Under 0. NOTE: Complete vertical welding before roundseam below is welded. If the material specification is unknown or obsolete, test coupons for the procedure qualification shall be taken from the actual plate to be used. Adding reinforcement plate to an unreinforced penetration. Installing a hot-tap connection.
Consideration should be given for extra NDE on hot taps. Additionally, plate greater than 1", the back- gouged surface of root pass and final pass each side shall be examined over its full length by a magnetic particle or liquid penetrate test. New plate to new plate: Same as API New plate to existing plate: Same as API , plus one 1 additional radiograph. Existing plate to existing plate: Same as API , plus one 1 additional radiograph.
New plate to existing plate: Same as API , plus one 1 additional radiograph for each 50 feet of horizontal weld. Existing plate to existing plate: Same as API , plus one 1 additional radiograph for each 50 of horizontal weld.. New plate to existing plate: Shall be radiographed. Existing plate to existing plate: Shall be radiographed. NOTE: All junctions between repair and existing weld shall be radiographed. A reconstructed tank. Any tank that has had major repairs or alterations See A tank where an engineering evaluation indicates the need for the hydrostatic test.
Major would therefore include: a. The installation of any shell penetration beneath the design liquid level larger than 12" or any bottom penetration within 12" of the shell.
Any shell plate beneath design liquid level or any annular plate where the longest dimension of plate exceeds 12". New bottom installation if the foundation under the new bottom is not disturbed.
The Annular ring remains intact 2. The welding repair does not result in welding on the existing bottom within the critical zone.
Partial of complete jacking of a tank shell. The repair has been reviewed and approved by an engineer, in writing. The tank owner or operator has authorized the exemption in writing. The Maximum spacing between measurement points shall be 32 feet. The following information is required a. Reconstructed to API Year reconstruction completed. If known, the original applicable standard and original date.
Nominal diameter f. Nominal height. Design specific gravity of product stored. Maximum permissible operating liquid level. Material for each shell course. Maximum operating temperature. Allowable stress used in calculations for each course. Component integrity evaluation, including brittle fracture considerations.
Re-rating data including liquid level. Repair and alteration considerations. Inspections including "t" measurements. Radiographs to be retained for at least one year. Brittle fracture considerations. Original construction data. Description of tank diameter, height and service. Design conditions i. Shell material and thickness by course. Tank perimeter elevations. Construction completion record. Basis for hydrostatic test exemption Initial settlement survey, at erection and hydro.
Planned frequency, per soil settlement predictions c. For existing tanks with no settlement history , monitoring should be based on visual observations and prior service history.
Tank should be emptied and releveling repair conducted. Localized bottom plate repair. Partial releveling of tank periphery. Major releveling of shell and bottom.
Local depressions may require other techniques. May vary in magnitude, depending on soil characteristics. It is the least severe or threatening settlement problem. It does not introduce stress in tank structure, but does present a potential problem for piping, nozzles and attachments. Rotates the tank in a tilted plane. Can also cause binding of peripheral seals in a floating roof and inhibit roof travel. This may be visible in the form of elongation of top shell ring in floating roof tanks.
Can affect tank nozzles that have piping attached to them. Due to a tank shell being a rather flexible structure, non-planer configuration type settlement often occurs.
Potential Problems: a. Increased stress levels. Elongation of upper shell. Floating roof travel interference and potential seal damage or roof "hang-up". Development of shell flat spots. Therefore, this type problem becomes very important to determine severity and evaluate properly.
Common approach for settlement survey: a. Obtain transit survey from the correct number of evenly spaced points. Determine magnitude of uniform and rigid body tilt from each point on tank periphery.
Develop a graphic line point representation of the involved data. A stress analysis method is now included in this paragraph.
B-4 for pictorial view. Localized bottom plate stresses. Void severity below the bottom plate. Not normally seen as extreme problem. When occurring, normally associated with new tank where no or insufficient load bearing soil test borings have been made.
Each condition must be evaluated, based on service conditions, construction materials, soil characteristics, foundation design and prior service history. The formula for calculating the maximum permissible deflection is shown on page B Requires technical assistance. Various repair techniques are acceptable. See Section 9. Several new figures have been added to Appendix B, however the bases for the new figures and requirements have been challenged.
There is no bases for the information in the figures.. The user is left to his own devices as how to use this information. Use these as guidance items only. Numerous items need not be checked by the inspector, but rather by plant personnel. Table C-1 In Service Inspection checklist includes separate items. The Technical Inquiry Responses have also been listed, but are not a part of the exam.
