GOST 14202-69 Pipelines of industrial enterprises. Identification painting, warning signs and labels.

This GOST defines the requirements for labeling labelspipelines. Coloring should be standard, warningsigns, the presence of an arrow that indicates the direction of movementsubstances and names of substances.

Colors and dimensions of pipeline marking in accordance with GOST 14202-69

Unmarked pipes can be hazardous to life and property. Accidents, injuries and damage to equipment can be authorized by people who do not know what is in a particular pipe.

Proper pipe identification prevents fatal errors. Accidents that occur due to negligence in enterprises lead to physical and psychological consequences for the personnel and are often very costly for the enterprise.

Proper pipe identification is a guarantee of the best understanding of the building structure and a clear understanding quickly for new workers and temporary staff. At the same time, this simplifies repair work and prevents time-consuming searches for the cause of a breakdown. In the event of an accident, correctly made identification will save such valuable time - and perhaps even help save someone's life.

We suggest you order and buy double-sided arrow stickers for pipelines in Moscow. Arrows markers are made of PVC film on an adhesive basis, operated in conditions from -40 to +80 degrees. The temperature during gluing the marking arrows must be at least +10 degrees. Arrow stickers are resistant to water and humidity; as well as exposure to slightly alkaline and slightly acidic environments.

PRICE

pipeline marking GOST 14202-69

Dimensions of the sticker for marking the pipeline, depending on the diameter of the pipe	sticker price In rubles with VAT 20%
Sticker for marking the pipeline arrow, size 126x26 mm for pipes with a diameter of up to 80 mm.	from 4.50
Sticker for marking the pipeline arrow, size 252x52 mm for pipes with a diameter of 81 to 160 mm.	from 13.90
Sticker for marking the pipeline arrow, size 358x74 mm for pipes with a diameter of 161 to 220 mm.	from 27.00
Sticker for marking the pipeline arrow, size 507x105 mm for pipes with a diameter of 221 to 300 mm.	from 46.80
Sticker for marking the pipeline arrow, size 716x148 mm for pipes with a diameter of more than 300 mm.	from 70.00

The minimum order amount is 5000 rubles.

Marking pipelines arrows, stickers.

All substances that are transported through pipelines are divided into 10 groups. Each group was assigned a color. This did not affect only the groups “Combustible gases” and “Non-combustible gases”, and “Combustible liquids” and “Non-combustible liquids” - all gases are indicated in yellow, and liquids in brown.

• Marking of pipelines "Water"

The Water group is green. Marking pipelines arrows (or stickers) "WATER" have a clarification of what water is transported through the pipes:

cold water, hot water, city water, hot water supply, hot water return, cold water supply, cold water return, heating supply, heating return, distilled water, return water, cold water, water for injection, clean water, technical water, drinking water, contaminated water, condensate, condensate supply, condensate return, saline water, purified water, drainage, make-up water, direct heating, direct boiler circuit, raw water, boiler circuit return, heating return, feed water, make-up water, direct DHW , chemically treated water, warm water, chilled water, sealing water, contaminated condensate, clean condensate, water for mixing, water for decanter, waste water, waste water, coolant supply, coolant return, fire extinguishing water

All these names of "Water" are depicted on a green background in white or black letters and have a white or black edging, respectively, around the perimeter of the marking arrow or a sticker on the pipeline.

• Marking pipelines "Steam"

The red background is used to designate the following group of substances transported through pipelines: "STEAM". Pipeline marking arrows (stickers) of the "PAR" group are:

steam, wet steam, wet saturated steam, steam return, deaf steam, heating steam, saturated steam, hot steam, high pressure steam, low pressure steam, medium pressure steam, clean steam, dry steam, industrial steam, fire extinguishing steam, superheated steam steam, dry saturated steam, steam supply, technical steam, return steam, supply steam, water steam, treated steam, live steam, flash steam.

These names are written in black or white letters on a red background. And the arrows for marking pipelines of the "PAR" group have a white or black border.

