On the scale of instruments designed to measure pressure in mandatory a red line must be drawn. What does it mean? For what purpose is it installed?
On the territory of our country there are many regulatory documents regulating the rules of operation of pipelines, containers, etc. And, almost every document states that a red stripe must be marked on the pressure gauge scale. Its purpose is to indicate the limit values of the measured parameter. Instead of drawing a line on the scale, it is permissible to use other marking methods, for example, a red metal flag. This is necessary so that you can observe the controlled parameter from afar.
In accordance with safety regulations in the oil and gas industry, it is expressly stated that pressure gauges located at a height of more than two meters must be marked with such a mark.
By its design, a technical pressure gauge is classified as a tubular-spring mechanism. Structurally, it consists of:
- housings;
- riser;
- hollow curved tube;
- arrow(s);
- sector with applied teeth;
- gears;
- springs.
The key part is the tube. Its lower end is connected to the hollow part of the riser. The upper end of the tube is sealed and can move, while it transmits movement to a sector mounted on the riser, and at the end of this mechanism, a gear is installed with an arrow attached to it. After connecting the pressure gauge to the container or pipeline on which the pressure will be measured. The pressure, which is concentrated inside the pressure gauge, tries to straighten the tube through the described mechanism. The movement of the tube, as a result, leads to the movement of the arrow. After all this, the arrow shows the measured pressure.
How to use a technical pressure gauge
Maintenance of a technical pressure gauge consists of several simple operations. In particular, this is checking its performance, reading information from the measuring scale, applying pressure, and performing zeroing. If the liquid in the device is contaminated, it must be changed, otherwise it will lead to distortion of the measurements taken. When carrying out maintenance, it is necessary to check that there is a sufficient amount of working fluid. If its level is insufficient, it must be topped up, guided by the requirements of the operating instructions for the measuring device.
All devices for measuring pressure must be leveled according to the level of measurement. Otherwise, the readings will vary.
Most inclined instruments have a built-in device for leveling the pressure gauge. The device can be rotated until the bubble in the level takes correct position at zero level.
Measuring pressure range
In practical activities they share the following types pressure: absolute, barometric, gauge, vacuum.
Absolute is a measure of pressure measured relative to a complete vacuum. This indicator cannot be below zero.
Barometric is atmospheric pressure. Its level is influenced by the height above the zero mark (sea level). At this height it is generally accepted that the pressure is 760 mm r.s. for pressure gauges this value is zero.
Gauge pressure is a measurement between absolute and brometric pressure. This is especially true when absolute pressure is relative to barometric pressure.
Vacuum is a value that shows the difference between absolute and barometric pressure, provided that barometric pressure is exceeded.
That is, vacuum pressure cannot exceed barometric pressure. In other words, vacuum measuring instruments measure the vacuum of the vacuum.
Each vessel and independent cavities with different pressures must be equipped with pressure gauges direct action. The pressure gauge is installed on the vessel fitting or pipeline between the vessel and the shut-off valve.
Pressure gauges must have an accuracy class of at least: 2.5 - at a vessel operating pressure of up to 2.5 MPa (25 kgf/cm2), 1.5 - at a vessel operating pressure above 2.5 MPa (25 kgf/cm2).
The pressure gauge must be selected with a scale such that the limit for measuring working pressure is in the second third of the scale.
The owner of the vessel must mark the pressure gauge scale with a red line indicating the operating pressure in the vessel. Instead of the red line, it is allowed to attach a metal plate painted red to the pressure gauge body and tightly adjacent to the glass of the pressure gauge.
The pressure gauge must be installed so that its readings are clearly visible to operating personnel.
The nominal diameter of the body of pressure gauges installed at a height of up to 2 m from the level of the observation platform must be at least 100 mm, at a height of 2 to 3 m - at least 160 mm.
Installation of pressure gauges at a height of more than 3 m from the site level is not permitted.
