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The HSB CT Engineering Services Division Manual par. 4541 (4)(a)&(b) requires the Authorized Inspector Supervisor to conduct "Periodic inspector meetings to discuss all aspects of ASME Code Inspection", and to have "technical discussions annually". So, every once in a while I send out questions with answers and paste them into an email. Keep in mind these are just opinions and if you have specific questions please direct them to one of the Supervisors. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25.
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VIII Div 1: U-1(c)(2)(j) 3,000 psi Limit: VIII-1, UG-99(g) No Leakage during Hydro Inspection VIII Div 1, UHA -51 High Alloy steel impacts? P-3A Data Report VIII-1, UG-44 and B16.9 and B16.11 Fittings Power Boiler field hydro Section IV Test Pressure requirements Changing bolts after hydrotest - UG-99(g) Section I, PG-109.3 - PP Stamping Scope VIII-1, PWHT Requirements for P-No. 4 Lamination in Plates VIII Div 1 - Marking of non-pressure parts Subcontracted welding? Use of separate WPS in combination Laminations in plate materials VIII DIV 1 - Code applicability for a vessel Accreditation, ASME Codes - CD Rom vs Books? Pin hole leaks not detected Required # of specimens for production impact tests WPS/PQR vs WPQ variables and Limits of Qualification ASME Section VIII Div 1 - UW-12(d) Stamping of "U" Parts ?, MTRs Section I and B31.1? Material Test Reports Section I ASTM vs ASME materials for Code use SMAW Welder qualification with F-3 and F-4 Welder Performance Qualification Limits Conditioning of electrodes Acceptable Code Edition and Addenda Certification of Data Reports and R Forms – sequence Weld joint prep requirements Socket Welded connections in boiler proper Boiler field erection of piping Submerged Arc Welding Questions: Section IX Welder "t" thickness range multiple process Material marking - VIII Div 1 Small Nozzle attachments - Section VIII Div1 Welding Qualification Ranges Welding Questions "Coded markings" (Material) - UG-77(a), PG-77.2 Section I double block valves & free blow drains
Pressure Relief Requirements - VIII Div 1 41. VIII Div 1 - seamless head "Quality Factor - E" Seamless Head "Quality Factor", UW-11(a)(b) 42. Welding Position Section IX, QW-461.9 43. VIII Div 1 - UW-13 head to shell alignment 44. QW-202.4 Combination Welding 45. Material Certification 46. Welder Continuity and Qualification 47. Section VIII Div 1 - "Low Temperature Vessel" 48. Calibration of pressure gauges 49. Tube hole deburring - Section IV 50. Calculated Test Pressure - VIII Div1 51. VIII Div 1 - Vacuum, RT- nameplate 52. SAW welding procedure Changes, PQR requirements for Corrosion Resistant Overlay 53. Inspection Openings - VIII Div 1 54. Root pass WPS - QW-200.4(b) 55. Use of SA 36 - VIII Div 1 56. Nozzle replacement - VIII Div 1 57. DA Tank - small nozzle welds 58. NCRs - Section I and VIII Div 1 59. WPS qualification with impacts 60. Section I - connection off water column, & B31.1 valve 61. PWHT - placement of thermocouples VIII Div 1 62. In process inspection by the AI? - VIII Div 1 63. WPS for Dissimilar Thickness Joint 64. RT designator Section VIII Div1? 65. Lifting Lug calculations VIII Div 1 66. VIII Div 1 - Opening Reinforcement Calculations 67. VIII Div 1 - production impact test? 68. Impact Test Exemptions for ERW Pipe 69. Section IX Welder Qualification using S numbers 70. VIII Div 1 - production impact test? 71. Impact Test Exemptions for ERW Pipe 72. Section IX Welder Qualification using S numbers 73. Internal Inspection 74. Application of UCS-68(c) to UG-20(f) 75. VIII-1 material marking and "piggy back welding" 76. Calculating the MDMT - VIII Div1 77. Material Test Reports - EDI (Electronic Data Interchange) 78. PWHT Question - ASME I 79. VIII Div 1 - UG-93 material marking 80. Boiler Parts and BEP 81. Section I - Use of SA-36 material 82. NDE Level III qualification 83. VIII Div 1 - UCS-66 - "GOVERNING" thickness for establishing MDMT? 84. Rods and Bars used as nozzles in VIII Div 1 vess els? 85. VIII Div 1 vessel hydrostatically tested in the vertical position 86. VIII Div 1 vessel Code boundary 87. VIII Div 1 UW-11(a)(5)(b) 88. Section I, PG-99, Application of Insulation Prior to Hydrostatic Test 40.
Pressure Relief Requirements - VIII Div 1 41. VIII Div 1 - seamless head "Quality Factor - E" Seamless Head "Quality Factor", UW-11(a)(b) 42. Welding Position Section IX, QW-461.9 43. VIII Div 1 - UW-13 head to shell alignment 44. QW-202.4 Combination Welding 45. Material Certification 46. Welder Continuity and Qualification 47. Section VIII Div 1 - "Low Temperature Vessel" 48. Calibration of pressure gauges 49. Tube hole deburring - Section IV 50. Calculated Test Pressure - VIII Div1 51. VIII Div 1 - Vacuum, RT- nameplate 52. SAW welding procedure Changes, PQR requirements for Corrosion Resistant Overlay 53. Inspection Openings - VIII Div 1 54. Root pass WPS - QW-200.4(b) 55. Use of SA 36 - VIII Div 1 56. Nozzle replacement - VIII Div 1 57. DA Tank - small nozzle welds 58. NCRs - Section I and VIII Div 1 59. WPS qualification with impacts 60. Section I - connection off water column, & B31.1 valve 61. PWHT - placement of thermocouples VIII Div 1 62. In process inspection by the AI? - VIII Div 1 63. WPS for Dissimilar Thickness Joint 64. RT designator Section VIII Div1? 65. Lifting Lug calculations VIII Div 1 66. VIII Div 1 - Opening Reinforcement Calculations 67. VIII Div 1 - production impact test? 68. Impact Test Exemptions for ERW Pipe 69. Section IX Welder Qualification using S numbers 70. VIII Div 1 - production impact test? 71. Impact Test Exemptions for ERW Pipe 72. Section IX Welder Qualification using S numbers 73. Internal Inspection 74. Application of UCS-68(c) to UG-20(f) 75. VIII-1 material marking and "piggy back welding" 76. Calculating the MDMT - VIII Div1 77. Material Test Reports - EDI (Electronic Data Interchange) 78. PWHT Question - ASME I 79. VIII Div 1 - UG-93 material marking 80. Boiler Parts and BEP 81. Section I - Use of SA-36 material 82. NDE Level III qualification 83. VIII Div 1 - UCS-66 - "GOVERNING" thickness for establishing MDMT? 84. Rods and Bars used as nozzles in VIII Div 1 vess els? 85. VIII Div 1 vessel hydrostatically tested in the vertical position 86. VIII Div 1 vessel Code boundary 87. VIII Div 1 UW-11(a)(5)(b) 88. Section I, PG-99, Application of Insulation Prior to Hydrostatic Test 40.
89. VIII Div 1 purpose of final pressure test 90. VIII Div 1 impact test requirements for UG-11 manway assemblies. 91. B31 Socket Weld Fitting Fit-Up Gap 92. Where in the ASME Code are international materials listed? 93. VIII Div 1, UG-10 and identical ASTM material 94: VIII Div 1 - UW-16(c) - Nozzle attachment welds, full penetration? penetration? 95: Titanium not reported as an unspecified element as required by SA-20 par. 7.1.1.1 96: ASME Section I - difference between tube and pipe 97: UG-99 - Hydrostatic test pressure - VIII Div 1
98: Section I power boiler hydrostatic test water temperature
1. VIII Div 1: U-1(c)(2)(j) 3,000 psi Limit: The 3,000 psi number is a conservative limit which i s intended to alert the designer to the fact that the design principles upon which the Code is based may not be satisfactory (from a manufacturing or economic point of view) for the design of high pressure vessels. The design rules of Section VIII, Division 1 are based on elastic behavior of thin shells in which failure is assumed to occur when the yield point is reached. According According to a survey that was made, pressure vessels up to 10,000 psi can be constructed to Section VIII, Division 1 without suffering a manufacturing or economic hardship. The service conditions of the vessel may require special engineering considerations which the Code does not address. For example, for vessels intended for very high pressure (>> 10,000 psi) it becomes necessary to base the design on plastic analysis, and to prestress (autofrettage) the vessel to meet the service conditions. These design deviations are necessary to satisfy the service conditions. It is recommended that for a high pressure vessel the designer shall design for a particular service and after the service conditions have been satisfied, the design can be reviewed for Code compliance. If the pressure vessel construction meets all Code requirements the "U" stamp can be applied. However, when deviations from Code rules are necessary to satisfy service conditions, and the vessel is to be operated in a state with a pressure vessel law, then the owner/user and/or his designated agent must petition the jurisdictional authority for a State Special Stamping. In most cases for pressures under 5,000 psi, special design considerations would probably not be necessary. As a minimum you should check that the thin shell equations of UG-27 are valid (See UG-27(c)(1)), and check if fatigue loads need to be considered per UG-22. To summarize, U-1(d) places no limit on the pressure press ure for which a vessel may ma y be designed and stamped according to Section VIII, Division 1. The paragraph alerts designers that for pressures greater than 3000 psi, design procedures unique to the design of high pressure equipment may be needed to meet the service requirements of the vessel. However, the Code Code symbol stamp may only be placed on the completed vessel if all of the requirements of the Code have been met. -------------------------------------------------------------------------------------------2. VIII-1, UG-99(g) No Leakage during Hydro Inspection Question: The new A97 requires that there be no leakage during the time of the hydro inspection. Does this applied to flanges on nozzles intended for flanged connections to piping?
