The production noise level should not be higher. Occupational noise and its impact on humans

In various sectors of the economy there are sources of noise - these are mechanical equipment, human flows, urban transport.
Noise is a collection of aperiodic sounds different intensity and frequencies (rustling, rattling, creaking, screeching, etc.). From a physiological point of view, noise is any unfavorably perceived sound. Long term exposure noise per person can lead to such an occupational disease as "noise disease".
According to its physical essence, noise is a wave-like movement of particles of an elastic medium (gas, liquid or solid) and therefore is characterized by oscillation amplitude (m), frequency (Hz), propagation velocity (m / s) and wavelength (m). Character negative impact on the hearing organs and the subcutaneous receptor apparatus of a person also depends on such noise indicators as sound pressure level (dB) and loudness. The first indicator is called the sound power (intensity) and is determined by the sound energy in ergs transmitted per second through a hole of 1 cm2. The loudness of the noise is determined by subjective perception hearing aid person. The threshold of auditory perception also depends on the frequency range. Thus, the ear is less sensitive to low-frequency sounds.
The impact of noise on the human body causes negative changes primarily in the hearing organs, nervous and cardiovascular systems. The degree of manifestation of these changes depends on the noise parameters, work experience in conditions of noise exposure, the duration of noise exposure during the working day, and the individual sensitivity of the body. The effect of noise on the human body is aggravated forced position body, increased attention, neuro-emotional stress, unfavorable microclimate.
The effect of noise on the human body. To date, numerous data have been accumulated that make it possible to judge the nature and features of the influence of the noise factor on the auditory function. The course of functional changes may have various stages. A short-term decrease in hearing acuity under the influence of noise from fast recovery function after the termination of the factor is considered as a manifestation of the adaptive protective-adaptive reaction of the auditory organ. Adaptation to noise is considered to be a temporary decrease in hearing by no more than 10-15 dB with its restoration within 3 minutes after the cessation of the noise. Prolonged exposure to intense noise can lead to re-irritation of the cells of the sound analyzer and its fatigue, and then to a persistent decrease in hearing acuity.
It has been established that the tiring and hearing-damaging effect of noise is proportional to its height (frequency). The most pronounced and early changes are observed at a frequency of 4000 Hz and a frequency range close to it. In this case, impulse noise (at the same equivalent power) acts more unfavorably than continuous noise. Features of its impact significantly depend on the excess of the impulse level above the level that determines background noise at work.
The development of occupational hearing loss depends on the total time of exposure to noise during the working day and the presence of pauses, as well as the total work experience. Initial stages occupational lesions are observed in workers with an experience of 5 years, expressed (hearing damage at all frequencies, impaired perception of whispered and colloquial speech) - over 10 years.
In addition to the effect of noise on the hearing organs, it has been established bad influence on many organs and systems of the body, primarily on the central nervous system, functional changes in which occur before a violation of auditory sensitivity is diagnosed. Damage to the nervous system under the influence of noise is accompanied by irritability, weakening of memory, apathy, depressed mood, changes in skin sensitivity and other disorders, in particular, the rate of mental reactions slows down, sleep disorders occur, etc. Workers mental labor there is a decrease in the pace of work, its quality and productivity.
Noise exposure can lead to illness gastrointestinal tract, shifts in metabolic processes(violation of the basic, vitamin, carbohydrate, protein, fat, salt exchanges), violation functional state of cardio-vascular system. Sound vibrations can be perceived not only by the organs of hearing, but also directly through the bones of the skull (the so-called bone conduction). The level of noise transmitted by this path is 20-30 dB less level perceived by the ear. If, at low noise levels, transmission due to bone conduction small, then at high levels it increases significantly and aggravates harmful action on the human body. When exposed to noise, high levels(more than 145 dB) tympanic membrane rupture is possible.
Thus, exposure to noise can lead to a combination of occupational hearing loss (neuritis auditory nerve) With functional disorders central nervous, autonomic, cardiovascular and other systems that can be considered as an occupational disease - noise disease. Occupational neuritis of the auditory nerve (noise disease) is most often found in workers in various branches of engineering, the textile industry, and so on. Cases of the disease are found in persons working on weaving looms, with chipping, riveting hammers, servicing press and stamping equipment, in test-mechanics and other professional groups exposed to intense noise for a long time.
Noise level regulation. When normalizing noise, two methods of normalization are used: by the limiting noise spectrum and by the sound level in dB. The first method is the main one for constant noise and allows you to normalize sound pressure levels in eight octave frequency bands with geometric mean frequencies of 63, 125, 250, 500, 1000, 2000, 4000 and 8000 Hz. Noise at workplaces should not exceed the permissible levels corresponding to the recommendations of the Acoustics Technical Committee when international organization for standardization.
The set of eight permissible sound pressure levels is called the limiting spectrum. Studies show that acceptable levels decrease with increasing frequency (more annoying noise).
The second normalization method general level noise, measured on the A scale, which mimics the sensitivity curve of the human ear, and called the sound level in dBA, is used for an approximate assessment of constant and intermittent noise, since in this case we do not know the noise spectrum. The sound level (dBA) is related to the limiting spectrum by the dependence 1a = PS + 5.
The main normalized parameters for broadband noise are given in Table. 1.4.

