5. HYDRAULIC (PNEUMATIC) TESTS
5.1. General requirements
5.1.1. Hydraulic (pneumatic) tests are carried out in order to check the strength and density of equipment, pipelines, their parts and assembly units, loaded with pressure. 5.1.2. Hydraulic tests are carried out: 1) after the manufacturer has manufactured the equipment or pipeline elements supplied for installation; 2) after installation of equipment and pipelines; 3) in during operation equipment and pipelines loaded with pressure of water, steam or steam-water mixture. 5.1.3. Instead of hydraulic tests, it is allowed to carry out pneumatic tests of equipment and pipelines loaded with gas pressure, operating under vacuum, in contact with a liquid metal coolant, as well as safety housings (casings) of NPPs with fast neutron reactors and protective shells ACT. The possibility of such a replacement must be approved by Gosatomnadzor of Russia. It is allowed not to conduct hydraulic tests (after manufacture and during operation) of experimental and research hulls nuclear reactors operating under the pressure of the weight of the liquid filling them, provided that during the manufacturing process 100% control of welds is carried out by ultrasonic flaw detection or radiographic method and surface flaw detection methods. 5.1.4. Hydraulic (pneumatic) tests after installation and during operation are carried out within the time limits specified in clause 8.2.6. 5.1.5. Conducting hydraulic (pneumatic) tests after installation during the commissioning of equipment and pipelines, as well as during operation (with the exception of cases of repair specifically stipulated in this document), is mandatory. 5.1.6. Hydraulic testing of parts or assembly units of pipelines manufactured at installation sites may be combined with hydraulic testing after installation is completed. 5.1.7. Equipment and pipelines after manufacture and installation must be subjected to hydraulic tests before applying protective anti-corrosion coatings or thermal insulation. On equipment and pipelines that are in contact with a liquid metal coolant during operation, it is allowed to apply thermal insulation before hydraulic tests with the specified coolant. It is allowed to carry out metallization (without applying coatings) welded joints pipelines before hydraulic testing, if this cannot be done after installation is completed, which should be specified in design documentation . 5.1.8. Hydraulic (pneumatic) testing of equipment and pipelines during operation should be carried out after the removal of thermal insulation in the places specified in clause 2.1.9, as well as specified in the design documentation. 5.1.9. Hydraulic tests of individual parts and assembly units of equipment and pipelines after their manufacture may not be carried out in the following cases: 1) the manufacturer performs hydraulic tests of these parts and assembly units as part of enlarged assembly units or products; 2) the manufacturer of equipment that does not contain welded joints I and I and category B of equipment made of pearlitic class steels or high-chromium steels carries out continuous ultrasonic and radiographic control of the base metal and welded joints, and of austenitic steels and iron-nickel alloys - continuous radiographic control of the base metal and welded joints, subject to all other requirements of the PC and design documentation; 3) the manufacturer of group C equipment made of pearlitic class steels and high-chromium steels carries out continuous ultrasonic testing of all welded joints, as well as their radiographic testing in a double volume compared to the prescribed PC, and of austenitic steels and iron-nickel steels - continuous radiographic testing all welded joints; in this case, all other requirements of the PC and design documentation must be observed; 4) the manufacturer of parts and assembly units of pipelines of groups B and C made of pearlite class steels and high-chromium steels carries out continuous ultrasonic testing of all welded joints, as well as radiographic testing of welded joints II a, II for categories in the amount of 100%, II c, II nv and III a categories - in the amount of 50%, III c - in the amount of 25%, and from steels of the austenitic class - continuous radiographic control of all welded joints, while all other requirements of the PC and design documentation must be observed; in addition, additional capillary or magnetic particle inspection of machined surfaces (bores, transitions, pipe bends, etc.) and ultrasonic or radiographic inspection of metal in areas of stress concentration and in areas subjected to deformation of more than 5% during manufacture (bends and extended ends of pipes, elongated necks, etc.) and to the extent established by the design documentation (for pipelines of group C, this additional control may not be carried out). 5.1.10. The quality assessment standards for the control according to clause 5.1.9 should be adopted for the base metal according to the standards or specifications for the relevant materials and semi-finished products, and for welded joints - according to the PC. 5.1.11. Hydraulic (pneumatic) tests of individual parts (for example, pipes) at the manufacturer may not be carried out if they have passed hydraulic tests at the supplier of these products and after that they have not been subjected to operations during which the material of these parts has undergone plastic deformation. 5.1.12. Hydraulic (pneumatic) tests after the manufacture of equipment elements and pipelines loaded during operation with external pressure may be carried out under loading internal pressure.5.2. Determination of the pressure of hydraulic (pneumatic) tests
5.2.1. The hydraulic test pressure must be at least determined by the formula:(bottom line)
And no more than the pressure at which the total membrane stresses equal to 1.35 [ ] Th, and the sum of general or local membrane and general bending stresses will reach 1.7 [ ] Th(upper limit). In the above formula To = 1.25 for equipment and pipelines and To= 1 for protective shells and safety housings (casings), R - design pressure when tested at the manufacturer's plant or operating pressure during tests after installation and during operation, [ ] Th- rated allowable stress at hydraulic test temperature T h for the structural element, [ ] T - rated allowable voltage at design temperature T considered structural element. For elements loaded with external pressure, the following condition must also be satisfied:
R h 1,25 [R].
