How to hydrotest pipelines. Pipeline testing

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PNEUMATIC TESTS

8.10. Pneumatic tests should be performed for steel pipelines with a working pressure of no higher than 1.6 MPa (16 kgf / cm 2) and a temperature of up to 250 ° C, mounted from pipes and parts tested for strength and tightness (density) by manufacturers in accordance with GOST 3845-75 (in this case, the factory test pressure for pipes, fittings, equipment and other products and parts of the pipeline must be 20% higher than the test pressure adopted for the installed pipeline).

Installation of cast iron fittings (except for ductile iron valves) during the tests is not allowed.

8.11. Filling the pipeline with air and raising the pressure should be done smoothly at a rate of no more than 0.3 MPa (3 kgf / cm 2) in 1 hour. equal to 0.3 test, but not more than 0.3 MPa (3 kgf / cm 2).

For the period of inspection of the route, the rise in pressure must be stopped.

When the value of the test pressure is reached, the pipeline must be maintained to equalize the air temperature along the length of the pipeline. After equalizing the air temperature, the test pressure is held for 30 minutes and then gradually decreases to 0.3 MPa (3 kgf / cm 2), but not higher than the operating pressure of the coolant; at this pressure, the pipelines are inspected with a mark of defective places.

Leak spots are identified by the sound of leaking air, by bubbles when covering welded joints and other places with soap emulsion and other methods.

Defects are eliminated only when the excess pressure drops to zero and the compressor is turned off.

8.12. The results of preliminary pneumatic tests are considered satisfactory if during the tests there was no pressure drop across the pressure gauge, no defects were found in welded seams, flange joints, pipes, equipment and other elements and products of the pipeline, there are no signs of shear or deformation of labor. pipeline and fixed supports.

8.13. Water pipelines in closed heat supply systems and condensate pipelines should, as a rule, be subjected to hydropneumatic flushing.

Hydraulic flushing with re-use of flushing water is allowed by passing it through temporary mud collectors installed along the flow of water at the ends of the supply and return pipelines.

Flushing, as a rule, should be carried out with technical water. Flushing with potable water is allowed with justification in the design of the work.

8.14. Water pipelines open systems heat supply and hot water supply networks must be flushed hydropneumatically with drinking water until the flushing water is completely clarified. At the end of flushing, the pipelines must be disinfected by filling them with water containing active chlorine at a dose of 75-100 mg / l with a contact time of at least 6 hours. coordination with the local authorities of the sanitary and epidemiological service, do not subject to chlorination and be limited to rinsing with water that meets the requirements of GOST 2874-82.

After flushing, the results of laboratory analysis of flushing water samples must comply with the requirements of GOST 2874-82. A conclusion is drawn up on the results of washing (disinfection) by the sanitary-epidemiological service.

8.15. The pressure in the pipeline during flushing should not be higher than the operating pressure. The air pressure during hydropneumatic flushing should not exceed the working pressure of the coolant and not exceed 0.6 MPa (6 kgf / cm 2).

The water velocities during hydraulic flushing must not be lower than the design velocities of the coolant specified in the working drawings, and in the case of hydropneumatic flushing, they must exceed the design velocities by at least 0.5 m / s.

8.16. Steam pipelines must be purged with steam and discharged into the atmosphere through specially installed purge nozzles with shut-off valves. To warm up the steam line, all start-up drains must be open before purging. The heating rate should ensure the absence of hydraulic shocks in the pipeline.

The steam velocities during blowing of each section must be not less than the operating velocities at the design parameters of the coolant.

Content

Upon completion of installation, all process pipelines are tested for strength and tightness in accordance with the requirements of SNiP. Pipelines can be tested for strength and tightness hydraulically or pneumatically.

Pneumatic testing of the pipeline for strength is carried out in cases where it is impossible to conduct a hydraulic test (negative ambient temperature, lack of water at the site, dangerous stresses in the pipeline and supporting structures from the weight of water), and also when the project provides for testing pipelines with air or inert gas.

Testing of pipelines is relied on under the direct supervision of the work manufacturer or foreman in strict accordance with the instructions in the project and special instructions and with requirements. Gosgortekhnadzor, as well as in compliance with safety regulations.

