6.11.1. Vessels are subject to hydraulic testing after their manufacture.

Hydraulic testing of vessels transported by parts and assembled at the installation site is allowed to be carried out after their assembly at the installation site.

6.11.2. Hydraulic testing of vessels should be carried out with fasteners and gaskets provided for in the technical documentation.

6.11.3. Test pressure R - at hydraulic test vessels is determined by the formula

Where R - design pressure, MPa (kgf / cm);

Allowable stresses for the material, respectively, at 20 ° C and design temperature t, MPa (kgf / cm).

6.11.4. The test pressure of the hydraulic test of the vessel is determined taking into account the minimum values ​​of the design pressure and the ratio of the allowable stresses of the material of assembly units (parts).

6.11.5. The test pressure during the hydraulic test of the vessel, calculated by zones, is determined taking into account the zone, the design pressure or design temperature of which is of lesser importance.

6.11.6. If the calculated test pressure (according to the formula given in clause 6.11.3) during hydraulic testing of a vessel operating under external pressure necessitates thickening of the vessel wall, then it is allowed to determine the test pressure by the formula

Where E and E - the elastic moduli of the material, respectively, at 20 ° C and the design temperature t, MPa (kgf / cm).

6.11.7. The test pressure for the hydraulic test of a vessel designed to operate under conditions of several modes with different design parameters (pressures and temperatures) should be taken equal to the maximum of the determined test pressures for each mode.

6.11.8. For vessels operating under vacuum, the design pressure is taken to be 0.1 MPa (1 kgf / cm).

6.11.9. The maximum deviation of the test pressure value should not exceed 5%.

6.11.10. Hydraulic testing of vessels installed vertically may be carried out in a horizontal position, provided that the strength of the vessel body is ensured. In this case, it is necessary to perform a strength calculation taking into account the adopted method of support for carrying out a hydraulic test.

The test pressure should be taken taking into account the hydrostatic pressure acting on the vessel during its operation.

6.11.11. For hydraulic testing of the vessel, water should be used.

In justified cases, the use of another liquid is allowed.

The water temperature should be taken not lower than the critical brittleness temperature of the vessel material and indicated in the technical documentation. If not specified, the water temperature should be between 5 ° C and 40 ° C.

The temperature difference between the vessel wall and the ambient air during the test shall not cause moisture condensation on the vessel wall surface.

6.11.12. When filling a vessel with water, it is necessary to remove air from the internal cavities. The pressure should be raised evenly until the test pressure is reached. The rate of pressure rise should not exceed 0.5 MPa (5 kgf / cm) per minute, unless otherwise indicated in the technical documentation.

The holding time under test pressure shall not be less than the values ​​specified in table 22.

After holding under test pressure, the pressure is reduced to the design pressure, at which a visual inspection of the outer surface, detachable and welded joints is performed. No knocking of the vessel is allowed during the tests.

A visual inspection of vessels operating under vacuum is carried out at test pressure.

Table 22

^ Holding time of the vessel under test pressure during hydraulic test

6.11.13. The test pressure during the hydraulic test should be monitored with two pressure gauges. Manometers are selected of the same type, measurement range, accuracy class, and the same scale division. Pressure gauges are selected with an accuracy class of at least 2.5.

6.11.14. After the hydraulic test, the water is completely removed.

6.11.15. The hydraulic test may be replaced by a pneumatic test (compressed air, inert gas or a mixture of air with an inert gas), provided that this test is controlled by the acoustic emission method or another safe method.

The control by the acoustic emission method should be carried out in accordance with the requirements of the normative and technical documentation on industrial safety.

Pneumatic testing should be carried out according to the instructions approved in the prescribed manner.

Test pressure should be determined in accordance with clause 6.11.3.

The holding time of the vessel under test pressure must be at least 5 minutes and indicated in the technical documentation.

After holding under test pressure, the pressure is reduced to the design pressure, at which a visual inspection of the outer surface and a check of the tightness of welded and detachable joints are performed.

6.11.16. The test results are considered satisfactory if during the test there are no:

pressure drop on the manometer;

leaks of the test medium (leakage, perspiration, air or gas bubbles) in welded joints and on the base metal;

signs of rupture;

leaks in detachable joints;

permanent deformations.

6.11.18. Testing of vessels operating without pressure (under filling) is carried out by pouring water to the upper edge of the vessel or, in justified cases, by wetting welds kerosene.