Note. Values [ ] Th , [ ] T, general and local membrane and general bending stresses; [ R] - the permissible external pressure at the hydraulic test temperature is determined according to the Strength Calculation Standards. 5.2.2. Under pressure R up to 0.49 MPa (5 kgf / cm 2) value R h should be more than 1.5 R, but not less than 0.2 MPa (2 kgf / cm 2). Under pressure R more than 0.49 MPa (5 kgf / cm 2) value P h must be determined from the conditions of clause 5.2.1, but not less than ( R + 0.29) MPa (( R+ 3) kgf / cm 2). These requirements do not apply to equipment and pipelines with liquid metal coolant. 5.2.3. In the event that hydraulic (pneumatic) tests are carried out on a system or circuit consisting of equipment and pipelines operating at different operating pressures and (or) design temperatures, or made of materials with different [ ] Th and/or [ ] T, then the pressure of hydraulic (pneumatic) tests of this system (circuit) should be taken equal to minimum value the upper limit of test pressures, selected from all relevant values for the equipment and pipelines that make up the system (loop). 5.2.4. Hydraulic test pressure values for equipment and assembly units (blocks) of pipelines must be indicated by the manufacturer in the equipment passport and the certificate of manufacture of parts and assembly units of the pipeline. The pressure values of hydraulic (pneumatic) tests of systems (circuits) must be determined by the design organization and reported to the owner of the equipment and pipelines, which specifies these values on the basis of the data contained in the passports of equipment and pipelines that complete the system (circuit).
5.3. Determination of the temperature of hydraulic (pneumatic) tests
5.3.1. Hydraulic (pneumatic) tests of equipment and pipelines must be carried out at a temperature of the test medium at which the temperature of the metal of the tested equipment and pipelines will not be lower than the minimum allowable temperature, determined in accordance with the Strength Calculation Standards. In this case, in all cases, the temperature of the test and environment should not be below 5 °C. 5.3.2. It is allowed to carry out hydraulic (pneumatic) tests after manufacture or installation without carrying out the calculation according to clause 5.3.1 at a metal temperature of at least 5 °C in the following cases: 1) the product is made of corrosion-resistant austenitic steel, non-ferrous or iron-nickel alloy; 2) the product is made of materials with a yield strength at a temperature of 20 ° C less than 295 MPa (30 kgf / mm 2) and has the largest wall thickness of not more than 25 mm; 3) the product is made of materials with a yield strength at a temperature of 20 ° C less than 590 MPa (60 kgf / mm 2) and. has the greatest wall thickness no more than 16 mm. It is also allowed, without carrying out the calculation according to clause 5.3.1, to determine the minimum allowable temperature of the metal during hydraulic tests T h from the following ratios:
where T to -
critical brittleness temperature of the material in the initial state, °C; S -
the largest nominal wall thickness of the product, mm; 
-
yield strength of the material at a temperature of 20 °C, MPa. Meaning T ko must either be specified in the design documentation and confirmed during the manufacturing process, or determined according to the methods given in the Strength Calculation Standards. 5.3.3. The allowable temperature of the metal during hydraulic tests carried out after manufacture must be determined by the design (design) organization in accordance with clauses 5.3.1, 5.3.2 and indicated in the drawings, equipment certificates and certificates for the manufacture of parts and assembly units of pipelines. The specified temperature may be determined using the actual properties of the metal used in the manufacture. 5.3.4. The permissible temperature of the metal during hydraulic (pneumatic) tests of equipment and pipelines as part of the system (circuit) after installation is taken as the maximum of all specified in accordance with paragraph 5.3.3 in the equipment passports (certificates for the manufacture of parts and assembly units of pipelines), and is given by the enterprise - owner in a comprehensive program (instructions) for hydraulic (pneumatic) tests. 5.3.5. The allowable temperature of the metal during hydraulic (pneumatic) tests during operation (including after repair) is established by the NPP administration based on strength calculation data, certificates of equipment and pipelines, the number of loading cycles recorded during operation, the actual fluences of neutrons with energy E 0.5 MeV, test data of witness samples installed in nuclear reactor vessels. (Changed edition. Rev. No. 1). 5.3.6. If, based on the analysis at the design stage according to paragraphs. 5.3.1-5.3.3 the allowable metal temperature during hydraulic (pneumatic) tests turns out to be such that it cannot be provided by standard means of this NPP, then the developer of the NPP project must provide a special device in the project to ensure the required temperature. (Changed edition. Rev. No. 1). 5.4. Requirements for hydraulic (pneumatic) testing
