Structural length of metal valves for flanged piping systems Piping and equipment pressure and leakage test scheme

Structural length of metal valves for flanged piping systems Piping and equipment pressure and leakage test scheme

References ARE INCLUDED IN THE TEXT OF THIS European STANDARD AT APPROPRIATE PLACES, INCLUDING REFERENCE STANDARDS WITH OR WITHOUT DEADLINES, AS WELL AS ARTICLES FROM OTHER PUBLICATIONS (STANDARDS CITED ARE ATTACHED BELOW). In the case of a REFERENCE standard marked with a deadline, the correction and revision shall apply only if this European STANDARD provides for the adoption of a subsequent modified or modified version of the reference STANDARD. For reference standards not marked with a deadline, the *** version is used. (face to face (FTF)) construction length (for straight through valves) is expressed in millimeters…
The introduction
Structural length tables (face to face and center to face) have been prepared for EN 558-1 metric series valves and EN 558- 2 inch series valves.
The basic series in this STANDARD are derived FROM THE series shown in Appendix A(INFORMATIVE).
Changes to the original series are not automatically incorporated into this standard.
The numbering of the basic series is consistent with that of 1SO/DIS 5752:1993.
1 scope
This ARTICLE specifies the inch face to face (FTF) CONSTRUCTION length and center to face (CTF) construction of metal valves for flanged piping systems
Length.
This section includes valves with the following pound class and nominal size (DN).
– The 125, 150, 250, 300 and 600 pound classes.
DN10, DN15, DN20, DN25, DN32, DN40, DN50, DN65, DN80, DN100, DN125,DN150, DN200, DN250, DN300, DN350, DN400, DN450, DN500, DN600, DN700, DN750,DN800, DN900, DN1000, DN1200, DN1400, DN1600, DN1800 and DN2000.
EN 26554 specifies the face – face construction length of automatic steam traps.
2 Reference Standards
References ARE INCLUDED IN THE TEXT OF THIS European STANDARD AT APPROPRIATE PLACES, INCLUDING REFERENCE STANDARDS WITH OR WITHOUT DEADLINES, AS WELL AS ARTICLES FROM OTHER PUBLICATIONS (STANDARDS CITED ARE ATTACHED BELOW). In the case of a REFERENCE standard marked with a deadline, the correction and revision shall apply only if this European STANDARD provides for the adoption of a subsequent modified or modified version of the reference STANDARD. For reference standards not marked with a deadline, their version is used.
En736-1 Valve terminology
Chapter 1 Valve type definition
EN26554 Automatic steam traps with flanges – side structure length
3 define
For the purposes of this standard, prEN 736-1 and the following definitions apply.
3.1 (Face to face (FTF)) construction length (for straight through valves) Distance in millimeters between two planes located at the ** end of the body channel and perpendicular to the body axis line. Or as specified in the relevant valve product standard (see Figures 1 and 2).
3.2(Center-face (CTF)) Construction Length (for angular valves) Distance in millimeters between one of two planes at the ** end of the body passage and perpendicular to the axis line of its passage and the axis line at the other end of the body passage (see Figures 1 and 2)
Structural length and tolerance
4.1 Basic Series
The basic series of face-to-face (FTF) and center-to-face (CTF) structural lengths shall conform to the specifications in Table 1. The BASIC SERIES TO BE CONSIDERED FOR EACH TYPE OF VALVE ARE GIVEN IN TABLES 3 THROUGH 17.
4.2 Structural length of unlined valves
4.2.1 Flat flange suitable for the valve flat flange:
– gray cast iron flanges, class 125;
– Copper alloy flanges for classes 150 and 300 LBS.
The length of the face-face (FTF) and center-face (CTF) structures should be consistent with Figures 1 and 2.
4.2.2 Convex flanges applicable to the valve include:
– Flange with 1.6mm convex table top
– gray cast iron flange, class 250 LBS.;
– Malleable cast iron flanges for classes 150 and 300:
– Steel flanges for classes 150 and 300.
– Flange with 6.4mm convex table top
– Steel flanges, class 600 LBS.