Before starting work on testing, the pipeline line is conditionally divided into separate sections, its external examination is carried out, and technical documentation, install air and drain valves, pressure gauges, temporary plugs and connect a temporary pipeline from filling and pressure testing. aggregates. The tested pipeline is disconnected from devices, machines and untested pipe sections using special plugs with shanks. The use of shut-off valves installed on the pipeline for this purpose is not allowed. Connect the pipeline to be tested to a hydraulic press, pump, compressor or air network that creates the required test pressure through two stop valves.

Pressure gauges used for testing pipelines must be checked and sealed. Pressure gauges must meet an accuracy class of at least 1.5 in accordance with GOST 2405-63, have a body diameter of at least 150 mm and a scale for a nominal pressure of about 4/3 of the measured pressure. Thermometers used in pneumatic testing must have a graduation value of not more than 0.1 gr.C.

By hydraulic test, pipelines are checked simultaneously for strength and tightness.

Strength test pressure installed by the project; it should be equal to:

• For steel pipelines at working pressures up to 4 kgf / cm 2 and for pipelines designed to work with wall temperatures above 400 ° C, 1.5 working pressure, but not less than 2 kgf / cm 2;
• For steel pipelines at operating pressures of 5 kgf / cm 2 and above 1.25 operating pressure, but not less than the operating pressure plus 3 kgf / cm 2;
• For other pipelines 1.25 working pressure, but not less than 2 kgf / cm 2 for cast iron, vinyl plastic, polyethylene and glass;
• 1 kgf / cm 2 for pipelines made of non-ferrous metals and alloys;
• 0.5 kgf / cm 2 for faolite pipelines.

To create the necessary pressure in the pipeline during hydraulic testing, plunger mobile pumps (NP600, GN1200400), piston hand pumps (TN500, GN200), hydraulic presses (VMS45M), gear drive (NSh40), as well as operating pumps are used.

The hydraulic test process consists of the following operations: connection of a hydraulic pump or press; installation of pressure gauges; filling the pipeline with water (in this case, the air vents should be kept open until water appears in them, which indicates the complete displacement of air from the pipeline); inspection of the pipeline when filling it with water in order to detect leaks through cracks and leaks in the joints; creating the required test pressure with a hydraulic press or pump and holding the pipeline under this pressure; reduction of pressure to working and repeated inspection of the pipeline; emptying the pipeline; removal of the hydraulic pump and pressure gauges.

All pipelines withstand test pressure within 5 minutes, with the exception of glass, which is kept for 20 minutes.

Inspect pipelines after reducing the pressure in the pipeline to the working one. When inspecting steel pipelines welds at a distance of 1520 mm on both sides of them, they are easily tapped with a rounded hammer weighing no more than 1.5 kg, and when inspecting pipelines made of non-ferrous metals with a wooden hammer weighing no more than 0.8 kg. Do not tap on pipelines made of other materials.

Hydraulic test results strength and tightness are considered satisfactory if during the test there was no pressure drop across the pressure gauge, and no leaks or sweating were found in welds, flanged joints and glands. If the test results are unsatisfactory, the defects should be eliminated and the test repeated.

At a negative ambient temperature, the hydraulic test of the pipeline is carried out, providing the necessary measures against freezing of water, especially in the drain lines (preheating or adding an aqueous solution of calcium chloride).

After a hydraulic test in the autumn-winter time, the pipelines are blown with compressed air to completely remove the water. Blow out very carefully to avoid stagnation of water at the lowest points of the pipeline.

Testing of pipelines. All pressure pipelines after installation of the water supply are tested for strength and tightness by hydraulic and pneumatic methods.

The test of pressure pipelines laid in trenches is carried out twice: before backfilling of trenches and installation of fittings (hydrants, safety valves, plungers) - preliminary strength test and after backfilling of trenches and completion of all work on this section of water pipelines, but before installing hydrants, safety valves and plungers, instead of which plugs are installed during the test - a final test for tightness.

