Measurement of the noise level at the workplaces of enterprises and institutions is carried out in accordance with GOST 20445-75.
According to the rules, in order to assess the noise levels at workplaces in the premises of industrial enterprises, measurements must be made at least at three points. The noise pickup microphone should be placed 1.5 m above the floor or work platform (or at the height of the head of a seated person).
The measurement results should characterize the noise impact during the working shift. Therefore, noise measurement is carried out when at least 2/3 of the installed process equipment is operating at least three times per shift.
When measuring, the total sound pressure levels, the spectral composition of noise in octave bands, as well as the equivalent sound levels in decibels A (dBA), which are normalized by the Sanitary Standards - CH 2.2.4 / 2.1.8.562-96, can be determined
The maximum permissible noise level is the level of a factor that, during daily (except weekends) work, but more than 40 hours a week during the entire working experience, should not cause diseases or deviations in the state of health detected by modern methods research. Compliance with the remote control does not exclude health disorders in overly sensitive individuals. A sound level meter is used to measure noise levels.
Device and application of sound level meters
Sound level meters are devices designed to measure noise in a free field. For example, a carpeted office with curtains and partitions is a free field. And the basement with concrete walls, without furniture, with a high level of sound reflection is already a reverberant sound field.The sound level meter device must comply with special state standards that regulate the requirements for such devices. In particular, the frequency range captured by the device is regulated, but the device itself may differ.
The device of the sound level meter contains certain solutions that allow you to create an unambiguous relationship between the readings of the device and the sound pressure that are perceived by the hearing aid. The noise level is proportional to the electrical signal.
The sound level meter is used to measure the noise level in the street and indoors. Physically, the sound level meter consists of a microphone, an amplifier, corrective filters, several detectors and indicators, as well as a voltmeter and a device for outputting measurement results (for example, a display).
Model range of TESTO sound level meters
Sound level meter testo 815
The testo 815 sound level meter has been factory calibrated. To control the error of the instrument, recalibration is recommended, especially when the instrument has not been used for a long time. The testo 815 sound level meter must also be checked with the calibrator before and after measurements under harsh conditions, such as high altitudes, high humidity levels, and where special requirements are placed on measurement uncertainty.
The Testo 815 sound level meter has the following advantages:
- Accuracy class 2 according to IEC 60651
- Easy adjustment (adjustment screwdriver included)
- Frequency weighting according to curves A and C
- Memory of maximum and minimum values
- Tripod mount (1/4")
- High level of accuracy (class 2)
- Switchable time weighing Fast/slow
- Frequency weighting
- present value
- Time weighing
- Switchable range
- Good value for money instrument
Sound level meter Testo 816.
Noise level meter, accuracy class 2, with microphone, wind protection cap, battery, headphone socket, in practical case
Compared to the testo 815, the testo 816 is equipped with a number of additional noise measurement features that make it ideal for experts who measure noise levels in the workplace, in production, and background noise.
The Testo 816 sound level meter has the following advantages:
- Accuracy class 2 to IEC 60651
- High level of accuracy
- Automatic switch of noise level measurement ranges
- Backlit display
- Work from the power supply
- Display with graphic pointer
- AC signal output for connection to a recorder or amplifier
- 10 mV/dB DC output for connection to recorders and recorders
- testo 816:
- Time estimate
- Setting the measuring range
- Frequency estimation
- present value
- Automatic range switching
- Display backlight
- Connecting to the mains power supply
- Histogram display
- AC output for connection to recorders and amplifiers,
- DC output with 10 mV/dB for connection to recorders and data loggers
- good price-quality ratio and price-functionality
Portable sound level meter Megeon 92130
Portable sound level meter Megeon 92130 is a unique combination of technical characteristics, practicality and ease of use. All necessary controls are located on the front panel of the device. Listed functional features allow you to use Megeon 92130 and measure noise parameters in almost any conditions. The device has an integrated light sensor, the signal of which turns on the backlight of the display if you work in a poorly lit room. This sound level meter is used by engineers in many industries, safety and health professionals, as well as for assessing the noise environment in offices, transport and the environment. It should be noted that the Megeon 92130 sound level meter operates in a wide range from 30 to 130 dB and complies with generally accepted international standards ANSI S1.4 (type 2) and IEC651 (type 2).Sound level meter Megeon 92131
The new sound level meter Megeon 92131 is a high-precision measuring device used for accurate and fast determination of sound parameters indoors and outdoors. This instrument is very popular among technicians and engineers as it offers excellent specifications and is light in weight and compact in size. Sound level meter Megaon 92131 makes it possible to measure noise in a wide range: from 40 to 130 dB.It should be noted that the measurement error does not exceed 2dB. The device has a built-in connector for connecting a frequency analyzer, thanks to which the user can observe the studied noise in the form of a graph. Megaon 92131 is equipped with a simple user interface. The display simultaneously shows the level of the studied sound in the form of a histogram and digital form. All controls are located on the front panel of the device.
