169. Hydraulic test in order to check the density and strength of equipment under pressure, as well as all welded and other joints, is carried out:
A) after installation (additional production) at the installation site of equipment transported to the installation site (additional production) in separate parts, elements or blocks;
B) after reconstruction (modernization), repair of equipment using welding of pressure elements;
During the dewatering process, significant and unexpected pressure changes often occur within the main pipeline and decomposition timeline. These changes can be caused by changes in the speed of the pig as it passes through bends in the pipeline, or by changes in the speed of the pig and the water due to changes in the height of the pipeline. Compressed air flowing around the pig, which may combine with air already present in the main pipeline at high points in the pipe, can also provide a source of stored energy in the main pipeline.
B) when conducting technical examinations and technical diagnostics in the cases established by these FNP.
Hydraulic testing of individual parts, elements or blocks of equipment at the place of installation (additional manufacturing) is not mandatory if they have passed a hydraulic test at the places of their manufacture or have been subjected to 100% ultrasound control or other equivalent non-destructive method defectoscopy.
These sudden pressure changes result in surges that are transferred from the main pipeline to a temporary dewatering line. This can cause the temporary drain line to move as the pressure can easily exceed the operating pressures and bending capabilities of the temporary couplings. Drainage line movement can force the temporary piping system to be forcibly abandoned, especially if the temporary piping is not properly secured. This situation can be exacerbated when temporary piping suddenly changes direction, when connectors or pipe sections are worn beyond the specified tolerances set by the drainage system manufacturer, or when the entire separation header is not designed sufficiently for the stresses that may be imposed during dewatering.
It is allowed to conduct a hydraulic test of individual and prefabricated elements together with the equipment, if under the conditions of installation (additional production) it is impossible to test them separately from the equipment.
Hydraulic testing of equipment and its elements is carried out after all types of control, as well as after the elimination of detected defects.
The potential for pressure line separation is a recognized hazard in related industries and applications. Oil and gas industry has long recognized this dangerous condition in several operations, and industry consensus standards have been published regarding the potential for such a failure. These standards recommend securing or securing pressurized, bleed and bleed piping to prevent movement.
In this case, the failure occurred at a pipe connector that did not meet the manufacturer's specified tolerances. With the added pressure of the dewatering process, a damaged or improper connector can contribute to the separation of temporary pipe sections. all connections and fixtures must be in proper working order. The groove installed on the pipe must comply with the manufacturer's specifications and recommendations, properly installed as specified by the engineer who develops the dewatering plan and is selected for the application.
170. Vessels having protective covering or insulation, subjected to a hydraulic test prior to coating or insulation.
Vessels with 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 working pressure after enamelling.
Excessive and variable pressure in the system. During dehydration, the pig is pushed through the pipeline using compressed air. The pressure exerted on pipeline system, including the drainage piping, can be much higher than the pressure indicated on the air compressor. Where the terrain includes hills, slopes, or other elevation changes, the pressure on the dewatering system can be greatly increased by hydrostatic head pressure, which adds the potential for pipe separation.
Perhaps the pigs are stalled or stuck in the line. If the pig is stuck due to airflow around the pig, or stuck due to debris inside the pipe or defective seals, freeing the stuck pig can be problematic. Sometimes workers will use high blood pressure air to try and move the pig. While it is common practice to increase line pressure, the safety pressure limits of piping and connections should never be exceeded.
171. Minimum value test pressure during a hydraulic test for steam and hot water boilers, superheaters, economizers, as well as for pipelines within the boiler, the following are accepted:
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 operating pressure plus 0.3 MPa.
If pressure limits are exceeded in main pipelines or drainage systems, catastrophic failure of a pipe or, more likely, a pipe connection may occur. Fittings such as elbows in piping systems and other factors can also contribute to pressure changes as lead travels through the piping. Forces associated with these pressure changes can be transferred to temporary piping systems and cause movement and breaks in joints and piping. Employers must consider the forces involved, and they must design and install anchorage systems to properly contain or control drainage.
When conducting 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 value of the test pressure, and for drumless and once-through boilers with forced circulation- pressure feed water at the entrance to the boiler, established by the project documentation.
It is imperative that employers train employees who perform or work in the vicinity of hydrotest disposal operations. Employers must ensure that employees involved in the disposal of pipelines understand the potential hazards of pressure lines and the precautions and controls necessary to protect themselves and others working in the vicinity.