The holding time of the vessel when tested with water in bulk should be at least 4 hours, and when tested by wetting with kerosene, not less than indicated in table 23.

Table 23

^ Holding time of the vessel and welds during the test by wetting with kerosene

6.11.19. The pressure value and test results are entered in the vessel passport.

^ 6.12. Leak test

6.12.1. The need for tightness control, the degree of tightness and the choice of test methods and methods should be specified in the technical documentation.

Leakage control should be carried out in accordance with the requirements of industrial safety regulations.

A hydraulic test for tightness with a luminescent indicator coating or a luminescent-hydraulic method may be combined with a hydraulic test.

6.12.2. Tightness control of pipe fastening for pipe systems, pipe-lattice connections, where medium mixing (liquid overflow) is not allowed, should be carried out with a helium (halogen) leak detector or fluorescent-hydraulic method.

6.12.3. The control of welded seams for tightness is allowed to be carried out by the capillary method - wetting with kerosene. In this case, the surface of the seam to be tested on the outside should be covered with chalk, and on the inside should be abundantly moistened with kerosene throughout the test period.

The holding time of welded joints during the test by wetting with kerosene should be not less than that specified in table 23.

6.12.4. A pneumatic test should be used to check the tightness of the welded seams of the reinforcing rings and the welded joints of the lining of branch pipes and flanges.

The test pressure of the pneumatic test should be taken equal to:

0.4-0.6 MPa (4-6 kgf / cm), but not more than the design pressure of the vessel - for welding seams of reinforcing rings;

0.05 MPa (0.5 kgf / cm) - for welded joints of the cladding.

Control must be carried out by smearing with soapy emulsion.

6.12.5. The quality of the welded joint should be considered satisfactory if, as a result of the application of any method corresponding to the specified class of tightness, no leak (s) are detected.

Vii. Completeness and documentation

7.1. Completeness

7.1.1. The vessel kit should include:

assembled vessel or separately transported parts with counter flanges, working gaskets and fasteners that do not require replacement during installation;

fixtures and spare parts (according to the instructions in the technical documentation);

foundation bolts for fastening the vessel in the design position (as indicated in the technical documentation);

documentation.

7.1.2. Parts and assembly units that may be damaged when sent assembled with the vessel may be removed and sent in separate packaging. The type and type of containers and packaging of these parts and assembly units, as well as purchased parts, must comply with the requirements of the technical documentation for a particular vessel.

7.1.3. The assembled vessel must be supplied with an internal protective coating in accordance with the requirements of the technical documentation.

Shotcrete, lining with piece materials, thermal insulation are carried out at the assembly site. Materials for gunning, lining with piece materials, thermal insulation, as well as non-metallic (ceramic, etc.) elements for protecting the inner lining may not be included in the delivery of the vessel. The metal elements to protect the inner lining provided for in the technical documentation are supplied with the vessel.

7.1.4. The transported parts of oversized vessels should be supplied with welded devices for assembling the field joint for welding.

It is allowed to cut off the devices after use. They should be removed at a distance of at least 20 mm from the walls of the case using methods that do not damage the walls.

7.1.5. The delivery of oversized vessels welded at the assembly site from the transported parts, except for justified cases, includes welding consumables and metal plates for control tests of welded seams. Welding consumables and plates must meet specified requirements.

7.1.6. Assembled vessels or transported parts of oversized vessels should be supplied with welded parts for fastening insulation, lining, service platforms, metal structures, etc., provided for in the technical documentation. Welded parts for fastening the insulation should be of standard types. The type of welded part is indicated in the documentation.

7.1.7. The delivery of a heavy or oversized vessel, if provided for by the technical documentation, includes special traverses, supporting devices (pins), trolleys or skids to support the lower part of the vessel, mounting clamps, removable load grippers, special sling devices, alignment devices and devices for translation vessels from horizontal to vertical.

7.1.8. Parts made of pipes (coils, sections, collectors, tube bundles, etc.), if they constitute parts of oversized vessels or are manufactured separately from the vessels, should be delivered assembled on gaskets provided for in the technical documentation.

7.1.9. The set of vessels with mechanisms and internal devices (reactors, crystallizers, tanks with submersible pumps, etc.) includes electric motors, gearboxes, pumps, etc., provided for in the technical documentation.

