API 510 (Pressure Vessel Inspection Code) – Flashcards

In-service inspection, repair, alteration, and rerating activities for pressure vessels and the pressure- relieving devices

a) vessels constructed with construction code b) vessels constructed with no construction code c) vessels constructed and approved as jurisdictional special d) A vessel fabricated with no nameplate or stamping

a. An authorized inspection agency b. A repair organization c. An engineer d. An inspector e. Examiners

a. If the requirements of this code are more stringent than the requirements of the regulation, then the requirements of this code shall govern. b. This code does not permit conflict with others regulatory requirements

a. Pressure vessels on movable structures ? Cargo or volume tanks for trucks, ships, and barges ? Air receivers associated with braking systems of mobile equipment. ? Pressure vessels installed in ocean-going ships, barges, and floating craft b. All classes of containers listed for exemption in the scope of the applicable construction code. ? Containers within the scope of other sections of the ASME Code ? Fired process tubular heaters ? Integral parts or components of rotating or reciprocating mechanical devices ? Structure transporting fluids from one location to another within a system ? Piping components ? vessel for containing water under pressure (Design Pressure 300 lbf/in.2 & Design temperature of 210ºF) ? Hot water supply storage tank heated by steam not exceed (200,000 Btu/hr, water temperature of 210ºF, water-containing capacity of 120 gal) ? Vessels with an internal or external operating pressure not exceeding 15 lbf/in.2 ? Vessels with an inside diameter, width, height, or cross-section diagonal not exceeding 6 in c. Pressure vessels that do not exceed the volumes and pressures ? Five ft3 volume and 250 lbf/in.2 design pressure. ? Three ft3 volume and 350 lbf/in.2 design pressure. ? One-and-one-half cubic feet in volume and 600 lbf/in.2 design pressure

a. API 579 Fitness for Service b. API 580 Risk-Based Inspection (RBI)

? API codes including RP 571-572, RP 576-582, Publ 2201 Procedures for Welding or Hot Tapping on Equipment in Service ? ASME including Section V,Section VIII: Division 1, Section VIII: Division 2, PCC-1, Section IX ? ASNT including CP-189, SNT-TC-1A ? NACE including RP 0472, MR 0103 ? OSHA 29 CFR Part 1910 Occupational Safety and Health Standards ? WRC Bulletin 412 Challenges and Solutions in Repair Welding for Power and Processing Plants ? National Board NB-23 National Board Inspection Code

Alternating current field measurement

A physical change in any component that has design implications that affect the pressure-containing capability of a pressure vessel

code generally accepted engineering standard or practice to which the pressure vessel was built or which is deemed by the owner/user or the engineer

a. The inspection organization of the jurisdiction b. The inspection organization of an insurance company c. The inspection organization of an owner or user of pressure vessels d. An independent organization or individual that is under contract to and under the direction of an owner/user

The rate of metal loss due to deteriotation with its environment

A person, acceptable to the owner/user, who has knowledge in corrosion

An imperfection, whose type or size, exceeds the applicable acceptance criteria.

Pressure vessel engineer who is knowledgeable and experienced in the engineering disciplines which affect the integrity and reliability of pressure vessels

a. A person who assists performing NDT on pressure vessel b. Does not evaluate the results of those examinations, unless specifically trained and authorized to do so by the owner/user c. No need API 510 d. The records shall be available to inspector

Corrosion that is distributed more or less uniformly

A point in the repair or alteration process beyond which work may not proceed until the required inspection been performed and documented

Flaws noted during inspection that may or may not exceed the applicable acceptance criteria.

A person who possesses an ultrasonic shear wave qualification from API (e.g. API-QUTE) or an equivalent qualification approved by the owner/user.

Inspection activities associated with a pressure vessel once it has been placed in service.

A legally constituted government administration

The lowest temperature at which a significant load can be applied to a pressure vessel

A condition where a pressure vessel has not been prepared for an internal inspection

An owner who exercises control over the operation, engineering, inspection, repair, alteration, pressure testing and rerating

a. The work necessary to restore a vessel to a condition suitable for safe operation at the design conditions. b. If any of the restorative work results in a change to the design temperature, MDMT, or MAWP, the work shall be considered an alteration and the requirements for rerating shall be satisfied.