During testing and dehydration, hazards may arise that may not have been fully controlled. This may include the possibility of unexpected high pressure in the pipe from internal faults or irregularities, as well as the failure of the pipe itself under full test pressure from undetected defective welds. Such situations may exceed the design capacity of the fasteners. Therefore, access to the test area can be limited to only those persons who are necessary for the test.
The maximum value of the test pressure is set by calculations for the strength of steam and hot water boilers.
The value of the test pressure (between the maximum and minimum) should ensure the greatest detection of defects in the boiler or its elements subjected to hydraulic testing.
172. The value of test pressure during hydraulic testing metal vessels(with the exception of cast), as well as electric boilers are determined by the formula:
It is recognized industry practice to secure or restrain dewatering piping to prevent death or serious injury when a dewatering piping ruptures. A full technical analysis must be carried out to determine the requirements for the installation and use of drainage systems. For these temporary pipelines, engineering structures and installation methods. In addition, employees involved in the installation of temporary pipelines must be trained in these designs and methods, and they must follow them when installing these temporary systems.
Where P - design pressure in case of additional production at the place of operation, in other cases - working pressure, MPa;
Permissible 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 the vessel (electric boiler) operating under pressure is taken according to the used materials of the elements (shells, bottoms, flanges, branch pipes, 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.
Employers must also ensure that couplings and piping systems are reliable and can withstand pressure. To this end, employers must ensure that proper procedures are followed and that employees who conduct de-irrigation processes are appropriately trained and aware of the proper procedures for limiting or securing watering lines. Following recommendations help reduce the risk of injury to mine action workers.
On the initial stage planning a dewatering operation, it is necessary to conduct a technical analysis of the existing and temporary piping system to determine the pressure associated with liquids and other forces that may adversely affect the integrity of the pipeline or the stability of the drainage and its components. The employer must design the dewatering system and develop installation methods based on the expected forces of the particular project. Alternatively, designs and methods can be developed for a "worst case" scenario that can be applied to all decontamination projects. It is industry practice to properly secure or secure dewatering pipelines to prevent movement and separation of the pipeline. Employers must create efficient systems bindings based on expected forces and ensure systems are used during dewatering projects. Ensure the condition of the couplings and parts. All couplings and parts of the dewatering system must be properly selected for their application. The associated piping that connects the couplings is a significant variable in the entire mechanical piping system. Couplings are manufactured in a controlled environment and differences in coupling quality should be limited. Employers must ensure that the couplings are within the manufacturer's tolerances and free from damage that could cause a connection to fail. A chain is only as strong as its weakest link - in drainage systems without water, the weakest link is often temporary dehydration and proper connection and fastening methods. Employers must ensure that employees understand the potential hazards of improperly installed dewatering systems, provide employees with a means of determining whether a pipe groove meets manufacturer's requirements, and the procedures they must implement to protect themselves and others working around them. Correct procedures. Employers must ensure that proper installation and dehydration procedures are followed in the workplace. Recommended Occupational Safety Practices for Drilling and Servicing Oil and Gas Wells.
- Examine the piping system.
- Attach water lines.
- American Petroleum Institute.
- Army Corps of Engineers.
- Occupational Safety and Health Guide.
The test pressure when testing a vessel calculated by zones should be determined taking into account the zone, the design pressure or design temperature of which is less important.
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 pressure values for each mode.
The test device includes a pressure transducer configured to measure the pressure in the vessel. The processor is configured to control during the test, the number of pulses transmitted from the pump and the pressure detected by the pressure sensor. The graphical user interface includes input fields for receiving user input of test parameter information and further includes a graphical representation of stroke readings and real-time measured pressure during a test.
A portable test device for carrying out a pressure test on a vessel, in which, during the test, an additional amount of liquid is supplied to the vessel by each successive pump stroke, the test device comprising:
If, in order to ensure strength and tightness conditions during testing, it becomes necessary to increase the diameter, number or replacement of the material of bolts (studs) of flange connections, it is allowed to reduce the test pressure to the maximum value at which, during testing, the strength conditions of bolts (studs) are provided without increasing them diameter, quantity or replacement of material.
A processor configured to monitor and store, during a test, the number of pump revolutions and the pressure detected by a pressure transducer. The test apparatus of claim 1, further comprising temperature sensors for measuring temperature and pipe temperature, respectively, wherein the processor is configured to monitor and store both measured temperatures during testing.