• Marking of pipelines "Air"

The marking of pipelines of the "AIR" group has a blue (cyan) color. Arrows marking "AIR" have different names:

air, atmospheric air, vacuum, high pressure air, low pressure air, pressure air, dry air, moist air, exhaust air, exhaust air, dry compressed air, instrumentation air, hot air, ventilation air, compressed air, blast air, polluted air, heated air, outdoor air, exhaust air, cooled air, purified air, supply air, recirculated air, sterile air, exhaust air, cooled air, cold air.

The letters and edging on the marker are contrasting - black or white.

• Pipeline marking "Gas"

The fourth group "GAS" combustible and non-combustible. Arrows for marking pipelines "GAS" of bright yellow color. Write in black on a yellow field:

gas, nitrogen, nitrogen for fire extinguishing, ammonia, argon, argon for fire extinguishing, acetylene, biomethane, bromoethylene, butane, hydrogen, exhaust gases, high pressure gas, low pressure gas, helium, gas-air mixture, dimethylamine, sulfur dioxide, flue gases, inert gas, malodorous gas, isobutane, methane, propane, hydrogen sulfide, liquefied gas, chlorine, ethylene, purified gas, sulfuric acid fumes, carbon dioxide, gas mixture, purge gas, vinyl chloride, oxygen, methane, ozone, nitrogen oxide, natural gas , fuel gas, carbon monoxide, freon, fluorine, hydrogen fluoride, chloromethane, pure gas, ethane, cyclopropane.

• Marking of pipelines "Acid"

The sixth acid group. On an orange background, in black letters:

acid, nitric acid, citric acid, sulfuric acid, hydrochloric acid, acetic acid, waste acid, acidic water.

• Marking of pipelines "Alkalis"

The seventh group of alkali. For the manufacture of markings on pipelines for the transportation of alkali, purple markers are used, with white or black writing of the transported substance:

alkali, ammonia, caustic soda 10%, caustic soda 17%, sodium nitrite.

• Marking pipelines "Liquid"

Liquids, whether flammable or not, are all displayed in brown. And, as a rule, they write in white on the arrows marking pipelines:

liquids, sewerage, centrifuge, oil, crude oil, refined oil, diesel fuel, sugar syrup, fresh yeast, cider base, juice concentrate, initial oil sludge, oil sludge for decanter, prepared oil sludge, oil sludge, substandard oil, flocculant, deacidified sulfate soap, tall oil, sulfate soap, black lye.

• Marking of pipelines "Other substances"

Gray color denotes other substances, including powder, loose, aqueous pulps, gels, etc.

Perhaps you will also find information on .

Arrows, names of the transported substance of own production in rolls

Hazard symbols applied to arrows marking pipelines

Flammable substances	Explosives	Toxic substances	Corrosive Substances	radioactive substances	Oxidizer	Biological hazard	Harmful and allergic substances

Liquids Acids

Alkali gas

Designation of the type of substance on the arrows

marking pipelines with numbers

Numerical designations	Substance being transported Name
1	Water
2	Steam
3	Air
4	combustible gases
5	Non-flammable gases
	nitrogen and gases containing it chlorine and gases containing it carbon dioxide and gases containing it inert gases sulfur dioxide and gases containing it other types of non-flammable gases waste non-combustible gases
6	acids
7	alkalis
8	Flammable liquids
9	Non-flammable liquids
0	Other substances

It is no coincidence that polypropylene pipelines are becoming increasingly popular with home craftsmen and professional installers. Polypropylene pipes have a number of advantages due to which they are gradually replacing products from traditional materials. The choice of plastic pipes today is simply huge and all products differ in their characteristics and purpose. To find out which of them are suitable for a heating system, cold or hot water supply, ventilation, decoding the marking of polypropylene pipes will help.

"Reading" information

• The name of the manufacturer usually comes first.
• Next comes the designation of the type of material from which the product is made: PPH, PPR, PPB.
• On pipe products, the working pressure must be indicated, which is indicated by two letters - PN, - and numbers - 10, 16, 20, 25.
• Several numbers indicate the diameter of the product and the wall thickness in millimeters.

• On domestic modifications, the class of operation in accordance with GOST may be indicated.
• The maximum allowed.