The device can be additionally equipped with a USB cable, which makes it possible to transfer the results to a PC for further analysis. Simple operation, light weight, and compact dimensions make this measuring tool an indispensable assistant, both at home and at industrial facilities.
Model range of sound level meters MEGEON
Buy sound level meters profitably
You can buy reliable sound level meters at a bargain price in our company. A large selection of sound level meters from the world's leading manufacturers is always presented in our company. Qualified specialists of our company will help you choose a sound level meter that best suits your task for measuring the noise level in your conditions.We will deliver sound level meters within one or two days to the cities: Taganrog, Novocherkassk, Azov, Shakhty, Volgodonsk, Salsk, Krasnodar, Tikhoretsk, Timashevsk, Sochi, Novorossiysk, Anapa, Tuapse, Gelendzhik, Yeysk, Maykop, Armavir, Volgograd, Elista, Astrakhan, Stavropol, Nevinnomyssk, Mineralnye Vody, Kislovodsk, Pyatigorsk, Zheleznovodsk, Cherkessk, Nalchik, Vladikavkaz, Grozny, Makhachkala.
Noise is one of the most pronounced environmental pollutants at present. Negative noise exposure can result in various diseases, general malaise, decreased performance, increased risk of injury and accidents, impaired auditory control of the operation of technological equipment, and reduced labor productivity. Today, it is important to control the noise level in various branches of human activity, for which a variety of methods and devices are used.
Sound level meter device
Noise meter, as a rule, consists of a sensor (microphone), an amplifier, frequency filters and frequency analyzers, and a recording device, which can be a recorder, a tape recorder, and with the development modern technologies and various portable devices such as Cell phones, smartphones or computers. In addition, the instrument is equipped with an indicator or a screen that shows the level of the measured value.
Portable sound level meters
Light and compact devices for measuring the noise level have recently appeared on the market of modern measuring equipment, which do not require special skills and abilities for operation, and also combine all of the above elements in one housing. These portable devices - sound level meters - are easy to use and allow you to determine the level of noise pollution with high accuracy both at workplaces and in production and in the environment.
Advantages of modern sound level meters
Today's portable sound level meters are designed for comfortable daily use, have a wide measurement range, are equipped with a liquid crystal display for information display, a backlight for working in low light conditions, and a variety of outputs for connecting additional accessories such as amplifiers or recorders. In addition, some models of sound level meters are equipped with an AC output for supplying the measured noise signal to analog recorders or recorders.
These devices can operate both from batteries, and the operating time reaches several days, and from USB ports and AC adapters. The built-in memory allows you to store the measurement results, and later, export them for reporting. Numerous built-in filters allow you to minimize extraneous influences and achieve the highest measurement accuracy. The presence of a special socket allows you to install the device on a tripod for long-term measurements.
Choose and buy a sound level meter in Moscow you can in the store or on the RUSGEOKOM website. We also deliver to other regions.
Noise measurements are made to control the compliance of the actual noise levels at the workplace with the permissible ones according to the current standards according to the methods according to GOST 12.1.050-86, GOST 12.1.012-90 and MU No. 1844-78.
Noise measurements should be made when at least 2/3 of the units of technological equipment installed in this room are in operation in the most frequently implemented (typical) mode of its operation.
During the measurements, ventilation, air conditioning equipment and other devices commonly used in the room that are a source of noise should be turned on.
Sound levels are measured by sound level meters of the 1st or 2nd accuracy class. The enterprise uses sound level meters of the Oktava-101A type.
Octave sound pressure levels are measured by sound level meters with octave electric filters connected to them.
Equivalent sound levels should be measured with integrating sound level meters and noise integrators.
The instrumentation is calibrated before and after the noise measurement is carried out in accordance with the instructions for use of the instruments.
