Last updated on May 15th, 2024 at 08:22 am
The major noise sources in industrialized society are:
a. road traffic
b. railways
c. aircraft, particularly airports
d. industry: factories, workshops, etc.
e. office machines (typewriters, teletype, accounting machines, etc.)
f. people in residences: conversation, singing, music, radio, records, TV, etc.
g. motorized appliances in general use (lawnmowers, portable tools, kitchen implements, etc.)
All these can occur in tropical conditions, but perhaps to a lesser extent. In rural areas, there seems to be no significant noise problem, but in an urban situation noise can be as bad in the tropics as anywhere.
Most of the tropical areas are in developing countries, where urbanization is gathering momentum. At present the the ratio of urban to rural areas is much less than in more industrialized societies, but:
1. urban areas themselves present the same problems
2. with rapid urbanization tomorrow’s problems may be the same even on a national scale
The car ownership rate is much less than in Western Europe, but traffic density in towns can reach the same level.
The railway network may not be as dense, but near railways, the problems are the same.
At some major airports, the density of aircraft movements reaches the level of secondary airports in Europe (e.g. Nairobi is about the same as Manchester), but this is rapidly increasing.
The noise generated by people is probably higher than in Europe, due to more med open-air activities, more uninhibited behavior, love for music, etc.
There is little heavy industry and even if there is, it is normally positioned with more foresight than in Europe away from noise-sensitive areas therefore industrial noise is usually better contained.
What do you mean by multilayer construction? Give the construction detail with the help of diagram
Where substantial noise reduction is required, but the use of massive multilayer construction is impracticable (e.g. for windows)- two or more layers of light construction could be used to advantage.
The greatest resistance to sound transmission is provided at the surface of the wall material. (The magnitude of this depends on the difference in density between air and the material.)
if the same amount (thickness) of material is used in two independent layers, rather than in one, TI will be double- provided no vibration is transmitted directly between the two layers.
This ideal case will never be reached in practice, but it can be approached if there is no rigid connection between the two (or more) layers and even the edge fixings or supports are flexible.
Figure 7.1 shows some practical constructional details. Faultless workmanship, hence strict supervision, is essential, as the slightest fault (for instance mortar droppings) can defeat the purpose of the effort and expense.
Placing an absorbent material in the cavity would reduce the build-up of reverberant sound within the cavity, thus it would further improve the TI value.
Windows are weak points in the building envelope from the noise insulation point of view (same as thermally). Their performance can, however, be improved by:
a. ensuring airtight closure by using gaskets
b. using double (or triple ) glazing, where each pane with its frame is independent of the other
c. placing absorbent material on the reveals, but this will only be effective if the reveal, i.e. the distance between the two panes, is at least 150 mm, but preferably 200 mm
Discuss the various steps to control the noise pollution
Following are the various steps to control noise pollution:
1. The first approach has been to reduce noise at the source. Design and fabrication of silencing devices and their use in aircraft engines, trucks, cars, motorcycles, industrial machines, and home appliances would be an effective measure. Protection to workers can be provided through wearing devices such as earplugs and earmuffs.
2. Making a change in the design and operation of machines, vibration control, soundproof cabins, and sound-absorbing materials can reduce it.
3. It can get reduced by prescribing noise limits for vehicular traffic, ban on honking of horns in certain areas, and planning main traffic arteries, industrial establishments, amusement areas, residential colonies, creating
of silent zones near schools and hospitals, and redesigning of building to make them noise proof.
Other measures can involve the reduction of traffic density in residential areas giving preferences to mass public transport system.
4. Control of Indoor noise. Where outdoor noise levels have been high, the following methods can be applied for reducing their effect.
a. Locate the building as far as possible from the noise source. The noise level drops about 6dB each time the distance is doubled.
b. Trees and shrubs may be planted in front of the building absorption of the sound.
c. Locate non-critical areas such as corridors kitchens, bathrooms, elevators, and service spaces in the noisy side and critical areas each as bedrooms and living spaces on the quiet side.
d. Back-to-back bathrooms or toilets should be avoided unless they are effectively sound isolated. Bathrooms, kitchen and laundry rooms should not be adjacent to the floor.
e. Bathroom walls, floor, and ceiling should be sound insulated using the construction of high sound insulation glasses.
f. Noisy toilets, is bettered by quiet siphon jet type flush toilets should be installed to reduce the noise from the source. Commode seats with a double siphon systems are now available and may be adopted wherever possible.