The minimum thickness without corrosion allowance for each element of a pressure vessel based on the appropriate design code calculations and code allowable stress that consider pressure, mechanical and structural loadings.

A change in either the design temperature rating, the MDMT or the MAWP rating of a vessel

Strips of metal plates that are welded to the inside of the vessel wall

The reduction in toughness due to a metallurgical change as a result of long term exposure in the temperature range of about 650ºF - 1100ºF

The temperature at which a material fracture mode changes from ductile to brittle

developing, documenting, implementing, executing, and assessing pressure vessel inspection systems and inspection/repair procedures that meet the requirements of this inspection code includes reporting to the inspector any process changes or other conditions that could affect pressure vessel integrity.

Responsible to the owner/user and shall provide the materials, equipment, quality control, and workmanship that is necessary to maintain and repair the vessel accordance with the requirements of this inspection code.

a. Responsible to the owner/user to assure that the inspection, NDE, and pressure testing activities. b. Evaluated and accepted NDE Results

Operating, maintenance who have special knowledge related to particular pressure vessels shall be responsible for promptly making the inspector or engineer aware of any unusual conditions that may develop.

a. A strategy how and when a pressure vessel will be inspected, repaired, and/or maintained b. Developed by inspector or engineer c. Required corrosion specialist when vessel operate at elevated temp above 750oF d. Shall be evaluated based on present or possible types of damage mechanisms

Shall contain the inspection tasks and schedule required to monitor damage mechanisms and assure the mechanical integrity of the equipment ? Type(s) of inspection needed ? Identify the next inspection date ? Describe the extent and locations of inspection and NDE ? Describe the surface cleaning requirements needed for inspection ? Describe the requirements of any needed pressure test ? Describe any required repairs OPTIONAL ? Describing the types of damage anticipated or experienced in the equipment ? Defining the location of the damage ? Defining any special access requirements

a. Used to determine inspection intervals and the type and extent of future inspection/examinations b. Include a systematic evaluation of both the probability of failure and the consequence of failure

Based on all forms of damage that could reasonably be expected to affect a vessel in any particular service

The consequence of a release is dependent on type and amount of process fluid contained in the equipment

All RBI assessments be thoroughly documented i, clearly defining all the factors contributing to both the probability and consequence of a failure

a. The assessment shall be updated after each vessel inspection. b. Assessment shall be updated each time process or hardware changes are made that could significantly affect damage rates or damage mechanisms.

Safety precautions are important in pressure vessel inspection and maintenance activities because some process fluids are harmful to human health

All tools, equipment, and personal protective equipment used during vessel work should be checked prior to use

?. Personnel should obtain permission to work in the vicinity from operating personnel responsible for the pressure vessel. ? When inside a vessel, all persons working around the vessel should be informed that people are working inside the vessel. ? Individuals working inside the vessel should be informed when any work is going to be done on the vessel's exterior

? Prior to entering a vessel, the vessel shall be isolated from all sources ? Before entering a vessel, individuals must obtain permission from the responsible operating personnel

Inspectors shall familiarize themselves with prior history of the vessels for which they are responsible

The inspector should be familiar with conditions and with the causes and characteristics of potential defects and damage mechanisms.

a. Internal inspection. b. On-stream inspection. c. External inspection. d. Thickness inspection. e. Corrosion under insulation (CUI) inspection Imperfections identified during inspections and examinations should be characterized, sized, and evaluated

? An inspection performed from the inside of a pressure vessel using visual and /or NDE techniques ? Shall be performed by inspector accordance with the inspection plan. ? A primary goal is to find damage that cannot be found by regular monitoring of external CMLs ? For equipment not designed for entrance by personnel, inspection ports shall be opened for examination of surfaces ? Inspectors may inspect the non-pressure internals, if requested by other operations personnel, and report current condition to the appropriate operation personnel

? Consultation with the corrosion specialist needed when it is necessary to remove deposits or linings to perform adequate inspections. ? Whenever operating deposits, it is important to determine whether these deposits adequately protect the vessel or do not cause deterioration of the surface ? External NDE techniques may be advisable to explore for damage beneath linings.