The microphone should be placed at a height of 1.5 m above the floor or work platform (if the work is performed while standing) or at ear height of the person exposed to noise (if the work is performed seated). The microphone must be oriented in the direction of the maximum noise level and at least 0.5 m away from the operator making the measurements.
To assess noise at permanent workplaces, measurements should be taken at points corresponding to the established permanent positions. To assess noise at non-permanent workplaces, measurements should be carried out in the working area at the point of the most frequent stay of the worker.
When measuring octave levels of sound pressure, the frequency response switch of the device is set to the "filter" position. Octave sound pressure levels are measured in bands with geometric mean frequencies of 63-8000 Hz.
When measuring sound levels and equivalent sound levels, dBA, set the instrument's frequency response switch to position "A".
When measuring sound levels and octave sound pressure levels of constant noise, the time response switch of the instrument is set to the "slow" position. The values of the levels are taken according to the average indicators when the instrument pointer fluctuates. The values of sound levels and octave levels of sound pressure are read from the instrument scale with an accuracy of 1 dBA, dB.
Measurements of sound levels and octave levels of sound pressure of constant noise should be carried out at each point at least three times.
When measuring equivalent sound levels of time-varying noise to determine the equivalent (in terms of energy) sound level, the time response switch of the instrument is set to the "slow" position. The values of the sound levels are taken according to the indications of the arrow of the device at the time of counting.
When measuring the maximum sound levels of time-varying noise, the time response switch of the instrument is set to the "slow" position. Sound levels are taken at the moment of maximum reading of the instrument.
When carrying out measurements of the maximum sound levels of impulse noise, the switch of the time characteristic of the device is set to the "impulse" position. Level values are taken according to the maximum reading of the device.
The intervals for reading the sound levels of time-varying noise during measurements of the equivalent level lasting 30 minutes are 5-6 s with a total number of readings of 360.
When measuring the equivalent sound levels of intermittent noise, the time response switch of the instrument is set to the "slow" position, the sound levels and the duration of each step are measured. /12/.
Vibration measurements are made to control the compliance of the actual vibration levels at the workplace with the permissible ones according to the current standards according to the methods in accordance with GOST 12.1.012-90, and MU No. 3911-85.
Vibrometers of the Oktava-101V type are used at the enterprise.
The averaging (integration) time of the device when measuring local vibration must be at least 1 s, and the total vibration - at least 10 s.
Measurements are carried out continuously or at regular intervals (discretely).
For discrete measurements of spectra and frequency-corrected values, the interval between readings must be at least 1 s for local vibration; for general vibration - at least 10 s. The countdown is carried out at the end of the selected interval.
Discrete measurements begin with an initial number of observations of at least 3. The required number of observations to ensure the required accuracy of the results is determined based on the results of processing the measurement results.
With continuous measurement of spectra and frequency-corrected values, the measurement duration should be: for local vibration - at least 3 s; for general vibration - at least 30 s.
When continuously measuring the vibration dose or an equivalent adjusted value of the controlled parameter, the duration of observation should be: for local vibration - at least 5 minutes; for general vibration - at least 15 min. /eleven/.
A sound level meter is an electronic device designed to measure sound levels in decibels. This equipment is widely used in everyday life and has a high degree of accuracy. It has a relatively low cost and does not require complex settings. To use the device, simply turn it on without the need for complex manipulations and studying the instructions in several pages.
Where is a sound level meter used?
Sound meters are primarily used to monitor the effectiveness of sound insulation that is installed in a room. They are used by builders to determine the level of sound insulation of objects. Based on them, you can check how much the building material used corresponds to the parameters declared by the manufacturer.
There are noise standards that are acceptable in residential areas during the day and at night. In case of violation of these norms, administrative liability is provided in the form of a fine or confiscation of sound equipment and tools that make noise. To bring the culprit to justice, you need to document the level of sound that he makes. A sound level meter is used specifically for this purpose, which allows you to obtain accurate data in decibels. This device is available to law enforcement officers who travel to respond to complaints of violations of living standards by noisy neighbors. With this equipment, you can determine whether they are subject to administrative liability for violating the rules of silence.
Sound level meters are also used to control working conditions in industries, since the noise level of various equipment is limited by labor laws. Exceeding the permissible sound carries a danger to human health in the form of partial hearing loss. In this regard, the control of this indicator is very important, and it is impossible to do without the use of a sound level meter.