Additionally indicated:

1. Regulatory documents in accordance with which pipe products are manufactured, international regulations.
2. Quality mark.
3. Information about the technology by which the product is made, and the classification according to MRS (Minimum Long-Term Strength).
4. 15 digits containing information about the date of production, batch number, etc. (the last 2 are the year of manufacture).

And now let us dwell in more detail on the most important characteristics of polypropylene pipes indicated in the marking.

Material and scope

Manufacturers from different countries use slightly different designations, but the PP marking will definitely be present, demonstrating that the pipe is made of polypropylene. Additional letters or numbers indicate a specific type of this material that has its own properties.

1. PRN (PP-type 1, PP-1) - the pipe is made of a homopolymer. Due to the characteristics of this type of polypropylene, it is intended only for cold water, as well as for ventilation.
2. РРВ (РР-type 2, РР-2) – the product is made of a block copolymer. It can be used for cold water supply and in low-temperature types of heating systems.
3. PPR (PP-2, PPR, PP-random, PPRC) - the pipe is made from a random copolymer. Products with this marking are most common due to their versatility. Due to the increased heat resistance, they can be used in heating systems of any kind, as well as for supplying hot and cold water to apartments and houses.

Rated pressure

The letters PN are the designation of the permitted working pressure. The next figure indicates the level of internal pressure in bars that the product can withstand during a service life of 50 years at a water temperature of 20 degrees. This indicator directly depends on the wall thickness of the product.

• PN10. This designation has an inexpensive thin-walled pipe, the nominal pressure in which is 10 bar. The temperature maximum that it can withstand is 45 degrees. Such a product is used for pumping cold water and underfloor heating.

• PN16. Higher nominal pressure, higher limiting liquid temperature - 60 degrees Celsius. Such a pipe is significantly deformed under the influence of strong heat, therefore it is not suitable for use in heating systems and for supplying hot liquids. Its purpose is cold water supply.

• PN20. The polypropylene pipe of this brand can withstand a pressure of 20 bar and temperatures up to 75 degrees Celsius. It is quite versatile and is used to supply hot and cold water, but should not be used in a heating system, since it has a high coefficient of deformation under the influence of heat. At a temperature of 60 degrees, a segment of such a pipeline of 5 m is extended by almost 5 cm.

• PN25. This product has a fundamental difference from previous types, since it is either fiberglass. In terms of properties, the reinforced pipe is similar to metal-plastic products, is less susceptible to temperature effects, and can withstand 95 degrees. It is intended for use in systems of heating, and also in GVS.

Below are answers to the most common questions about marking pipelines for industrial and civil facilities.

What color should the pipelines be painted in the central heating station, ITP, boiler room?

According to GOST 14202, the marking of pipelines does not depend on the object, but depends on the substance in the pipeline.

Pipelines with the transported substance WATER are painted green, STEAM - red, AIR - blue, GAS - yellow, ACIDS - orange, ALKALINE - violet, LIQUIDS - brown, OTHER - gray.

How to mark pipelines in the central heating station, ITP, boiler room?

The most common substances in the pipelines of the central heating substation/ITP/boiler rooms are water, steam, and gas.

The pipeline with water should be painted green, with steam - red, with gas - yellow. Identification coloring is allowed to be applied in sections.

It is also necessary to indicate the name and direction of movement of the substance using or. Their color must be the same as that of the identification markings. The locations of the shields are regulated by regulatory documentation.

What color should the hot/cold water/coolant pipes be painted?

All pipelines transporting substances, the main component of which is water, are painted green in accordance with.

How, according to regulatory documentation, to distinguish the color of the supply pipeline from the return pipeline in the central heating station, ITP, boiler room?

If the pipelines are marked in accordance with, then the supply and return pipelines are painted green (if the heat carrier is water).

To identify the supply and return pipelines, use the appropriate designations with the direction of movement and the inscription, for example “HEATING TRANSPORT SUPPLY”

Is it correct to mark the coolant supply / return pipelines with yellow and brown rings on a green background?

The requirement to mark the supply pipeline of the heating network with a yellow ring on a green background, and the return pipeline - with a brown ring on a green background, is borrowed from the now inactive "Typical instructions for the operation, repair and control of stationary pipelines of network water RD 34.39.501, TI 34-70-042- 85" and was valid only for network water pipelines that are on the balance sheet of power plants.