a. An inspection performed from the outside of a pressure vessel while it is on-stream b. Should be conducted by either an inspector or examiner where examiner needed authorized and approved by the inspector c. In situations where on-stream inspection is acceptable, such inspection may be conducted either while the vessel is depressurized or pressured

? A visual inspection performed from the outside of a pressure vessel to find conditions that could impact the vessel's ability ? Performed by Inspector. Qualified personnel may conduct when acceptable to inspector and shall have appropriated training ? Any signs of leakage should be investigated so that the sources can be established. ? Vessels shall be examined for visual indications of bulging, out-of-roundness, sagging, and distortion. ? Any personnel who observe vessel deterioration should report the condition to the inspector.

Determine their external surface condition. The inspection interval shall be based on corrosion rate information obtained ? During maintenance activity on connecting piping of similar material ? From the interval examination of similarly buried corrosion test coupons of like material ? From representative portions of the actual vessel ? From a vessel in similar circumstances.

a. Taken to verify the thickness of vessel components b. Shall be obtained by the inspector or examiner. c. on-stream thickness monitoring is a good tool for monitoring corrosion and assessing potential damage due to process or operational changes. D. corrosion specialist should be consruct when the short term corrosion rate changes significantly from the previous identified rate to determine the cause

Forms of corrosion under insulation including stress corrosion cracking Shall be considered for externally-insulated vessels and those that are in intermittent service or operate between: ? 10°F and 350°F for carbon and low alloy steels ? 140ºF and 400ºF for austenitic stainless steels.

a. Carbon steel usually causes localized corrosion b. Austenitic usually in form of stress corrosion cracking c. When developing the inspection plan for CUI inspection, areas that are most susceptible to CUI should consider d. If CUI damage is found, the inspector should inspect other susceptible areas on the vessel.

a. It is not necessary to remove insulation for inspection of the vessel when it is in good condition b. Considerations for insulation removal are not limited to but include: ? History of CUI for the vessel or comparable equipment. ? Visual condition of the external covering and insulation. ? Evidence of fluid leakage, e.g. stains. ? Equipment in intermittent service. ? Condition/age of the external coating, if applicable.

Designated areas on pressure vessels where periodic examinations are conducted to monitor the presence and rate damage.

a. shall be monitored by performing a representative number of examinations at CMLs to satisfy the requirements for an internal or on-stream inspection b. Corrosion rates, the remaining life and next inspection intervals should be calculated to determine the limiting component. c. The rate of corrosion/damage shall be determined from successive measurements and the next inspection interval appropriately established. d. Where thickness measurements are obtained at CMLs, the minimum thickness at a CML can be located by ultrasonic measurements or radiography. e. The thinnest reading or an average of several measurement readings taken within the area of an examination point shall be recorded and used to calculate the corrosion rates. f. Examination points should be permanently recorded to allow repetitive measurements at the same CMLs. Repeating measurements at the same location improves accuracy of the calculated damage rate

A decision on the type, number, and location of the CMLs should consider results from previous inspections, the patterns of corrosion and damage that are expected and the potential consequence of loss of containment.

1. A close visual inspection of pressure vessel components should not be performed until the vessel pressure is at or below the MAWP. 2. the pressure-relieving device(s) should be removed when test that will conducted exceed the pressure test 3. Test clamps can be used to hold down the valve disks. 4. Applying an additional load to the valve spring by turning the compression screw is prohibited 5. When the pressure test has been completed, pressure-relieving devices and appurtenances removed or made inoperable during the pressure test shall be reinstalled or reactivated

1. Supporting structures and foundation design should be reviewed to assure suitable to conduct hydrostatic load. 2. Type 300 series stainless steel should be conducted with potable water or steam condensate having a chloride concentration of less than 50 ppm. 3. The vessel should be completely with inspector should verify the specified water quality used after drained and dried

? May be used when hydrostatic testing is impracticable ? When used, the potential personnel and property risks of pneumatic testing shall be considered by an inspector or engineer before conducting the test

? Most brittle fractures, however, have occurred on the first application of a high stress level (the first hydrostatic or overload) involved. ? Special attention should be given when testing low-alloy steels, especially 2-1/4 Cr-1Mo, because they may be prone to temper embrittlement

Appropriate NDE shall be specified and conducted when a pressure test is not performed after a major repair or alteration. Substituting NDE procedures for a pressure test after an alteration may be done only after the engineer and inspector have approved.