7.1.10. The spare parts kit should include a set of working gaskets for flanges. If, according to the operating conditions of the vessel, a larger number of spare gaskets are required during the stipulated service life, then their delivery is carried out in accordance with the requirements of the technical documentation for the vessel.

7.2. Documentation

7.2.1. The following documentation is attached to the vessels:

passport in accordance with the requirements of regulatory and technical documentation on industrial safety for pressure vessels;

installation instructions;

operation manual, including start-up and shutdown procedures;

spare parts list;

strength calculations;

applications in accordance with the requirements of these Rules;

drawings of wearing parts (if necessary);

certificate of control assembly or control verification of dimensions, assembly marking diagram, assembly drawings in triplicate (for vessels transported by parts);

operational documentation, including safety measures, procedure for operation, control, repair, diagnostics and certification;

technical documentation for components (electric motors, gearboxes, pumps, etc.).

7.2.2. It is allowed to attach a passport to the vessels in a form that includes:

serial number and year of manufacture;

information about the manufacturer;

name and designation (drawing number) of the vessel;

characteristics of the vessel and components;

assigned and estimated service life;

material of the main elements;

information about the tests;

information from the admitted agreed deviations from the documentation;

a list of the attached documentation;

certificate of the quality of manufacturing and installation, acceptance and commissioning with signatures of officials;

information on repairs, inspection and diagnostics, dismantling and disposal.

7.2.3. The installation instructions and operating instructions should provide for the requirements of industrial safety rules and regulations and measures to prevent unauthorized personnel actions during operation, installation, diagnostics, repair and inspection of the vessel.

7.2.4. Regulations for starting and stopping vessels and apparatus in winter time must comply with safety requirements.

7.2.5. Parts and assembly units should be accompanied by documents (certificate, certification) on quality.

7.2.6. The completeness of the documentation supplied with the vessel, in justified cases, can be changed and supplemented.

VIII. Marking, preservation and painting. Packaging, transportation and storage

8.1. Marking

8.1.1. Vessels must have a standard type plate.

The plate may not be installed on vessels with an outer diameter of 325 mm or less. In this case, the required data is entered on the vessel body.

8.1.2. The plate is placed in a conspicuous place.

The plate is affixed to a welded backing plate, weld bracket, weld beads or weld on bracket.

8.1.3. The plate should be marked with:

name and designation of the vessel;

the serial number of the vessel according to the manufacturer's numbering system;

design pressure, MPa;

working or nominal pressure, MPa;

test pressure, MPa;

permissible maximum and (or) minimum working temperature of the wall, ° С;

vessel weight, kg;

Year of manufacture;

technical control stamp;

Compliance mark, if any.

8.1.4. On the outer surface of the vessel wall, markings should be applied:

manufacturer's name or trademark;

serial number according to the manufacturer's numbering system;

Year of manufacture;

technical control stamp;

name and designation of the vessel.

Vessels with a shell wall thickness of 4 mm or more are marked by stamping or engraving, and those with a wall thickness less than 4 mm - by engraving or indelible paint. The marking is enclosed in a frame made of weather-resistant paint and protected with a colorless varnish (a thin layer of grease). The depth of marking by stamping or engraving should be within 0.2-0.3 mm.

The shape and color of the marking must comply with the requirements of the state standard and be clearly distinguishable for a long time.

8.1.5. It is allowed to mark the plate welded to the vessel body.

8.1.6. The typeface for flat and bump markings must comply with national standards.

8.1.7. In addition to the main marking, it follows:

a) make two check marks at the top and bottom of the shell at an angle of 90 ° on non-insulated vertical vessels that do not have special devices for verifying their verticality on the foundation;

b) apply mounting marks (risks) fixing the main axes of the vessel in the plan, in order to reconcile its design position on the foundation;

c) apply a distinctive color to the sling devices with indelible paint;

d) attach (or cast) an arrow indicating the direction of rotation of the mechanisms, while the arrow must be painted red with indelible paint;

e) apply assembly markings (for oversized vessels transported by parts);

f) make marks indicating the position of the center of mass on the shell of the vessels, while placing the marks on two opposite sides of the vessel;

g) indicate the diameter of the holes for the adjusting bolts with indelible paint near one of the holes (if there are adjusting bolts in the supporting structure of the vessel).

