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182 Cards in this Set
- Front
- Back
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According to API 510, what is an alteration? |
An alteration is a change that takes a pressure vessel or component outside of its design criteria. |
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What do European codes call MAWP? |
Design pressure |
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Are fired tubular heaters covered under API 510? |
No, Appendix A (code exemptions) states that they are not covered because they are exempt from Sec. VIII. |
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How many gallons of water under pressure acting as a cushion can a vessel of any pressure contain and still be excluded from API 510? |
Up to 120 gallons |
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Which API code covers welding on equipment in service? |
API 2201 |
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When would adding or replacing nozzles on a vessel not qualify as an alteration as per API 510? |
It is not an alteration if: The reinforced nozzles are equal to or smaller than the ones they are replacing, or the nozzles that are added do not require reinforcement. |
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A pitted vessel is measured at an average of 10 mm thick and has a designed corrosion allowance of 1.6 mm. What thickness is used to calculate the MAWP? |
8.4 mm |
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When must a corrosion specialist be consulted for developing an inspection plan for a vessel? |
1. When needed to clarify potential damage mechanisms and specific locations where they may occur. 2. For vessels that operate at temperatures above 750 deg. F. 5.1.1.1 |
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What must be considered when developing insp. intervals for a vessel? |
1. Type of damage. 2. Rate of damage progression 3. Tolerance of equipment to the type of damage. 4. Probablility of the NDE method to identify the damage. 5. Max intervals as defined in codes and standards. |
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What are the two factors that determine risk for an RBI assessment? |
1. Probability of failure. 2. Consequence of failure. In accordance with API 580 |
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What must an inspector do before performing an inspection of a vessel? |
1. Review prior insp. results. 2. Review prior repairs. 3. Review current insp. plan, and/or similar service inspections. 4. Review types of damage and failure modes as listed in API 571 and API 579. |
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What damage mechanisms can cause general and local metal loss? |
1. Sulfidation 2. Oxidation 3. Microbiological induced corrosion. 4. Naphthene acid corrosion 5. Erosion-corrosion 6. Galvanic corrosion |
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What types of damage mechanisms can cause surface connected cracking? |
1. Fatigue 2. Caustic stress corrosion cracking 3. Sulfide stress corrosion cracking |
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What types of damage mechanisms can cause subsurface cracking? |
Hydrogen induced cracking |
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What types of damage mechanisms can cause microfissure/microvoid formation? |
1. High temp. hydrogen attack 2. Creep |
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What type of damage mechanisms can cause metallurgical changes? |
1. Graphitization 2. Temper embrittlement |
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What type of damage mechanisms can cause blistering? |
Hydrogen blistering |
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What type of damage mechanisms can cause dimensional changes? |
1. Creep and stress rupture 2. Thermal |
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What type of damage mechanisms can cause material properties changes? |
Brittle fracture
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What is an acceptable method of measuring the depth of localized pitted corrosion? |
You can use a gauge from the non corroded surfaces within the vessel when they are in the vicinity of the pitted areas. |
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Above what temperature should corrective measures be utilized so that the accuracy of thickness measurements is not impacted? |
Above 150 degrees F. |
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After repairs, a pressure test shall be applied if: |
The inspector believes that one is necessary. |
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How do you determine the min. test pressure for a code hydrotest of a vessel? |
The test pressure is in accordance with the code of construction that is used to determine MAWP. Prior to 1999 = 1.5 MAWP x Stest/Sdesign After 1999 = 1.3 MAWP x Stest/Sdesign |
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SS steels should be tested with potable water or water or steam condensate with a chloride content of less than: |
50 ppm |
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To minimize the risk of brittle failure during a hydrotest: |
1. Temp should be maintained at least 30 deg. F. above MDMT for vessels more than 2 in. thick. 2. Temp should be at least 10 deg. F. above MDMT for vessels 2 in. thick or less. |
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Crack like flaws and environme ntal cracking shall be assessed by: |
An engineer |
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Preferential weld corrosion shall be assessed by: |
The inspector |
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What information do you use to determine inspection plans? |