The current regulatory documentation for marking pipelines with coolant refers exclusively to the requirements of GOST 14202.

How to mark gas pipelines correctly?

Pipelines transporting any gases are painted yellow in accordance with.

You must specify the name of the gas and the direction of movement using or.

It is also necessary, depending on the parameters of the gas, to apply warning rings of red or yellow color (table 3), and if the gas has a dangerous property (flammability, toxicity, oxidizing agent), then it is necessary to apply the appropriate hazard sign.

How to mark steam pipelines?

Steam pipelines must be painted red and a red shield with the name and direction of its movement must be applied.

If the pressure in the steam pipeline is more than 1 kgf / cm² and the temperature of St. 120C, a yellow warning ring must be applied over the paint. With an increase in steam parameters, the number of applied rings increases (see Table 3

GOST 14202-69 has the status of a valid document.

What materials should be used when marking pipelines in accordance with GOST 14202-69?

There are also no documents prohibiting marking with self-adhesive tapes and PVC-based markers.

Moreover, the use of self-adhesive materials is more expedient (generally accepted all over the world) - more convenient, faster, more accurate, allows you to more accurately comply with the important requirements of GOST for color, size, font and shape.

Crimping is not just a hydraulic test of the system. This is a whole series of measures aimed at preparing the system for the heating season. This includes the repair of emergency sections, the replacement (repair) of valves, and the verification of pressure gauges, cleaning filters and much more.

In this article I will describe the main points that representatives of regulatory authorities pay attention to. The following is not the ultimate truth, each inspector has his own cockroaches in his head. But the necessary minimum of work must be done in any case.

So let's go...

First, let's figure out what we will crimp. There are several options for connecting the building to the heating network. The first, most common option is when introductory valves are installed near the wall at the entrance from the city. With this option, the boundary of the division of responsibility is the flange of the inlet valve, for everything further (including the inlet valve), the owner of the building is responsible. Accordingly, the heating unit and the heating system of the building are pressed.

The second option is when the heating unit is located inside the building, and an internal heating main runs through the building from the inlet valves to it. With this connection option, you need to specify where the demarcation line passes. The “Heat Supply Agreement”, which is concluded between the owner and the heat supply company, will help us with this. This agreement has an appendix, which indicates where the demarcation line passes.

If the inlet valves are considered to be the demarcation boundary, we press three elements of the system: the internal heating main, the heating unit and the heating system. If the delineation of responsibility passes through the valves at the heating unit, naturally, we only pressure test the elevator (heat) unit and the heating system.

Pressure gauges

Perhaps the first thing the inspector turns his attention to when accepting a pressure test is pressure gauges.

Checking the pressure gauge

The pressure gauges must be checked every year. Verification is a check of the measuring device for the accuracy of the readings. If the pressure gauge readings exceed the allowable error, it must be sent for calibration or replaced. Calibration, in fact, is the adjustment of the pressure gauge, aimed at reducing the error in the accuracy of measurements.

After verification, the stamp of the Metrological Service is applied to the pressure gauge body.

1. Month of the year (1, 2, 3, etc.), quarter (I, II, III, IV).
2. Sign of the State Standard.
3. The last digits of the year (here 2002).
4. Individual sign of the believer.
5. Code of the Metrological Service.

New pressure gauges are subject to verification only after 18 months, that is, one year after commissioning. But when checking, you must provide passports for these devices (they are included).

Pressure gauge connection

The pressure gauge must only be connected to a three-way valve or a ball valve with a pressure relief valve. Ordinary ball valves do not work.

Three-way faucets often leak. Tip: to avoid leakage, rotate the valve stem several times around its axis before installation. Thus, you will evenly lubricate the stem and the inner surface of the valve with grease, which was applied during assembly.

Where should the gauges be?