8.1.8. The center of gravity marks are made according to the state standard and technical documentation. If the coordinates of the center of mass of the product and the cargo shipped without packaging in a container coincide, then apply the "sign" once on both sides, and if they do not coincide, then apply the "sign" twice on both sides. Add letters "CM" to the "sign" defining the coordinates of the "center of mass".

8.1.9. Shipping points should be marked in accordance with the state standard and technical documentation.

8.1.10. On the transported parts of oversized vessels, the following should be indicated:

vessel designation;

serial number according to the manufacturer's numbering system;

designation of the transported part.

8.1.11. On each vessel, delivery unit, oversized parts of the vessel, the attachment points of the slings and the position of the center of mass should be indicated. It is necessary to provide for the supply of fixtures and fittings in accordance with the technical documentation, ensuring the installation in the design position of the assembled vessel or delivery unit.

After the completion of all repair and installation work, the pipeline is tested for strength and density. In this case, plugs are installed at the ends of the test section of the pipeline. It is forbidden to use shut-off valves to disconnect the tested section of the pipeline. At the highest point of the pipeline, a fitting with fittings for air release is installed - an air vent, and at the lowest point - a fitting for draining water - drainage.

Hydraulic testing of pipelines should be carried out mainly in the warm season at a positive ambient temperature. The water temperature should be between 5 and 40 o C.

The value of the test pressure when testing the pipeline for strength is determined by the formula

P pr = 1.25 R , but not less than 0.2 MPa,

Where R- design pressure; [σ] 20 - allowable stress for the pipeline material at 20 о С; [σ] t is the allowable stress for the pipeline material at the maximum design temperature.

The value of the test pressure during strength testing for vacuum pipelines and pipelines operating without excess pressure should be taken equal to 0.2 MPa. Taping of pipelines during testing is not allowed.

The pressure in the test section of the pipeline should be increased gradually. The rate of pressure rise is indicated in the technical documentation. The air from the pipeline must be completely removed.

When testing the pipeline for strength, the created test pressure is maintained for 10 minutes, after which the pressure is reduced to working pressure, at which density tests are performed by examining the welded seams. At the end of the inspection, the pressure is again increased to a test one and kept for another five minutes, after which it is again reduced to a working one and the pipeline is carefully inspected for the second time.

The duration of the tightness test is determined by the inspection time of the pipeline. After the end of the hydraulic test, the pipeline must be completely free of water.

The results of a hydraulic test for strength and density are considered satisfactory if during the test did not occur:

ü breaks and visible deformations;

ü pressure drop according to the manometer;

ü in welds, detachable connections, tie-ins, valve bodies, no leaks were detected.

Pneumatic testing of the pipeline with air or inert gas should be carried out only during daylight hours. The value of the test pressure (test pressure) is determined in the same way as during hydraulic tests.

If gray cast iron fittings are installed on the pipeline, the strength test pressure should not exceed 0.4 MPa.

When carrying out pneumatic tests of pipelines, it is recommended to increase pressure smoothly at a rate equal to 5% of R y, but not more than 0.2 MPa per minute with periodic inspection of the pipeline at the following stages:

a) for pipelines operating at pressures up to 0.2 MPa, inspection is carried out in two stages - at a pressure equal to 0.6 of the test pressure and at operating pressure;

b) for pipelines operating at pressures above 0.2 MPa, inspection is carried out in three stages - at a pressure of 0.3 and 0.6 of the test pressure and at operating pressure.

During inspection, pressure build-up and tapping of pipelines are not allowed. Leak points are identified by soap emulsion bubbles or other methods. A guarded (safe) area should be established at the time of pneumatic tests. When laying the pipeline on the ground, the minimum distance of the zone should be at least 25 m, when laying underground - at least 10 m. The stay of people in the protected area during the rise in pressure and when the test pressure is reached in it is not allowed.

The final inspection of the pipeline is carried out when the test pressure is reduced to the design pressure.

All pipelines of groups A, B (a) and B (b), as well as vacuum pipelines, must be subjected to an additional leak test. Additional tightness tests are carried out with a pressure equal to the working pressure, and for vacuum pipelines with a pressure of 0.1 MPa (1 kg / cm 2). For pipelines under construction, the test duration should be at least 24 hours. When testing the pipeline after repair, the test duration should be at least 4 hours.