5.4.1. Holding time of equipment and pipelines under pressure R h during hydraulic tests should be at least 10 min. After holding, the pressure of hydraulic tests decreases to values of 0.8 R h and inspection of equipment and pipelines is carried out in accessible places during the time necessary for inspection. The minimum allowable metal temperature during holding should be determined according to the strength calculation standards. Pressure measurement during hydraulic tests should be carried out using two independent verified pressure gauges or measurement channels. The error of pressure measurement during hydraulic tests, taking into account the accuracy class of the sensor (pressure gauge), should not exceed ± 5% of the nominal value of the test pressure. The accuracy class of the sensor (pressure gauge) must be at least 1.5. 5.4.2. Holding time under pressure P h when testing after the manufacture of fittings with an inner diameter of the connecting pipes of not more than 100 mm, it is allowed to install according to technical documentation on the product. 5.4.3. During hydraulic testing, pressure fluctuations are allowed due to changes in fluid temperature. Permissible values of temperature and pressure fluctuations in each particular case should be established by calculation or experimentally, while the pressure should not go beyond the lower and upper limits according to clauses 5.2.1, 5.2.3. Lowering the temperature below that set according to clause 5.3 is not allowed. It is allowed to compensate for leaks provided for by the design of the pump shaft seals by pumping the test medium. 5.4.4. Hydraulic tests must be carried out using a non-flammable medium that does not adversely affect the equipment or pipeline. Requirements for the quality of the test environment are established specifications per product and must be indicated in the passports of equipment and pipelines or in certificates of manufacture of parts and assembly units of pipelines. 5.4.5. Metal temperature control should be carried out by thermal control devices. Temperature control may not be carried out if the temperature of the liquid and the ambient temperature are higher than the temperature of the hydraulic tests established in clause 5.3. The temperature must be controlled by sensors and instruments with a total error not exceeding ± 3% of the maximum value of the measured temperature. 5.4.6. When conducting hydraulic tests of equipment and pipelines, measures must be taken to prevent the accumulation of gas bubbles in cavities filled with liquid.5.5. Pneumatic tests
5.5.1. Pneumatic test pressure R R must be at least determined by the formula:
(bottom line),
Where To R= 1.15 for equipment and pipelines; To R= 1 for protective shells and safety housings (casings). The upper bound is the same as in Section 5.2.1. For elements loaded with external pressure, the condition
The requirements of clause 5.2.2 are not valid for pneumatic tests. 5.5.2. If there is a column of liquid metal in the equipment and pipelines during operation, which is impossible to have during pneumatic tests, then the lower limit of the pressure of pneumatic tests should be determined by the formula
Where H- height of liquid metal column; - specific gravity of liquid metal at design temperature; R - operating pressure of the gas above the liquid metal level. 5.5.3. During pneumatic testing of protective shells, safety housings (casings), the equipment or pipelines covered by them may be under external pressure, as a result of which it may be necessary to create back pressure in the equipment or pipelines P g . In this case, it must be done next condition:
5.5.4. When determining the minimum allowable temperature metal should be guided by the instructions of clause 5.3. 5.5.5. During pneumatic tests, the requirements of clauses 5.2.3, 5.2.4, 5.3, 5.4.1 (in terms of the requirements for error and measurements and the accuracy class of the instrument), clauses 5.4.3, 5.4.5 must be observed. 5.5.6. Holding time of equipment and pipelines under pressure R R during pneumatic tests should be at least 30 min. After exposure, the pressure is reduced, and equipment and pipelines are inspected in accessible places for the required time. The inspection is carried out at a pressure determined by the person responsible for carrying out the tests on the basis of safety conditions, but in all cases this pressure should not exceed 0.85 R R . The holding time under pressure for fittings with an inner diameter of connecting pipes of not more than 100 mm during pneumatic tests is set by the technical conditions for delivery. 5.5.7. The valves of the filling pipeline intended for pneumatic testing and instruments for measuring pressure and temperature must be removed outside the room in which the tested equipment is located, to a place safe for personnel. During the rise in gas pressure in the tested equipment and pipelines, holding under pressure R R and reducing the pressure to the value set for the inspection, the personnel must be in safe place.