It is allowed to carry out a preliminary test of the pipeline only after it has been secured by tamping the sinuses with soil, powder polyethylene pipes plumbing, device stops, as well as other measures provided for by safety regulations. Preliminary testing of steel pipelines is carried out with positive results of quality control of welding and insulation.

Welded joints and flange connections at a test pressure of less than 0.6 MPa, they must be without insulation at a distance of at least 100 mm from the joint axis in each direction and are accessible for inspection.

Hydraulic strength test. The strength of the pressure pipelines is checked by internal pressure. The working and test pressure of the pressure pipelines is set by the project.

When conducting a preliminary hydraulic test of water pipelines, the valves installed on this water supply must be fully open. To disconnect the tested section of the water supply system from the existing one, blind flanges or plugs are installed; the use of valves for this purpose is not permitted.
Piping made of cast iron and reinforced concrete pipes are tested in sections with a length of not more than 1 km, and pipelines from polyethylene pipes no more than 0.5 km. The length of the test sections of steel pipelines with the hydraulic test method, it is allowed to take more than 1 km.

Preliminary hydraulic testing of metal and reinforced concrete pipelines should last at least 10 minutes, and polyethylene - at least 30 minutes, after which the pressure is reduced to working and the pipelines are inspected. Maintaining the test and operating pressure in the pipeline for the period of its inspection and detection of defects during preliminary testing is allowed to be carried out by pumping water.

A pressure pipeline is considered to have passed the preliminary hydraulic test if, under the test pressure, there was no rupture of pipes and fittings and a violation of the sealing of butt joints, and no water leaks were found under the operating pressure.

The noticed defects must be eliminated, after which the pipeline must be subjected to a preliminary test again.

Hydraulic tightness test. The final hydraulic test of pressure pipelines can be started if at least 24 hours have elapsed since filling the trench with soil and filling the pipeline with water for metal and polyethylene pipes, and at least 72 hours for reinforced concrete pipes. If the pipeline was filled with water before filling the trenches with soil, then the holding time of the test pressure is set from the moment of backfilling.

During the final test of pressure water supply pipelines, the actual water leakage from the pipelines must be determined, while the leakage must not exceed the permissible limits.

A section of a water supply system made of polyethylene pipes is considered to have passed the hydraulic test if, after successively finding the water supply system under test and working pressure for 30 minutes during the next 10 minutes under working pressure, the pressure drop in the water supply system did not exceed 0.01 MPa.

On a section of the pipeline that is completely accessible to inspection in working order, a leak is not specifically determined, and it is considered to have passed the hydraulic test if its integrity is not violated at the test pressure, and no water leaks are found in the pipeline at operating pressure.

Water leaks from the pipeline are determined by the formula, l / min:

q = Q / BT,
where T is the time from the start of the leak test to the moment the gauge needle returns to its original position (min) T = T1-T2; B - coefficient taken equal to 1 with a pressure drop of no more than 20% of the test pressure.

If within 10 minutes the pressure drops below the working pressure, then the pipeline is considered to have failed the test and the volume of water Q required to restore pressure in it is not determined. If, after this time, the pressure drop turns out to be insufficient, then it should be increased to the required one by dumping water from the pipeline. The leaks are then calculated using the above formula. Water from the pipeline is allowed to be discharged before the expiration of the above period, but the discharge of water may be greater than the actual leak.

If, when testing a pipeline made of reinforced concrete pipes, the actual leakage is greater than the allowable one, it is allowed to retest the pipeline (without preliminary curing). If, upon retesting, the actual leakage does not exceed the permissible by more than 20%, the pipeline can be declared fit for operation (with a guarantee that the builders will correct all defects within a year).

If, during the retest, the actual leakage exceeds the permissible by more than 20%, it is recommended to keep the pipeline under operating pressure for 10 days in order to additionally saturate the pipe walls. After this, the pipeline test must be carried out again.

When filling the pipeline with water in winter conditions, the temperature difference between the pipe and water is allowed no more than 10 ° C. The final hydraulic test of the pipeline in winter conditions should be carried out at a water temperature of at least 1 ° C.