The principle of operation of the device and its device
The Sumerians have a relatively simple design, if you equate them with high-tech electrical devices. At the heart of the design is a conventional omnidirectional microphone, the membrane of which vibrates with sound waves. The signal taken from it is passed through several filters and fed to an indicator device, which is arranged as. The level of generated noise corresponds to the level of voltage electric current in the device. In this regard, the indicator of the electrical signal is fully consistent with how loud the output sound is. A mechanical scale or an electronic dial displays volume indicators in decibels.
If we consider the device of the sound level meter in more detail, then we can distinguish its following components: omnidirectional microphone, amplifier, filters, detector, integrator, indicator.
The presence of filters allows you to cut off from measurements the readings of sound waves that are not perceived by human hearing. This makes it possible to conduct an objective assessment, focusing on those indicators that really affect others. Sounds that the ear does not perceive are filtered out.
Noise standards
To use a sound level meter and draw the right conclusions about the data obtained with it, you need to understand what kind of noise is dangerous. If a person encounters noise at a level of 70-90 dB for a long period, he develops a disease of the central nervous system. He becomes irritable, suffers from insomnia and impaired reflexes. Such noise is observed in many industries, so employees of such enterprises use protective headphones
Increasing the sound level up to 100 dB leads to partial hearing loss. This deviation can be both short-term and permanent. If you increase the noise to 200 dB, there are serious damage to the central ear, up to cerebral hemorrhages. This level in some cases is fatal, at best it leads to concussion with hearing loss for life.
The optimal noise level in the premises is up to 40-50 dB during the daytime. This is a safe sound level that does not pose a danger to the hearing aid. At night, this rate is lower, and is 30-40 dB. It should be borne in mind that in different countries and individual cities, the upper bar of the permitted volume may differ.
How to use the device correctly
To obtain accurate data, it is important to use the sound level meter correctly. The device does not require special treatment or lengthy training before use. Simply bring it closer to the source of noise and turn on the power. After that, his microphone will start sending data to the reading element. Depending on the model of the sound level meter, measurements can be taken for several seconds or more. After that, the device stops recording the indicators and displays the level of the strongest sound wave that was read during the measurement.
When working with a sound level meter, make sure that the microphone is not covered. To check that the device works, it can be tested by taking measurements in a quiet room. In domestic conditions, it is almost impossible to create conditions in which there are no sound waves. In this regard, it is impossible to achieve that the sound level meter shows the volume level at the minimum limit of its sensitivity. If the room is really quiet, then the noise level emitted by the device will be close to the minimum mark. A damaged sound level meter will record too high readings, so you can determine the unsuitability of its filters or other elements.
Mobile Apps for Noise Measurement
For modern smartphones, applications have been written that, after installation, allow you to measure the noise level using the technical capabilities of the phone. They are issued under the operating Android systems and iOS. It is worth noting that such applications in some senses can replace household sound level meters, but it should be understood that the accuracy of the data obtained remains in doubt. It all depends on the quality of the smartphone. If we consider how accurately such applications work on Apple equipment, then we can certainly judge sufficient accuracy. As for the cheaper range of smartphones, their sound level accuracy is questionable.
Applications can be used if necessary to measure approximate data on the volume level within the colloquial norm, that is, up to 60 dB. The hardware capabilities of smartphones and tablets are limited because they are not designed for loud sounds. The task of their microphone is only in the perception of a person's voice, which usually sounds in the range up to 40 dB. Waves above this indicator are perceived by applications with an error or ignored, so smartphones cannot serve as a device for taking volume indicators.
Classes of sound level meters
Sumerians are divided into classes depending on the accuracy of the research issued. Class 0 covers the most accurate laboratory instruments that serve as a reference for the control of other equipment. Such devices are the most expensive and give a very small error due to the fact that they use expensive materials, complex filters and other elements that affect accuracy.
The next in terms of accuracy are class 1 instruments, which are used for sanitary and hygienic research. With their help, working conditions are assessed. This equipment works with near laboratory accuracy, so it can be used as a reference to control the performance and measurement accuracy of lower class instruments.
Devices of the 2nd class are used to take indicators during the technical inspection of vehicles, to assess the volume of operating equipment, when there is no question of sanitary working conditions. Appliances of class 3 are household. They are most often found on sale and allow you to get approximate loudness levels, which may differ from the data taken from the reference equipment by 1-4 dB.