A three-way valve or a device replacing it must be installed between the pressure gauge and the vessel, allowing periodic checking of the pressure gauge using a control valve.
In necessary cases, the pressure gauge, depending on the operating conditions and the properties of the medium in the vessel, must be equipped with either a siphon tube, or an oil buffer, or other devices that protect it from direct exposure to the medium and temperature and ensure its reliable operation.
On vessels operating under pressure above 2.5 MPa (25 kgf/cm2) or at ambient temperatures above 250°C, as well as with explosive atmospheres or hazardous substances of the 1st and 2nd hazard classes according to GOST 12.1.007-76 Instead of a three-way valve, it is possible to install a separate fitting with a shut-off valve for connecting a second pressure gauge.
On stationary vessels, if it is possible to check the pressure gauge in established by the Rules timing by removing it from the vessel, installation of a three-way valve or a replacement device is optional.
Pressure gauges and pipelines connecting them to the vessel must be protected from freezing.
The pressure gauge is not allowed for use in cases where:
· there is no seal or stamp indicating verification;
· the verification period has expired;
· when it is turned off, the arrow does not return to zero reading scale by an amount exceeding half the permissible error for a given device;
· the glass is broken or there is damage that may affect the accuracy of its readings.
Checking of pressure gauges with their sealing or branding must be carried out at least once every 12 months. In addition, at least once every 6 months, the owner of the vessel must carry out an additional check of the working pressure gauges with a control pressure gauge and record the results in the control check log. In the absence of a control pressure gauge, it is allowed to carry out an additional check with a proven working pressure gauge that has the same scale and accuracy class as the pressure gauge being tested.
The term “pressure gauge” used in the text is general and, in addition to pressure gauges itself, also implies vacuum gauges and pressure-vacuum gauges. IN this material Digital devices are not considered.
Pressure gauges are one of the most common devices in industry and housing and communal services. For more than a hundred years they have been reliably serving people. The needs of production initiated the development of pressure gauges for various purposes, differing in size, design, connecting thread, ranges and units of measurement, accuracy class. Incorrect choice devices leads to their premature failure, insufficient measurement accuracy or overpayment for unnecessary functionality.
Pressure gauges can be classified according to the following criteria.
- By area of application.
1.1. Standard technical pressure gauges are designed for measuring excess and vacuum pressure of non-aggressive, non-crystallizing liquids, steam and gas.
1.2. Technical special - pressure gauges for working with specific media or under specific conditions. The following pressure gauges are special:
Oxygen;
Acetylene;
Ammonia;
Corrosion resistant;
Vibration resistant;
Ship;
Railway;
Pressure gauges for Food Industry.
Oxygen pressure gauges are structurally no different from technical pressure gauges, but during the production process they undergo additional cleaning from oils, since when oxygen comes into contact with oils, ignition or an explosion can occur. The designation O 2 is applied to the scale.
Acetylene pressure gauges are manufactured without the use of copper and its alloys. This is due to the fact that the interaction of copper and acetylene produces explosive copper acetylene. Acetylene pressure gauges are marked with the symbols C 2 H 2.
Ammonia and corrosion resistant pressure gauges have mechanisms made of of stainless steel and alloys that are not subject to corrosion when interacting with aggressive environments.
The design of vibration-resistant pressure gauges ensures operability when exposed to vibration in a frequency range approximately 4-5 times higher than the permissible vibration frequency of standard technical pressure gauges.
Some types of vibration-resistant pressure gauges can be filled with damping fluid. Glycerin (operating temperature range from -20 to +60 o C) or PMS-300 liquid (operating temperature range from -40 to +60 o C) is used as a damping liquid.
Pressure gauges for the food industry do not have direct contact with the medium being measured and are separated from it by a membrane separating device. The space above the membrane is filled with a special liquid, which transmits force to the pressure gauge mechanism.