Regarding the installation site of pressure gauges, there is a whole bunch of standards (DBN V.2.5-39 -, SNiP 2.04.01 - Internal water supply and sewerage of buildings, SNiP 2.04.05 Heating, ventilation and air conditioning, SNiP II-35 Boiler installations). In simple words, I will say this: pressure gauges should be placed before and after any equipment that can affect the change in pressure: on all outgoing and passing pipelines before and after shutoff valves, before and after control equipment, before and after mud collectors (to control its condition) and etc.

Another nuance that the inspector can pay attention to is the pressure gauge rating. In heat points, pressure gauges with a nominal value of up to 1.6 MPa (16 bar) should be installed.

thermometers

The sleeve (pocket) of the thermometer should go 2/3 into the pipeline, so that the immersed part is in the center of the flow.

Shown here is a wrong gauge connection.

To ensure good thermal contact, the thermometer sleeve must be filled with mineral oil (GOST 8.586.5-2005 p.6.3.9.).

Washing of filters and mud collectors

Cleaning filters and mud collectors is a mandatory procedure in the process of preparing heating for the heating season. The process of flushing the sump is quite simple: the flange is untwisted, and all the dirt is cleaned out of the sump. The same goes for the oblique filter.

Elevator

The main requirement for the elevator assembly is the flushing of the cone (nozzle). The diameter of the hole in the cone is 5-7 mm (calculated individually for each building), if the cone clogs, the building will not receive the required amount of heat.

The elevator must be sealed. To flush the nozzle, the seal must be removed, but in order to avoid unnecessary questions, this must first be agreed with the inspector who will take the pressure test from you. After washing, the elevator is sealed again.

Often, inspectors require that a tag hang on the elevator with the diameter of the hole in the cone indicated on it.

Insulation and warning color rings on pipelines

All pipelines in the ITP (CTP) must be painted and insulated. Insulation should not hang in tatters, everything should be neat. Accounting units and elevators are also isolated.

The direction of movement of the coolant should be indicated on the pipeline with markers. To identify the contents of the pipes, warning colored rings are applied to them. For heating, green (main color) and yellow rings are used on the supply, green and brown on the return. The same marking is used for DHW. Drainage and cold water are indicated by green rings.

Shut-off valves

Shut-off valves must perform their main function - to block the flow of coolant. If there are valves on the thermal unit that “do not hold”, they must be replaced. Different parts of the system are pressure tested under different pressures, and if there is a non-working valve in the circuit, it will definitely show itself.

Reinforcement marking

Ideally, everything should look like this: the heating point should have a diagram showing numbered and marked inlet and outlet pipelines, shut-off and control valves, drain and drainage devices. The scheme must correspond to the current state of the system, that is, if changes have been made to the system, they must be displayed on the diagram.

All of the above devices must have tags with symbols corresponding to the symbols in the diagram (1,2 - shutoff valves on the supply and discharge pipelines, t1 and t2 - thermometers, P1 and P2 - pressure gauges, etc.).

In practice, in small heating points, inspectors do not always focus on this. The main thing is to make it clear what goes where, for example: “supply to the left wing”, “return from the right wing”, “supply to ventilation”, etc. But if everything is "feng shui" - this is an additional plus.

Revision of gate valves

Old-style wedge gate valves require additional attention during operation.

Wedge valve device: 1 - wedge, 2 - cover, 3 - handwheel, 4 - seat, 5 - body, 6 - sealing ring, 7 - spindle, 8 - threaded bushing, 9 - bushing, 10 - stand, 11 - stuffing box flange , 12 - gland seal made of thermally expanded graphite.

In such valves, it is mandatory to carry out stuffing of the stuffing box every year. And during the year, in the event of a leak from the stuffing box, it is necessary to tighten the flange. If this is not done, the valve will become unusable.

To replace the gland packing, unscrew the nuts on the cap bolts, lift the flange, remove the old gland packing and fill in a new one. The seal is wound in rings around the spindle and pressed against the flange.

When tightening the flange, you need to be careful: if you overdo it, the cast-iron flange can burst, and its replacement is very problematic, in practice it is easier to change the valve completely.

The valve must show no signs of rust. The body must be painted black, the flywheel red, and the retractable spindle must be lubricated with grease.