It is worth noting that the class of equipment also affects the range of measurements. The sound level meter with class 0 and 1 is capable of capturing audio signals in the frequency range from 20 Hz to 18 kHz. Class 2 operates in the range from 20 Hz to 8 kHz. Class 3 takes sound waves ranging from 30 Hz to 8 kHz. Also, devices differ in decibels that they can record. Household appliances operate with a volume range of 30 to 130 dB.
Differences between devices
When choosing a sound level meter, you should pay attention to its class, the level of error, as well as the sensitivity range in decibels. As for the power source, this is a matter of taste. In some cases, it is convenient to use network devices that connect to a power outlet, while in others it is better to buy devices on or. Also, the devices differ in screen size. Expensive models can, in addition to numbers, display a graph of the strength of sound waves.
Modern devices are equipped with an attached microphone and display measurement data on a digital screen. They are much more convenient to use than the old devices equipped with an arrow. The earlier equipment had a drawback, namely the convenience of capturing the highest audio signal received. As a result of the absence of an automatic stop, the resulting indicator depends solely on the professionalism of the operator who is engaged in the removal of indicators. If you blink and do not notice in time how far the arrow has deviated, then you can miss the maximum noise and record a smaller indicator. Such equipment is now found on sale only from the hands, since manufacturers have abandoned this design. When choosing a device, you should avoid dial models without automatic fixation of the upper measurement indicator.
The main instruments for measuring noise are sound level meters. In the sound level meter, the mechanical sound vibrations perceived by the microphone are converted into electrical ones, which are amplified and then, after passing through corrective filters and a rectifier, are recorded by a pointer instrument. The range of measured total noise levels is usually 30-130 dB with frequency boundaries of 20-16,000 Hz.
To determine the noise spectrum and its levels in octave bands, the sound level meter is connected to filters and analyzers.
For measurements, domestic sound level meters Sh-71, PI-14, ISHV-1 are used complete with octave filters. Acoustic equipment from RFT (Germany) and Brüel & Kjær (Denmark) has become widespread in our country.
Noise measuring means consist of a sound level meter (in accordance with GOST 17187-71) and octave electrical filters that pass a certain frequency band of electrical oscillations.
The action of the sound level meter is based on the conversion of sound vibrations into electrical vibrations by the microphone, which, after amplification and passing through octave filters, are transmitted to the measuring device - a dial indicator.
In practice, measuring systems of the type ISHV-1 (with built-in octave filters) of the Vibropribor plant (Taganrog) or ShVK-1 (with separate filters of the FE-2 type of the same plant) and type 00017 (with built-in filters) of the RFT company are used GDR.
To measure only the sound level without frequency analysis, sound level meters of the types “Shum-1, ShM-1, Sh-63 or 00014 from RFT (GDR) are used.
For ultrasonic noise (frequency more than 11.2 kHz), the normalized parameters are established by GOST 12.1.001-75 “SSBT. Ultrasound. General safety requirements”.
Vibration is measured by instruments based on mechanical and electrical methods. Electrical measuring instruments provide higher measurement accuracy in a wide range of vibration frequencies of high and low intensity. They allow you to record vibrograms at a considerable distance from the object of vibration, which ensures the safety and convenience of carrying out measurements.
Vibration measurement is carried out in accordance with GOST 12.4.012-75 “SSBT. Means of measurement and control of vibrations at workplaces. Technical requirements". These requirements are met by a sound level meter of the ShVK-1 type, equipped with a vibration sensor.
For stationary equipment, vibration measurement points are selected at workplaces. The vibration sensor is attached to the work platform or the seat of the worker. Local vibrations transmitted to the hands when working with manual machines are measured by vibration velocity in the geometric mean octave bands from 8 to 1000 Hz. The vibration sensor is mounted at the points of contact of the hands with vibrating surfaces. Manual machines must comply
requirements of GOST 17770-72 “Hand-held machines. Permissible vibration levels.
Conclusion
The factors discussed in the lecture - noise, vibration, infrasound and ultrasound - are harmful, negatively affecting performance, causing occupational diseases and other adverse effects.
Noise is a wave-like mechanical oscillatory motion of particles of an elastic (gas, liquid or solid) medium. Its effect on the human body is mainly associated with the use of new, high-performance equipment, with the mechanization and automation of labor processes: the transition to high speeds during the operation of various machines and units. Prolonged exposure to noise and vibration on the human body leads to the development of chronic overwork, contributes to the development of general and occupational diseases, hearing loss, disorders of the central nervous system and the cardiovascular system of a person.