The length of the face-face (FTF) and center-face (CTF) structures should be consistent with Figures 1 and 3.
4.2.3 Ring connection flanges are suitable for valves designed to connect flange faces with metal rings having octagonal or elliptical profile structure. The length of FTF and CTF structures should be consistent with FIG. 4.
4.2.4 Other flange faces are suitable for Class 150, 300 and 600 valves with internal and external threaded surfaces or with convex and concave surfaces. The length of the face-to-face (FTF) and center-to-face (CTF) structures should be consistent with Figures 1 and 5.
4.3 Structural length of lined valves
4.3.1 For valves with gaskets connected to elastic lining matching flanges, the face. Face (FTF) AND CENTER – FACE (CTF) STRUCTURE LENGTHS SHALL BE THE DISTANCE BETWEEN THE TWO ENDS OF THE VALVE UNDER MOUNTING conditions. The manufacturer shall provide the overall length of the valve prior to assembly.
4.3.2 For elasto-lined or hard-lined valves as a common production characteristic, the thickness of the lining on the matching surface shall be included within the length of the face-to-face (FTF) and center-to-face (CTF) construction, unless the valve design does not include this part. If THE FACE-TO-FACE (FTF) AND CENTER-TO-FACE (CTF) LENGTHS given IN TABLE 1 are NOT DESIGNED to INCLUDE LINING SECTIONS, THEN THE LENGTH OF SUCH LINING SHALL BE ADDED TO THE BASE DIMENSIONS.
4.3.3 For valves with elastic or hard lining that are not normally a feature of production, the lining thickness on the flange face may be added to the face-to-face (F”TF) and center-to-face (CTF) structural lengths given in Table I.
4.4 Tolerances Tolerances for the length of face-to-surface (FTF) and center-to-surface (CTF) structures are given in Table 2.
Figure 1
FIG. 2 Flat flange
FIG. 3 Convex flange
(face – face) Structure length = Table 1 dimensions +X
(Center side) Structure length = Table 1 dimensions + 0.5x unit mm
Figure 4.
Note.FTF=(face – face) structure length; CTF=(center-face) structure length.
The unit is millimeter.
The dimensions in Table 1.
Figure 5
Pipeline and equipment pressure and leakage test scheme 1, preparation basis 1. Gb50235-2003 “Industrial metal pipeline engineering Construction and acceptance Code” 2. Gb50236-2001 “Field equipment, process pipeline welding engineering construction and acceptance Code” 2, the purpose of pressure and leakage test and use of medium after the construction and installation of any equipment, pipeline, In order to test the construction quality and prevent accidents caused by running, running, dripping and leakage during production, pressure test and leakage test should be carried out at welding points, valves and flange joints before commissioning test. Generally speaking, the pressure vessel and the pipeline pressure test water as the medium
First, the preparation basis
1. Gb50235-2003 Code for Construction and Acceptance of Industrial Metal Pipeline Engineering
2. Gb50236-2001 “Code for Construction and Acceptance of Welding Engineering of Field Equipment and Pipeline Process”
Two, the purpose of pressure and leakage test and the use of medium
After the construction and installation of any equipment and pipeline, in order to check the construction quality and prevent accidents caused by running, running, dripping and leakage during production, pressure test and leakage test should be carried out at the welding point, valve and flange connection before the commissioning test.
Generally speaking, the pressure vessel and pipeline pressure test water as the medium, and shall not use dangerous liquid. For the gas pipeline whose nominal diameter is greater than 500mm, the safety bearing capacity of the pipeline corridor may not be enough when the pressure test is carried out with water, so air or nitrogen can be used as the pressure test medium.
Since the risk of air pressure test is much greater than that of water pressure test, except for the requirements stipulated in the design drawing to replace liquid for pressure test and take reliable safety measures, other equipment and pipelines are not allowed to use gas for pressure test.