Pressure gauge housings are usually painted in a color corresponding to the application: ammonia - yellow, acetylene - white, for hydrogen - dark green, for flammable gases, for example, propane - red, for oxygen - blue, for non-flammable gases - in black.
2. Electric contact (signaling) pressure gauges.
Electric contact (signaling) pressure gauges include contact groups for connecting external electrical circuits. Used to maintain pressure in technological installations within a given range.
Contact groups of electrical contact (signaling) pressure gauges in accordance with GOST 2405-88 can have one of four designs:
III - two break contacts: left indicator (min) - blue, right (max) - red;
IV - two closing contacts: left indicator (min) - red, right (max) - blue;
V - left normally open contact (min); right closing contact (max) - both indicators are blue;
VI - left normally open contact (min); right contact is normally closed (max) - both indicators are red.
Most Russian factories accept version V as standard. That is, if the application does not indicate the design of the electrical contact pressure gauge, then the customer is almost guaranteed to receive a device with contact groups of this design. In the absence of a passport, you can determine the design of the contact groups by the color of the indicators.
Electroconical (signaling) pressure gauges are divided into general industrial and explosion-proof. The ordering of explosion-proof pressure gauges must be approached very carefully so that the type of explosion protection of the device corresponds to the high-risk facility.
3. Pressure units.
Pressure gauge scales are calibrated in one of the following units: kgf/cm2, bar, kPa, MPa. However, you can often find pressure gauges with a double scale. The first scale is graduated in one of the units listed above, the second in psi - pound-force per square inch. This unit is non-systemic and is used mainly in the USA. In table 1 shows the relationship between these units.
Table 1. Ratio of pressure units
|
Pa |
kPa |
MPa |
kgf/cm 2 |
bar |
|
|
Pa |
10 -3 |
10 -6 |
10,197*10 -6 |
10 -5 |
|
|
kPa |
10 3 |
10 -3 |
10,197*10 -3 |
10 -2 |
|
|
MPa |
10 6 |
10 3 |
10,1972 |
||
|
kgf/cm 2 |
98066,5 |
98,0665 |
0,980665 |
0,980665 |
|
|
bar |
10 5 |
1,0197 |
|||
|
6894,76 |
6,8948 |
6,8948*10 −3 |
70,3069*10 −3 |
68,9476*10 −3 |
Instruments calibrated in kPa are called pressure gauges for measuring low gas pressures. A membrane box is used as a sensing element, while in pressure gauges for high pressures a curved or spiral tube is used.
4. Range of measured pressures.
In physics, there are several types of pressure: absolute, barometric, excess, vacuum. Absolute pressure is pressure measured relative to absolute vacuum. Absolute pressure cannot be negative.
Barometric is atmospheric pressure, which depends on altitude, temperature and humidity. At zero meters above sea level it is taken to be 760 mm Hg. In technical pressure gauges, this value is taken as zero, that is, the value of barometric pressure does not affect the measurement results.
Gauge pressure is the difference between absolute pressure and barometric pressure, provided that the absolute pressure exceeds the barometric pressure.
Vacuum is the difference between absolute pressure and barometric pressure, when absolute pressure is less than barometric pressure. Therefore, vacuum pressure cannot be greater than barometric pressure.
Based on this, it becomes clear that vacuum gauges measure vacuum. Pressure and vacuum gauges cover the area of vacuum and excess pressure. Pressure gauges measure excess pressure. There is another class of instruments called differential pressure gauges. Differential pressure gauges are connected to two points of one system and show the pressure difference of gaseous or liquid substances.
The ranges of measured pressures are standardized and assumed to be equal to a certain range of values, which are given in table. 2.