This information is useful in actual application of API This is a very good section that will be useful to the user. This is G. One common type of G. It does not include aboveground storage tank inspector the visual examination that is included in certified by API see 3. The procedure can include multiple methods and tools, G. This record must contain the data for all essential G. This G. APIC b. API c. API 2. Which of the following have the ultimate responsibility for complying with API standard provisions?
On-site Inspector b. Contractor Involved c. Relevant State or Federal Agency 3. Internal pressures inside tanks may vary. Which of the following pressures represent the maximum amount and is still considered to be atmospheric storage? What is the joint efficiency of a lap riveted joint with one 1 row of rivets? Where a testing medium other than water was used. When external UT "t" measurements are used to determine a rate of general, uniform corrosion relevant to shell integrity which of the following values cannot be exceeded?
What primary factor determines the interval between internal and external inspections? Jurisdictional regulations b. Tank service history, unless special reasons indicate an earlier inspection is required.
Known or suspected corrosion activity of product. What is the minimum dimension for a shell ring replacement piece or segment?
The actual area requiring renewal, plus 6" on all four surrounding sides. Which of the areas described below are considered to be the "critical zone" involving tank bottom repair? Within the annular ring, within 12" of shell, or within 12" of inside edge of annular plate ring.
Any area where 3—plate laps are located c. Within 36" measured vertically from any shell penetration above. Within 3" from the shell on the bottom plates Select the minimum number of "t" measurements required along the circumference of any proposed "hot-tap" nozzle location : a. One 1 on horizontal centerline 3" from edge on each side of proposed shell opening cut.
Four 4 c. Eight 8 d. Establishment of both a minimum and average "t" over the entire nozzle installation area. What type of contour cut if any and what degree of bevel if any is required on the nozzle "barrel" end that is to be joined to shell during a "hot-tap". Cut to shell contour and outside beveled for full penetration attachment weld. No contour cut required. When reconstructing tank shells with a material "t" exceeding 1. In re-erecting a tank shell, what length "sweep-board" and what are maximum allowable values for weld seam peaking?
AWS b. Relevant to new or repaired vertical joints in existing shell plates, how many radiographs are required? Twice those required by API API requirements plus one 1 in every joint. One 1 for each welder or operator involved on each ring. Two 2 for each welder or operator involved on each ring for all plate thicknesses. There is one area of general corrosion on the north side of the shell 38 inches wide and 20 inches tall.
The tank was built to API , 7th Edition. Calculate the minimum thickness for the first course based on product alone. There are four pits lined vertically on the south side of the tank in the first course. The pits measure 1", 1.
The pit depth is approximately 0. A repair is required. Because of the vertical pits, no repair is required. If the pit depth is only. Scattered pits may be ignored. A bulge is found on the tank floor, the diameter of the bulge is 30 inches, what is the maximum permissible height for the bulge? An area of edge settlement in the tank bottom 6 feet from the tank shell has sloped down and settled. The settlement measures 2 inches at the deepest point. The edge settlement area has bottom lap welds approximately parallel to the shell.
A more rigorous stress analysis must be performed. The area must be repaired. Sloped edge settlement is usually no problem d. The area should be documented and checked during the next inspection. Figure B Using figure B the area is acceptable, it should be documented. NOTE: In larger tanks over feet in diameter , use of higher tensile strength steel, plus increased NDE procedures reduces plate "t". API stops at the face of the first flange.
API stops at the first sealing surface. API stops at the first threaded connection. API stops at the first circumferential weld. NOTE: Most common plates used: 1. ASTM A 3. Customer may require a set of charpy v-notch impact specimens.
Special toughness requirements may be specified. NOTE: Also must be at least as thick as primary plate! Shell nozzles and manway materials shall be equal or greater yield and tensile strength and shall be compatible with the shell material.
Be knowledgeable about the eight 8 types listed. Verticals shall be butt joints with complete penetration and fusion that will provide the same quality of deposited metal on both outside and inside weld surfaces.
Vertical joints in adjacent shell courses shall not be in alignment. An off-set from each other of "5t" where "t" is the thickest course at the point of offset. Welded on top side only full fillet only.
On other than annular doughnut rings the plate under the shell must have the outer end of the joint fitted and welded to form a smooth bearing for the shell plate. Parallel edges - either square or v-grove beveled. A 12" minimum space from each other or tank shell also applies.
See Par. Two 2 weld passes minimum are required. Welded top side only with continuous full-fillet. Butt welds are also permitted. Top angle horizontal leg may extend either inside or outside. A 1" minimum width to project beyond outside edge of shell, on lap weld bottoms i. Annular bottom plates must be 24 inches wide. A 2 inch projection beyond the outside of the shell.
NOTE: Normally designed to be filled with water i. Required shell "t" including CA for design product and hydro test. Nominal "t" used, i. Material specification.