Answer: The mention of leakage at temporary seals only applied to plugs etc. used on nozzles intended for welded connections. Thus if the flange is included within the scope of the vessel, and the shop uses a blind flange to close off the opening, this flanged joint cannot leak at 2/3 the test pressure. -------------------------------------------------------------------------------------------3. - VIII Div 1, UHA -51 High Alloy steel impacts? Question: * The base material is 304L 0.77" in thickness. * The desired MDMT is -320 F. ' Per UHA-51(d) the base material and HAZ are exempted from impact tests based on thickness. thickness. * Per UHA-51(e)(1) the weld metal is required to be impact tested, since MDMT < -150F. * Per UHA-51(b) the WPS must be qualified with impacts. * Per QW-451 the shop can prepare a coupon which is 1/16" thick and qualify for actual base metal thickness of 0.077". * Then Per UG-84(c)(3) impact tests would not be required since a Charpy specimen with a width along the notch greater than or equal to 0.099" cannot be obtained. In my opinion this would always take precedence over any other Code requirements that would require impact tests. Production impact tests would not be required again per UG-84(c)(3). If the shop instead qualifies their procedure with a coupon equal to or greater in thickness than 0.099", then they would have to qualify the procedure with impacts. However production impact tests would still not be required per UG-84(c)(3).
4. - P-3A P-3A Data Report Report Question: There is no place on The P-3A Data Reports for an Engineering Contractor to document Partial Data Reports such as is on the P-3. Can this be done by attaching a P-6 to the P-3A? Answer: No. PG-112.2.2 requires a P-3 Data Report to be used to record all items on a water tube boiler. If an Engineering contractor is going to accept overall responsibility, then the P-3 is checked as not being the Master. The P-3A then becomes the Master and the Engineering Contractor will certify it to accept responsibility for the design certification. All boiler components are certified on the appropriate Manufacturer's Data Reports. All Partial Data Reports would be referenced on the P-3. (see PG-112.2.4), PG-112.2.4), or P-6 attached to the P-3. If the engineering contractor has fabricating facilities (see PG-104, Note 1), fabrication activities would be documented on the appropriate Manufacturer's Data Report. The P-3A is used only to certify design. Note: Because of the multiple use of the P-3, the P-3 used to document all boiler components may also have attached (and referenced) P-3's. -------------------------------------------------------------------------------------5. - VIII-1, UG-44 and B16.9 and B16.11 Fittings Question: What is the Code's true intentions for the rating of ASME B16.9 and B16.11 fittings. UG-44 states, Pressure-temperature Pressure-t emperature ratings shall be in accordance with the appropriate standard except that the pressure-temperature ratings for ASME B16.9 and B16.11 fittings shall be calculated as for straight seamless pipe in accordance with the rules of this Division including the maximum allowable stress for the material. "From this statement and ASME Interpretation VIII-1-83-217, one could logically conclude that the
Code's intentions were to exclude ASME B16.9 and and B16.11 fittings from UG-45. Also, one could argue that UG-44 states that the fitting shall be rated as a straight seamless pipe to all rules of the division which includes includes UG-45. Is it the intention of the Code to exclude ASME B16.9 and and B16.11 fittings from UG-45? Answer: There have been numerous Code interpretations on this subject. However, as you discovered, VIII-1-83-217 essentially states that UG-45 does not apply to B16.11 couplings since no nozzle neck applies. I have given that opinion in the past, and would extend it to B16.9 fittings as well. I published a short explanation of establishing a pressure/temperature rating for a B16.11 fitting in one of my previous newsletters (I will be mailing the complete set to you today). I've clipped in Word format this portion of the newsletter, plus the set of interpretations dealing with the subject. subject. So in conclusion, conclusion, I believe that ASME B16.9 and B16.11 do not require UG-45 consideration. Question 1: I need to use ASME B16.11 fittings in a pressure vessel that I am constructing to Section VIII, Division 1. How do I figure out the allowable pressure/temperature rating for the fitting? Answer: ASME B16.11 is listed as an acceptable reference standard in both Table U-3 and paragraph UG-44 of Section VIII-1. Normally if you are purchasing B16.11 fittings from a manufacturer's catalog per UG-11(a) of Section VIII, it will provide the pressure/temperature rating for the fittings based on either B31 piping applications or Section VIII. If a manufacturers' pressure/temperature rating is unavailable, you can use the following method to establish an MAWP. Per UG-44, the pressure/temperature rating for a B16.11 fitting is calculated for straight seamless pipe in accordance with rules of Section VIII including the maximum allowable stress for the material. Let's look at an example. Assume that we need to use an NPS 1 B16.11 threaded coupling coupling for a vessel designed for 400 psi and 800oF. We need to select a class designation for the fitting, so as a first cut let's select a Class 3000 fitting. Per 5.1 the material for the fitting shall consist of forgings, bars, seamless pipe, or tubular products listed in Table 1 of ASME/ANSI B16.34. From Table 1 select a carbon forging SA-105. Per B16.11 2.1.1 and Table 2, the pipe schedule corresponding to a Class 3000 fitting is Sch 160. The nominal wall thickness for NPS 1 Sch 160 from B36.10 is 0.25 in. The allowable stress for SA-105 at 800oF is 12.0 12.0 ksi. Using the minimum thickness of the Sch 160 pipe by accounting for the manufacturer's undertolerance ( tmin = 0.875 x 0.25 = 0.219 in), the calculated ressure is: P = SEt/Ro + 0.6t = 12000(1)(.219)/.658 +0.56(0.219) = 3,329 psi Question: Is impact testing required for the welds in SA-53 Type E ERW pipe under the following conditions? (a) When the thickness at the weld exceeds « in. for all minimum design metal temperatures? (b) When the thickness at the weld exceeds 5/16 in. and the minimum design metal temperature is lower than 50oF? Reply: Yes to (a) and (b). However, the only time one would apply UCS-67(b) to ERW pipe, is if the pipe were fabricated in the Code Manufacturer's shop. Otherwise, ERW pipe is treated as material and the weld is ignored. ------------------------------------------------------------------------------------------6. - Power Boiler field hydro
Determination of Hydrostatic test pressure Detail: Inquirer is getting conflicting information on how to determine the correct test pressure for a field erected boiler. It seems the designer is stating the correct test pressure for the boiler, and the erector does not think it is correct. The erector is wanting to consider the pressure ratings for the piping support systems to determine the test pressure. It appears that the problem is they want to test everything at once at one pressure, but do not know what MAWP to use as the basis for calculating the test pressure. A simultaneous test is permissible per the requirements of paragraph 137.3.1 of B31.1 for boiler external piping only. When a simultaneous test of the boiler and the boiler external piping is conducted, test pressure shall be based on the MAWP of the boiler proper as required by PG-99.1. Applying the requirements of PG-99.3 is inappropriate for a drum type boiler. These requirements only apply to forced flow steam generators which different pressure ratings within the boiler proper. Separate tests are to be conducted for nonboiler external piping per paragraph 137.3.2; for each of the boiler support piping systems at their required test pressures per paragraph 137.4 of B31.1. This will require some disassembly and isolation blanking to preclude over pressurizing limiting components, if not performed as a bench hydro at the fabrication point. If the piping systems are disassembled, when reassembled they should be retested at the normal operating pressure for a final mechanical joint integrity verification. ----------------------------------------------------------------------------------------7. Section IV Test Pressure requirements Detail: Paragraphs HG-510(a) and (b) tend to be confusing when taken together. How do these limits work together? Response: It is the intent of Section IV that all boilers built to their Section be tested at a pressure of at least 60 PSI, but not greater than 1.5 times Design pressure. For example, a 15 psi steam boiler is tested at 60 psi which is the greater of 60 psi vs 1.5 times MAWP (37.5 psi). The greatest pressure it may be tested at is 1.5 times design or 60 psi, whichever is greater. If this boiler is designed for an MAWP of 15 psi steam, but the design is based on a design rating of 50 psi, it could be potentially be tested at 75 psi maximum vice 60 psi. This would give you an acceptable test pressure range of 60-75 psi; with the lower limit based on MAWP, and the upper limit based on Design pressure. Keep in mind that design pressure and MAWP do not have to be the same number. The maximum overpressure is limited to 10 psi over the maximum limit, so if the test pressure of 60 psi is selected, then the maximum pressure should be 70 psi, but could theoretically be allowed to reach 85 psi applying these guidelines. ---------------------------------------------------------------------------------8. - Changing bolts after hydrotest - UG-99(g) Question: Is it acceptable to change the bolts on the vessel after final hydro? The vessel is 100' long and is comprised of 15' shell sections that are bolted together. The hydro is performed on the entire vessel using SA-193 B7 bolts then dismantled for shipping. The vessel is then reassembled on-site using different bolts (SA-193 B7 - Teflon coated). The AI had told the shop that if they are ultimately going to use Teflon coated bolts then they have to use Teflon coated bolts at the hydro. Answer: Regarding the vessel that is being hydrostatically tested, dismantled and reassembled using different bolts. These are mechanical joints and therefore the Code does not specifically address the use of different bolting materials during hydro and final