The test apparatus of claim 1, wherein the processor is configured to collect sequential data sets, each data set including a stroke counter and a pressure value at that number of cycles and after collecting each sequential data set to calculate the difference between the stroke count of the current data set and the number of attempts of the previous data set and generate the first alarm if the difference exceeds the first specified threshold. The test apparatus of claim 7, wherein the processor is configured to determine the first threshold based on a difference between pressure values of two data sets that were collected some time before the recently collected two data sets were collected.
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 is determined on the basis of the ultimate strength or creep limit, it is allowed in formulas (1), instead of using the allowable stress at the design temperature , obtained only on the basis of time-independent characteristics: yield strength and tensile strength without taking into account creep and long-term strength.
During hydraulic testing of technological pipelines, the value of the test pressure is determined by the formula (1) .
173. The value of test pressure during hydraulic testing of cast and forged vessels is determined by the formula
It is allowed to test castings after assembly and welding in an assembled unit or a finished vessel with a test pressure accepted for vessels, subject to 100% control of castings by non-destructive methods.
174. Hydraulic testing of vessels and parts made of non-metallic materials with an impact strength of more than 20 J / cm2 must 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/cm2 or less must be carried out with a test pressure determined by the formula:
175. The value of test pressure during hydraulic testing of cryogenic vessels in the presence of vacuum in the insulating space is determined by the formula:
176. Hydraulic testing of metal-plastic vessels must be carried out with a test pressure determined by the formula:
Where is the ratio of the mass of the metal structure to total mass vessel;
1.3 - for non-metallic materials with an impact strength of more than 20 J/cm2;
1.6 - for non-metallic materials with an impact strength of 20 J/cm2 or less.
177. Hydraulic testing of vessels installed vertically may be carried out in a horizontal position; in this case, the strength of the vessel body must be calculated taking into account the accepted method of support for hydraulic testing.
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 must be established by the developer of the design technical documentation and is listed in the user manual for the vessel.
178. The minimum value of test pressure during hydraulic testing of pipelines of steam and hot water, their blocks and individual elements should be 1.25 working pressure, but not less than 0.2 MPa. 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 set by calculations for the strength of pipelines.
The value of the test pressure (between the maximum and minimum) should ensure the greatest detection of defects in the pipeline or its elements subjected to hydraulic testing.
179. For hydraulic testing of equipment under pressure, water should be used. The water temperature should not be lower than 5 °C and not higher than 40 °C, unless the technical documentation of the equipment manufacturer specifies a specific temperature value that is allowed 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 upper limit water temperature can be increased by agreement with the design organization up to 80 °C. If the metal temperature of the top of the drum exceeds 140 °C, filling it with water for hydraulic testing is not allowed.
The water used for hydraulic testing must not contaminate the equipment or cause severe 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 substantiated cases provided by the manufacturer, it is allowed to use another liquid when conducting a hydraulic test during the operation of vessels.
180. When filling equipment with water, air must be completely removed from it.
The pressure in the equipment under test should be raised smoothly and evenly. The total pressure rise time (up to the test value) must be indicated in the technological documentation. Water pressure during hydraulic testing should be controlled by at least two pressure gauges. Both pressure gauges choose the same type, measurement limit, the same accuracy classes (not lower than 1.5) and divisions.
The use of compressed air or other gas to pressurize equipment filled with water is not permitted.
The exposure time under test pressure for steam and hot water boilers, including electric boilers, steam and hot water pipelines, as well as vessels assembled at the installation site, is set by the manufacturer in the operating manual and must be at least 10 minutes.
The exposure time under test pressure of vessels of element-by-element block supply, additionally manufactured during installation at the place of operation, must be at least:
A) 30 min. with vessel wall thickness 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 of more than 100 mm.
For cast, non-metallic and multilayer vessels, regardless of the wall thickness, the holding time must be at least 60 minutes.
The exposure time of process pipelines under test pressure during a hydraulic test must be at least 15 minutes.
If the process pipeline is tested together with the vessel (apparatus) to which it is connected, the exposure time is taken according to the time required for the vessel (apparatus).
181. After exposure under test pressure, the pressure is reduced to a value justified by the strength calculation, but not less than the operating pressure, at which visual inspection of the outer surface of the equipment and all its detachable and one-piece connections is carried out.
