneconomic. In such cases, noise control is achieved in the path: </li></ul><ul><li>Putting major noise sources at one place & separating it from quieter area. </li></ul><ul><li>Using acoustic barriers, sound absorbing linings & sound insulating partitions. </li></ul><ul><li>Complete or partial enclosure of noisy equipment. </li></ul><ul><li>Providing silencers on the intake as well as exhaust side of flow machines, like, blowers, fans etc. </li></ul>
<ul><li>Insertion of damping material between machine bases and foundations and use of anti vibration mountings. </li></ul>
<ul><li>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. </li></ul><ul><li>Receivers can protect himself by: </li></ul><ul><li>Making use of ear muffs, ear plugs etc. </li></ul><ul><li>Using acoustically closed cabin. </li></ul>
<ul><li>As high as 50 dB(A) reduction is possible by properly enclosing a machine </li></ul>
<ul><li>LATEST DEVELOPMENT </li></ul><ul><li>Music Monitor and Controller </li></ul><ul><li>For Clubs, Discos, Public Entertainment Venues </li></ul><ul><li>Noise levels automatically controlled </li></ul><ul><li>Easy to install </li></ul><ul><li>Visual warning of excessive noise levels </li></ul><ul><li>Cuts off music if the warnings are ignored </li></ul>
Desk Noise Meter - Monitoring Office Noise <ul><li>The VisioBel desk noise monitor is ideal for: </li></ul><ul><li>Monitoring office noise levels. </li></ul><ul><li>Hospital Ward Noise Levels </li></ul><ul><li>The noise meter on desk, clearly shows the surrounding noise levels and allows one to make decisions based on facts rather just perception. </li></ul><ul><li>The Visio-Bel shows the noise level in dB on its digital display. also as a bar, giving an instant indication of whether the levels are low or high or which way they are changing. </li></ul>