assembly. Therefore it would be acceptable to use SA-193 B7 bolts for the hydrostatic test at the shop and SA-193 B7 Teflon coated bolts for the final assembly. ---------------------------------------------------------------------------------------9. - Section I, PG-109.3 - PP Stamping Scope Question: Under PG-109.3 the PP stamp holder can fabricate boiler parts, such as headers or other parts, involving only welding as covered by PW-41. PW-41 are requirements only for welding of circumferential joints in pipes, tubes and headers. Can PP stamp holder fabricate headers, involving also nozzles to header shell welding which is not covered by PW-41? Response: The intent of this requirement is that components within the scope of the PW-41 limitations may be fabricated by PP stamp holders. This change was made fairly recently (97 Addenda if I remember correctly), to recognize that since we already allow PP holders to assemble piping within the limits of BEP by welding, and since the components referenced in PW-41 are within the limits of BEP but outside the boiler proper, it only makes sense to allow the PP holder to fabricate those items as well. The statement within PG-109.3 was intended to prohibit the use of a PP stamp to assemble drums and shells, or other major pressure components of boilers, while allowing PP holders to fabricate smaller piping related components. This change was part of the general movement to shift technical requirements for those things which are outside the boiler proper to the Power Piping Code, B31.1. ------------------------------------------------------------------------------------------10. : VIII-1, PWHT Requirements for P-No. 4 Question: Client is welding an 8" thick tubesheet made from SA-182 F12 Cl2 material (P No. 4 Gr. 1) to a 1 3/8" shell made from P-No. 1 material. Is PWHT required? Answer: UCS-56(c) addresses the PWHT requirements for welded joints involving different P-Number groups. It states that the more restrictive PWHT requirement shall apply to the joint. The P-No.1 material is exempt from PWHT, however the P-No. 4 will require PWHT, since there are no applicable exemptions for your application. Per UW-40(f)(5)(c) the governing nominal thickness for determining the holding time will be the thickness of the shell. -------------------------------------------------------------------------11. Lamination in Plates Question: Is lamination in general a cause for rejection of a plate? Background: The specific application is a bolted cover with a coupling in the center attached with a single external fillet weld as a penetration. When pressurized with air, it bubbles through the lamination and out the periphery of the plate. Question: Is this acceptable? Response: Obviously the leakage is unacceptable, but the lamination is not a problem. Since the full thickness of the plate is present to resist the load due to pressure, the lamination is not of itself a cause for rejection. To stop the leakage, back weld the coupling penetration to seal the lamination from having a leak path. A minimum fillet weld to act as a seal weld is sufficient. Laminations are not desirable where plates are joined to form a corner joint, because of the potential for the load to be borne by a section thickness that is less than the nominal plate thickness. This is why VIII Div 1, UG-93 requires that edge preps for corner joints be examined by PT or MT to check for laminations. Another potential problem area is
when the plate is a heat transfer surface, and such a lamination may develop into a blister or bulge and affect performance of the part, as well as allowing localized overheating of the metal to the point of failure. In a pure pressure loading application such as a shell or head, the full section thickness is carrying the load, so the lamination is not detrimental. --------------------------------------------------------------------------------------------12. - VIII Div 1 - Marking of non-pressure parts Question: What are the marking requirements for non-pressure parts welded to pressure vessels in Section VIII Div 1? Answer: Marking requirements for non-pressure parts UG-4(b) requires that non-pressure parts attached to pressure retaining parts be of "weldable quality". UW-5(b) gives requirements for proving "weldable quality", which means that a WPS has been qualified with this material. Material identification requirements for non-pressure parts welded to pressure retaining parts are found in UW-5(b)(1) and (2). Both reference the requirements of UG-10, UG-11, UG-15, and UG-93. UG-10 requires identification per the specification. UG-11 permits reduced markings for pressure parts. UG-15 provides recertification and redesignation of a material in the same fashion as UG-10, with markings per specification. UG-93 requires all product forms other than plate to be marked with the specification , grade, type, and class; trace ability to a specific heat and lot is not required. When the Manufacturer begins subdividing the material, UG-94 allows the use of a coded marking, referencing UG-77. UG-77 requires control of transferred markings to be addressed in the quality control system. Additionally, UG-93(a)(3)(b) makes a similar statement. Consequently, if the required markings are used, no QC Manual description of the system is required. If a coded marking system is used, it's description is required in the QC Manual. This is consistent with the issued interpretations on this subject. --------------------------------------------------------------------------------13. - Subcontracted welding? Question: Is it possible to subcontract welding and other fabrication operations to other organizations? Answer: There are two scenarios. One involves one Certificate Holder subcontracting fabrication to another Certificate Holder, having the subcontractor report the work performed on a U-2 form (Partial Data Report), and then incorporating this component into a completed vessel with stamping and certification by the original Certificate Holder. The responsibility for design may be assumed by either party. Responsibility for component fabrication is assumed by the subcontractor. The subcontractor would have his own Code certificate, his own welding procedures and welder qualifications, his own inspection and certification. The work performed by him would be reported to the final Manufacturer, who accepts responsibility for it when incorporating the component into the final vessel. This type of approach works well with either a full time or a part time fabrication operation. It is a good way to outsource some work due to cost considerations, manage cyclic production demands, or compensate for equipment limitations. The second scenario involves what is referred to as a "welding by others" program. This requires a modification of the Certificate Holder's QC Program to incorporate the requirements of UW-26(d). This provides details of how such a program is implemented and controlled, and includes the designation of individuals responsible for the various actions and oversight required. In this situation, the Certificate Holder (using his own welding procedures) conducts welder qualification testing of the
subcontractors welders. He then employs the subcontractors welders to weld products of his design, using his welding procedures, under his direct control and supervision. This is usually accomplished by assigning a specific individual to the subcontractors shop to oversee operations. The Authorized Inspector is involved in the implementa tion of this program to the extent he feels necessary. Usually the Inspector will rotate between the Certificate holder's facility and the subcontractor's facility. I have only seen this applied to a full time inspection location. It would be difficult to coordinate with a part time location. This offers some advantages for cost reduction and cyclic production demands as well. -------------------------------------------------------------------------------14. Use of separate WPS in combination Detail: Inquirer called to ask if it is possible to apply two separately qualified WPS to the same joint in combination without qualification of a combined PQR. Response: Per QW-200.4, it is acceptable to apply both WPS to the same joint without further qualification. The deposited weld metal qualification ranges may be "stacked", allowing the application of the maximum qualified thickness of deposited weld metal for each WPS/process in a single joint. However, the user is cautioned that the maximum base metal thickness qualified for the most limiting WPS must be applied. The base metal thickness ranges cannot be "stacked" to qualify for a greater thickness in combination. -------------------------------------------------------------------------------15. - Laminations in plate materials Question: What is the acceptability of laminations in plate materials in pressure vessels. Answer: Since the full thickness of the plate is present to resist the load due to pressure, the lamination is not a cause for rejection. Laminations are not desirable where plates are joined to form a corner joint, because of the potential for the load to peel the laminations and reduce the strength of the material section. This is why UG-93(d) of Section VIII, Division 1 requires that edge preps for corner joints be examined by PT or MT to check for laminations. Another potential problem area is when the plate is a heat transfer surface, and such a lamination may develop into a blister or bulge and affect heat transfer performance of the part, as well as allowing localized overheating of the metal to the point of failure. In a pure pressure loading application such as a shell or head, the full section thickness is carrying the load, so the lamination is acceptable and not detrimental. Some specific customers may have objections to laminations in shell or head plates. But, this is a matter of agreement between the client and the Manufacturer. The ASME Code has no prohibitions against plate laminations other than as described above for corner joints. -------------------------------------------------------------------------------16. - VIII DIV 1 - Code applicability for a vessel Question: About Code applicability for a specific vessel design. It is a shell and tube heat exchanger used as a waste heat recovery heater, using flue gases to heat water. The intended application is for 15 psi or less on the water side, the gas side is vented to atmosphere as the gasses escape.