Table 2. Standard range of values for calibration of scales.
|
Device type |
Ranges of measured pressures, kgf/cm 2 |
|
Vacuum gauges |
1…0 |
|
Pressure and vacuum gauges |
1…0,6; 1,5; 3; 5; 9; 15; 24 |
|
Pressure gauges |
0…0,6; 1; 1,6; 2,5; 4; 6; 10; 16; 25; 40; 60; 100; 160; 250; 400; 600; 1000; 1600 |
|
0…2500; 4000; 6000; 10000
|
5. Accuracy class of pressure gauges
Accuracy class - allowable error device, expressed as a percentage of the maximum scale value of this device. The accuracy class is applied by manufacturers to the scale. The lower this value, the more accurate the device. The same type of pressure gauge may have different class accuracy. For example, the Manotom plant produces standard devices with an accuracy class of 1.5, and can produce similar devices with an accuracy class of 1.0 upon request. In table 3 shows data on accuracy classes in relation to various types pressure gauges.
Table 3. Accuracy class of pressure gauges from Russian manufacturers.
|
Device type |
Accuracy class |
|
Exemplary pressure gauges |
0,15; 0,25; 0,4 |
|
Pressure gauges for precise measurements |
0,4; 0,6; 1,0 |
|
Technical pressure gauges |
1,0; 1,5; 2,5; 4 |
|
Ultra-high pressure gauges |
For imported devices, the accuracy class value may differ slightly from Russian analogues. For example, European technical pressure gauges may have an accuracy class of 1.6.
The smaller the diameter of the device body, the lower its accuracy class.
6. Case diameter
Most often, pressure gauges are manufactured in cases with the following diameters: 40, 50, 60, 63, 100, 150, 160, 250 mm. But you can find devices with other body sizes. For example, vibration-resistant pressure gauges produced by Fiztekh, type DM8008-Vuf (DA8008-Vuf, DV8008-Vuf) are manufactured in cases with a diameter of 110 mm, and a smaller version of this device, DM8008-Vuf (DA8008-Vuf, DV8008-Vuf) Version 1, has diameter 70 mm.
Pressure gauges with a body of 250 mm are often called boiler gauges. They do not have special designs and are used at thermal power facilities and allow the operator to control pressure at several nearby installations from the operator’s workplace.
7. Design of pressure gauges
A fitting is used to connect the pressure gauge to the system. There are radial (bottom) location of the fitting and axial (rear) location. The axial fitting can be centrally located or offset relative to the center. Many types of pressure gauges available design features They are not available with an axial fitting. For example, signaling (electrical contact) pressure gauges are made only with a radial fitting, since an electrical connector is located on the back side.
The size of the thread on the fitting depends on the diameter of the body. Pressure gauges with diameters of 40, 50, 60, 63 mm are manufactured with threads M10x1.0-6g, M12x1.5-8g, G1/8-B, R1/8, G1/4-B, R1/4. On larger pressure gauges, M20x1.5-8g or G1/2-B is used. European standards provide for the use of not only the above types of threads, but also conical ones - 1/8 NPT, 1/4 NPT, 1/2 NPT. In addition, industry uses specific connections. Pressure gauges measuring high and ultra-high pressures can have internal conical or cylindrical threads.
The design of the pressure gauge body depends on the installation method and location. Devices installed openly on highways, as a rule, do not have additional fastenings. When installed in cabinets, control panels, pressure gauges with a front or rear flange are used. The following versions of pressure gauges can be distinguished:
With radial fitting without flange;
With radial fitting with rear flange;
With axial fitting with front flange;
With axial fitting without flange.
Standard pressure gauges usually have a degree of protection IP40. Special pressure gauges, depending on the application, can be manufactured with degrees of protection IP50, IP53, IP54 and IP65.
In some cases, pressure gauges must be sealed in order to prevent the possibility of unauthorized opening of the devices. For this purpose, some manufacturers make an eye on the body and complete it with a screw with a hole in the head, allowing the seal to be installed.
8. Protection against high temperatures and pressure changes
Temperature has a serious influence on the measurement error and service life of pressure gauges. This factor affects internal elements structures in contact with the measured medium, and externally through the ambient temperature.