Table 1.4
Permissible sound pressure levels in octave bands, sound levels and equivalent levels for broadband noise

Rice. 1.6. Anti-noise headphones:
1 - plastic case; 2 - glass wool; 3 - sealing gaskets; 4 - removable covers made of film and flannel
In Russia, a system of health-improving and preventive measures to combat noise in industries has been developed, among which sanitary norms and rules occupy an important place. The implementation of the established norms and rules is controlled by the bodies of the sanitary service and public control.

Based on the materials of the book - "Life Safety" Edited by prof. E. A. Arustamova.

noise is one of the most common unfavorable physical factors of the environment, acquiring important social and hygienic significance due to urbanization, as well as mechanization and automation of technological processes, further development aviation, transport. Noise is a combination of sounds of different frequency and strength.

Sound - vibrations of particles of the air environment, which are perceived by the human hearing organs, in the direction of their propagation. Production noise characterized by a spectrum that consists of sound waves of different frequencies. the normally audible range is 16 Hz - 20 kHz.

ultrasonic range - over 20 kHz, infrasound - less than 20 Hz, stable audible sound - 1000 Hz - 3000 Hz

Harmful effects of noise:

the cardiovascular system;

unequal system;

hearing organs (tympanic membrane)

Physical characteristics of noise

sound intensity J, [W/m2];

sound pressure Р, [Pa];

frequency f, [Hz]

Intensity - the amount of energy carried by a sound wave in 1 s through an area of ​​​​1m2, perpendicular to the propagation of a sound wave.

Sound pressure - optional air pressure that occurs when a sound wave passes through it.

Prolonged exposure to noise on the human body leads to the development of fatigue, often turning into overwork, to a decrease in productivity and quality of work. Noise has a particularly unfavorable effect on the organ of hearing, causing damage to the auditory nerve with the gradual development of hearing loss. As a rule, both ears are affected equally. The initial manifestations of occupational hearing loss are most often found in people with about 5 years of work experience in noise conditions.

25 Classification of industrial noise and vibration.

Noise is classified by frequency, spectral and temporal characteristics, the nature of its occurrence.

Occupational noise classification is given in Table 37.

The nature noise spectrum are divided into broadband(with a continuous spectrum more than one octave wide) and tonal in the spectrum of which there are discrete tones.

In practical noise assessments, a standard series of 8 octave bands is used, the geometric mean of which is 63, 125, 250, 500, 1000, 2000, 4000, 8000 Hz.

By spec noise composition is divided into low frequency(maximum sound energy falls at frequencies below 400 Hz); mid-frequency(maximum sound energy at frequencies from 400 to 1000 Hz) and high-frequency (maximum sound energy at frequencies above 1000 Hz).

By temporal characteristics noises are divided into permanent(the sound level over an 8-hour working day changes less than 5 dB over time) and fickle(the levels of which change by more than 5 dBA over an 8-hour working day). Persistent noise refers to fluctuating noise, at which the sound level changes continuously with time; intermittent noise(the sound level remains constant for an interval of 1 second or more); impulse noise, consisting of one or more sound signals lasting less than 1 second.

From rede distribution p Distinguish between airborne and structural noise.

airborne noise radiated into the surrounding space and propagated in the air while moving Vehicle on open areas, overpasses and bridges, as well as from sound signaling devices, stationary equipment, in the course of repair and maintenance of tracks and roads, reloading operations, maintenance and repair of rolling stock on the territory of transport enterprises.

Structural noise excited by dynamic forces at the point of contact of the wheel with the road or rail during movement. It spreads across superstructure path, load-bearing structures of the roadway and is transmitted through the ground to nearby buildings. Structural noise is especially strong when traffic is moving in tunnels, underground.

The impact of vibration on a person is classified:

according to the method of transmitting vibration to a person;

according to the source of occurrence;

in the direction of vibration;

by the nature of the spectrum;

by frequency composition;

according to the time characteristic of vibration.

By mode of transmission per person distinguish:

general vibration transmitted through the supporting surfaces to the body of a seated or standing person;

local vibration transmitted through human hands.

Note. Vibration transmitted to the legs of a seated person and to the forearms in contact with the vibrating surfaces of the desktops refers to local vibration.

By direction of action the vibration is subdivided according to the direction of the axes of the orthogonal coordinate system.