Previous experience, similar service, or RBI |
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What information do you use to determine inspection frequency? |
Previous experience, half life calculations, or RBI |
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At what temps are low carbon/alloy steels at risk for CUI? |
10 deg. F. to 350 deg. F. |
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At what temps are austenitic stainless steels at risk for CUI? |
140 deg. F. to 400 deg. F |
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When is a pressure test normally required? |
1. After an alteration 2. When the inspector decides a pressure test is needed after a repair. |
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Acoustic emission testing is used to detect: |
Structurally significant defects. |
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Cracks and other elongated discontinuations can be found by: |
MT |
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CML's should be distributed: |
Appropriately over a vessel |
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An RBI assessment may by used to establish insp. intervals: |
Internal, external, and on stream |
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How often should an external insp. be performed on an above ground vessel? |
5 years |
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PRV's should be inspected, tested, and maintained according to which code? |
API 576 |
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The max test/insp. interval for PRV's in typical process service is: |
5 years |
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How can you estimate a corrosion rate for a new vessel? |
1. Calculate based on vessels in similar service. 2. Estimate based on experience. 3. Estimate it from published data. 4. Measure by taking on stream thickness measurements after a min. of 1000 hours of operation. |
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When can widely scattered pitting be ignored? |
1. The remaining thickness of any pit is more than half the "t" required thickness.....and, in addition......the total area of the pits that are deep enough to be less than "t" required do not exceed 7 square inches in any circle that is 8 in. in diameter....and...in addition, if the sum of the dimensions of the pits that are less than "t" required along any straight line within an 8 inch circle do not exceed 2 inches. |
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Which API code covers fitness for service? |
API 579 |
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If the extent of radiography used during manufacturing of a vessel is not known, what joint efficiency should you use? |
E = 0.7 |
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What is the correct inspection period for a vessel that has only 2 years of remaining life? |
2 years API 510 6.5.1.1 |
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What is the correct inspection period for a vessel that has only 1 year of remaining life? |
1 year |
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Define an alteration |
1. A physical change with design implications that affect pressure retaining capability. 2. Any work that results in a change in MAWP or MDMT. |
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Which repairs or alterations is thae API inspector able to authorize alone? |
Repairs to ASME VIII division 1 vessels. |
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When can temp repairs remain in place past the first opportunity for replacement? |
1. Eng. approves 2. Insp. approves 3. The details are evaluated and documented. |
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The circ. fillet welds attaching a lap band repair to a vessel shell should be designed with an assumed joint efficiency of: |
0.45 |
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Controlled deposition welding in lieu of PWHT can only be used on what types of steels? |
P1, P3, and P4 steels |
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What is the cut off point to determine if a vessel is a pressure vessel? |
15 psi min. pressure |
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At what temp. is brittle fracture likely to occur. |
At temps. below the Charpy impact transition temperature. |
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What type of material change will reduce the risk of brittle fractur? |
Use a material with a higher ductility. |
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Cracks resulting from brittle fracture will most likely be predominantly: |
Straight and non branching |
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As a practical rule, thermal cracking may be caused by temp swings of approx: |
200 deg. F |
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Cracks resulting from thermal fatigue will most likely b: |
Dagger shaped |
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In the absence of water, corrosioon rates are relatively low at metal teps less than: |
450 deg. F |
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API 510 permits on stream inspection in lieu of an internal under certain conditions. When used, how many UT readings must be taken? |
A representative number. |
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One example of where creep cracking has been experienced is: |
1-1/4 Cr. steels above 900 deg. F. |
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Improper tightening of flanged or threaded joints is classified as what type of faulty fabrication? |
Improper fit. |