Response: The heat exchanger design presented may be considered outside the scope of the ASME Code, Section VIII, Division 1 for Unfired Pressure Vessels by the following reasoning: (a). Paragraph U-1(c)(2)(h) excludes vessels of unlimited size from the scope of the Code when rated for internal or external pressures of less than 15 psi. (b). Paragraph U-1(c)(2)(f) excludes vessels containing only water under pressure, provided the pressure does not exceed 300 psi and the temperature does not exceed 210F. Code Interpretations have been issued which confer applicability of this paragraph to heat exchanger applications. (c). Paragraph U-1(c)(2)(g) excludes hot water storage tanks heated by steam or other indirect means when the heat input is limited to 200, 000 BTU/hr, temperature is limited to 210F, and volume is 120 gals or less. While it is difficult to conclusively determine that these parameters are not exceeded with the information provided, it appears that they are not. Paragraph U-1(c)(2) permits the application of the Code symbol to objects which are normally outside the Scope of the Code when constructed to meet all the applicable requirements. So, even if the object is determined to be outside the scope, it may be built to meet the Code and stamped as being in compliance with it. -------------------------------------------------------------------------------17. Accreditation, ASME Codes - CD Rom vs Books? Company called to ask if it is required to have hard copies of the ASME Code available for the ASME joint review. They currently have them on CD ROM, and was told they needed hard copies as well. Response: Yes, hardcopies are required. It is not clearly indicated in the ASME application package sent to applicants, because it says in the cover letter that the applicant must have a "published copy" of the Code. The ASME considers the definition of a published copy to be a hard copy as purchased from ASME. Not a photocopy or CD ROM. Since the ASME only has direct control of what is published in the hard copies, it does not recognize any other form. The CD ROM version is produced under license, and not by ASME, so they cannot be certain of content. -------------------------------------------------------------------------------18. - Pin hole leaks not detected A manufacturer of ASME pressure vessels and a distributor of vessels that are made by others has a situation with their major supplier. They make a 20" diameter horizontal air receiver for us. A particular end user has consistently returned vessels for pin hole leaks. These vessels have been made in different production runs over the past year. This end user tests with n itrogen gas at 75 psi. The fabricator hydrotests at 300 psi. Question: Is it conceivable that these leaks that are detectable by the end user, could go unnoticed during the fabricators' hydrotest? The most recent leaking vessel was returned to the fabricator with the leaks marked, and the fabricator said that it took 1.5 and 3 hours to detect the two leaks. Response: It is definitely possible. Think of it this way, which molecule is larger, N2 or H2O? Depending on the aspect the molecule presents, the N2 is definitely more likely to slip out of a tight opening, especially if it is monataomic Nitrogen. Pneumatic testing or other tests using a gas instead of a fluid more readily leak when a pin hole exists for this reason. It has always been harder to detect very small leaks with hydrostatic tests. If the vessel will see
gaseous service, or this type of leak test is a potential acceptance criteria, then I suggest that the vessel be pneumatically tested; either in addition to, or in place of, the hydrostatic test. Even at that, the leaks may be small enough that they could be missed if the tester is not thoroughly inspecting the vessel. This type of tight pinhole is characteristic of Subarc welds made with a heavily recycled flux. After breaking down in the heat of the welding process, the flux fragments into a fine powder, called "flux flour". This "flux flour" more readily absorbs moisture and clings to dirt, oil, grease. grinding debris, and other c ontaminants which cause the formation of very fine pinhole porosity. Fabricators which are aggressively recycling flux are suggested to dump the batch about once a month, or sift out the "flux flour" with a screen. -------------------------------------------------------------------------------19. - Required # of specimens for production impact tests Question: "For production impact test plates of a Section VIII Div 1 vessel which the base metal is over 1.5 inch in thickness, how many sets of test specimens be tested?" Specifically UG-84(i)(1), which tells the user to perform production impact tests per UG-84(g). Are three sets of specimens were required [2 in the weld deposit, 1 in the HAZ; per UG-84(h)(3)] due to the material thickness, or only two sets of specimens were required [1 in the weld deposit, and 1 in the HAZ; per UG-84(g)] for production impact tests? Answer: The three sets of specimens in the question refer to are impact tests of Welding Procedure Qualifications on base metal thick nesses greater than 1-1/2 inches, as set forth in UG-84(h)(3). This requires the weld to be tested in the weld metal within 1/16 in.of the surface, in the weld metal near the center, and in the HAZ of the base metal. This requirement exists for Welding Procedure Qualification Tests only. The regular weld impact test requirements of UG-84(g) only mandate two sets of specimens; one of the weld metal within 1/16 in. of the surface, and the HAZ of the base metal. Production impact tests are mandated as a check of the fabricating process to ensure the qualified properties are being obtained in the production component. The tests are invoked when extremes of service onditions warrant additional verification. Since the production impact test is only a verification of previously qualified properties during fabrication, it is not intended to invoke the full qualification test regimen, but merely a check regimen. Production testing only requires two sets of specimens to be taken from the locations called for in UG-84(g). -------------------------------------------------------------------------------20. - WPS/PQR vs WPQ variables and Limits of Qualification Detail: I am confused about the Welding Performance Qualification. For instance, a welder used SA53 pipe test material which is P1 material, I want to know what kind of material he will be qualified for? Is he qualified to weld production material SA-240-304(P8) by using SA53 as testing coupon? I know there is a paragraph regarding welding qualification in QW423.1. On the other hand, the base material in the WPS is a essential variable. Response: This is a very common problem. It is very easy to confuse procedure and performance requirements and try to apply them inappropriately. The welder you described who qualifies on a SA-53 pipe coupon becomes qualified for that base metal and the following additional weld metals: P-No.1 thru P-No. 11, P-No. 34, and P-No. 4X (where X is a placeholder, indicating the 40 series P-Nos. which are nickel alloys). This sounds great, huh? However, there are some traps here. The welder must use the same process, with the
same essential variables as qualified, such as the F-No., position, thickness limits, etc.; unless he has other WPQs that support the extension of the limits of qualification for the essential variables. The actual essential variables change with the process, as shown in QW-416 and QW-350. At the same time, the welder may be qualified to weld the other base metals, but unless he has a WPS that has been qualified for those base metals (and all processes have base metal as an essential variable) he cannot weld it in compliance with Code requirements. There are one or two minor exceptions found in QW-424, but this is generally true. One example that I have seen is where the welder welded stainless with a WPS qualified for carbon steel. When I pointed this out, the client stated that the process was covered by QW-423, since the welder is qualified for the various base metals as stated above. Sure the welder is qualified, I said, but the process was not qualified for these base metals so the weld is not acceptable. Once he realized that I was right, we looked through his extensive book of WPSs and found one that was identical to the carbon steel WPS, but was qualified for stainless. Everything else was identical except the base metal. I have also seen people try to use the welder's qualified deposited weld metal thickness range to try to weld using a procedure that was qualified for lesser thickness' than the production base metal using the same reasoning as above. Remember that Code welding is a two by two matrix. Across the top are: "Welder Not Qualified" and "Welder Qualified". Down the left hand side are: "Procedure Not Qualified" and "Procedure Qualified". Unless you are in the box where the coordinates "Procedure Qualified" and "Welder Qualified" intersect, it's not a Code compliant weld. Procedure qualification and Welder qualification are achieved and verified independently, unless the welder in question was the welder who made the test coupons for the PQR. Then the test is documented on separate PQR and WPQ forms using the sam e data. -------------------------------------------------------------------------------21. - ASME Section VIII Div 1 - UW-12(d) Question: UW-12(d) requires a spot radiograph [per UW-11(a)(5)(b)] be taken on each 50 feet of circumferential seams attaching elliptical or torispherical heads to a seamless shell to apply a joint efficiency of 1.0 in the calculation of the shell or head thickness, even if they are seamless. If this RT requirement is not applied, 85% is the highest permitted joint efficiency. In the application to ERW pipe shells, it appears to be a "double penalty"; since ERW stress values already have an 85% efficiency applied to them, and this requirement reduces the efficiency even further. Response: This requirement is the result of a compromise worked out when Section VIII revised it's design philosophy to become a "design by joint" Code. It became apparent that designing a vessel with a seamless shell and seamless dished heads would rate the same joint efficiency in shell and head thickness calculations as a totally seamless vessel, since the circumferential seams need only be half as strong as the seamless shell. The fact that a welded vessel could be designed for the same thickness as a seamless one was a distasteful possibility for the Code committee, so this provision was put in place to gain acceptance for the Code revision. If a seamless hemispherical head is attached to the shell, the head is calculated with an efficiency determined from Table UW-12. The shell is calculated under the provisions of UW-12(d). However, if a flat head (tube sheet, or flange also) is attached at both ends of a shell, you may ignore the radiography requirements of UW-12(d) and apply the appropriate joint efficiency for the shell (based upon joint type and degree of examination) from Table UW-12 to the shell thickness calculation. This is permitted because of the difficulty in shooting and