The foreseen holding of the pipeline with water without pressure must be carried out in the presence of a flow, that is, water must be pumped through the pipeline to warm it up. Testing of pipelines in winter can be allowed only if it is absolutely necessary to put them into operation during the current winter period.

All installed pipelines must be hydrostatically tested. At a test pressure not exceeding 0.8 MPa, a pneumatic test method is allowed.

Tests of pipelines should be performed in accordance with the requirements of SNiP “Rules for production and acceptance of works. Water supply, sewerage and heat supply. External networks and facilities ".

The test pressure is set by the project. In the absence of special instructions in the project, the hydraulic test pressure during preliminary and final tests should be equal to the working pressure plus 0.3 MPa.

The ends of the pipeline section before the hydraulic test must be hermetically closed with plugs, the butt joints of which are recommended to be the same as on the main pipeline, that is, using rubber sealing rings. For the plugs, steel connecting pipes can be used, designed for the installation of fittings and fittings. When using steel pipes as plugs, a blind flange with gas pipe connections must be welded to the free end of the pipe for filling the pipeline with water and venting.

To hold the end caps, it is advisable to use stops of a metal structure with hydraulic cylinders. These cylinders can be driven by any tractor equipped with a hydraulic system. The design of such a stop can be reused.

In the absence of stops of a metal structure, a concrete or reinforced stop can be used, which must have the design strength by the time the pipeline is filled with water, therefore, such stops are recommended to be installed simultaneously with the laying of the pipeline. The design of the temporary end stops should be provided for in the pipeline design.

By the time of the hydraulic test of the pipeline, all its butt joints, both inside and outside, must be sealed with a cement-sand mortar, which must be kept for at least 2 days before testing the pipeline.

Gate valves installed on the pipeline must be fully open during testing. The valves that disconnect the pipeline from the branches can be either open or closed for the test period, but in all cases dry flanges must be installed after them. It is not allowed to use valves to disconnect the tested section of the pipeline from the existing networks.

The pipeline is filled with water from a lowered section in order to provide the best conditions for removing air from the pipeline. The valves on the branch pipes through which the air is removed should be closed only after the complete removal of air.

The pipeline is considered to have passed the test, if there is no loosening of the butt joints and violation of the integrity of pipes, fittings and fittings, no unacceptable defects are found both in open places and in places where the sinuses of the trenches are filled with soil.

The pipeline is considered to have passed the final hydraulic test if there is no water leakage from the pipeline.

Pneumatic test used at the discretion of the construction organization in case of difficulties during the hydraulic test (winter time, lack of water at the test site, etc.). These tests are also carried out in two stages: preliminary - for strength, final - for density.

After filling the steel pipeline with air, before the start of the tests, the external pipelines must be kept for some time to equalize the air temperature in the pipeline with the temperature of the soil. The minimum holding time at the nominal diameter of the pipeline Dy = 300 mm is 2 h, Dy = 600 mm -4 h, Dy = 900 mm -8 h; Dy = 1200 mm - 16 h and Dy = 1400 mm - 24 h.

The minimum holding time of reinforced concrete prestressed pipelines with the nominal pipeline diameter Dу = 300 mm is 6 hours; Dy = 300-500 mm-12 h; Dy more than 500 mm -24 h.

A preliminary pneumatic test of pipelines after their partial backfilling is carried out as follows:

• steel and polyethylene pipelines with an operating pressure of up to 0.5 MPa - with a test pressure of 0.6 MPa;
• at a working pressure over 0.5 MPa - with a test pressure equal to the working pressure, with a coefficient of 1.15;
• cast iron, reinforced concrete prestressed pipelines - with a test pressure of 0.15 MPa.

If it is impossible to create the test pressure specified for steel and polyethylene pipelines, the preliminary test is allowed to be carried out at the maximum pressure developed by the compressor, but not less than 0.6 MPa.

Pneumatic testing of pipelines should be carried out in sections no longer than 1 km. Defects are eliminated after reducing the pressure in the pipeline to atmospheric, then the test is repeated.