Three. Preparation before pressure test and leakage test
1. Installation and inspection of equipment pipelines and accessories;
2. Repeatedly check the equipment and pipeline under pressure test to see if the process is correct;
3. Before the pressure test, all safety valves and pressure gauges should be closed at the root valve, and the relevant instruments should be isolated or removed to prevent take-off or over-range damage;
4. Clean the environment of pressure test and leakage test
5. The personnel participating in the pressure test and leakage test have passed the technical training;
6. Prepare water pressure pump, air pressure pump and other equipment for pressure test and record of pressure test;
7. If there is external insulation, it should be carried out after pressure test.
Four, test construction requirements
1. In addition to painting and thermal insulation, the pipeline installation works within the test scope have been completed according to the drawings, and passed the inspection by supervision and on-site technical personnel.
2. During the pressure test, the test medium, pressure and stability time should meet the design requirements and be carried out in strict accordance with the relevant regulations.
3. When inspecting the equipment and pipes of the car, the side and opposite side of the flange and flange cover can not stand.
4. The pipeline is qualified for nondestructive inspection and reaches the detection ratio.
5. The test pressure gauge is qualified, and its accuracy is not less than 1.5 grade during the test period. The full scale of the table should be 1.5~2 times of the test pressure, and the pressure gauge for the pipe section should not be less than 2 pieces.
6. Effectively isolate the pipeline under test from irrelevant systems with blind boards or other measures, hang sign plates at the isolation place, and temporarily connect pipelines and reinforce equipment have been completed.
7. All pressure testing and air-tight machines are ready.
8 in the process of pressure test, pressure equipment, pipeline such as abnormal noise, pressure drop, surface paint peeling, pressure gauge pointer does not move or swing back and forth and other abnormal conditions, should immediately stop the test, pressure relief to find out the cause, is the specific situation in deciding whether to continue the test.
Five, pressure test leakage test quality standards
1. The equipment storing liquid under atmospheric pressure shall be free of leakage during the water injection test.
2. For equipment with operating pressure below 50KPa (gauge pressure), weld seams shall be inspected with ** shuo oil. If there is any defect, it shall be eliminated and the tightness test shall be carried out under operating pressure after elimination. The time is 24 hours, and the average leakage does not exceed 0.25% per hour.
3. The operating pressure in 50-700 kpa pressure (table) of equipment, with pressure equal to 1.25 times the test pressure strength test, the time for 5 minutes, then fell to operating pressure for inspection, if there are defects, to eliminate, eliminate test at operating pressure closely degrees, after time for 24 hours, average leak amount shall not exceed 0.25% per hour.
4. Vacuum equipment should be in 200KPa (gauge pressure) strength test for 5 minutes, and eliminate the defects found in the test, and then 100KPa (gauge pressure) pressure test for tightness test, time for 24 hours, the average leakage does not exceed 0.25% per hour.
5. For equipment with special design requirements, the test shall be carried out according to the design requirements.
Six, air pressure test leakage test
1. The test pressure is 1.25 times of the design pressure
2 pressure test boost speed should not be greater than 50KPa/min, boost to the test pressure of 50% stop 3min check, if there is no abnormal phenomenon, then 10% of the test pressure step by step boost. Stop for 10min at each stage, stop for 10min after reaching the designed pressure, and then carefully check all parts if there is still no abnormality, the pressure can be increased to the test pressure. Stop for 10min if there is no step-down, no leakage and no visual deformation, it is qualified.
3. After the pressure strength test is qualified, the pressure is reduced to the design pressure, and the tightness is checked by brushing soapy water.
4. The stop-pressure time of pressure tightness shall ensure that the whole system has enough inspection time, during which no leakage or depressurization phenomenon shall occur.
5 after the test should be slowly reduced pressure, discharge port should try to use the system of the empty pipe, such as temporary pipe should be connected to outdoor emissions, discharge port should not be placed in the place often through personnel.
6. In case of leakage during pressure test, it is not allowed to repair with pressure. It is necessary to release the pressure and re-test the pressure after the defect is eliminated.
7. The leakage test should focus on the inspection of valve stuffing box, flange or thread connection, vent valve, exhaust valve, drainage valve, gasket, welding port, no leakage to the blowing agent test for qualified.
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