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In addition to painting, what is one of the best methods of protecting steel structures from corrosion? |
Galvanizing. |
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When do brittle fractures occur? |
At temps. below the ductile to brittle transition temperature. |
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How many mils per year is it possible to lose if exposed to a marine environment? |
20 mpy |
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API 510 exempts certain vessels such as: |
1. Vessels on moveable structures. 2. All vessels exempted by Sect. VIII Div. 1 of the ASME code. 3. Vessels that do not exceed given volumes and pressures. |
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Widely scattered pits may be ignored if the following are true: |
1. No pit is greater than half the vessel wall thickness without adding in corrosion allowance. 2. The total area of the pits does not exceed 7 square inches in any 8 inch diameter circle. 3. The sum of their dimensions along any straight line within the circle does not exceed 2 inches. |
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What code do you look to for guidance on conducting a pressure test? |
The original code of construction. |
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Who can repair pressure relief valves? |
A qualified organization, having a fully documented written quality control system and repair training program for repair personnel. |
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Which kind of repairs can the Inspector alone approve? |
Routine repairs that will not require a pressure test. |
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What steps must be followed if applying a local PWHT is approved by the eng.? |
1. Min. preheat of 300 deg. F. 2. Preheat distance from weld is not less than 2T of the base metal. 3. At least two thermocouples shall be used. 4. Heat must be applied to any nozzle or attachment within the local PWHT area. |
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When and where may fillet weld patches be used on a vessel? |
Either inside or outside......as a temp. repair. Must comply with other jurisdictions (which may prohibit their use) Must have rounded corners. |
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When is a hydrotest required after a repair to a vessel? |
When the Inspector believes one is necessary. |
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When is a hydrotest required after an alteration. |
Normally one is required. May use NDE in lieu of hydrotest with prior approval by an Eng. |
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What steps are required for rerating a vessel? |
1. Calculations. 2. Compliance to the current const. code. 3. Current insp. records indicating fitness 4. pressure testing. 5. Approval by the API inspector. |
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What is the final step in rerating a vessel? |
The attachment of an additional nameplate with the required information given in Sect. 5.3 |
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Define rerating |
A change in either the temp. range or max allowable pressure of a vessel or both. |
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In terms of creep....what must be considered? |
Time, temp. and stress |
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What metals might be susceptible to brittle failure even at room temperature? |
Carbon, low alloy, and other ferritic steels. |
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Name five methods other than visual that might be used to inspect a vessel. |
1. MT 2. PT 3. RT 4. UT 5. Acoustic Emission 6. Metallographic examination 7. Hammer test |
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When new code vessel in installed, must a first internal insp. be performed? |
No, as long as manufacture report (Data) assures that the vessel is satisfactory for the intended use is available. |
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When developing an insp. plan for a vessel, when should a corrosion specialist be consulted, and when is it required that one be consulted? |
A corrosion specialist should be consulted when needed to clarify potential damage mechanisms and specific locations where they may occur. A corrosion specialist shall be consulted when developing an insp. plan for vessels that operate at elevated temps above 750 deg. F. |
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Name damage mechanisms that can result in general and local metal loss: |
1. Sulfidation 2. Oxidation 3. Microbiologically induced corrosion 4. Napthenic acid corrosion 5. Erosion, erosion-corrosion 6. Galvanic |
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Name damage mechanisms that can result on surface connected cracking: |
1. Fatigue 2. Caustic stress corrosion cracking 3. Sulfide stress corrosion cracking |
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Name damage mechanisms that can result in subsurface cracking: |
Hydrogen induced cracking |
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Name damage mechanisms that can result in Microfissuring: |
1. High temp hydrogen attack 2. Creep |
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Name damage mechanisms that can result in Metallurgical changes: |
1. Graphitization 2. Temper embrittlement |
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Name damage mechanisms that can result in blistering: |
Hydrogen blistering |
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Name damage mechanisms that can result in dimensional changes: |
1. Creep and stress rupture 2. Thermal |