The pressure drop in the pipeline is calculated using the equation

Δ R= 100 / τ,

Where R n, R k - absolute pressure at the beginning and end of the test; T n, Tк - temperature in the pipeline at the beginning and at the end of the test.

It is considered that pipelines of groups A, as well as vacuum pipelines, have passed the test if the pressure drop rate is not more than 0.1% per hour. For pipelines of groups B (a); B (b) the rate of pressure drop should not exceed 0.2% per hour. The rate of pressure drop for pipelines of other groups is set by the project.

The specified standards apply to pipelines with an inner diameter of up to 250 mm inclusive. When testing pipelines of large diameters, the rates of pressure drop in them are reduced by the value of the correction factor

Where D vn - inner diameter of the pipeline in mm.

If the tested pipeline consists of several sections of different diameters, its average diameter is determined by the formula

D Wed = ,

Where D 1 ,D 1 ,D n is the inner diameter of the pipeline sections; L 1 , L 2 , L n - corresponding lengths of pipeline sections, m.

After the end of the test, an act is drawn up for each pipeline in the prescribed form.

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RULES FOR THE DEVICE AND SAFE OPERATION OF STEAM AND HOT WATER PIPELINES - PB 03-75-94 (approved by Resolution ... Actual in 2017

4.12. Hydraulic test

4.12.1. A hydraulic test in order to check the strength and density of pipelines and their elements, as well as all welded and other joints, are subject to:

a) all elements and details of pipelines; their hydraulic test is not mandatory if they have been subjected to 100% ultrasound control or another equivalent method of non-destructive flaw detection;

b) pipeline blocks; their hydraulic test is not mandatory if all their constituent elements were tested in accordance with paragraph "a", and all welded joints made during their manufacture and installation were checked by non-destructive flaw detection methods (ultrasound or radiography) along their entire length;

c) pipelines of all categories with all elements and their fittings after completion of installation.

4.12.2. It is allowed to carry out a hydraulic test of individual and prefabricated elements together with the pipeline, if during manufacture or installation it is impossible to test them separately from the pipeline.

4.12.3. The minimum value of the test pressure during hydraulic testing of pipelines, their blocks and individual elements should be 1.25 working pressure, but not less than 0.2 MPa (2 kgf / sq. Cm).

The fittings and fittings of pipelines must be subjected to a hydraulic test with test pressure in accordance with GOST 356.

4.12.4. The maximum test pressure is set by the strength calculation according to NTD, agreed with the Gosgortekhnadzor of Russia.

The value of the test pressure is chosen by the manufacturer (design organization) within the range between the minimum and maximum values.

4.12.5. For the hydraulic test, water with a temperature not lower than +5 ° C and not higher than +40 ° C should be used.

Hydraulic testing of pipelines should be carried out at a positive ambient temperature. During hydraulic testing of steam pipelines operating at a pressure of 10 MPa (100 kgf / cm3) and above, the temperature of their walls must be at least + 10 ° C.

4.12.6. The pressure in the pipeline should be increased gradually. The rate of pressure rise must be specified in the NTD for the manufacture of the pipeline.

Compressed air must not be used to build up pressure.

4.12.7. The test pressure shall be monitored with two pressure gauges. In this case, manometers of the same type are selected with the same accuracy class, measurement limit and division price.

The holding time of the pipeline and its elements under test pressure must be at least 10 minutes.

After reducing the test pressure to the working pressure, a thorough inspection of the pipeline along its entire length is carried out.

The difference between the temperatures of the metal and the ambient air during the test shall not cause moisture deposition on the surfaces of the test object. The water used for hydrotesting must not contaminate the object or cause intense corrosion.

4.12.8. The pipeline and its elements are considered to have passed the hydraulic test, if it is not found: leaks, sweating in welded joints and in the base metal, visible permanent deformations, cracks or signs of rupture.

Hydraulic (pneumatic) test

Question

Answer. A hydraulic test to check the density and strength, as well as all welded and other joints, is carried out:

a) after installation (additional manufacture) at the installation site of equipment transported to the installation site (additional manufacture) by individual parts, elements or blocks;

b) after reconstruction (modernization), repair of equipment using welding of elements working under pressure;

c) when carrying out technical examinations and technical diagnostics in the cases established by these FNP.

Hydraulic testing of individual parts, elements or units of equipment at the installation site (additional manufacture) is not mandatory if they have passed the hydraulic test at the sites of their manufacture or have been subjected to 100% ultrasound control or another equivalent non-destructive flaw detection method.