5.6. Hydraulic (pneumatic) testing programs
5.6.1. Before hydraulic (pneumatic) testing of equipment and assembly units (parts) of pipelines, the manufacturer must draw up a production program (or technological instruction, technological process) tests. 5.6.2. To carry out hydraulic (pneumatic) tests after installation and during operation, the design organization must draw up a comprehensive test program, on the basis of which the NPP administration (or specialized organization determined by the decision of the relevant ministry) a working test program should be drawn up. (Changed edition. Rev. No. 1). 5.6.3. The production program (technological instruction, technological process) of hydraulic (pneumatic) testing of equipment and assembly units (parts) of pipelines after manufacture must include the following data: 1) name of equipment or assembly units (parts) of pipelines; 2) design pressure; 3) pressure of hydraulic (pneumatic) tests; 4) temperature of hydraulic (pneumatic) tests; 5) test media and requirements for their quality; 6) allowable rates of increase and decrease in pressure; 7) allowable rates of temperature increase and decrease; 8) holding time at test pressure P h (P p); 9) the pressure at which the inspection is to be carried out; 10) pressure source; 11) method of heating the test medium (if necessary); 12) installation points of sensors (devices) for pressure control and their accuracy class; 13) installation points of sensors (devices) for temperature control and their accuracy class; 14) permissible limits of pressure and temperature fluctuations during holding; 15) safety requirements; 16) places of installation of technological plugs; 17) a list of organizational measures, including the appointment of persons responsible for testing. The program must be approved by the chief engineer (director) of the manufacturer and agreed with the relevant design organization. 5.6.4. A comprehensive program of hydraulic (pneumatic) testing of systems, their parts or certain types equipment and pipelines after installation and during operation should include the following data: 1) the name and boundaries of the system under test (parts of the system, equipment, pipelines); 2) working pressure; 3) pressure of hydraulic (pneumatic) tests; 4) temperature of hydraulic (pneumatic) tests; 5) test media and requirements for their quality; 6) allowable rates of increase and decrease in pressure; 7) allowable rates of temperature increase and decrease; 8) the pressure at which the inspection is to be carried out; 9) methods for filling and draining the test environment; 10) source of pressure; 11) method of heating the test medium (if necessary); 12) points of installation of sensors (devices) for pressure control; 13) points of installation of sensors (devices) for temperature control; 14) permissible limits of pressure and temperature fluctuations during holding. The integrated program must be agreed upon by the management of the design organization and approved by the NPP administration. (Changed edition. Rev. No. 1). 5.6.5. Working programm hydraulic (pneumatic) tests, in addition to the information listed in clause 5.6.4, must contain the following data: 1) specification of the pressure and temperature values of hydraulic (pneumatic) tests according to the passports of the components of the tested equipment and pipelines; 2) the place of connection of the pressure source; 3) a list of used sensors and instruments for monitoring pressure and temperature, indicating the accuracy class; 4) test schedule (stages of pressure rise and fall, temperature rise and fall, holding time, etc.); 5) methods for monitoring the condition of the tested equipment and pipelines during the inspection and after completion of the tests; 6) measures to prepare for testing (indicating the valves to be closed and opened, limiting the tested system or part of it); 7) a list of places for removing thermal insulation; 8) measures of protection against excess pressure above the test one; 9) safety requirements; ten) organizational arrangements(including the appointment of a person responsible for testing); 11) the number of the integrated program on the basis of which the work program has been drawn up. The work program must be approved by the NPP administration. (Changed edition. Rev. No. 1). 5.6.6. After completion of the tests, a protocol must be drawn up, including the following data: 1) the name of the enterprise that conducted the tests; 2) the name of the tested system (parts of the system, equipment, pipelines, assembly units, parts); 3) design (working) pressure; 4) design temperatures; 5) pressure testing; 6) test temperature; 7) test environment; 8) exposure time at test pressure; 9) the pressure at which the inspection is carried out; 10) number of the working (production) program; 11) test result; 12) signature of the responsible person and date.5.7. Evaluation of the results of hydraulic (pneumatic) tests