properly interpreting a radiograph for a corner joint (or fillet welds attaching flanges). The Code committees decided that in this scenario, the rules of UW-12(d) would be waived. If there is a flat head at one end and a dished head at the other end, the rules of UW-12(d) still apply to the shell and dished head calculations. -------------------------------------------------------------------------------22. - Stamping of "U" Parts ?, MTRs Section I and B31.1? Question: What is the the proper stamping of "parts", and does the Code require such things as RT2, W, or the other things addressed in UG-116(a) through (f). Response: The only required information to be stamped or included in the nameplate of a "Part" under Section VIII, Division 1 rules is as set forth in UG-116(h). The information in UG-116(a) thru (f) is for stamping or nameplates of the completed vessel. Information concerning any of the aspects addressed by these markings (PWHT, RT, etc) is addressed on the U-2 or U-2A, and not the stamping. The Manufacturer of the final vessel is obligated to address these areas on the final U-1 or U-1A and stamping or nameplate upon final certification of the completed vessel. 23. Material Test Reports Section I Question: What are the MTR requirements are for piping when fabricated under Section I and B31.1. Response: The following references and requirements apply: (a). B31.1 explicitly requires MTRs for materials used in pressure retaining service in paragraph 123.2.2(A).(power piping) (b). Section I makes no direct explicit requirement for MTRs in the main text of the book, but alludes to it in the Appendix, in paragraph A-302.4. It is widely understood that MTRs are required for Section I construction (boiler proper piping). -------------------------------------------------------------------------------24. - ASTM vs ASME materials for Code use Question: Under what conditions, may ASTM Specification materials be used for ASME pressure items? Answer: The following would apply: (1). If the ASTM Material has an identical corresponding ASME Specification with the same number (i.e.: A-106B corresponds to SA-106B); and the date code For the ASTM Material is one of the acceptable dates listed in Appendix A of Section II, Part A; and the corresponding ASME Specification is acceptable for the construction Code which applies. If this is the case, the material can be accepted as is, and used as ASME Specification material. No recertification or remarking is necessary. (2). If the ASTM Material does not have an identical corresponding ASME Specification with the same number (i.e.: A-106B corresponds to SA-106B), it may be compared to a known ASME Specification acceptable for the construction Code which applies. If comparison of the chemical composition and mechanical properties show the material to meet the requirements for the ASME Specification, it may be accepted for use as the ASME
Specification material. The procedure for recertification and remarking of the material is found in the construction Code. For example for Section VIII, Division 1, it is found in UG10. Slip-on-flanges - limitations B31.1 and I. The boiler external piping limitations are "except slip-on flanges shall be limited in application to no higher than Class 300 primary service rating" - B31.1 par. 104.5.1 . Also boiler proper Section I par. PG-42.4.7 states "slip=on flanges shall not exceed NPS 4". -------------------------------------------------------------------------------25. - SMAW Welder qualification with F-3 and F-4 Welder Performance Qualification Limits Detail: Inquirer called to ask for assistance in verifying the limits of qualification applicable to a given WPQ scenario. The welder deposited a 1/8 " weld root pass using SMAW with an F-3 Electrode without backing. He then filled the rest of the 0.412" thick coupon using SMAW with an F-4 Electrode, now with the root pass as a backing. Since F-4 or F-3 electrodes qualify the welder to apply all lower F-Nos. with backing, how should the limits of qualification be listed on the WPQ? Response: Weld Deposit Thickness- Range Qualified is: F-1 thru F-4 qualified for 0.824" deposited weld metal with backing, F-3 qualified for 0.25" without backing. Reference: ASME Section IX - QW-353, 404.15, 433, 306 -------------------------------------------------------------------------------26. - Conditioning of electrodes Question: What about the proper conditioning of coated SMAW electrodes. The specific electrodes in question are E-7018. Response: ASME Section II C, Table A-1 in the Annex for SFA-5.5 gives specific guidance for the conditioning of SMAW electrodes. The text of A6.11 has some information of significance as well. In general, low hydrogen electrodes have to be kept in a controlled and usually heated environment. Other electrodes may be kept at ambient temperature. In fact, it states in A6.11.4 that some electrodes may be damaged if kept in heated storage, as it will dry them out too much, and they do not function as intended without some amount of moisture in the coatings. If the manufacturer does not provide recommendations for conditioning, follow the guidelines of Table A-1. Many manufacturers of low hydrogen electrodes have simply recommended storage at 50F above ambient to preclude absorption of moisture. -------------------------------------------------------------------------------27. - Acceptable Code Edition and Addenda Question: Is it possible to for a Manufacturer to accept a contract to fabricate a pressure vessel to a previous Edition and Addenda of the Code. If not, where is this prohibited? Response: In the Forward of of Section VIII, Division 1 the Code it states: "After Code revisions are approved by Council they may be used beginning with the date of issuance shown on the Addenda. Revisions become mandatory as minimum requirements six months after such date of issuance, except for boilers or pressure vessels contracted for prior to the end of the six-month period." This means that the vessel may only be contracted for the Code Edition and Addenda in effect at the time of the contract. During this six month "window" of
voluntary implementation of the Addenda, either Addenda (or Edition) may be applied as a matter of agreement between the Manufacturer and the customer. Once the vessel is contracted for, that Edition and Addenda may be followed until the vessel is completed, even if the construction covers a prolonged period. 28. Welder limits Question: Welder qualification thickness limits are based on both the deposit weld metal and the F number. If a welder qualifies using both F3 and F4, the qualified deposited weld metal thickness for F4 will only be twice the actual deposited thickness of the F4 weld metal. F3 would be the combined F3 & F4. is this correct? Response: Don't forget the important role that backing plays in this application. QW-433 spells this out very clearly. Since F-4 also qualifies F-3 and the lower F Numbers with backing, the qualified thickness range for depositing weld metal with backing using the F-3 and lower F Number electrodes is equal to twice the total deposited weld metal thickness (F-3 and F-4 combined). If depositing weld metal without backing, the qualified thickness range for deposited weld metal would only be twice the actual deposited thickness for each F Number, and then only if each was deposited without backing during the qualification test. Chances are only one F Number was deposited without backing, and the other F Number was deposited over the top of it (essentially with backing). Follow-up to the above question: QW-306 clearly identifies that the thickness qualification parameters are a function of all other variables. This does not simply effect F# and thickness. The words encompass thickness qualification being dependant upon ANY essential variable. Question: If a welder is qualified on a 3" sch 5 (.083) coupon in the 6G and qualified on a 1" sch 80 (.179t) pipe coupon in the 1G, all other variables being the same, he is only qualified to weld on a 2" pipe up to .166t in any position. After attaining that thickness he must change to 1G. If the 3" coupon was F4 with backing and the 1" coupon was F3 without backing, then the welder is not qualified on 2" pipe with F4 over .166t even in the 1G. response: If the 3" coupon was F4 with backing and the 1" coupon was F3 without backing, then the welder is not qualified on 2" pipe with F4 over 166t even in the 1G. The F-4 qualification is no good for welding the 2" pipe at all if it is intended to be welded without backing. F-4 may be used to deposit 0.166" of weld metal only if welding with backing. -------------------------------------------------------------------------------28. - Certification of Data Reports and R Forms – sequence It has been brought to our attention that some Inspectors have been signing Data Reports and R Forms prior to the Manufacturer's representative. In order to clarify HSB and ASME/NB requirements please review the following: The HSB Engineering Services Manual paragraph 4552.9(a) states "All Data Reports (and R Forms per par (b)) shall be properly completed and certified by the manufacturer prior to being signed by the Inspector".