5. Road Noise. Vegetation buffer zones must be created in different parts of the city. Efforts should be made for roadside plantations.
6. An urgent need for legislation to control noise pollution. We have seen that in India, in absence of a specific legislation for the control and prevention of noise pollution, one has to seek provisions from various branches of law and regulations.
There has been no doubt that the available provisions in various branches of law are adequate, unscientific, and crude.
In most of the developed countries, specific legislations have been made and scientific methods for the investigation of noise pollution have been invented.
The science of audiometers and other branches related to sound have been control and prevented noise pollution. developed and it becomes comfortable to devise various legal provisions to
What are the various effects of noise pollution?
Following are the various effects of noise pollution:
Deafness, temporary or permanent, is one of the most prevalent effects of noise pollution. Mechanics, locomotive drivers, telephone operators, etc all have their hearing impairments.
The first and foremost effect of noise is a decrease in the efficiency in working. Research has proved the fact that human efficiency increases with noise reduction.
Too much of noise disturbs the rhythms of working, thereby affecting the concentration required for doing a work.
The noise of traffic or the loudspeakers or different types of horns divert attention, thus causing harm in the working standard.
Fatigue caused is another effect of noise. Due to lack of concentration, people need to devote more time to complete their tasks, which leads totiredness and fatigue.
Noise pollution acts as a stress invigorator, increasing stress levels among people.
Sometimes, being surrounded by too much of noise, people can be victims of certain diseases like blood pressure, mental illness, etc.
Noise pollution indirectly affects vegetation. Plants require a cool & peaceful environment to grow. Noise pollution causes poor quality of crops.
Animals are susceptible to noise pollution as well. It damages the nervous system of the animals.
Noise indirectly weakens the edifice of buildings, bridges, and monuments. It creates waves, which can be very dangerous and harmful and put the building in danger condition.
What is noise pollution? Discuss some detail about this
Noise pollution is excessive, displeasing human, animal or machine-created environmental noise that disrupts the activity or balance of human or animal life.
The word noise comes from the Latin word nausea, meaning seasickness.
The source of most outdoor noise worldwide is mainly construction and transportation systems, including motor vehicle noise, aircraft noise, and rail noise.
Poor urban planning may give rise to noise pollution since side-by-side industrial and residential buildings can result in noise pollution in the residential area.
Indoor and outdoor noise pollution sources include car alarms, emergency service sirens, mechanical equipment, fireworks, compressed air horns, grounds keeping equipment, barking dogs, appliances, lighting hum, audio entertainment systems, electric megaphones, and loud people.
What are the effects of noise on human health
Noise effects health and behavioral in nature. The unwanted sound is called noise. This unwanted sound can damage physiological and psychological health.
Noise pollution can cause annoyance and aggression, hypertension, high-stress levels, tinnitus, hearing loss, sleep disturbances, and other harmful effects.
Furthermore, stress and hypertension are the leading causes to health problems, whereas tinnitus can lead to forgetfulness, severe depression, and at times panic attacks.
Chronic exposure to noise may cause noise-induced hearing loss. Older males exposed to significant occupational noise demonstrate significantly reduced hearing sensitivity than their non-exposed peers, though differences in hearing sensitivity decrease with time, and the two groups are indistinguishable by age 79.
A comparison of Maaban tribesmen, who were insignificantly exposed to transportation or industrial noise, to a typical U.S. population showed that chronic exposure to moderately high levels of environmental noise contributes to hearing loss.
High noise levels can contribute to cardiovascular effects and exposure to moderately high levels during a single eight-hour period causes a statistical rise in blood pressure of five to ten points and an increase in stress and vasoconstriction leading to the increased blood pressure noted above as well as to the increased incidence of coronary artery disease.
Noise pollution is also a cause of annoyance. A 2005 study by Spanish researchers found that in urban areas households are willing to pay approximately four Euros per decibel per year for noise reduction.