Drainage

Heating points are equipped with a drain for gravity water drainage, and if it is impossible to implement, a drainage pit with a pump (SP 124.13330.2012 Heat networks. Updated edition of SNiP 41-02-2003 p. 14.20). The pit is closed with a removable grate. The latest innovation is that the edge of the pit should be painted with yellow and black stripes.

If there is a safety valve in the TP, then it must be equipped with a drainage pipeline so that no one (or nothing) is injured in the event of a drawdown.

Outcome

There were cases when the inspector said in plain text that he would find ten comments on two meters of the heating unit. It doesn't matter that last year there were no such remarks. In the eyes of the regulatory authorities, an ideal system does not exist. But that's a topic for another conversation...

Marking of pipelines, in accordance with current standards, is carried out to identify the substance transported in it. Usually, the recognition of substances is carried out using color analyzers. Special identification rings, stickers with warning inscriptions can also be applied (this applies to hazardous substances).

Modern marking of pipelines, etc. is done only in accordance with GOST. The surface of the pipeline is painted in a certain color, special inscriptions are attached. Heat exchangers, as well as pipelines through which hot water or steam is supplied, are painted with heat-resistant enamel. It is necessary that all inscriptions exactly comply with the rules for the safe operation of steam and hot water. On the main lines, a number must be applied in Roman numerals, as well as an arrow showing the direction of movement of the transported substance. The same trunk number is applied to trunk branches. All inscriptions must be clearly visible, they must not be obscured by valves and gate valves.

According to GOST 14202 69, if the surface of the pipeline is covered with metal sheathing, the coloring of this sheathing is optional, but a symbol of its type and class of the transported substance can be applied to the pipeline. The coloring and inscriptions on these pipelines must strictly comply with the same standard.

All equipment carrying hot liquid or steam must be adequately insulated. This is done to avoid burns. The temperature at the surface of the insulation must not cause damage to the skin when touched.

The pipelines must have arrows showing the movement of the working fluid. All inscriptions must be visible and printed only. Highly visible serial numbers should also be applied to pumping units, valves, gates and other mechanisms. Also, pipes need appropriate markings, which should indicate their purpose. In this case, it can be easily identified.

All state standards are obligatory for observance by all subjects of housing and communal services, heat supply, regardless of their form of ownership. Failure to comply with such rules can lead to accidents, fires and other man-made incidents.

Reliable and simple reducer Ch-80
Worm gearboxes, such as the Ch-80 gearbox, carry out the transfer of forces most confidently and at the same time change the direction of transmission. Their use provides a significant reduction in the speed of rotation of the shafts.

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Gate valves with electric drive - convenience in the operation of the pipeline
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STP OmGUPS–1.13–04

Enterprise Standard

Approved and put into effect by order No.

Date of introduction 01.06.04

1 area of ​​use

This standard establishes rules for the design of thermal circuits.

The requirements of the standard apply to student educational and final qualification papers performed at all departments of the university.

2 Normative references

GOST 2.780-96. ESKD. Conditional graphic designations. Working environment conditioners, hydraulic and pneumatic tanks;

GOST 2.781-96. Eskd. Conditional graphic designations. Hydraulic and pneumatic devices, control devices and instrumentation;

GOST 2.782–96. ESKD. Conditional graphic designations. Pumps and motors hydraulic and pneumatic;

GOST 2.784–96. ESKD. Conditional graphic designations. Elements of pipelines;

GOST 21.205–93. SPDS. Symbols for sanitary systems;

GOST 21.206–93. SPDS. Symbols of pipelines;

GOST 21.403–80. SPDS. Conditional graphic designations in schemes. Energy equipment;

GOST 21.404–85. SPDS. Automation of thermal processes. Conventional designations of devices and automation equipment in diagrams;

GOST 21.604–82. SPDS. Water supply and sewerage. External networks;

GOST 21.605–82. SPDS. Thermal networks. Working drawings;

GOST 21.606-95. SPDS. Rules for the implementation of working documentation for thermal mechanical solutions of boiler rooms;

GOST 21.609–83. SPDS. Gas supply. Internal devices. Working drawings;

STP OmGUPS–1.1–02. Works student educational and final qualifying. Basic provisions;

STP OmGUPS–1.3–02. Works student educational and final qualifying. General rules for the design of drawings;

STP OmGUPS–1.4–02. Works student educational and final qualifying. General rules for the implementation of schemes;

STP OmGUPS–1.11–03. Works student educational and final qualifying. Rules for the design of construction drawings.