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Name damage mechanisms that can result in material properties changes: |
Brittle fracture |
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During an external inspection, what is an area to pay particularly close attention to? |
Component attachment welds for cracking or other defects. |
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What is the insp. interval for a buried vessel based on? |
It is based on corrosion rate information obtained from one or more of the following: 1. During maintenance activity 2. From the interval examination of similarly buried corrosion test coupons of like material. 3. From representative portions of the actual vessel. 4. From a vesse in similar circumstances. |
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Insp. for CUI shall be considered externally insulated vessels and those that are in intermittent service or operate between: |
10 deg F and 350 deg F for carbon and low alloy steels. 140 deg F and 400 deg F for austenitic stainless steels. |
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What is normally the result of CUI on carbon and low allow steels? |
Localized corrosion |
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What is normally the result of CUI in austenitic stainless steels? |
Stress corrosion and cracking |
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What are considerations when choosing the type and location of CML's? |
The potential for localized corrosion and service specific damage. |
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MT is particularly useful for: |
examination for cracks and other elongated discontinuities that extend to the surface of the material, and for outlining other surface imperfections. |
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Above what temp. should corrective measures be taken to account for the impact that high temps can have on accuracy of thickness measurements? |
Above 150 deg. F |
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When are pressure tests normally required? |
1. After an alteration. 2. After a repair, when the inspector believes one is necessary. |
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What must occur if both the ownership and location of a vessel is changed? |
1. The vessel shall be internally and externally inspected. 2. Allowable service conditions shall be established. 3. Inspection interval shall be established for the new service. |
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What are typical permanent repair techniques? |
1. Excavating the defect, then blend grinding. 2. Excavating, and repair welding. 3. Replacing section or component with defect. 4. Weld overlay. 5. Adding strip or plate lining to the interior surface. |
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When can insert (flush) patches be used? |
1. Full penetration groove welds required. 2. Welds are RT'ed to code or UTSW substituted if NDE procedures approved by inspector. 3. Rounded corners with 1" min. radius. |
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For repairs to weld overlay and cladding in equipment in which the base metal operates, or is exposed to hydrogen service at elevated temps., what are some additional factors that must be considered by the engineer when developing a test plan? |
1. Outgassing the base metal. 2. Hardening of the base metal due to welding, drinding, or arc gouging. 3. Preheat and interpass temp. control. 4. PWHT to reduce hardness and restore mechanical properties. |
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What precautions must be taken when using local PWHT instead of 360 deg. banding? |
1. Procedure reviewed by eng. 2. Procedure is suitable after being evaluated for: a. Base metal thickness b. Decay thermal gradients. c. Material properties d. Changes due to local PWHT. e. The need for full pen. welds. f. Surface and volumetric exam after local PWHT. g. local strain created by heating a restrained area. 3. min. preheat of 300 deg. F. 4. PWHT temp. maintained for at least 2T distance from the toe of the weld, and at least two thermocouples are used. 5. Heat shall be applied to any nozzle or attachment within the PWHT zone. 6. If PWHT performed for environmental reasons, a metallurgical review is required. |
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When considering using preheat, or controlled deposition welding in lieu of PWHT, what are some factors that should be considered? |
1. Original reason for PWHT 2. Susceptibility to stress corrosion cracking. 3. Stresses in the location of the weld. 4. Susceptibility to high temp. hydrogen attack. 5. Susceptibility to creep. |
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When using preheat in lieu of PWHT on materials that do not require notch testing, what base metals are you limited to? |
P-1, group 1,2,3 P-3, group 1,2 ( excluding Mn-Mo steels in group 2) |
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How does API 510 Sect. 9 treat portable pressure vessels and portable compressed gas containers associated with machinery? |
As part of that machinery, and subject to the rules and regs. applicable to that type of machine or container. |
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What is a progressive inspection? |
An inspection whose scope is increased as a result of findings. |
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In UW-12, what is a Type 1 joint, and what joint efficiency does each category provide? |
Type 1 is a fully welded double bevel butt joint. A. Full RT= 1.0 B. Spot RT= .85 C. No RT= .70 |
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In UW-12, what is a Type 2 joint, and what joint efficiency does each category provide? |