ASME Section VIII Div 1 requires the Manufacturer to "prepare the Manufacturer's Data Report and have it certified by the Inspector". UG-90(b)(18). Paragraph UG-90(c)(1)(n) discusses the Inspector signing the Data Report when the "vessel, to the best of his knowledge and belief, is in compliance with all provisions of the Code". This includes the certification signature of the Manufacturer's representative. The NBIC paragraph RA-2151(p) discusses the responsibility of the Manufacture for preparing, signing, and presenting the R Form to the Inspector. Paragraphs RC-2071(b) and 3051 goes on to state "the Inspector shall indicate acceptance by signing the R Form". -------------------------------------------------------------------------------29. - Wed joint prep requirements Question: How about minimum requirements for weld joint preparation, and where a hole is flame cut into a shell, and a coupling is welded to the shell with a single fillet weld from the outside only? No preparation is made to the flame cut edge prior to welding. Answer: UW-31(a) states "When plates are shaped by oxygen or arc cutting, the edges to be welded shall be uniform and smooth and freed of all loose scale and slag accumulation before welding.(See UG-76 and UCS-5)". UG-76(a) states "After oxygen or arc cutting, all slag or detrimental discoloration of material which has been molten shall be removed by mechanical means prior to further fabrication or use." UCS-5 prohibits flame cutting and welded construction using materials with a carbon content greater than 0.35% Section I PW-29.1 states "The preparation of joints prior to welding may involve any of the conventional methods in use such as machining, thermal cutting, chipping, grinding, or combinations of these." PW-29.2 states "Where thermal cutting is used, the effect on the mechanical and metallurgical properties of the base metal shall be taken into consideration." PW-29.3 states "The method of base metal preparation used shall leave the welding groove with reasonably smooth surfaces and free from deep notches, striations, or irregularities. The surfaces for welding shall be free of all scale, rust, oil, grease, or other foreign materials." Section IV HW-801(a), (b), and (c) are identical to PW-29.1, .2, and .3 respectively. Edges left behind by plasma cutting machines are the only arc cuts that might be acceptable for further welding without preparation. These edges are almost always uniform in thickness, smooth edged, and contain virtually no slag. The heat input is so highly localized that virtually no detrimental effects on the properties of the remaining base materials are observed. Edges cut by flame or oxygen cutting generally have slag, and irregular edge, and often an irregular thickness. This is not conducive to ensuring adequate penetration and fusion throughout the full thickness of the joint without inclusions. A Manufacturer wanting to flame cut a hole into a shell, and attach a coupling to the shell with a single fillet weld from the outside only with no joint preparation prior to welding, should be required to demonstrate that he is able to complete an acceptable quality weld under such conditions. Satisfactory completion of such a demonstration, with appropriate testing of the finished weld joint, satisfies the Manufacturer's burden of proof to the Inspector the he has achieved compliance with the requirements of the Code paragraphs cited above without joint preparation. HW-810(c) requires that tack welds "be removed completely when they have served their purpose, or their stopping and starting ends shall be properly prepared by grinding or other suitable means so that they may be satisfactorily incorporated in the final weld." Are these requirements satisfied when the tack weld is made in such a manner that the starting and stopping ends are blended into the base
metal and therefore suitable for incorporation into the final weld without modification, or when the tack welds are completely re-melted and consumed into the root of the weld? Reply: Yes, with concurrence of the Authorized Inspector. -------------------------------------------------------------------------------30. - Socket Welded connections in boiler proper Question: What about the acceptability for a socket welded joint within the boiler setting. The intention is to weld a NPS 4 socket welded fitting into the shell with double full fillet welds, and then socket weld piping to the fitting for attachment of the safety relief valve. Is this an acceptable arrangement? Answer: Use of a socket welded fitting within the boiler setting is acceptable under PG-42, provided it complies with ASME B16.11. Attachment of the fitting to the boiler shell with double full fillet welds is permitted per Figure PW-16.1, Sketch (d). Socket welded joints of this size within the boiler setting are not permitted per PW-41.5.1, however this particular joint is not within the boiler setting. This joint is the point of termination of the Scope of the Section I technical jurisdiction as shown in Figure PG-58.3.1. This weld joint and the attached piping come under ASME B31.1 Power Piping. Socket welded fittings are permitted in this size for this service, but socket welded flanges are restricted in size. -------------------------------------------------------------------------------31. - Boiler field erection of piping Question: What is the required documentation for valves, flanges, and other components of piping being welded together in a boiler field erection. The components themselves do not require documentation as they are acceptable as standard pressure parts under PG-11, and meet the referenced specifications under PG-42, including markings. The issue is whether or not the components need to be included on a P-4A, P-4B, P-6 or other documentation for the piping. Answer: In researching this issue, the following ASME interpretation applies: Question: May an Authorized Inspector accept valves, fittings, and flanges meeting the requirements of PG-42 without such valves, fittings, and flanges being identified on a Manufacturer's Data Report? Reply (4): Yes. The interpretation addresses this issue quite nicely. In addition, the guides for preparing the P-4A and P-4B data reports tell the reader only to document the piping itself, and not the components. We have to assume that the reason for this is because the valves, flanges and other components are adequately marked to identify them as being in compliance with the Code without further documentation. This is not true of the piping, as the material markings will often be covered by paint, or otherwise lost. In conclusion we believe that it is appropriate to accept the valves and other non-pipe components based upon their own markings, and that they do not need to be included on the P-4A, P-4B, or P-6 forms used to document piping assemblies. --------------------------------------------------------------------------------
32. Submerged Arc Welding Questions: Question(1): What requirements exist regarding the recycling of subarc flux that was not incorporated into the weld or the slag layer? Question (2): Why is there a supplementary essential variable for procedure qualification when changing from multiple pass welds to single pass welds in SAW? Response: 1. No specific requirements exist for recycling unincorporated flux for reuse in Section IX or the Construction Codes. This is a widely accepted practice, because failure to recycle the flux can result in very high production costs. Some important things to keep in mind when recycling the flux: (a). Flux contamination with grease, oil, dirt, grinding dust, and excessive moisture absorption are all problems for subarc welds. These are all known to cause excessive porosity, often very characteristic for the specific type of contamination involved. Keeping excess flux in closed and airtight containers to control such contamination is a good start. Minimizing grinding in the vicinity of the welding is another. Keeping the area clean is another. Having a mechanism that "catches" the flux instead of letting it fall into uncontrolled areas is also good. Finally, be careful not to allow slag fragments to fall into the flux system. (b). Flux breaks down after repeated exposure to welding heat to a very fine dust referred to as "flux flour". This dust has a very high affinity for absorption of moisture, and consequently can affect weld quality. Occasionally dumping the recycling system or mechanically separating the dust from the flux is the best way to control this effect. ( c). Some shops use recrushed slag as flux because it is cheaper. This is acceptable, provided that the welding procedure has been qualified for this electrode-flux combination. Special testing requirements need to be met for recrushed slag fluxes prior to their use. Response (2): When welding a joint with the subarc process, a significant heat affected zone is created. In a single pass the effect is very pronounced. In a multiple pass procedure, the subsequent passes serve to partial stress relieve the previous passes heat affected zones (HAZ). Since the greatest area of vulnerability for brittle fracture is the HAZ of a weld, this is why changing from multiple passes to single passes is an essential variable for impact tested applications. A significant difference in the fracture toughness properties results from the change, which obviously affects the impact properties of the HAZ. -------------------------------------------------------------------------------33. - Section IX Welder "t" thickness range multiple process Question: regarding the application of QW-452.1 performance qualification ranges for the following WPQ conditions: Pipe Coupon with 0.864" wall thickness, Welded with 0.187 GTAW root, and 0.670 SMAW fill. Response: (Note: 0.187 + 0.670 = 0.857") Applying QW-452.1, for a coupon thickness of 3/4 inch and over, the qualified deposited weld metal thickness is "max to be welded". This assumes only a single welder applying a single process is being considered. Note 1 points out that multiple welders for the same coupon are only qualified to the extent of 2t for the weld metal deposited by each welder with each process, and that these deposited weld metal thick nesses need to be considered separately in the thickness column. I would also call your attention to QW-351. It clearly states that a welder is qualified based upon the thickness of weld metal deposited with each process.