3 Terms and definitions

3.1 Thermal scheme - a type of energy scheme, which, using conventional graphic symbols, shows the main and auxiliary equipment of a heat and power facility (boiler house, CHPP, TPP, etc.), combined by pipeline lines for transporting heat carriers in the form of steam or water.

3.2 Depending on the main purpose, the thermal scheme can be structural, principal, connections (assembly).

3.2.1 Structural diagram - a diagram that defines the main functional parts of the product, their purpose and relationships. Structural diagrams are developed when designing products (installations) at stages preceding the development of other types of diagrams, and are used for general familiarization with the product (installation). In the thermotechnical literature, such a scheme is called a principle.

3.2.2 Schematic diagram (complete) - a diagram that determines the complete composition of the elements and the relationships between them and, as a rule, gives a detailed idea of ​​the principles of operation of the product (installation). Schematic diagrams are used to study the principles of operation of products (installations), as well as during their adjustment, control and repair. They serve as the basis for the development of other design documents, such as wiring diagrams (installation) and drawings. In the thermotechnical literature, such schemes are called deployed.

3.2.3 Connection diagram (installation) - a diagram showing the connections of the component parts of the product (installation) and determining the pipelines that make these connections, as well as the places of their connections and input. Connection diagrams (installation) are used in the development of other design documents, primarily drawings that determine the laying and methods of fastening pipelines in a product (installation), as well as for making connections, when monitoring, operating and repairing products (installations). In the thermotechnical literature, such a scheme is called a working scheme, it is usually performed in an orthogonal, and individual complex nodes in an axonometric image.

3.3 In the main inscription, the name of the circuit is indicated in full, for example: Thermal circuit.

3.4 The designation of the scheme should be composed of the letter "P" (energy scheme) and the number 1 (structural), 3 (principal) or 4 (installation).

Marking of pipelines, in accordance with current standards, is carried out to identify the substance transported in it. Usually, the recognition of substances is carried out using color analyzers. Special identification rings, stickers with warning inscriptions can also be applied (this applies to hazardous substances).

Modern marking of pipelines, etc. is done only in accordance with GOST. The surface of the pipeline is painted in a certain color, special inscriptions are attached. Heat exchangers, as well as pipelines through which hot water or steam is supplied, are painted with heat-resistant enamel. It is necessary that all inscriptions exactly comply with the rules for the safe operation of steam and hot water. On the main lines, a number must be applied in Roman numerals, as well as an arrow showing the direction of movement of the transported substance. The same trunk number is applied to trunk branches. All inscriptions must be clearly visible, they must not be obscured by valves and gate valves.

According to GOST 14202 69, if the surface of the pipeline is covered with metal sheathing, the coloring of this sheathing is optional, but a symbol of its type and class of the transported substance can be applied to the pipeline. The coloring and inscriptions on these pipelines must strictly comply with the same standard.

All equipment carrying hot liquid or steam must be adequately insulated. This is done to avoid burns. The temperature at the surface of the insulation must not cause damage to the skin when touched.

The pipelines must have arrows showing the movement of the working fluid. All inscriptions must be visible and printed only. Highly visible serial numbers should also be applied to pumping units, valves, gates and other mechanisms. Also, pipes need appropriate markings, which should indicate their purpose. In this case, it can be easily identified.

All state standards are obligatory for observance by all subjects of housing and communal services, heat supply, regardless of their form of ownership. Failure to comply with such rules can lead to accidents, fires and other man-made incidents.

Reliable and simple reducer Ch-80
Worm gearboxes, such as the Ch-80 gearbox, carry out the transfer of forces most confidently and at the same time change the direction of transmission. Their use provides a significant reduction in the speed of rotation of the shafts.

RTI in household appliances
RTI (rubber products) are used not only in industry, but also in everyday life: without RTI it is difficult to imagine modern household appliances (refrigerators, washing machines, dishwashers, food processors, etc.) present in every home.