1. During repairs or alterations of pressure vessels, the inspector shall verify that all new materials (including carbon steel) are consistent with the specifications 2. At the discretion of the owner/user or the inspector, this assessment can be made by 100% verification checking or by sampling a percentage of the materials in critical situations.

When preferential weld corrosion or cracking is noted, additional welds of the pressure vessel should be examined.

? Flanged joints should be examined for evidence of leakage. ? Accessible flange faces should be examined for distortion and to determine the condition of gasket-seating surfaces. ? Flange fasteners should be examined visually for corrosion and thread engagement.

Pressure vessels shall be inspected by an inspector at the time of installation including: a. Verify the nameplate information is correct b. Verify equipment is installed correctly; supports are adequate and secured, exterior equipment c. Verify pressure-relieving devices satisfy design requirements Internal field inspection of new vessels is not required provided appropriate documentation, e.g. manufacturer's data reports, assures that the vessels comply with the specified designs.

? Inspection intervals shall be established for the new service conditions. ? If both the ownership and the location of a vessel are changed, the vessel shall be internally and externally inspected before it is reused.

? To establish the appropriate inspection intervals for internal, on-stream, and external inspections. ? When exceed 10 years, RBI shall be reviewed and approve by Engineer and Inspector at interval less than 10 years.

1) above ground vessel shall be given a GVI at an interval that does not exceed the lesser of five years or the required internal/on-stream inspection during operation. 2) Established by Engineer @ inspector

1) Shall not exceed one half remaining life or 10 years 2) When Remaining life less than 4 years, the remaining life up to max of 2 years. 3) Established by Engineer inspector accordance to owner

1) When the requirements of 6.5.2.1b are not met, the next inspection shall be an internal inspection. The assessment should include a review of past process conditions and likely future process condition 2) When an on-stream inspection is conducted, the type of extent of NDE should be specified in the inspection plan.

? For a large vessel with two or more zones of differing corrosion rates, each zone may be treated independently when determining the inspection intervals or for substituting the internal inspection with an on-stream inspection. ? Each zone shall be inspected based on the interval for that zone.

Pressure-relieving devices shall be tested and repaired by a repair organization experienced in valve maintenance

Each repair organization shall also have a fully documented training program that shall ensure that repair personnel are qualified within the scope of the repairs.

The inspection interval for all pressure-relieving devices is determined by either the inspector, engineer, or other qualified individual per the Owner/User's quality assurance system.

? Suitable use of short-term versus long-term corrosion rates shall be determined by the inspector. ? Short-term corrosion rates are typically determined by the two most recent thickness readings whereas long-term rates use the most recent reading and one taken earlier in the life of the equipment.

t (actual) = actual thickness CML in recent t (required) = required thickness at CML by design formula DOES NOT include corrosion allowance/tolerence

1) MAWP for the continued use of a pressure vessel shall be based on computations that are determined using the latest applicable edition of the ASME Code or the construction code to which the vessel was built. The result should be lower than original MAWP unless a rerating is performed The maximum gauge pressure permitted at the top of a pressure vessel in its operating position for a designated temperature.

Scattered pits may be ignored as long as all of the following are true: a. The remaining thickness below the pit is greater than one-half the required thickness (1/2 trequired). b. The total area of the pitting that is deeper than the corrosion allowance does not exceed 7 in.2 (45 cm2) within any 8-in. (20- cm) diameter circle. c. The sum of the pit dimensions that is deeper than the corrosion allowance along any straight 8-in. (20-cm) line does not exceed 2 in. (5 cm).

For a corroded area of considerable size the wall thicknesses may be averaged over a length not exceeding the following: ? For vessels with inside diameters less than or equal to 60 in. (150 cm), one-half the vessel diameter or 20 in. (50 cm), whichever is less. ? For vessels with inside diameters greater than 60 in. (150 cm), one-third the vessel diameter or 40 in. (100 cm), whichever is less.