For general vibration, the direction of the axes X about , Y about , Z about and their relationship with the human body is as follows: the X axis o is horizontal from the back to the chest; Y axis o - horizontal from the right shoulder to the left); Z l - vertical axis, perpendicular to the supporting surfaces of the body at the points of its contact with the seat, floor, etc.

For local vibration, the direction of the axes X l , Y l , Z l and their connection with the human hand is as follows: X axis l - coincides with or parallel to the axis of the place of coverage of the vibration source (handle, lodgment, steering wheel, control lever held in the hands of the workpiece, etc.); axis Y l - perpendicular to the palm, and the axis Z l - lies in the plane formed by the axis X l and the direction of supply or application of force, and is directed along the axis of the forearm.

By origin vibration is:

local vibration transmitted to a person from manual power tools(with engines), manual controls for machines and equipment;

local vibration transmitted to humans from manual non-mechanized tools(without motors), e.g. straightening hammers different models and workpieces, sleeper tamps;

general vibration category 1 – transport vibration;

general vibration category 2 – transport and technological vibration;

general vibration category 3 – process vibration.

at permanent workplaces of industrial premises of enterprises;

at workplaces in warehouses, canteens, household, duty and other industrial premises where there are no machines that generate vibration;

at workplaces in the premises of the plant management, design bureaus, laboratories, training centers, computer centers, health centers, office premises, work rooms and other premises for mental workers;

general vibration in residential premises and public buildings from external sources: urban rail transport (shallow and open lines of the Metropolitan, tram, rail transport) and vehicles; industrial enterprises and mobile industrial installations (during the operation of hydraulic and mechanical presses, planing, punching and other metalworking mechanisms, reciprocating compressors, concrete mixers, crushers, construction machines, etc.);

general vibration in residential premises and public buildings from internal sources: engineering and technical equipment of buildings and household appliances (elevators, ventilation systems, pumping stations, vacuum cleaners, refrigerators, washing machines, etc.), as well as built-in trade enterprises (refrigeration equipment), public utilities, boiler houses, etc. d.

By the nature of the spectrum vibrations are:

narrow-band vibration, in which the controlled parameters in one 1/3 octave frequency band are more than 15 dB higher than the values ​​in adjacent 1/3 octave bands;

broadband vibration - with a continuous spectrum more than one octave wide.

By frequency composition vibrations are:

low frequency vibration(with a predominance of maximum levels in the octave frequency bands 1÷4 Hz for general vibrations, 8÷16 Hz for local vibrations);

mid-frequency vibration(8÷16 Hz - for general vibration, 31.5÷63 Hz - for local vibration);

high frequency vibration(31.5÷63 Hz - for general vibration, 125÷1000 Hz - for local vibration).

By time characteristic vibrations are:

constant vibration, for which the value of the normalized parameters changes by no more than 2 times (by 6 dB) during the observation time;

fluctuating vibration, for which the value of the normalized parameters changes by at least 2 times (by 6 dB) during the observation time of at least 10 minutes when measured with a time constant of 1 s, including:

time-varying vibration, for which the value of the normalized parameters changes continuously in time;

intermittent vibration when the contact of the person with the vibration is interrupted, and the duration of the intervals during which the contact takes place is more than 1 s;

impulse vibration, consisting of one or more vibrational impacts (for example, shocks), each with a duration of less than 1 s.

At present, the operation of the vast majority of technological equipment, power plants is inevitably associated with the occurrence of noise and vibration of various frequencies and intensities, which have an adverse effect on the human body. Prolonged exposure to noise and vibration reduces performance and can lead to the development of occupational diseases.

Noise like hygiene factor, is a set of sounds that adversely affect the human body, interfering with its work and rest. Noise is a wave-like oscillatory motion of particles of an elastic (gas, liquid or solid) medium. Noise is usually a combination of sounds of varying frequency and intensity.

Intense noise from daily exposure leads to occupational disease- hearing loss, the main symptom of which is a gradual hearing loss in both ears, initially lying in the high frequency region (4000 Hz), with subsequent spread to lower frequencies, which determine the ability to perceive speech. With very high sound pressure, a rupture of the eardrum can occur.

In addition to a direct effect on the hearing organ, noise affects various departments brain, changing normal processes higher nervous activity. Typical complaints are fatigue, general weakness, irritability, apathy, weakening of memory, insomnia, etc. Noise lowers labor productivity, increases marriage in work, can be indirect cause industrial injury.

Depending on the nature harmful effects On the human body, noise is divided into disturbing, irritating, harmful and traumatic.

Interfering - this is noise that interferes with speech communication (conversations, movements of human flows). Annoying noise - defiant nervous tension, reduced performance (humming of a faulty fluorescent lamp in the room, slamming the door, etc.). Harmful noise- defiant chronic diseases cardiovascular and nervous systems ( different kinds industrial noise). Traumatic noise - sharply disturbing physiological functions human body.