Most pressure gauges should be operated at an ambient and measured medium temperature of no more than +60 o C, maximum +80 o C. Some manufacturers manufacture instruments designed for temperatures of the measured medium up to +150 o C and even +300 o C. However, measurements at high temperatures can be produced using standard pressure gauges. To do this, the pressure gauge must be connected to the system via a siphon outlet (cooler). A siphon outlet is a specially shaped tube. At the ends of the outlet there is a thread for connecting to the main line and attaching a pressure gauge. The siphon outlet forms a branch in which there is no circulation of the measured medium. As a result, at the point where the pressure gauge is connected, the temperature may differ significantly from the temperature in the main line.
Another factor that affects the longevity of pressure gauges is sudden pressure changes or water hammer. To reduce the influence of these factors, dampers are used. The damper can be made as a separate device installed in front of the pressure gauge or mounted in the internal channel of the device holder.
There is another way to protect the pressure gauge. In cases where there is no need to constantly monitor the pressure in the system, a pressure gauge can be installed through a push-button valve. Thus, the device will be connected to the controlled line only for the time during which the tap button is pressed.
PRESSURE MEASURING DEVICES
Pressure- one of the most important parameters technological processes.
Pressure is the ratio of the force acting on an area to the magnitude of the area.
Where F- force;
S- square.
There are different pressures:
1) barometric (atmospheric) - P atm;
2) absolute - P abs;
3) excess - P hut;
4) vacuum (vacuum) - P wack
1. Barometric pressure is the pressure of the atmosphere surrounding the globe.
2. Absolute pressure is the total pressure under which a liquid, gas or vapor is located.
R abs = R g + R atm
3. Overpressure - this is pressure above atmospheric.
P ex = P abs - P atm
4. If some of the air is pumped out from a closed vessel, the absolute pressure inside the vessel will decrease and become less than atmospheric pressure. This pressure inside the vessel is called vacuum.
Vacuum - this is a lack of pressure to atmospheric pressure.
Pvac = P atm - P abs
Rice. 2.1 Types of pressure
The residual pressure is determined by the formula:
R ost = P atm – P vac,
where P atm = 760 mm Hg.
Pressure units
SI unit of pressure- Pascal (Pa).
Pascal- this is pressure with a force of 1 N per area of 1 m 2 .
Non-system units: kgf/cm 2 ; mm water column; mmHg st; bar, atm.
The relationship between units of measurement:
1 kgf/cm 2 = 98066.5 Pa
1 mm water column = 9.80665 Pa
1 mmHg = 133.322 Pa
1 bar = 10 5 Pa
1 atm = 9.8* 10 4 Pa
Classification of pressure measuring instruments
I. Based on the operating principle:
1) liquid;
2) deformation;
3) deadweight piston;
4) electric.
II. By type of quantity being measured:
1) pressure gauges- instruments for measuring absolute and excess pressure;
2) vacuum gauges- instruments for measuring vacuum;
3) pressure and vacuum gauges- for measuring excess pressure and vacuum;
4) differential pressure gauges- to measure the difference between two pressures;
5) barometers- for measuring atmospheric pressure;
6) pressure gauges(micromanometers) - for measuring small excess pressure;
7) draft gauges- instruments for measuring small vacuums;
8) thrust gauges- instruments for measuring small excess pressures and small vacuums.
Deformation devices
(spring pressure gauges)
In these devices, pressure is determined by the deformation of elastic elements.
Fig.2.3 Elastic elements of spring pressure gauges:
a) single-turn tubular spring (Bourdon tube);
b) multi-turn tubular spring;
c) elastic membrane;
d) membrane box;
d) bellows
Pressure gauges with single-turn tubular spring OBM
OBM-100; OBM-160 - pressure gauges general purpose;
100, 160 - body diameter in mm.
These devices are the most common. Their advantages: simplicity of the device; reliability in operation; compactness; large measuring range; low cost.
