Noise is usually called sounds of different frequencies and intensities that are perceived by the human hearing organs. Usually this concept affects the manufacturing sector, since work in enterprises occurs with varying degrees of volume. There is a classification of noise by various parameters.
physical characteristics
Often noise measurement is performed to determine the degree of its impact on humans. The physical characteristics of this include:
- power (W / m);
- frequency (Hz);
- amplitude (min);
- wavelength (m);
- propagation speed (m / s);
- sound pressure (N / m2).
Noise characteristics are taken into account when isolating rooms, when installing equipment. Only acceptable indicators can be comfortable for a person. Noise classification allows you to distribute sounds in several ways.
By spectrum
Noise on this basis is divided into:
- stationary;
- non-stationary.
The first type has constant average parameters: intensity and autocorrelation action. Such sounds are manifested from independent sources, for example, from a crowd of people, the sea, industrial equipment, and an air vortex.
Unsteady noise does not last long. It can be the sound of passing vehicles, knocks at the factory, interference in technology.
By the nature of the spectrum
Noise classification divides sounds into:
- broadband: the sound spectrum has a width of more than 1 octave;
- tonal: has pronounced tones (frequency excess by 7 dB).
By frequency
Noise measurement allows you to determine its frequency:
- low frequency;
- midrange;
- high frequency.
By time
If we consider the temporal characteristics, then the noise can be:
- permanent - no more than 5 dBA;
- intermittent - more than 5dBA.
The second kind of sounds is oscillating, intermittent, impulsive.
By nature of occurrence
The noise classification distributes it to:
- mechanical;
- aerodynamic;
- hydraulic;
- electromagnetic.
Noise measurement
Measurement indicators allow you to determine the noise impact on a working person. There are noise standards necessary for industrial and domestic conditions. Their rules also apply in apartment buildings, according to which it is determined that this indicator should not be more than 30 dB.
When neighbors carry out repairs, the noise level may be greater than the permissible value. Moreover, some carry out such work at night, which is illegal. Then it is necessary to correctly measure it in order to bring violators to justice.
Noise measurement is performed by professionals who have a special device. The device has a sensitive microphone with which sounds are recorded, after which they are transferred to the monitor. This method allows you to determine the level in decibels.
To independently perform noise measurement, you need to use a computer, tablet, iPhone and other equipment. You will need to install a special application. It can be paid and free. Since it is not necessary to know the exact indicators, the measurement performed will determine the approximate characteristics.
Noise measurement is also required at workplaces in the production room. When performing this operation, ventilation, air conditioning and other equipment should be included.
Norms
The permissible noise level in various buildings is prescribed in GOST. This applies to public buildings, residential buildings, jobs. The norm setting is determined in 2 ways:
- on the basis of the noise spectrum, the permissible values are determined in 10 octaves with frequencies of 63, 125, 250 Hz;
- dBA: the method is used to normalize intermittent sounds when there is no information about the spectrum of real noise.
Noise affects not only the auditory analyzer. It has an effect on the central nervous system and autonomic NS, which is why changes in organs occur. The permissible noise level for a person is 55 dB during the day, and 40 dB at night. Such indicators are not harmful to health.
There is protection against any kind of noise. The room needs high-quality insulation, and then it will be comfortable to be in it. This work will be done with the help of special materials.
Specific noise effect
Loud sounds harm the auditory function in the temples, the analyzer due to prolonged vasospasm. Because of this, degenerative changes in the nerve endings begin to appear. "Noise disease" is divided into 3 stages:
- adaptation: when there is a high level of noise, the auditory threshold reaches 10-15 dB, but after 3 minutes the acuity normalizes;
- fatigue: hearing acuity decreases by 15-20 dB within a few hours after exposure to sound;
- progressive hearing loss: hearing loss occurs in both ears.
The last stage is considered incurable, so it is necessary to diagnose noise sickness with auditory fatigue and protect a person from exposure to loud sounds.
Nonspecific effect of noise
Under the influence of noise, excitation of the cerebral cortex, hypothalamus, and spinal cord is observed, and transcendental inhibition is rapidly developing. Nerve processes lose balance, after which there will be depletion of nerve cells. Symptoms of this condition include irritability, emotional instability, impaired attention.
When excitation passes into the pituitary gland and the cortical substance of the adrenal glands, then this is stressful for the body. This is considered the cause of changes in the functioning of the heart, blood vessels and gastrointestinal tract. Noise disease affects the hearing, nervous system.
How to protect yourself from noise?
In order not to appear “noise disease”, high-quality protection against noise is needed. For this, collective means are used:
- noise reduction in the source;
- proper placement of equipment;
- fight against noise.
To protect against noise, sound insulation means are used, the installation of silencers, including acoustic treatment of the surfaces of the room. The most effective means of eliminating sounds include the fight against the source.
The reduction of mechanical noise occurs when equipment is repaired, shock processes are replaced by shockless ones. It is necessary to lubricate friction surfaces, use the balancing of rotating parts. Reduce the aerodynamic sound will be due to a decrease in the gas flow rate, restoration of aerodynamics, sound insulation.
Nowadays, methods are actively applied to reduce noise along the path of its propagation by installing soundproofing means. These include screens, partitions, covers, cabins. Porous materials, for example, mineral felt, glass wool, and foam rubber, have excellent sound absorption.
Any room can now be equipped with soundproofing, since there are many materials for this. Moreover, all work is performed both during construction and during repair. You can put protection against loud sounds on all surfaces of the home.
If noise is not adversely affected by hearing, there will be no adverse effects. Ears should be provided with rest: often to be in silence, not to listen to music loudly, not to be near powerful equipment for a long time. If you spend more time in a relaxed atmosphere, this will prevent the load on your ears.
Noise protection can be done in the following ways:
- competent organization of work and leisure in the workplace;
- suitable layout of rooms and equipment;
- use of high-quality machine parts;
- the use of non-metallic elements instead of metal;
- sound absorption should be installed in the place of low-frequency noise;
- the use of soundproofing agents;
- the use of silencers;
- use of protective equipment: tampons, headphones, headsets.
Protection from exposure to noise is important for humans, because it is directly related to health. Therefore, premises for work and rest should be equipped to the required standards. If these standards are not met, then such situations should be addressed in time.