-------------------------------------------------------------------------------34. - Material marking - VIII Div 1 Question: (1) Is UG-77 only applicable to plates ? Question: (2) Is Marking and traceability of materials (UG-94) for all other product forms than plates, is governed by the rules of UG-93(a)(2)? Answer: 1. Only product form plate must be supplied with the complete marking per the material specification. [UG-93(a)(1)] 2. For all other product forms, Section VIII-1 would accept reduced marking containing specification designation, including the grade/type/class as applicable. [UG-93(a)(2)]. 3. UG-77 applies to all material in the pressure vessel, independent of product form. However, when employing a coded marking system to maintain trace ability of the material, one only needs to be able to trace back to the original marking required by VIII-1; this means the marking required by UG-93(a). This is stated in the 2nd sentence of UG-77(a). 4. While UG-93 addresses receiving inspection, UG-77 only deals with material identification and trace ability during fabrication. Why would we need trace ability to more marking information during fabrication than what was needed at the time of receiving? I recognize that UG-77 uses the phrase .original identification markings required in the specifications, but I believe we have to apply the test of common sense when dictating what amount of information we need to have trace ability to. Therefore, it is my opinion that for all product forms other than plate, the Manufacturer need only retain trace ability of the material to the original marking information required at the time of rec eipt inspection per UG-93. -------------------------------------------------------------------------------35. - Small Nozzle attachments - Section VIII Div1 Question: What about the legality of applying the attachment requirements of UW-16 (f)(3)(a) when attaching a nozzle made of pipe materials with a single fillet weld from the outside only. Is this permitted by the Code? Response: This is not an appropriate paragraph to apply to a pipe nozzle. It is only intended to apply to forged fittings with single fillet welds. The text of the paragraph refers only to fittings, which is rather vague. Paragraph UW-16(e)(2) is a good fit for attaching such a nozzle to the shell with fillet welding from the outside only. The following Interpretation supports this application. This makes the weld sizing requirements a bit different, and requires a pretty tight fitup. -------------------------------------------------------------------------------36. - Welding Qualification Ranges Question: What about the qualification ranges of QW-451.1 and QW-452.1? How do you evaluate the qualified thickness range of a welder whose performance coupon was conducted using a groove procedure for the full thickness of 3/4 inch base metal? The QW-452.1 table seems to indicate that there is no maximum thickness limit on welder performance, but QW451.1 limits such a coupon to 2T (twice the coupon base metal thickness). What is correct? Response: Welder performance limitations and procedure performance limitations are not the same. Qualfied welding occurs when the welding is conducted with the qualified range limits
of welder performance and the procedure qualification. When both are satisfied, everyone is happy. While successfully welding a 3/4 inch test coupon qualifies the welder for a "maxium to be welded" or "unlimited" base metal thickness, unless he has a procedure qualified for the thickness of base metal he intends to weld, he cannot weld it and be in compliance with the Code. Mixing the procedure and performance qualification limits unintentionally is the most common problem associated with using Section IX. -------------------------------------------------------------------------------37. - Welding Questions 1: Question: Is it a necessity of qualifying a WPS for PWHT if the PWHT is applied as a non-mandatory requirement (not Code required) to improve machine ability of the vessel? Only a PWHT type heat application is intended, and not an annealing heat treatment. Answer: Application of PWHT is an essential variable for all welding processes per Section IX of the Code. Since all the construction Codes require welding to be qualified per Section IX (except where specified otherwise), this mandates the WPS to be qualified for the condition of heat treatment applied to the production vessel to comply with the requirements. 2: Question: What about welding operator's qualified welding position in the following example? The issue is, a welding operator for SAW process was qualified on a 1G position. The production weld in question was a groove weld with a cover fillet weld on a tubesheetto-shell weld welded on a rotated flat positioner. According to QW-461.9 and QW-461.2 of Section IX, the cover fillet weld was deposited in a horizontal position, for which the welding operator lacks qualification. Answer: To qualify for the production weld in question the welding operator, as minimum, needs to pass a 2F or 2G position qualification test, or use the alternative rule in QW-305 by examining the first 3ft of his production weld by radiography. -------------------------------------------------------------------------------38. - "Coded markings" (Material) - UG-77(a), PG-77.2 Question 1: Can one unique No. be assigned to steel plates of same specification but with different heat Nos. ? Question 2: How about if the "plates" is substitute d by "pipe or tube" in question one? Response: 1. No. When traceability to the original markings or to a material test report is required, a coded marking must be unique for a given specification and heat number of a material. If the plates are of different thickness but of the same specification and heat, a common code marking may be applied. If two plates have the same specification but different heat numbers, they must have separate coded markings. 2. When material test reports are required, trace ability to the original markings is required. When trace ability to the original markings or material test reports are not required. generic marking identifying the material to a given specification is acceptable. For Section I construction, it is generally understood that all pressure retaining materials require test reports. For Section VIII, Division 1 test reports ar e only required for plate. --------------------------------------------------------------------------------
39. - Section I double block valves & free blow drains Question: What are the actual requirements for a double block and free blow arrangement on the steam isolation valves for a multiple boiler arrangement. The situation is a building with two boilers installed, and connected to a common header. One is a 300 horsepower unit that is large enough to have a manway installed. The second is a 40 horse unit that does not have a manway. The larger boiler has a double block and free blow arrangement on it's steam outlet. The smaller only has double block valves, without the free blow. Is this acceptable per the Code? What are the references for the requirements? Answer: Per Section I (PG-58.3.2) and B31.1 [122.1.7(A.3)]:"When two or more boilers are connected to a common steam header, or when a single boiler is connected to a header having another steam source (e.g., a turbine extraction line),the connection from each boiler having a manhole opening shall be fitted with two stop valves having an ample free blow drain between them." Double block valves with free blow drains are not specifically required for boilers that do not have a manhole. The intent of this arrangement is for personnel safety. A single stop valve has never been considered an adequate safety barrier for OSHA lock out and tag out requirements. If it were to leak, a person inside a boiler could be subjected to steam intrusion. Double block valves help to prevent such an intrusion. Since both valves may have some leakage, the free blow drain is required to be open so that if the first valve leaks, it leaks to atmosphere and does not put pressure on the upstream side of the second valve. There is no provision for such an arrangement when installing boilers without manholes. The common practice of interpreting the Code is to consider it to be permissive when silent, so long as such an interpretation follows good engineering judgment. Therefore the smaller of the two boilers does not require a free blow drain. By the same reasoning, it could not even require a second stop valve. However, the Code doesn't prohibit the described arrangement. It is common for plant arrangements for the piping to have double valve isolation capability for maintenance of equipment. -------------------------------------------------------------------------------40. - Pressure Relief Requirements - VIII Div 1 Question: What about the need to include something about the users' responsibility for relief valves in the remarks section of Section VIII Data Reports? Answer: It is not required for the Manufacturer to supply the pressure relief devices as stated in UG-125(a) and as supported by the Interpretation below: Interpretation: VIII-78-129 Subject: Section VIII, Division 1, UG-134, Pressure Relief Valves Date Issued: October 4, 1978 File: BC-78-583 Question (1): What are the requirements in Section VIII, Division 1 pertaining to set pressure of pressure relief devices on vessels storing liquefied compressed gases and which satisfy the conditions of UG-125(c)(3)? Reply (1): Such relief devices may be set in accordance with UG-125(c)(3)(b) and UG-134 including the special provisions of UG-134(e)(2).
Question (2): Is it required that the vessel Manufacturer furnish the pressure relieving device(s) prescribed by UG-125(a)? Reply (2): No. Footnote 31 indicates that safety devices need not be provided by the vessel Manufacturer, but overpressure protection shall be provided prior to placing the vessel in service. Applicable urisdictional requirements should be reviewed to determine limitations which may be different or more restrictive than the Code rules referenced in Question (1). There are no requirements for the Manufacturer to provide any specific information regarding the incorporation of pressure relief devices (PRD) on the data report other than to identify the PRD opening provided on the vessel if an opening is so designated [see note 41 in Table W-3 of Appendix W]. If the purchaser has not designated any opening as being specifically provided for the attachment of a PRD, then sometimes the Manufacturer will put a statement in the remarks something like "Pressure relief protection external to the vessel". This indicates that the vessel is intended to be protected from overpressure by devices installed within the piping or other system connections to which the vessel is attached. The responsibility for the correct installation of the PRDs is the responsibility of the vessel user as stated in UG-125(a). Since users do not always have Code books, it is a good idea for the Manufacturer to alert the user to this requirement in any installation and operating instructions he may provide. The Jurisdiction will sometimes provide this information, but in states which do not have a Pressure Vessel law, this may not be the case. -------------------------------------------------------------------------------41. -Section VIII Div 1 - seamless head "Quality Factor - E" Seamless Head "Quality Factor", UW-11(a)(b) Question: Customer inquired about the subject quality factor. He has a vessel with a single course shell with a Category A double butt weld seam and a seamless head on both ends. The head-to-shell joints are double butt Category B welds. The shell Category A weld was spot RT'd per UW-11(b) and UW-52, hence he used E=0.85 for the shell (circumferential stress) thickness calculation (UG-27). The question was, what is the examination required in order to use an E=1.0 (in the UG-32 head formula) for the seamless head t hickness calculation? Answer: The reference is UW-11(a)(5)(b) which requires a spot RT per UW-52 on the Category B head-to-shell joint and also the flow charts i n Appendix L, p 525. -------------------------------------------------------------------------------42. - Welding Position Section IX, QW-461.9 Question: A welding operator for SAW process was qualified on a 1G position. The production weld was a groove weld with a cover fillet weld on tubesheet-to-shell weld welded on a rotated flat position. Is the welding operator qualified for the production weld positions? Answer: According to QW-461.9 and QW-461.2 of Section IX and the sketch supplied by the contractor, the cover fillet weld was deposited in a horizontal position, for which the welding operator lacks the qualification. To qualify for the production weld in question the welding operator, as minimum, needs to pass a 2F or 2G position qualification test, or use the alternative rule in QW-305 by examining the first 3ft of his production weld by radiography.