It is allowed to carry out a hydraulic test of individual and prefabricated elements together with the equipment, if, under the conditions of installation (additional manufacture), their testing separately from the equipment is impossible.

Hydraulic testing of equipment and its elements is carried out after all types of control, as well as after elimination of detected defects (169).

Vessels having a protective coating or insulation are hydrostatically tested before the coating or insulation is applied.

Vessels having an outer casing are subjected to a hydraulic test before the casing is installed.

It is allowed to subject enamelled vessels to a hydraulic test with operating pressure after enameling (170).

Question... How are the minimum and maximum test pressures determined during hydraulic pressure testing of equipment?

Answer. Minimum test pressure P pr during hydraulic testing for steam and hot water boilers, superheaters, economizers, as well as for pipelines in the boiler limit, take:

a) at a working pressure of not more than 0.5 MPa - 1.5 working pressure, but not less than 0.2 MPa;

b) at a working pressure over 0.5 MPa - 1.25 working pressure, but not less than the working pressure plus 0.3 MPa.

When carrying out a hydraulic test of drum boilers, as well as their superheaters and economizers, the pressure in the boiler drum is taken as the operating pressure when determining the test pressure value, and for drumless and once-through boilers with forced circulation - the feed water pressure at the boiler inlet, established by the design documentation.

The maximum test pressure is established by strength calculations of steam and hot water boilers.

The value of the test pressure (between the maximum and the minimum) should provide the greatest detectability of defects in the boiler or its components subjected to a hydraulic test (171).

Question... How are the test pressure values ​​determined during hydraulic testing of metal vessels?

Answer. Test pressure value P pr during hydraulic testing of metal vessels (with the exception of cast ones), as well as electric boilers, it is determined by the formula:

R - design pressure in case of additional manufacture at the place of operation, in other cases - working pressure, MPa;

[σ] 20, [σ] t - allowable stresses for the material of the vessel (electric boiler) or its elements, respectively, at 20 ° C and design temperature, MPa.

The ratio of materials of assembly units (elements) of a vessel (electric boiler) operating under pressure is taken according to that of the used materials of elements (shells, bottoms, flanges, nozzles, etc.) of the vessel, for which it is the smallest, with the exception of bolts (studs), as well as heat exchange tubes of shell-and-tube heat exchangers.

The test pressure when testing the vessel, calculated in zones, should be determined taking into account the zone, the design pressure or design temperature of which is of lesser importance.

The test pressure for testing a vessel designed to operate in several modes with different design parameters (pressures and temperatures) should be taken equal to the maximum of the determined test pressures for each mode.

If, to ensure the conditions of strength and tightness during testing, it becomes necessary to increase the diameter, number or replace the material of the bolts (studs) of flange joints, it is allowed to reduce the test pressure to the maximum value at which the strength conditions of the bolts (studs) are provided during the tests without increasing them. diameter, quantity or replacement of material.

If the vessel as a whole or individual parts of the vessel operate in the creep temperature range and the allowable stress for the materials of these parts at the design temperature [σ] t is determined on the basis of the ultimate strength or creep limit, it is allowed in formulas (1), (7) instead of [σ] t use the value of the allowable stress at the design temperature [σ] m, obtained only on the basis of time-independent characteristics: yield strength and ultimate strength without taking into account creep and creep strength.

Formula (1) is used to determine the value of the test pressure during hydraulic testing of process pipelines (172).

Question... How are the test pressure values ​​determined during hydraulic tests of cast and forged vessels?

Answer. Test pressure value P pr during hydraulic testing of cast and forged vessels is determined by the formula

Testing of castings is allowed to be carried out after assembly and welding in an assembled unit or a finished vessel with a test pressure adopted for vessels, provided that the castings are 100% controlled by non-destructive methods (173).

Question... How are the test pressure values ​​determined during hydraulic testing of vessels made of non-metallic materials?