When the vessel surface away from a weld is corroded and the joint efficiency is less than 1.0, an independent calculation using the appropriate weld joint factor (typically 1.0) can be made. For this calculation, the surface at a weld includes 1 in. (2.5 cm) on either side of the weld (measured from the toe) or twice the required thickness on either side of the weld, whichever is greater

The required thickness at corroded areas of ellipsoidal and torispherical heads can be determined as follows: a. In the knuckle region of the head, use the appropriate head formula in the construction code. b. In the central portion of the head, use the hemi-spherical head formula in the construction code. The central portion of the head is defined as the center of the head with a diameter equal to 80% of the shell diameter.

Services with high potential failure, engineer should consider increasing the required thickness above the calculated minimum thickness to provide for unanticipated or unknown loadings, undiscovered metal loss, or resistance to normal abuse

1. Perform inspection to determine condition of the vessel. 2. Define design parameters and prepare drawings. 3. Perform design calculations based on applicable codes and standards. Do not use allowable stress values of the current ASME Code (based on design factor of 3.5) for vessels designed to an edition or addendum of the ASME Code earlier than the 1999 Addenda and was not designed to Code Case 2290 or 2278.

Records shall contain four types of information pertinent to mechanical integrity as follows: a. Construction and design information. b. Inspection history. c. Repair, alteration, and rerating information. d. Fitness-for-service assessment documentation requirements are described in API 579, Part 2.8

1. All repair and alteration work must be authorized by the inspector before the work is started by a repair organization. 2. Alterations to pressure vessels that comply with ASME should an engineer has also authorized the work. The inspector will designate the hold points that are required. 3. The inspector may give prior general authorization for limited or routine repairs on a specific vessel provided the inspector is satisfied with the competency of the repair organization and the repairs are the kind that will not require a pressure test.

1. Inspector may establish hold points to be implemented during the work execution. 2. For alteration, engineer should be the one who approve 3. Before any repairs or alterations are performed, all proposed methods of design, execution, materials, welding procedures, NDE, and testing must be approved by the inspector 4. An engineer shall approve all nozzle installations.

? The material used in making repairs or alterations shall conform to the applicable construction code. ? Carbon or alloy steel with carbon content over 0.35% shall not be welded

Temporary repairs may remain in place for a longer period of time only if evaluated, approved, and documented by the engineer & inspector.

a. Location of the temporary repair b. Specific details about the repair c. Details of analyses performed d. Requirements for future inspections e. Due date for installing permanent repair

1. May be used to make temporary repairs 2. Cracks shall not be repaired in this manner unless the engineer determines that the cracks will not be expected to propagate from under the patch. In some cases, the engineer may need to perform a fitness-for-service analysis. 3. Temporary repairs using fillet-welded patches shall be approved by an inspector and engineer. 4.The use of fillet-welded patches may be subject to the acceptance of the governing jurisdiction.

a. The fillet-welded patches provide design safety equivalent to reinforced openings designed according to the applicable construction code. b. The fillet-welded patches are designed to absorb the membrane strain of the parts so that in accordance with the rules of the applicable construction code, the following result: 1. The allowable membrane stress is not exceeded in the vessel parts or the patches. 2. The strain in the patches does not result in fillet-weld stresses that exceed allowable stresses for such welds.

a. The design is approved and documented by the engineer and inspector. b. The repair is not covering a crack in the vessel shell. c. The band is designed to contain the full vessel design pressure. d. All longitudinal seams in the repair band are full penetration butt welds with the design joint efficiency and inspection consistent with the appropriate code. e. The circumferential fillet welds attaching the band to the vessel shell are designed to transfer the full longitudinal load in the vessel shell, using a joint efficiency of 0.45. Where significant, the eccentricity effects of the band relative to the original shell shall be considered in sizing the band attachment welds. f. Appropriate surface NDE shall be conducted on all attachment welds. g. Fatigue of the attachment welds, such as fatigue resulting from differential expansion of the band relative to the vessel shell, should be considered, if applicable. h. The band material and weld metal are suitable for contact with the contained fluid at the design conditions and an appropriate corrosion allowance is provided in the band. i. The damage mechanism leading to the need for repair shall be considered in determining the need for any additional monitoring and future inspection of the repair.