Type 2 is a single bevel butt weld with a backing strip that remains in place. A. Full RT= .90 B. Spot RT= .80 C. No RT= .65 |
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In UW-12, what is a Type 3 joint, and what joint efficiency does each category provide? |
Type 3 is a single bevel butt joint without the use of a backing strip. A. Full RT= NA B. Spot RT= NA C. No RT= .60 |
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In UW-12, what is a Type 4 joint, and what joint efficiency does each category provide? |
Type 4 is a double full fillet lap joint. A. Full RT= NA B. Spot RT= NA C. No RT= .55 |
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In UW-12, what is a Type 5 joint, and what joint efficiency does each category provide? |
Type 5 is a single full fillet lap joint with plug welds. A. Full RT= NA B. Sport RT= NA C. No RT= .50 |
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In UW-12, what is a Type 6 joint, and what joint efficiency does each category provide? |
Type 6 is a single full fillet lap joint without plug welds. A. Full RT= NA B. Spot RT= NA C. No RT= .45 |
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Are Torispherical, Ellipsoidal, and Hemispherical heads considered seamless by code? |
Hemispherical heads = Never seamless Formed Torispherical = Seamless Formed Ellipsoidal = Seamless |
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If service is lethal, what Type and category of welds are permitted? |
Cat. A shall be type 1 only. Cat. B,C can be type 1 or type 2. |
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What is a type 1 weld? |
A double bevel butt weld made without permanent backing. |
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What is a type 2 weld? |
A single bevel butt weld made with permanent backing. |
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Before taking up any inspection, who must develop and inspection plan? |
The Inspector or the engineer. |
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What is the primary goal of internal inspection? |
To find damage that cannot be found by regular monitoring of external CML's. |
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When can on stream insp. be used in lieu of internal insp.? |
It shall be conducted by either insp. or examiner. It may include several NDE techniques to check for various types of damage. |
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What type of vessels require CUI inspection? |
Insulated vessels where moisture ingress is likely.........AND....... Vessels that operate between 10 deg to 350 deg. F. for CS and low alloy steels. Vessels that operate between 140 deg. F. to 400 deg. F for Austenitic Stainless Steels. |
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How is Hydro test pressure for vessels determined? |
1. Vessels built before 1999 = 1.5 x MAWP. 2. Vessels built after 1999 = 1.3 x MAWP. |
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How does MDMT affect hydro test pressure? |
1. Vessels up to 2" = MDMT + 10 degrees. 2. Vessels more than 2" = MDMT + 30 degrees. |
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How often are external vessel inspections required? |
The lesser of the internal insp. interval, or 5 years. |
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How often are internal and on-stream vessel inspections required? |
Frequency not more than 1/2 Life or 10 years.....whichever is less. If remaining Life is less than 4 years, insp. interval may be full remaining life up to a max. of 2 years. |
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When can the 10 year limit on inspection intervals be waived? |
Upon completion of an RBI assessment. |
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When must new inspection intervals be calculated for a vessel? |
1. Service conditions change. 2. Both ownership......and.....location change. |
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When can on-stream inspection be substituted for internal inspection of a vessel? |
If the inspector approves....for the following: 1. Corrosion rate less than 5 mpy as confirmed for at least 5 years. 2. Vessel remaining life at least 10 years. 3. Vessel is not operating in creep temp. range. 4. Vessel is not subject to SCC. 5. Vessel does not have non integral lining inside. |
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What is the testing and insp. interval for PRD's? |
1. 5 years typical service. 2. 10 years clean and non corrosive service. |
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How can the corrosion rate be established for new vessels or those that have had a change in service? |
Based on: 1. Data collected on vessels in same or similar service. 2. May be est. from published data. 3. Determined after 1000 hours of service. |
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How can you average locally thinned areas of corrosion? |
Over a length (L) not exceeding: 1. For vessel I.D. up to 60", L= lesser of ID / 2 or 20" 2. For vessel I.D. greater than 60", L=lesser of ID / 3 or 40" |
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When can widely scattered pits be ignored? |
If all of the following are true: 1. Remaining T under the pit is greater than 1/2 req. thickness. 2. Total pitted area ( deeper than corrosion allowance) does not exceed 7 sq. inches. 3. The sum of pit dimensions that are deeper than corrosion allowance in any 8" straight line does not exceed 2". |
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How can you evaluate a vessel if you do not know what type of carbon steel was used in construction? |
If the material spec. for CS is not known, you may use allowable stress value (S) for: A.A. 2836 Gr. C |