Answer. Hydraulic testing of vessels and parts made of non-metallic materials with an impact strength of more than 20 J / cm 2 should be carried out with a test pressure determined by the formula:

Hydraulic testing of vessels and parts made of non-metallic materials with an impact strength of 20 J / cm 2 or less should be carried out with a test pressure determined by the formula (174):

Test pressure value P pr during hydraulic testing of cryogenic vessels in the presence of vacuum in the insulating space, it is determined by the formula (175):

P pr = 1,25R – 0,1, (5)

Hydraulic testing of metal-plastic vessels should be carried out with a test pressure determined by the formula:

where: K m is the ratio of the mass of the metal structure to the total mass of the vessel;

α = 1.3 - for non-metallic materials with an impact strength of more than 20 J / cm 2;

α = 1.6 - for non-metallic materials with an impact strength of 20 J / cm 2 or less (176).

Question... How is pressure testing performed on vertical vessels and combination vessels?

Answer. Hydraulic testing of vessels installed vertically is allowed to be carried out in a horizontal position, while the strength of the vessel body must be calculated taking into account the accepted method of support for conducting a hydraulic test.

In combined vessels with two or more working cavities, designed for different pressures, each cavity must be subjected to a hydraulic test with a test pressure determined depending on the design pressure of the cavity.

The procedure for testing such vessels should be established by the developer of the design technical documentation and specified in the vessel's operating manual (177).

Question... How are the test pressure values ​​determined during hydraulic testing of steam and hot water pipelines?

Answer. The minimum value of the test pressure during hydraulic testing of steam and hot water pipelines, their blocks and individual elements should be 1.25 working pressure, but not less than 0.2 MPa. The fittings and fittings of pipelines must be subjected to a hydraulic test with test pressure in accordance with the technological documentation. The maximum value of the test pressure is established by calculating the strength of the pipelines.

The value of the test pressure (between the maximum and minimum) should provide the greatest detectability of defects in the pipeline or its elements subjected to hydraulic testing (178).

Question... What are the requirements for water during hydraulic pressure testing of equipment?

Answer. For hydraulic pressure testing of equipment, water should be used. The water temperature must not be lower than 5 ° C and not higher than 40 ° C, unless a specific temperature value is indicated in the technical documentation of the equipment manufacturer, permissible under the conditions for preventing brittle fracture.

During hydraulic testing of steam pipelines operating at a pressure of 10 MPa and above, the temperature of their walls must be at least 10 ° C.

During hydraulic testing of steam and hot water boilers, the upper limit of the water temperature can be increased by agreement with the design organization up to 80 ° C. If the temperature of the drum top metal exceeds 140 ° C, it is not allowed to fill it with water for hydrostatic testing.

The water used for hydraulic testing should not contaminate the equipment or cause intense corrosion.

The temperature difference between the metal and the ambient air during the hydraulic test should not lead to moisture condensation on the surface of the equipment walls.

In technically justified cases provided by the manufacturer, during the hydraulic test during the operation of vessels, it is allowed to use another fluid (179).

Question... How is hydraulic pressure testing carried out on equipment?

Answer. When filling the equipment with water, the air must be completely bled.

The pressure in the equipment under test should be raised smoothly and evenly. The total pressure rise time (up to the test value) should be indicated in the process documentation. The water pressure during the hydraulic test should be monitored with at least two pressure gauges. Both manometers are selected of the same type, measurement range, the same accuracy classes (not less than 1.5) and scale divisions.

The use of compressed air or other gas to pressurize equipment filled with water is not permitted.

The holding time under test pressure of steam and hot water boilers, including electric boilers, steam and hot water pipelines, as well as vessels delivered to the installation site as an assembly, is set by the manufacturer in the operation manual; it must be at least 10 minutes.

The holding time under test pressure of the vessels of the element-by-element block supply, additionally manufactured during installation at the site of operation, must be at least:

a) 30 min with a vessel wall thickness of up to 50 mm;

b) 60 min with a vessel wall thickness over 50 to 100 mm;

c) 120 min with a vessel wall thickness over 100 mm.

For cast, non-metallic and multilayer vessels, regardless of the wall thickness, the holding time should be at least 60 minutes.

The holding time of technological pipelines under test pressure during hydraulic testing should be at least 15 minutes.

If the process pipeline is tested together with the vessel (apparatus) to which it is connected, the holding time is taken according to the time required for the vessel or apparatus (180).

After holding under test pressure, the pressure is reduced to the value justified by the strength calculation, but not less than the operating pressure, at which the external surface of the equipment and all its detachable and non-detachable joints are visually inspected (181).

After the hydraulic test, it is necessary to ensure that water is removed from the equipment under test.

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