a. Excavating the defect, and blend-grinding to contour in accordance with API 579, Part 5. b. Excavating a defect and repair welding of the excavation. c. Replacing a section or the component containing the defect. d. Weld overlay of corroded area. e. Adding strip or plate lining to the interior surface.

a. Full-penetration groove welds are provided b. The welds are radiographed in accordance with the applicable construction code. Ultrasonic examination, by an industry-qualified UT shear wave examiner, may be substituted for the radiography if the NDE procedures are approved by the inspector. c. All insert plate corners that do not extend to an existing longitudinal or horizontal weld shall be rounded having a 1 in. (25mm) minimum radius. d. Weld proximity to existing welds shall be reviewed by the engineer.

filler metal used for weld repairs should have minimum specified tensile strength equal to or greater than the minimum specified tensile strength of the base metal

a. Repair thickness shall not be more than 50% of the required thickness of the base metal (excludes corrosion allowance). b. Thickness of the repair weld shall be increased by a ratio of minimum specified tensile strength of the base metal and minimum specified tensile of the filler metal used for the repair. c. The increased thickness of the repair shall have rounded corners and shall be blended into the base metal using a 3-to-1 taper. d. The repair shall be made with a minimum of two passes.

Shall be reviewed and approved by the engineer and inspector before implementation.

1. All repair and alteration welding shall be in accordance with the applicable requirements of the ASME Code or the applicable construction or repair code 2.Welders must weld within their ranges qualified on the WPQ(s) 3. WPQ(s) records shall be available to the inspector before the start of welding.

1. Preheat temperature used in making welding repairs shall be in accordance with the applicable code and qualified welding procedure. 2. Prior to used alternative method, metallurgy and exceptions must be approved by the engineer. 3. The inspector should assure that the minimum preheat temperature is measured and maintained.

May be substituted for 360-degree banding on local repairs on all materials

a. The application is reviewed, and a procedure is developed by an engineer experienced in the appropriate engineering specialties. b. The suitability of the procedure shall be evaluated based on (Base metal thickness, decay thermal gradients, material properties, changes due to local postweld heat treatment, the need for full penetration welds, surface and volumetric examinations after local postweld heat treatment and the overall and local strains and distortions) c. A preheat of 300ºF (150ºC) or higher, as specified by specific welding procedures, is maintained during welding. d. The required local postweld heat treatment temperature shall be maintained for a distance of not less than two times the base metal thickness measured from the toe of the weld e. Controlled heat shall be applied to any nozzle or any attachment within the local postweld heat treatment area. f. When PWHT is performed for environmental-assisted cracking resistance, a metallurgical review shall be conducted to assess whether the procedure is acceptable.

a. The materials shall be limited to P-No. 1, Group 1, 2, and 3, and to P-No. 3, Group 1 and 2 (excluding Mn-Mo steels in Group2). b. The welding shall be limited to the shielded-metal-arc welding (SMAW), gas-metal-arc welding (GMAW), and gas-tungstenarc welding (GTAW) processes.

1. The weld area shall be preheated and maintained at a minimum temperature of 300°F and should be checked to assure that 4 in. of the material or 4 times the material thickness (whichever is greater) on each side of the groove is maintained at the minimum temperature during welding. 2. The maximum interpass temperature shall not exceed 600°F. When the weld does not penetrate through the full thickness of the material, the minimum preheat and maximum interpass temperatures need only be maintained at a distance of 4 in. or four times the depth of the repair weld, whichever is greater on each side of the joint.