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What 4 types of information are typically found in pressure vessel records? |
1. Construction and design information. 2. Inspection History. 3. Repair, Alteration, and re-rating information. 4. Fitness for service records. |
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Who give authorization for repairs/alteratins on vessels complying with: ASME Sec. VIII Div. 1? ASME Sec. VIII Div. 2? |
Div. 1: Repairs by Inspector. Div. 2: Both repairs and alterations to be authorized by Inspector and Engineer. |
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Who approves repair and alteration work at hold points and at completion? |
The Inspector. |
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Carbon or alloy steels with carbon content greater than _____% shall not be welded? |
Carbon content greater than 0.35% shall not be welded. |
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Who normally has to approve if temp. repairs are allowed to remain past the next turnaround or maintenance opportunity? |
Both the Engineer and the Inspector. |
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How can fillet weld patches be used? |
For making temporary repairs only. |
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When can flush patches be used as permanent repairs? |
1. Full pen welds used. 2. Welds are RT'ed to code. 3. Patches shall have rounded corners with 1" min. radius. |
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When can filler metal for overlays be lower strength than the base metal? |
1. Repair thickness does not exceed 50% of required thickness. 2. Thickness of repair weld is increased by ratio of tensile strength of base metal to tensile strength of filler. 3. Increased thickness is given 1:3 taper. 4. Repair min. with min. of two passes. |
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When repairing damaged SS cladding with base metal exposed to hydrogen migration, what should be done before repair? What should be done after repair if bse metal is P3, P-4, or P-5 material? |
Degassing. U.T. should be done at least 24 hours after repair. |
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Which API code can be referred to for online welding? |
API 2201 |
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How is MAWP determined for the continued use of an existing pressure vessel? |
It is determined using computations from the latest applicable edition of the ASME code, or the construction code to which the vessel was built. The resulting MAWP shall not be greater than the original MAWP, unless a rerating is done. |
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When must a corrosion specialist be consulted in developing an insp. plan? |
1. When needed to clarify potential damage mechanisms and specific locations where they occur. 2. When vessels operate at temps. above 750F. |
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What metals might be subject to brittle fracture even at ambient temperatures? |
CS, low alloy steels, and other ferritic steels. |
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What is a tightness test? |
A pressure test that is conducted on pressure vessels after maintenance or repair to prove that it is leak free. It is conducted at a pressure that is determined by O/U, and is no higher than MAWP. |
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Define transition temperature |
The temp. at which a material fracture mode changes from ductile to brittle. |
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Why are IOW's (integrity operating windows) used? |
They are used to avoid exceeding process parameters, and to avoid impacting equipment integrity. |
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Who develops the inspection plan? |
The inspector and/or engineer. |
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Who decides if it is necessary to remove deposits or linings from a vessel in order to perform an adequate inspection? |
The Inspector, in consultation with the corrosion specialist. |
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Who authorizes and approves all on stream inspections? |
The Inspector |
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In situations where on stream inspection is acceptable in lieu of internal inspection.....should the vessel be depressurized or pressured? |
Either |
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Who performs visual external inspections of vessels? |
The Inspector, or someone who is qualified and acceptable to the Inspector. |
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What information is used as the basis for determining the inspection interval for buried piping? |
1. An assessment of the cathodic protection system (if any). 2. The corrosion rate. |
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How do you gain information on buried pipe to determine the effectiveness of a cathodic protection system, and to calculate the corrosion rate? |
1. During maintenance activity. 2. From periodic examination of similarly buried corrosion test coupons of like material. 3. From representative portions of the actual vessel. 4. From a vessel in similar circumstances. |
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What should be taken into account when considering excavating buried pipe for inspection? |
1. The potential for damaging the coating or cathodic protection systems. |
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Who obtains thickness measurements? |
The Inspector or examiner. |
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What is the CUI temp. range for CS, SS, and duplex steels? |