Infrasound is a mechanical vibration propagating in an elastic medium with frequencies less than 20 Hz, which are below the threshold of human hearing. Unlike noise, infrasound propagates over long distances due to low absorption. When a person is exposed to infrasound, changes in the rhythms of breathing and heartbeats, indigestion and the central nervous system, and headaches occur.
In the prevention of the harmful effects of factors, preventive and current sanitary supervision and medical prophylaxis are of great importance.
The main measures to combat noise: elimination of the cause of noise or its significant weakening at the source itself in the development of technological processes and equipment design; isolation of the noise source from the environment by means of sound - and vibration protection, sound - and vibration absorption; reduction in the density of sound energy of rooms reflected from walls and ceilings; rational layout of premises; use of personal protective equipment against noise; rationalization of the working regime in noisy conditions; medical preventive measures. The most effective way to reduce noise is to replace noisy technological operations with low-noise or completely silent ones. Personal protective equipment (anti-noise) includes liners, headphones and helmets.
Means of protection for reducing the level of infrasound: increasing the shaft speed to 20 or more revolutions per second; increasing the rigidity of large oscillating structures; eliminating low-frequency vibrations; introduction of constructive changes in the structure of sources.
Noise levels are measured at workplaces or in working areas to compare with the requirements of sanitary standards, as well as to assess the noise characteristics of machinery and equipment in order to develop measures to combat noise. Guidance on the measurement and hygienic assessment of noise is given in GOST 12.1.003-76 and GOST 20445-75 “Buildings and structures of industrial enterprises. Method for measuring noise at workplaces”, as well as in the Guidelines for the measurement and hygienic assessment of industrial noise 1844-78 of the USSR Ministry of Health.
For this purpose, the frequency spectrum of the measured sound pressure level in octave frequency bands is used, which is compared with the limit spectrum normalized in GOST 12.1.003-76 (Table 6.1 is given with abbreviations).
Table 1. Permissible sound pressure levels and sound levels
Workplaces |
Sound pressure levels, dB, in octave bands with geometric mean frequencies, Hz 63, 125, 250, 500, 1000, 2000 4000, 8000 |
Sound level and equivalent sound level, dBA |
||||||||||||||||
Premises of design bureaus, laboratories for theoretical work | ||||||||||||||||||
Control rooms, work rooms | ||||||||||||||||||
Observation and remote control cabins with voice telephone communication, rooms and precision assembly areas | ||||||||||||||||||
Laboratories for experimental work |
For a tentative assessment of the noise situation at the workplace, it is allowed to use a one-digit parameter (independent of frequency), the so-called sound level in dBA, measured without frequency analysis, according to the A scale of the sound level meter, which approximately corresponds to the frequency response of human hearing, as a characteristic of constant noise.
A characteristic of intermittent noise at workplaces is the equivalent (in terms of energy) sound level in dBA, also determined on the A scale of the sound level meter.
The human hearing aid is more sensitive to high-frequency sounds, so the normalized sound pressure values decrease with increasing frequency.
A characteristic of constant and non-constant (except for fluctuating in time) noise at workplaces are sound pressure levels in octave frequency bands from 63 to 8000 Hz.
A characteristic of noise fluctuating over time at workplaces (for example, during operation of a metal-cutting machine with a variable operating mode) is the equivalent (in terms of energy) sound level in dBA, determined according to GOST 20445-75 and having the same effect on the hearing aid as a constant noise at the same level.
Main literature:
1. Karakeyan V. I., Nikulina N. M. Life safety. Textbook. - M. - "Yurait", - 2014
2. Kholostova E. I., Prokhorova O. G. Life safety. Textbook.-
M. - "Dashkov and K", - 2013
Additional literature:
1. Alekseev V.S. Life safety. Lecture notes / V.S. Alekseev, O.I. Zhidkova, N.V. Tkachenko. - M.: Eksmo, 2008. - 160 p. S.24-26.
2. Devyasilov V.A. Occupational safety: textbook / V.A.Devisilov. - M.: FORUM, 2009. - 496 p. pp.145-168.
3. Mikhnyuk T.F. Occupational safety: study guide for students / T.F. Mikhnyuk. - Minsk: Information Center of the Ministry of Finance, 2010. - 320 p. pp.111-133.