The equipment and pipelines are considered to have passed the hydraulic (pneumatic) tests, if no leaks and metal breaks were found during the tests and inspection, during the exposure according to clause 3.4.1, the pressure drop did not go beyond the limits specified in clause 5.4.3, and after testing, no visible residual deformations were revealed. During hydraulic (pneumatic) testing of equipment and assembly units (parts) of pipelines, leaks through process seals intended for testing are not a rejection sign.Page 12 of 16
PNEUMATIC TESTS
8.10. Pneumatic tests should be performed for steel pipelines with a working pressure not exceeding 1.6 MPa (16 kgf / cm 2) and temperatures up to 250 ° C, mounted from pipes and parts tested for strength and tightness (density) by manufacturers in accordance with GOST 3845-75 (at the same time, 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).
The installation of cast iron fittings (except for ductile iron valves) is not allowed for the duration of the test.
8.11. Filling the pipeline with air and raising the pressure should be done smoothly at a rate of not more than 0.3 MPa (3 kgf / cm 2) per 1 hour. Visual inspection of the route (entrance to the security [dangerous) zone, but without descending into the trench] is allowed at a pressure value , 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 pressure increase must be stopped.
When the test pressure is reached, the pipeline must be held to equalize the air temperature along the length of the pipeline. After equalizing the air temperature, the test pressure is maintained for 30 minutes and then gradually decreases to 0.3 MPa (3 kgf / cm 2), but not higher than the working pressure of the coolant; at this pressure, pipelines are inspected with a mark of defective places.
Leaks are identified by the sound of leaking air, by bubbles when covering welded joints and other places with soapy emulsion and using other methods.
Defects are eliminated only when the excess pressure is reduced to zero and the compressor is turned off.
8.12. The results of preliminary pneumatic tests are considered satisfactory if during their conduct there was no pressure drop on the pressure gauge, no defects were found in welds, flange joints, pipes, equipment and other elements and products of the pipeline, there are no signs of shear or deformation of the pipeline pipeline and fixed supports.
8.13. Pipelines of water networks in closed systems heat supply and condensate pipelines should, as a rule, be subjected to hydropneumatic washing.
Hydraulic flushing is allowed with reuse flushing water by passing it through temporary sumps installed in the direction of water movement at the ends of the supply and return pipelines.
Washing should normally be done industrial water. Flushing with utility and drinking water is allowed with justification in the project for the production of works.
8.14. Pipelines of water networks open systems heating and hot water supply networks must be flushed hydropneumatically with drinking-quality water until the flushing water is completely clarified. After 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. Pipelines with a diameter of up to 200 mm and a length of up to 1 km are allowed, in agreement with the local bodies of the sanitary and epidemiological service, not to be subjected to chlorination and limited to flushing with water, corresponding to the requirements of GOST 2874-82.
After washing, the results of laboratory analysis of samples wash water must comply with the requirements of GOST 2874-82. A conclusion is drawn up on the results of washing (disinfection) by the sanitary and epidemiological service.
8.15. The pressure in the pipeline during flushing should not be higher than the working one. The air pressure during hydropneumatic flushing should not exceed the working pressure of the coolant and be no higher than 0.6 MPa (6 kgf / cm 2).
Water velocities during hydraulic flushing must not be lower than the design coolant velocities indicated in the working drawings, and during hydropneumatic flushing, exceed the calculated ones 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 pipes with shut-off valves. To warm up the steam pipeline, 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 the blowing of each section must be at least the operating velocities for the design parameters of the coolant.