182. During a hydraulic test, the boiler is considered to have passed the test if it is not found:
A) visible residual deformations;
B) cracks or signs of rupture;
C) leaks in welded, detachable joints and in the base metal;
The equipment and its elements, in which defects are revealed during the hydraulic test, after they are eliminated, are subjected to repeated hydraulic tests with test pressure.
186. Hydraulic testing of technological pipelines with a pressure of not more than 10 MPa, as well as vessels, may be replaced by a pneumatic test ( compressed air, an inert gas or a mixture of air with an inert gas) subject to simultaneous control by the method of acoustic emission.
Test pressure during pneumatic testing should be determined by the formula:
Where: P - working pressure.
If the probability of brittle fracture during a pneumatic test is greater than under operating conditions, and its consequences represent a significant danger, the test pressure must be reduced to a technically justified level, but not less than the operating pressure.
In technically justified cases provided by the manufacturer, when conducting pneumatic tests, during operation of the equipment, it is allowed to use the gaseous working medium of the test object as a loading medium, while the test pressure is determined by formula (7) .
Vessel holding time ( process pipeline) under test pressure during pneumatic testing should be at least 15 min. and indicated in the technological documentation.
After exposure under test pressure, the pressure is reduced to a value justified by the strength calculation, but not less than the operating pressure, at which visual inspection of the outer surface and the tightness of welded and detachable joints are carried out.
General information
Based on the Rules technical operation thermal power plants (approved by order of the Ministry of Energy of the Russian Federation dated March 24, 2003 N 115), heating network enterprises during the operation of thermal network systems must ensure the reliability of heat supply to consumers, the supply of heat carriers (water and steam) to them with a flow rate and parameters in accordance with temperature graph regulation and differential pressure at the inlet.
During operation, all operating heating network must be tested for strength and density to detect defects no later than two weeks after the end of the heating season.
Hydraulic tests pipelines of water heating networks in order to check the strength and density should be carried out by test pressure with the results entered into the act.
Trial pressure - excess pressure at which a hydraulic test of thermal power plants and networks for strength and density should be carried out.
The minimum value of the test pressure during a hydraulic test is 1.25 working pressure, but not less than 0.2 MPa (2 kgf / cm 2).
The maximum value of the test pressure is set by the strength calculation according to the normative and technical documentation agreed with the Gosgortekhnadzor of Russia. The value of the test pressure is chosen by the manufacturer (design organization) within the limits between the minimum and maximum values.
Hydraulic tests are carried out by the person responsible for safe operation heating networks together with personnel authorized to operate heating networks.
Hydraulic tests
When conducting hydraulic tests for the strength and density of heat networks, the equipment of heat networks (stuffing box, bellows compensators, etc.), as well as sections of pipelines and connected heat-consuming power plants that are not involved in the tests, should be turned off with plugs.
Strength and density tests are carried out in the following order:
disconnect the tested section of the pipeline from the existing networks;
at the highest point of the section of the pipeline under test (after filling it with water and venting), set the test pressure (control by pressure gauge);
the pressure in the pipeline should be increased smoothly;
the rate of pressure rise must be specified in the regulatory and technical documentation (NTD) for the pipeline.
Strength and density tests are carried out in compliance with the following basic requirements: pressure measurement during testing should be carried out using two certified spring pressure gauges (one - control) of class at least 1.5 with a case diameter of at least 160 mm. The pressure gauge must be selected from the condition that the measured pressure value is within 2/3 of the instrument scale; test pressure must be provided at the top point (mark) of the pipelines; water temperature should not be lower than 5 °C and not higher than 40 °C; when filling with water, air must be completely removed from the pipelines; the test pressure must be maintained for at least 10 minutes and then reduced to working pressure; at operating pressure, a thorough inspection of pipelines along their entire length is carried out.
The test results are considered satisfactory if during the test there was no pressure drop and no signs of rupture, leakage or fogging were found in the welds, as well as leaks in the base metal, in valve bodies and glands, in flanged joints and other pipeline elements. In addition, there should be no signs of shifting or deformation of pipelines and fixed supports.
An act of the established form is drawn up on the results of testing pipelines for strength and density.
The results of hydraulic tests of the pipeline for strength and tightness are considered satisfactory if during their implementation there was no pressure drop, no signs of rupture, leakage or fogging in welds, as well as leaks in the base metal, flange joints, fittings, compensators and other elements of pipelines , there are no signs of shear or deformation of the pipeline and fixed supports.