Operating principle is based on balancing the measured pressure by the force of elastic deformation of the spring.
Under the influence of pressure, the cross-section of the tube tends to take round shape, as a result of which the tube rotates by an amount proportional to the pressure. When the pressure decreases to atmospheric pressure, the tube returns to its original shape.
Sensing element (SE) The pressure gauge is a single-turn tubular spring, which is a tube bent around the circumference with a cross-section in the shape of an oval. The tubular spring is made of bronze, brass or steel, depending on the purpose of the device and the measurement limits.
One end of the tube is soldered into a holder with a fitting, which is designed to connect the pressure gauge to a pressure source.
The second end of the tube is free and hermetically sealed.
A rod is attached to the free end of the tubular spring. The other end of the rod is connected to the shank of the gear sector. The shank of the gear sector has a slot (slide), along which the end of the rod can be moved when adjusting the device.
The toothed sector is held on an axle and meshes with a small gear called a trib. It is rigidly mounted on the arrow axis.
To eliminate the “backlash” of the pointer caused by the presence of backlash in the connections, the pressure gauge is equipped with an elastic spiral-shaped hair made of phosphor bronze. The inner end of the hair is attached to the arrow axis, and the outer end is attached to the stationary part of the device.
Under the influence of pressure inside the tube, its free end moves and pulls the rod along with it. In this case, the gear sector and the trib, on the axis of which the arrow is mounted, rotate. The end of the arrow shows the measured pressure on the instrument scale.
Rice. 2.4 Spring pressure gauge:
1 – nipple;
2 – holder;
3 - (housing) board;
5 – gear (tribe);
6 – spring;
7- Bourdon tube;
8 - sealed end;
9 - gear sector;
10 – arrow;
Depending on their purpose, pressure gauges have the following markings:
MTP, MVTP - vibration-resistant;
SV - ultra-high pressure;
MTI, VTI - precise measurements (accuracy class 0.6; 1.0);
MO, VO - exemplary (class 0.4);
MT, MOSH, OBM - technical.
Standard scales pressure gauges
0,6; 1,0; 1,6; 2,5; 4,0
60 100 160 250 400
600 1000 1600 kgf/cm 2
How to choose the right technical pressure gauge.
Each vessel or pipeline must be equipped with pressure gauges. The pressure gauge is installed on the vessel fitting or pipeline between the vessel and the shut-off valve. Pressure gauges must have an accuracy class of at least: 2.5 - at a vessel operating pressure of up to 2.5 MPa (25 kgf/cm2), 1.5 - at a vessel operating pressure above 2.5 MPa (25 kgf/cm2). The pressure gauge must be selected with a scale such that the limit for measuring working pressure is in the second third of the scale. The owner of the vessel must mark the pressure gauge scale with a red line indicating the operating pressure in the vessel. Instead of the red line, it is allowed to attach a metal plate painted red to the pressure gauge body and tightly adjacent to the glass of the pressure gauge. The pressure gauge must be installed so that its readings are clearly visible to operating personnel. The diameter of the body of pressure gauges installed at a height of up to 2 meters from the level of the observation platform must be at least 100 mm, at a height of 2 to 3 meters - at least 160 mm. Installation of pressure gauges at a height of more than 3 meters from the site level is not permitted.
The pressure gauge is not allowed for use in cases where:
there is no seal or stamp indicating verification;
the verification period has expired;
when it is turned off, the arrow does not return to the zero scale reading by an amount exceeding half the permissible error for this device;
The glass is broken or there is damage to the case, which may affect the accuracy of its readings.
Checking of pressure gauges with their sealing or branding must be carried out at least once every 12 months. In addition, at least once every 6 months, the site must carry out an additional check of the working pressure gauges with a control pressure gauge and record the results in the control check log.