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Pneumatic test pipelines are carried out to check them for strength and density or only for density. In the latter case, the pipeline must be pre-tested for strength. hydraulically. Ammonia and freon pipelines are not tested for hydraulic strength.
Pneumatic testing is supposed to be carried out with air or an inert gas, for which they use mobile compressors or factory network compressed air. Test pressure the strength and length of the tested section of the pipeline of the above-ground laying should not exceed the values \u200b\u200bspecified in Table. 20.
In exceptional cases, arising from the requirements of the project, it is allowed to carry out a pneumatic strength test of pipelines with a deviation from the data given in the table. In this case, the test must be carried out in strict accordance with a specially developed (for each case) instruction that ensures proper work safety.
Pneumatic strength testing of elevated cast iron, as well as faolitic and glass pipelines is prohibited. In the case of installation of cast iron fittings on steel pipelines (except fittings made of ductile iron), pneumatic strength testing is allowed at a pressure not exceeding 4 kgf / cm 2, at the same time, all cast-iron fittings must undergo a preliminary hydraulic test strength in accordance with GOST 356-59.
The pressure in the tested pipeline should be raised gradually, inspecting it when it reaches: 0.6 of the test pressure - for pipelines with a working pressure of up to 2 kgf / cm 2; 0.3 and 0.6 of the test pressure - for pipelines with a working pressure above 2 kgf / cm 2. When inspecting the pipeline, an increase in pressure is not allowed. The final inspection is carried out at operating pressure and combined with a pipeline tightness test. At the same time, the tightness of welded joints, flange joints and glands is checked by coating them with soap or other solution. Tapping with gold on a pipeline located under pressure, not allowed. The results of the pneumatic test are considered satisfactory if during the strength test there was no pressure drop on the pressure gauge and during the subsequent tightness test, no leaks or gaps were found in the welds, flange joints and glands.
Pipelines transporting potent toxic substances and other products with toxic properties, liquefied petroleum gases, flammable and active gases, as well as flammable and combustible liquids transported at temperatures above their boiling point, are subjected to an additional density test. In this case, the test is carried out with the determination of the pressure drop. Shop pipelines transporting the products listed above undergo additional density tests together with the equipment to which they are connected.
The density test with the determination of the pressure drop can only be carried out after the temperatures inside the pipeline have equalized, for which thermometers should be installed at the beginning and end of the test section. Test duration intershop pipelines on the density with the determination of the pressure drop is set by the project; it must be at least 12 h. The pressure drop in the pipeline during its density test is determined by the formula:
where ∆ R- pressure drop value, %;
R con and P start is the sum of the gauge and barometric pressures at the end and beginning of the test, respectively, kgf / cm 2;
T con and T beginning -absolute air temperature or gas, respectively, at the end and beginning of the test deg.
The pressure and temperature of air or gas in the pipeline is determined as the arithmetic average of the readings of all pressure gauges and thermometers installed on the pipeline.
where D BH- inner diameter of the tested pipeline, mm. If the pipeline consists of sections of different diameters, its average internal diameter is determined by the formula:
Intershop pipeline with conditional passage 250 mm pass additional test on the. density if the pressure drop in it is 1 h as a percentage of the test pressure is not more than: 0.1 - when transporting toxic products; 0.2 - when transporting explosive, flammable, combustible and active gases (including liquefied ones). When testing pipelines of other diameters, the fall rates in them are determined by multiplying the above figures by a correction factor calculated by the formula:
L 1 , L 2 , ... L n- lengths of the corresponding sections of the pipeline, mm;
where D 1 , D 2 , ... D n- internal diameters of pipeline sections, m.
For the duration of pneumatic tests, both indoors and outdoors, it is necessary to establish a protected area and mark it with flags. Minimum distance in any direction from the pipeline under test to the boundary of the zone: at overhead laying - 25 m, and with underground - 10 m. Control posts are set up to monitor the protected area. During the rise in pressure in the pipeline and when testing it for strength, it is not allowed for people to stay in the protected area, except for persons specially designated for this purpose and instructed.
An act is drawn up for the results of pneumatic tests of the pipeline.
1. In what order are pneumatic strength tests carried out?
2. How is a pneumatic test of pipelines for tightness carried out?
3. How is a pneumatic strength test of pipelines carried out with the determination of pressure drop?