Allowable stresses. Tables , , , , , , and A great deal of confusion has been relieved with the addition of figure , minimum weld requirements for openings in shells according to section 3. NOTE: Self-supported roofs may require thicker plate. The maximum spacing for inner ring rafters i. Not necessary if "I" or "H" sections are used as rafters. If pipe, it must be sealed or provisions for draining or venting made.
Raja Ahmed Hassan. Sunil Vp. Popular in Science. Ahlem Lahidheb Blagui. Johnard Jumagdao. Umer Khan. Itoqui Guillen. Zabala Duval ZD Ingenieria. Keyang Sun. Chintakayala Saikrishna. Guen Min Shiti. Peter Thomson. Veeresh Kabadi. Marcelo Passos. Zubair Ahmed. Elliot Benner. Dua persyaratan terakhir ini pada dasarnya berarti bahwa hanya pemilik komponen perangkat keras yang cukup baru yang akan diberikan akses ke pembaruan Windows Menurut Microsoft, persyaratan ini ditempatkan untuk memastikan keamanan yang lebih besar bagi pengguna dan data mereka.
Meskipun ringan, aplikasi diagnostik sistem ini dapat membantu siapa saja untuk menentukan apakah PC mereka siap untuk Windows Thereafter, without regard to the number of welders or welding operators, one additional spot radiograph shall be taken in each additional 30 m ft approximately and any remaining major fraction of vertical joint of the same type and thickness 1.
In addition to the foregoing requirements, one random spot radiograph shall be taken in each vertical joint in the lowest course 3 see the top panel of Figure 8. Vertical spot radiograph in accordance with 8.
Horizontal spot radiograph in accordance with 8. Vertical spot radiograph in each vertical seam in the lowest course see 8. Spot radiographs that satisfy the requirements of Note 1 for the lowest course may be used to satisfy this requirement.
Complete radiograph of each vertical seam over 25 mm 1 in. The complete radiograph may include the spot radiographs of the intersections if the film has a minimum width of mm 4 in. In addition, all junctions of vertical and horizontal joints in plates in this thickness range shall be radiographed 4 ; each film shall clearly show not less than 75 mm 3 in.
In the lowest course, two spot radiographs shall be taken in each vertical joint: one of the radiographs shall be as close to the bottom as is practicable, and the other shall be taken at random see the center panel of Figure 8. All junctions of vertical and horizontal joints in this thickness range shall be radiographed 4 ; each film shall clearly show not less than 75 mm 3 in. All junctions of vertical and horizontal joints in this thickness range shall be radiographed; each film shall clearly show not less than 75 mm 3 in.
Thereafter, one radiograph shall be taken in each additional 60 m ft approximately and any remaining major fraction of horizontal joint of the same type and thickness.
These radiographs are in addition to the radiographs of junctions of vertical joints required by Item c of 8. If two welders or welding operators weld opposite sides of a butt joint it is permissible to examine their work with one spot radiograph.
If the radiograph is rejected, additional spot radiographs shall be taken? The film shall be centered on the weld and shall be of sufficient width to permit adequate space for the location of identification marks and an image quality indicator IQI penetrometer minimum diagnostic length of 6 in.
Extra care must be exercised in the interpretation of radiographs of single- welded joints that have a permanent back-up bar. In some cases, additional exposures taken at an angle may determine whether questionable indications are acceptable.
The minimum radiographic length of each radial joint shall be mm 6 in. Locations of radiographs shall preferably be at the outer edge of the joint where the shell plate and annular plate join. Final acceptance of radiographs shall be based on whether the prescribed penetrameter image and the specified hole can be seen. API 8. Degree of Unacceptable imperfections Radiographic Examination.
If the weld at either of the adjacent sections fails to comply with the requirements of 8. If the welding is replaced, the inspector shall have the option of requiring that one radiograph be taken at any selected location on any other joint on which the same welder or welding operator has welded.
If any of these additional spots fail to comply with the requirements of 8. Only the cutting out of defective joints that is necessary to correct the defects is required. Gasket see Note 1 : mm 20 in. OD c mm 20 in. OD c mm 24 in. OD c mm 30 in. OD c mm 36 in. Figure Rounded corners T b mm [6 in.
See mm 36 in. Gasket material shall be specified by the Purchaser. See 5. The minimum centerline elevations allowed by Table 5. The gasketed face shall be machine-finished to provide a minimum chaser. See Table 5. For Dimension DP see Table 5. Table 5. The size of the weld shall equal the thickness of the thinner member 9. When design and construction details are not given, and are not available in the as-built standard, details that will provide a level of integrity equal to the level provided by the current edition of API must be used.
This standard recognizes fitness-for-service assessment concepts for evaluating in-service degradation of pressure containing components.
0コメント