9. Technological diagram of the hydrogen sulfide stripping column UPVSN (DNS) - description.
The hydrogen sulfide stripping column is designed to remove hydrogen sulfide from oil. The meaning of the process is that gas, purified from hydrogen sulfide through repeated contact with hydrogen sulfide containing oil, releases hydrogen sulfide from the oil. The better the contact between gas and oil, the better the oil purification.
Description technological scheme:
Hydrogen sulfide containing oil, after PTB-10 furnaces No. 1,2,3, is supplied to the upper part of the K-1 column. To ensure good contact of oil with gas, the column cavity is filled with special nozzles of the AVR type (see figure), through which oil flows to the lower part of the column.
To prevent gas from leaking through the bottom of the column, it is necessary to maintain a certain level of liquid in the lower part of the column; it is maintained automatically using an electric valve.
1) maintain an appropriate ratio of gas to oil. If the electric valve is fully open, but there is not enough gas, then the MUSO does not provide required quantity gas, it is necessary to allow it to MUSO and warn the responsible engineers of the workshop.
2) if the level in the column is higher than the maximum and there is a sharp increase in pressure in the column, it means that the column is filled with oil and oil gets onto the heat exchanger. It is necessary to immediately reduce the consumption of oil N-1, N-2, check the electric valve (if it is closed), slightly open the bypass on the electric valve.
10. Level gauge U-1500 – purpose, device, principle of operation.
The U1500 level gauge is designed for automatic remote determination of the liquid level (or phase interface level) in a tank using two independent channels (sensors) and displaying measurement results on a digital display with alternate indication for each channel, as well as issuing measurement results in the form of an analog current signal (only on the first channel) and in the form of a digital signal via a serial channel in the B5-485 standard for use in control, alarm and recording systems.
In addition, it is possible to set and continuously monitor two level values: the upper signaled level (ASL) and the lower signaled level (LSL), upon reaching which sound and light alarms are triggered, as well as the corresponding relays and optocouplers are activated.
During operation, the performance of sensors and communication lines is continuously monitored with appropriate light and sound signaling of failures on each channel.
Measuring range, m 0.2..15
Measurement resolution, cm 1
Communication line length, m, no more than 1000
Cable type coaxial (RK-50, RK-75)
- The procedure for preparing the device for repair.
TO independent work ODU operators are allowed to service pressure vessels:
At least 18 years of age; in fields with high hydrogen sulfide content, persons at least 21 years of age are allowed;
Having a medical certificate confirming their suitability to work in self-contained breathing apparatus;
Those who have undergone training, knowledge testing and have a certificate for the right to service pressure vessels;
Those who have passed introductory training, on-the-job training and knowledge testing on the specifics of the work performed, including electrical safety, with the assignment of qualification group II; - have completed fire safety training and have a fire safety certificate.
Before starting work, it is necessary to check and put in order the overalls, safety shoes and other personal protective equipment (insulating filter gas mask, hose gas mask PSh-1 or PSh-2, safety belt, mittens, ladders, rescue ropes, helmets, dielectric gloves). All protective equipment must be tested and have appropriate documentation of the control performed. Before carrying out work on servicing the vessel (revision of the safety control system, internal inspection of the vessel), a work permit must be issued for carrying out gas-hazardous work. Before carrying out an internal inspection, the device must be stopped, the pressure released to atmospheric pressure, freed from the medium filling it, and plugs installed in flange connections inlet and outlet pipelines. Then steam the device for at least 24 hours, drain the condensate into the sewer, then cool it to a temperature not exceeding 30 degrees Celsius, install a plug on the drain valve. Take an analysis of the air environment for gas contamination in several places inside the device. If gas contamination exceeds the maximum permissible concentration, the apparatus is steamed again, then an analysis of the air is taken. Before starting gas-hazardous work, the person responsible for carrying it out must interview each performer about his well-being. You can enter a gas hazardous area only with the permission of the person responsible for the work and wearing appropriate protective equipment outside the danger zone.