1. CS 10F-350F 2. SS 140F-350F 3. Duplex 280F-350F |
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How is CUI normally seen in CS? |
With localized corrosion. |
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How is CUI normally seen in SS? |
External chloride stress corrosion cracking. |
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What shall be considered when selecting the type and placement of CML's? |
The potential for localized corrosion and service specific damage. |
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What are examples of different types of CML's? |
Locations for thickness measurement, locations for stress corrosion cracking examinations, and locations for high temperature hydrogen attack examinations. |
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Who should the Inspector consult with when choosing examination techniques for a vessel inspection? |
The engineer or corrosion specialist. |
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Who must approve the use of NDE in lieu of a hydrotest? |
The Inspector and Engineer. |
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When hydrotesting solid or clad austenitic stainless steel, what is the max water temp. that should be used? |
120F |
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Who shall assess crack like flaws and environmental cracking? |
The Engineer. |
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What is the purpose of the initial inspection of a vessel at installation? |
1. Verify safe for operation. 2. Verify no damage from transportation. 3. To initiate inspection records. 4. Collect baseline CML readings. |
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When an RBI interval for the internal or on stream inspection exceeds the 10 year limit, who must review and approve the RBI assessment? |
The Engineer and Inspector shall review and approve the RBI assessment at intervals not greater than 10 years. |
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How often must vessels be externally inspected? |
At intervals not longer than 5 years, or the required internal/on-stream inspection.....whichever is less. |
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How often must vessels have internal or on-stream inspections? |
1/2 Life or 10 years.......whichever is less, unless justified by an RBI assessment. When 1/2 Life is 4 years..........the inspection interval may be the full remaining life up to 2 years. |
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Who decides if an on-stream inspection may be substituted for an internal inspection? |
It is at the discretion of the Inspector. |
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What are reasons for substituting on-stream inspection for internal inspection? |
1. Vessel entry is impossible. 2. Vessel entry is possible and all of the following apply: a. Corrosion rate known to be less than .005 ipy. b. Vessel remaining life more than 10 years. c. Corrosiveness of contents has been est. by 5 years of same or similar service. d. No questionable condition found during ext. insp. e. The operating temp. below lower temp. limits for creep rupture range of the vessel material. f. The vessel is not subject to environmental cracking or hydrogen damage from fluids inside. g. The vessel does not have strip lining or plate lining. |
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What are the 4 design types of shell and tube heat exchangers? |
1. Fixed tube sheet with a floating head. 2. Two fixed tube sheets. 3. One fixed tube sheet with U-tubes. 4. Double tube sheet. |
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What does a reboiler do? |
Boosts heat back up to a desired level at an intermediate step in the process stream. |
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Name three shapes of pressure vessels. |
Cylindrical, Spherical, and Spheroidal. |
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Name four types of internals that are found in pressure vessels. |
Demister pads, traps, baffles, spray nozzles. |
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How can carburized sustenetic stainless steel sometimes be detected? |
With a magnet. |
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What is the "short life cap" clause, when calculating inspection intervals for external inspection? |
Instead of 10 years or 1/2 Life If remaining life is less than 4 years. The insp. interval may be the full remaining life up to a max. of 2 years. |
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When rerating a vessel, do you have to rerate it to the latest edition of the code? |
As a matter of principle, the objective is to utilize improvements in the code. However, if this is not possible, they the vessel may be rerated according to the edition to which the vessel was built. |
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What are the two main issues to consider after a rerating? |
1. Pressure testing- Normally req...but not mandatory as you can sub with NDE if acceptable to pressure vessel eng. 2. Requires an additional nameplate to be put on the vessel, Additional stamping is okay if you cannot put on another nameplate. Either must be witnessed by the Inspector. |
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Is a pressure test mandatory after an alteration? |
A pressure test is "normally required" after an alteration. |
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When can the Inspector give prior general authorization for limited or routine repairs? |
1. It is for a specific vessel. 2. The Inspector is happy with the repair contractor's competence. 3. The repair type does not require pressure testing. |