In preparation for the pneumatic test, it is necessary to check the installation of the stops; sprinkle the pipeline with soil at least 25 cm above the sheath; clean the inner surface of the pipeline from soil, scale and remove other blockages by blowing or in another way; fix the security zone with warning signs (red flags) during pneumatic testing of pipelines.

When testing pipelines laid on the streets, the boundaries of the zone are established taking into account local conditions and acceptance additional measures are sewn up.

It is allowed to inspect pipelines and mark defective spots only after reducing the pressure in the pipeline to 0.1 MPa, and defects should be eliminated at atmospheric pressure.

Pressing equipment. For testing pipelines, the industry produces pressure testing units and pumps.

Installation of pipelines

8.1 According to SNiP 3.05.04, pressure and non-pressure water supply and sewerage pipelines are tested for strength and tightness (tightness) hydraulically or pneumatically twice (preliminary and final).

8.2 The preliminary test (excess) hydraulic pressure during the strength test, performed before backfilling the trench and installing the fittings (hydrants, safety valves, plungers), should be equal to the design working pressure multiplied by a factor of 1.5.

8.3 The final hydraulic test pressure for density tests performed after backfilling of the trench and completion of all work on this section of the pipeline, but before the installation of hydrants, safety valves and plungers, instead of which plugs are installed during the test, should be equal to the calculated working pressure multiplied by coefficient 1.3.

8.4 Prior to testing pressure pipelines with socket connections with O-rings, temporary or permanent stops should be arranged at the ends of the pipeline and on branches.

8.5 Preliminary hydraulic test of pressure pipelines should be performed in the following order:

Fill the pipeline with water and hold it without pressure for 2 hours;

Create a test pressure in the pipeline and maintain it for 0.5 h;

Reduce the test pressure to the design pressure and inspect the pipeline.

Holding the pipeline under the operating pressure is carried out for at least 0.5 hours. Due to the deformation of the pipeline shell, it is necessary to maintain the test or operating pressure in the pipeline by pumping water until it is completely stabilized.

The pipeline is considered to have passed the preliminary hydraulic test if no ruptures of pipes or joints and fittings are found under the test pressure, and no visible water leaks are found under the operating pressure.

8.6 A final hydraulic tightness test is carried out in the following order:

A pressure equal to the design working pressure should be created in the pipeline and maintained for 2 hours; when the pressure drops by 0.02 MPa, water is pumped;

The pressure is raised to the test level for a period of not more than 10 minutes and maintained for 2 hours.

The pipeline is considered to have passed the final hydraulic test if the actual water leakage from the pipeline at the test pressure does not exceed the values ​​specified in Table 5.

Outside diameter of pipes, mm	Permissible leakage, l / min, for pipes
	with permanent (welded, adhesive) joints	with socket connections on O-rings

8.7 Hydraulic tests of gravity sewer networks are performed after the completion of waterproofing works in wells in two stages: without wells (preliminary) and together with wells (final).

8.8 The final test of the sewage pipeline together with the wells is carried out in accordance with SNiP 3.05.04.

8.9 Hydraulic testing of systems from polymer materials internal pipelines are carried out at a positive temperature environment not earlier than 24 hours after the completion of the last welded and glued joint.

8.10 Hydraulic tests of internal drainage systems are carried out by filling them with water to the entire height of the risers. Tests are carried out after external inspection of pipelines and elimination of visible defects. Hydraulic testing of glued pipelines begins no earlier than 24 hours after the last connection. The drainage system is considered to have passed the test if, after 20 minutes after its filling, an external examination of the pipelines did not reveal a leak or other defects and the water level in the risers did not drop.

8.11 Pneumatic tests of pipelines made of polymeric materials are carried out during their above-ground and above-ground laying in the following cases: the ambient temperature is below 0 ° С; the use of water is unacceptable for technical reasons; there is no water in the amount required for testing.

The procedure for pneumatic testing of pipelines made of polymeric materials and safety requirements during testing are established by the project.