Gate valves with electric drive - convenience in the operation of the pipeline
The advantages of gate valves on an electric drive include: versatility, that is, shut-off equipment can be used in any pipelines; high flow shutoff speed; durability and reliability.

PVC electrical tape - the best of electrical tapes
The most common area where electrical tape is used is electrical insulation in everyday life, in industry and during construction work.

Plasma cutting machines - their features and benefits
Currently, manual rollers are used for single-piece production of bulk products, and modern equipment equipped with automation is more suitable for large-scale production. In addition to bending flat sheet and metal profiles, the production of products requires metal cutting, and now such operations are carried out using high-precision equipment.

The rules set out in GOST 21.205–93, regulate exactly how alphanumeric characters should be applied on the drawings pipeline designations plumbing systems that relate to external networks of heat supply, sewerage and water supply, as well as to internal water and sewer networks, heating networks, ventilation and air conditioning systems.

Alphanumeric designation	Name
Water pipes
B0	General designation of the water supply
IN 1	Domestic and drinking water supply
IN 2	Fire water supply
Industrial plumbing
AT 3	General designation of industrial water supply
AT 4	Plumbing of circulating water supply
AT 5	Circulating water pipeline, return
AT 6	Soft water plumbing
AT 7	For river water
AT 8	For river clarified water
AT 9	For underground water
Sewerage
K0	General designation of the sewer
K1	domestic sewerage
K2	Rain sewer
industrial sewerage
K3	General designation of industrial sewage
K4	Sewerage for mechanically polluted waters
K5	sludge sewerage
K6	Sewage for sludge-containing waters
K7	For chemically polluted waters
K8	Sewerage for acidic waters
K9	For alkaline waters
K10	For acidic waters
K11	For cyanide waters
K12	For chromium-containing waters
Heat pipe
T0	General designation of the pipeline
For heating, ventilation, air conditioning and technical processes
T1	Supply pipeline
T2	Return pipeline
Pipeline for hot water supply
T3	Server
T4	circulation
Hot water for technological processes
T5	Supply pipeline
T6	Return pipeline
Steam heating
T7	Steam pipeline
T8	Condensate line

Note:

For those pipeline systems of sewerage and water supply that are not provided for in the table, designations must be adopted by establishing a serial numbering that is a continuation of the one indicated in the table.

If an industrial or domestic drinking water supply system simultaneously performs the role of a fire-fighting one, then it is assigned exactly the same number as the industrial or domestic drinking water supply. At the same time, an appropriate explanation is applied to the drawing.

Pipeline

In modern technology, pipelines are such devices that are designed to transport a variety of liquid, gaseous and granular media. The main components of pipeline systems are: straight pipes that are tightly interconnected; hangers and supports; control and measuring equipment; shut-off and control devices; fasteners; seals and gaskets; means of automation.

In addition, the elements of pipeline systems include the materials necessary to ensure effective protection of all the above components from the harmful effects of low and high temperatures, as well as from electrochemical corrosion.

The locations of the elements of pipeline systems are their branches, turns, as well as transitions to a different diameter. They serve to ensure a long service life of the system as a whole, as well as the tightness of the entire structure. Practice shows that almost no pipeline system is implemented without such elements as bends, tees and transitions.

Liquid Properties

Liquids are those substances that are in a liquid state of aggregation. It, in turn, is intermediate between the aggregate state of solid and gaseous. The liquid also has a property that is not found in any other state of aggregation: it is capable of changing its shape under the influence of tangential mechanical stresses within practically unlimited limits. In this case, mechanical stresses can be very small, and the volume of the liquid remains unchanged.

Another important property inherent in all liquids is surface tension. Neither gases nor solids have it, but it is explained by the following reasons: due to the fact that the balance of the forces acting on the molecules of the surface is disturbed, a certain new resultant force directed inside the substance appears. This explains the fact that the surface of a liquid is always "stretched". If we consider this situation from the point of view of physics, then it can be argued that surface tension is nothing but the force due to which the molecules of a liquid do not move from its surface to the deep layers. It is the force of surface tension that explains the shape of falling drops of any liquid.