a. Notch toughness testing, such as that established by ASME Code Section VIII: Division 1, parts UG-84 and UCS-66, is necessary when impact tests are required by the original code of construction or the construction code applicable to the work planned. b. The materials shall be limited to P-No. 1, P-No. 3, and P-No. 4 steels. c. The welding shall be limited to the shielded-metal-arc welding (SMAW), gas-metal-arc welding (GMAW), and gas-tungstenarc welding (GTAW) processes. d. A weld procedure specification shall be developed and qualified for each application. The welding procedure shall define the preheat temperature and interpass temperature and include the post heating temperature requirement in f(8). The qualification thickness for the test plates and repair grooves shall be in accordance with Table 8-1. The test material for the welding procedure qualification shall be of the same material specification (including specification type, grade, class and condition of heat treatment) as the original material specification for the repair. If the original material specification is obsolete, the test material used should conform as much as possible to the material used for construction, but in no case shall the material be lower in strength or have a carbon content of more than 0.35%. e. When impact tests are required by the construction code applicable to the work planned, the PQR shall include sufficient tests to determine if the toughness of the weld metal and the heat-affected zone of the base metal in the as-welded condition is adequate at the minimum design metal temperature (such as the criteria used in ASME Code Section VIII: Division I, parts UG-84 and UCS 66). If special hardness limits are necessary (for example, as set forth in NACE RP 0472 and MR 0103) for corrosion resistance, the PQR shall include hardness tests as well.

1. The supplementary essential variables of ASME Code, Section IX, Paragraph QW-250, shall apply. 2. The maximum weld heat input for each layer shall not exceed that used in the procedure qualification test. 3. The minimum preheat temperature for welding shall not be less than that used in the procedure qualification test. 4. The maximum interpass temperature for welding shall not be greater than that used in the procedure qualification test. 5. The preheat temperature shall be checked to assure that 4 in. (100 mm) of the material or four times the material thickness (whichever is greater) on each side of the weld joint will be maintained at the minimum temperature during welding. When the weld does not penetrate through the full thickness of the material, the minimum preheat temperature need only be maintained at a distance of 4 in. (100 mm) or four times the depth of the repair weld, whichever is greater on each side of the joint. 6. When used SMAW, GTAW and GMAW, electrodes and filler metals that are classified by the filler metal specification with an optional supplemental diffusible-hydrogen designator of H8 or lower. When shielding gases are used with a process, the gas shall exhibit a dew point that is no higher than -60°F (-50°C). Surfaces on which welding will be done shall be maintained in a dry condition during welding and free of rust, mill scale and hydrogen producing contaminants such as oil, grease and other organic materials. 7. The welding technique shall be a controlled-deposition, temper-bead or half-bead technique. The specific technique shall be used in the procedure qualification test. 8. For welds made by SMAW, after completion of welding and without allowing the weldment to cool below the minimum preheat temperature, the temperature of the weldment shall be raised to a temperature of 500°F ± 50°F for a minimum period of two hours to assist out-gassing diffusion of any weld metal hydrogen picked up during welding. This hydrogen bake-out treatment may be omitted provided the electrode used is classified by the filler metal specification with an optional supplemental diffusible-hydrogen designator of H4 (such as E7018-H4). 9. After the finished repair weld has cooled to ambient temperature, the final temper bead reinforcement layer shall be removed substantially flush with the surface of the base material.

After the weld is completed, it shall be examined by NDE technique specified in the repair specification to determine that no defects exist using acceptance standards NDE techniques may be used provided they are approved by the engineer and inspector. Acceptance criteria for welded repairs or alterations should be in accordance with the applicable sections of the ASME or another applicable vessel rating code.

a. Calculations performed by either the manufacturer or an owner/user engineer (or his designated representative) experienced in pressure vessel design, fabrication, or inspection shall justify rerating. b. Rerating shall be performed in accordance with the requirements of the vessel's construction code. c. Current inspection records verify that the pressure vessel is satisfactory for the proposed service conditions and that the corrosion allowance provided is appropriate. An increase in allowable working pressure or design temperature shall be based on thickness data obtained from a recent internal or on-stream inspection. d. The vessel shall be pressure tested using the applicable testing formula from the code used to perform the rerating calculations unless either of the following is true: 1. The pressure vessel has at some time been pressure tested to a test pressure equal to or higher than the test pressure required by the rerate code; and, 2. The vessel integrity is confirmed by special nondestructive evaluation inspection techniques in lieu of testing. e. The rerating is acceptable to the engineer.

9.1.1 This section sets forth the minimum alternative inspection rules for pressure vessels that are exempt from the rules set forth in Section 6 except as referenced in 9.4 and 9.5. Except for Section 6, all of the sections in this inspection code are applicable to Exploration and Production (E;P) pressure vessels