8.12 Preliminary and final tests of gravity sewer networks from large-diameter pipes are allowed to be carried out pneumatically. Preliminary tests are carried out before the final backfilling of the trench ( welded joints do not fall asleep with soil). The test pressure of compressed air, equal to 0.05 MPa, is maintained in the pipeline for 15 minutes. At the same time, welded, glue and other joints are inspected and leaks are detected by the sound of leaking air, by bubbles formed in places where air leaks through butt joints covered with a soap emulsion.

The final pneumatic tests are carried out at a groundwater level above the pipe in the middle of the tested pipeline of less than 2.5 m. The final pneumatic tests are subjected to sections with a length of 20-100 m, while the difference between the highest and lowest points of the pipeline should not exceed 2.5 m. Pneumatic tests are carried out 48 hours after filling the pipeline. The test overpressure of compressed air is shown in table 6.

Groundwater level h	Test pressure, MPa			Pressure drop,
from the pipeline axis, m	excess initial p	the final p 1	p - p 1, MPa
0 < h < 0,5
0,5 < h < 1
1 < h < 1,5
1,5 < h < 2
2 < h < 2,5

8.13 Acceptance of pipelines for operation must be carried out in accordance with the main provisions of SNiP 3.01.04, as well as SNiP 3.05.04. When testing water supply and pressure sewerage pipelines and putting them into operation, the following should be drawn up:

Certificates for hidden works (on the base, supports and building structures on pipelines, etc.);

Acts of external inspection of pipelines and elements (nodes, wells, etc.);

Test certificates for strength and density of pipelines;

Acts for flushing and disinfection of water pipes;

Establishing the compliance of the work performed with the project;

Acts of incoming quality control of pipes and fittings.

8.14 In addition to accepting hidden works and checking certificates for testing pipelines for density and external inspection, acceptance of free-flow pipelines should be accompanied by a check of straightness, as well as an instrumental check of trays in wells.

When accepting internal water pipelines, passports or certificates for polymer pipes, fittings and fittings are additionally checked.

Hydraulic tests are carried out in accordance with SNiP. After their completion, an act is drawn up indicating the performance of the system.

They are performed on different stages operation of communications. The check parameters are calculated for each system separately, depending on its type.

Content of the article

Why and when to carry out hydraulic tests?

Hydraulic testing is a kind non-destructive testing, which is carried out to check the strength and tightness of piping systems. All operating equipment is subjected to them at different stages of operation.

In general, there are three cases in which tests must be carried out without fail, regardless of the purpose of the pipeline:

• after finishing production process for the release of equipment or parts of the pipeline system;
• after the completion of the installation work of the pipeline;
• during the operation of the equipment.

Hydraulic testing is an important procedure that confirms or refutes the reliability of an operating pressure system. This is necessary to prevent accidents on highways and preserve the health of citizens.

The procedure for hydraulic testing of pipelines in extreme conditions is being carried out. The pressure under which it passes is called the test pressure. It exceeds the usual working pressure by 1.25-1.5 times.

Features of hydraulic tests

The test pressure is supplied to the pipeline system smoothly and slowly so as not to provoke water hammer and the formation of accidents. The magnitude of the pressure is determined not by eye, but by a special formula, but in practice, as a rule, it is 25% more than the working pressure.

The power of the water supply is monitored on pressure gauges and measurement channels. According to SNiP, jumps in indicators are allowed, since it is possible to quickly measure the temperature of the liquid in the pipeline vessel. When filling it, it is imperative to monitor the accumulation of gas in different parts of the system.

This possibility should be ruled out at the initial stage.

After filling the pipeline, the so-called holding time begins - the period during which the equipment under test is under increased pressure. It is important to ensure that it is on the same level during aging. After its completion, the pressure is minimized to the working state.

While the test is in progress, no one should be near the pipeline.

The operating personnel must wait in a safe place, as checking the system functionality can be explosive. After the end of the process, the results are evaluated in accordance with SNiP. The pipeline is inspected for, metal explosions, deformations.