The degree of harmfulness of noise is characterized by its strength, frequency, duration and regularity of exposure.

Noise regulation is carried out in two directions: hygienic regulation and regulation of noise characteristics of machinery and equipment.

The current noise standards at workplaces are regulated by SN 9-86-98 “Noise at workplaces. Guidelines"and GOST 12.1.003-83 SSBT. "Noise. General requirements security."

According to specified documents industrial noise is divided into:
- noise spectrum: broadband and tonal;
- temporary characteristics: permanent and non-permanent.

In turn, intermittent noises are: fluctuating in time (howling), intermittent, impulsive (following one after another with an interval of more than 1 second).

For an approximate assessment of noise, the sound level is taken, determined by the so-called A scale of the sound level meter in decibels - dBA.

The norms establish permissible noise levels in working premises for various purposes. At the same time, zones with a sound level above 85 dBA must be designated special characters workers in these areas to be provided with personal protective equipment. The basis of measures to reduce industrial noise is technical regulation.

In accordance with GOST 12.1.003-83, two methods are used for noise standardization:
- according to the limiting noise spectrum;
- normalization of the sound level in dB on the A scale of the sound level meter, which has different sensitivity to different sound frequencies (copies the sensitivity of the human ear).

The first method is the main one for constant noise. The second method is used for a rough estimate of constant and intermittent noise.

The standard prohibits even a short stay of people in areas with sound pressure levels above 135 dB.

Sound meters of various modifications are used for measurement.

Permissible noise levels at workplaces are determined by sanitary standards.

In rooms for mental work without noise sources (offices, design bureaus, health centers) - 50 dB.

In office premises with noise sources (PC keyboard, teletypes, etc.) - 60 dB.

At workplaces of industrial premises and on the territory of industrial enterprises - 85 dB.

In residential areas in an urban area, 2 m from residential buildings and the boundaries of recreation areas - 40 dB.

Indicative data can be used for a preliminary noise determination (without instrument). For example, the noise level of turbochargers is set at 118 dB, centrifugal fans - 114 dB, a motorcycle without a silencer - 105 dB, when riveting large tanks - 125-135 dB, etc.

Production noise

How are the harmful effects of occupational noise manifested?

Loud noise affects hearing, the nervous system, causing physiological and mental disorders in activity human body: decreased attention, difficulty in responding to workers sound signals. As a result, efficiency decreases and the possibility of industrial injuries increases.

How is it customary to characterize the level of noise intensity or sound power?

Sound is the vibration of an elastic medium: solid, liquid or gaseous. Therefore, it is characterized by an oscillation frequency, the unit of which is hertz - one oscillation per second. Sound is perceived by a person if the oscillation frequency is in the range from 16-20 to 16000-20000 Hz.

To characterize the level of noise intensity or sound strength, a special unit is adopted - the decibel (dB), which evaluates the relative changes in sound strength, and not its absolute values.

Is there a relationship between the frequency of sound and its effect on the human body?

There is such a dependency. It has been established that the higher the frequency of sound, noise, the more negatively it affects the human body.

What noise level is considered harmless for workers?

Sanitary noise level standards are set depending on its frequency: the higher the frequency, the lower the norm.

According to the frequency composition, noise is divided into three classes:

I - low-frequency noise (noise of low-speed non-impact units, noise penetrating through soundproof barriers - walls, ceilings, casings). The highest levels of these noises in the spectrum are located below the frequency of 350 Hz.

For such noises allowable level- 90-100 dB.

II - mid-frequency noise (noises of most machines, machine tools, non-impact units). The highest levels of these noises in the spectrum are located below the frequency of 800 Hz. For such noise, the permissible level is 85-90 dB.

III - high frequency noise(ringing, hissing and whistling noises characteristic of gas flows, units operating at high speeds). The highest levels of these noises in the spectrum are located above the frequency of 800 Hz. For such noise, the permissible level is 75-85 dB.

Maximum permissible noise level depending on the sound frequency at the workplaces of drivers and service personnel tractors, self-propelled, trailed and other machines, as well as stationary units, the following:

How to determine the noise level in the workplace?

The noise level in the workplace is determined by sound level meters. In practice, the most common noise and vibration meter IShV-1.

What are the ways to deal with industrial noise?

The fight against industrial noise is carried out in several directions.

1. Noise reduction at the source of its occurrence due to constructive, technological and operational measures.

2. Weakening of noise propagating from its sources through the air and hull structures, through the use of sound absorption and sound insulation directly on machines, units and at their installation sites.

3. Replacement of equipment less noisy, the introduction of remote control; rational placement and planning of equipment operation time.

4. Personal prevention of employees. This includes measures to reduce the harmful effects of noise and vibration on the body of workers at the expense of personal protective equipment; organization rational regime labor; conducting periodic inspections, etc.

The above activities can be carried out separately, in various combinations or in a complex.