Hydraulic test parameters

When checking the quality of the pipeline, it is necessary to determine the indicators of the following work parameters:

1. Pressure.
2. Temperatures.
3. Exposure time.

The test pressure lower limit is calculated using the following formula: Ph = KhP... The upper limit should not exceed the sum of the total membrane and bending stresses, which will reach 1.7 [δ] Th. The formula is deciphered as follows:

• P is the design pressure, the parameters of which are provided by the manufacturer, or the working pressure if the tests are carried out after installation;
• [δ] Th is the rated voltage that is allowed at the test temperature Th;
• [δ] T is the allowable stress at the design temperature T;
• Kh is a conditional coefficient that takes on a different value for different objects. When checking pipelines, it is equal to 1.25.

The water temperature should not fall below 5˚С and not rise above 40˚С. The only exceptions are those cases when the temperature of the hydro component is specified in technical conditions the object under study. Be that as it may, the air temperature during the test should not fall below the same 5˚С.

The holding time must be specified in project documentation to the object. It should not be less than 5 minutes. If the exact parameters are not provided, then the holding time is calculated based on the thickness of the pipeline walls. For example, with a thickness of up to 50 mm, the pressure test lasts at least 10 minutes, with a thickness of over 100 mm - at least 30 minutes.

Testing fire hydrants and water mains

A hydrant is an equipment that is responsible for the speed of eliminating fire ignitions, so it must always be in working order. The main task of fire hydrants is to provide the optimal amount of water to fight a fire at its initial stage.

Pressure pipelines are checked in accordance with SNiP B III-3-81.

Pipes made of cast iron and asbestos are tested with a pipeline length of no more than 1 km at a time. Polyethylene water mains are checked in 0.5 km sections. All other water supply systems are checked in sections of no more than 1 km. The holding time for water supply pipes made of metal must be at least 10 m, for polyethylene pipes - at least 30 m.

Heating systems testing

Heating networks are checked immediately after the completion of their installation. Heating systems are filled with water through the return pipeline, that is, from the bottom up.

With this method, liquid and air go in the same direction, which, according to the laws of physics, with promotes the removal of air masses from the system. The drainage occurs in one and the same way: through the outlets, tank or plungers of heating systems.

If the heating networks are filled too quickly, air pockets may appear due to the filling of the risers with water faster than the heating devices of heating systems. pass under the lower working pressure of 100 kilo Pascal and the test pressure - 300 kilo Pascal.

Heating networks are checked only when the boiler and expansion tank are disconnected.

Heating systems are not monitored during winter. If they have worked without breakdowns for up to about three months, then the acceptance of heating networks into operation can be carried out without hydraulic tests. When checking closed heating systems, the control work must be carried out before the furrows are closed. If insulation of heating networks is planned, then - before its installation.

According to SNiP, after the end of the tests of heating systems, they are washed, and at their lowest point, a coupling with a cross section of 60 to 80 mm2 is mounted. Water is drained through it. Washing heating networks carried out with cold water several times, before acquiring transparency. Heating systems are approved if, within 5 minutes, the test pressure in the pipeline does not change by more than 20 kilo Pascal.

Hydraulic test of the heating and water supply system (video)

Hydraulic testing of heating networks and water supply systems

After the completion of hydraulic tests of heating systems in accordance with SNiP, an act of hydraulic tests of heating networks and water supply systems is drawn up, indicating the compliance of the pipeline parameters.

According to SNiP, its form contains the following information:

• title of the position of the head of the enterprise that provides maintenance of heating networks;
• his signature and initials, as well as the date of verification;
• information about the chairman of the commission, as well as its members;
• information on the parameters of heating networks: length, names, etc .;
• conclusions about the control, the conclusion of the commission.

Adjustment of the characteristics of heating lines is carried out by SNiP 3.05.03-85. According to the specified SNiP, its the rules apply to all highways, which transport water with temperatures up to 220˚С and steam - up to 440˚С.

For the documentary completion of the hydraulic tests of the water supply system, an act is drawn up for the external water supply system in accordance with SNiP 3.05.01-85. According to SNiP, the act contains the following information:

• system name;
• the name of the technical supervision organization;
• data on the value of the test pressure and test time;
• pressure drop data;
• the presence or absence of signs of damage to the pipeline;
• date of inspection;
• withdrawal of the commission.

The act is certified by a representative of the supervision organization.