-------------------------------------------------------------------------------43. - VIII Div 1 - UW-13 head to shell alignment Question: What if the vessel head to shell joint offset differs by more than 1/4 the thickness of the thinner section or by more than 1/8", then does the subject par. apply, otherwise, the joint shall be evaluated by UW-33? Is this correct? Response: If the situation is similar to that shown in UW-13(b)(3). This paragraph describes the requirements for a joint depicted in Figure UW-13.1 Sketches (l),(m),(n), and (o). Sketches (l) and (m) are when the shell is thicker than the head, Sketches (n) and (o) are when the head is thicker than the shell. Here is what the essence of the requirements are. If one element has a thickness that is greater the other element (regardless of which one is the thicker element), by more than the lesser of 1/4t (where t is the thickness of the thinner element) or 1/8 inch, a mandatory tapered transition between the different thicknesses is required. This taper shall be at a 3:1 ratio. The reference point for the taper is the tangent point of the head knuckle. The tangent point is where the head acts more like a shell than a head under stress analysis. The shell shall have the minimum required thickness on it's side of this point, and the head shall have it's minimum required thickness on it's side of this point. Material may be added to either element to achieve the transition taper as needed. But, material may not be removed from these elements reducing either below the minimum required thickness on their respective sides of the tangent point. Example: A thick head is attached to a thinner shell. The head has a straight flange beyond the tangent point. The required thickness of the straight flange in the area between the tangent point and the attachment where it meets the shell is the required thickness for the shell. Since it does not have the same required thickness as the head in this area, some of the excess material may be removed to achieve the transition taper. Therefore, the straight flange may be tapered to accomplish the required transition. If the difference in thickness is less than the lesser of 1/4t (where t is the thickness of the thinner element) or 1/8 inch, no transition taper is required. Centerline misalignment is controlled as well to limit a differential bending moment across the joint around the circumference. -------------------------------------------------------------------------------44. - QW-202.4 Combination Welding Question: If welder welds a test coupon that is 1-1/2 inches thick, using two different welding processes (GTAW and SMAW) for a deposited weld metal thickness of 3/4 inch for each, what are the limits of qualification for this coupon for procedure and performance? Is it possible for the welder to weld the coupon in more than one position, sa y 2G and 3G, and get benefit for both in qualification limits? Response: Question 1: Qualified Procedures may be used in combination, or a single procedure with multiple processes may be qualified. If applying the situation as described, the limits of qualification are: Procedure: Base metal thickness: 3/16 to 8 inches; Weld metal thickness: GTAW and SMAW both qualified for 8" max (if 3/4" min. deposited) Performance: Weld metal thickness: GTAW and SMAW both qualified for "Max to be welded"
Question 2: The coupon could be partially welded in one position and then another position, with the qualified weld metal thickness limits for each position based on the actual weld metal thickness deposited in each position. Example: Same coupon described as above. Weld in 2G position with 3/8" GTAW and 3/8" SMAW, change the position to 3G and weld 3/8" GTAW and 3/8" SMAW again. If the coupon successfully passes the required tests, the welder would be qualified to weld in 1G, 2G, or 3G using GTAW and SMAW with a qualified deposited weld metal thickness of 3/4" maximum for each position. Only the first process (GTAW) would be qualified without backing, and then only in 2G and 1G. SMAW would be qualified with backing only in positions 1G, 2G, and 3G. GTAW is qualified in 3G with backing only. -------------------------------------------------------------------------------45. Material Certification Question about a material acceptability issue. The shop rolled and welded a shell out of ASME Material, and documented their work on an ASME Partial Data Report. The shell was received by the purchaser, who was sent a copy of the Material Test Report (MTR) along with the Partial Data Report. They were balking at accepting the part, because the MTR had a different Edition and Addenda for the material specification than the Current Edition and Addenda as listed on the Partial Data Report. Is this a problem? Response: Editions and Addenda's do not apply to Material Specifications. ASME Materials are always acceptable as ASME Materials. If the newly published specification has more restrictive requirements than the material was manufactured to, this needs to be evaluated. If the material has an ASTM Specification date on it, this can be checked against Appendix A of the Section II, Part A book for acceptability of the date code. If only designated with an ASME Specification number, it is acceptable under that specification. This is addressed in the Foreword of the Code books, where it discusses Addenda, and states "Revision, except for revisions to material specifications in Section II, Parts A and B, become mandatory six months after the date of issuance,…". It is the intent of this statement to specifically exempt the material specifications from the Addenda mandatory implementation date. New materials shall always be ordered against the current Code requirements, but materials in inventory are acceptable under their material designation if ASME Spec material. -------------------------------------------------------------------------------46. Welder Continuity and Qualification Question: A welder that was an employee before, left the company and went to weld for another firm, and then came back. The period away from the company was greater than six months. The first company (original qualifier) wanted to reinstate the welder as fully qualified, based upon a phone conversion with the interim employer stating that the welder had been continuously welding. Is this acceptable? Response: This is not in keeping with the letter or intent of the Code. Welder qualifications are specific to an employer, unless a pooled qualification scheme has been applied as stated in QW-300.2 of Section IX. A pooled qualification scheme does not appear to be the case here. The welder's continuity gap with a specific employer exceeds six months, requiring requalification under the provisions of QW-322.1. The re-qualification i s very simple, requiring the welder to weld only one coupon with a given process per QW-322.2(a). If the coupon passes the requirements of QW-301 and 302, the welder is fully reinstated in that process for
all of his previous qualification ranges. The tes t may be a simple as a spot RT on a production weld, or two bend tests on a test coupon. This can be done for all processes previously qualified. For those processes not previously qualified, or when the qualifications have been revoked for cause per QW-322.1(b), full qualification tests are required. -------------------------------------------------------------------------------47. - Section VIII Div 1 - "Low Temperature Vessel" Question: What defines a "low temperature service" vessel? If a vessel is considered a low temperature service vessel, what requirements are to be met? Response: All of the following are considered to be "low temperature service" vessels: 1. Vessels made of Part UCS materials with an MDMT of colder than 55F and have a coincident ratio of greater than 0.35, as set forth in UCS-68(a). 2. Vessels made of Part UHA materials that require impact testing of the base metal or weld metal per the rules of UHA-51. 3. Vessels fabricated under the rules of Part ULT of Section VIII, Division 1. For vessels in categories (1) or (2) above, the provisions of UW-2(b) must be met. These provisions limit weld joint of specific Categories to a specific joint type. Vessels in category (3) above need to meet the requirements of Part ULT. -------------------------------------------------------------------------------48. - Calibration of pressure gauges Question: What is ASME's policy is with respect to the calibration of pressure gauges for: * New construction pressure testing (non nuclear) * In-service pressure testing and testing and setting of safety valves. (NBIC) (Boilers, air receivers, pressure equipment generally) Is it required that these pressure gauges to be traceably calibrated back to a national standard? Answer: The AI is required to verify that the Manufacturer follows their QC Manual, which is in line with our role as an Authorized Inspection Agency. The QC Manual is written in accordance with the applicable sections of the Code that the fabricator deals with. Each of the ASME Non-nuclear Boiler & Pressure Vessel Codes has specific paragraphs regarding calibration of test equipment. Essentially they say it has to be done and traceability maintained but do not specify a standard. For example, Section VIII, Division 1, UG-102(c) states "All pressure gages shall be calibrated against a standard dead weight tester or a calibrated master gage. Gages shall be recalibrated at any time that there is reason to believe that they are in error." Except for Section VIII, Division 2 & 3, which require recalibration every 6 months, there are no references to frequency or specific standards. Section III (nuclear) requires recalibrating before each test or series of test (anything within 2 week period). Although it is not specifically stated in any of the code books, it is commonly understood and industry practice that the Manufacturers use some nationally recognized standard for calibration and how the records/certifications can be traced back to the standard and state so in the QC Manual. This national standard that is used may be one established by the National Institute of Standards and Technology (NIST) or any other agency recognized by a government as a standards organization (i.e., they may use NIST, DIN, JIS, etc.). I believe the ASME changed this so that it was not nation specific (restraint of free trade and all that). In-service testing would be the same. The requirement would be included in the owner's or repair organization's QC manual. As far as testing/setting of safety valves this
would fall under the Valve Repair organization's manual. Again this would reference a specific national standard and some frequency for recali bration. -------------------------------------------------------------------------------49. Tube hole deburring - Section IV Question: What about requirements to deburring tube holes in Section IV boiler construction. The tube to header attachment is by welding as shown in Figure HW-731, sketch (y). The requirements for deburring are found in HG-360.1(b). Similar requirements are found in HLW-309(a), but are addressed to rolled tube attachments only. Should this be necessary for welded attachments? Response: The Code does not specifically limit this requirement to rolled attachments. The primary objective of deburring the hole edges is to minimize the cutting effect they would have on the tube when rolling, and removing anything that would interfere with a solid seating of the tube into the hole. No personnel safety issues are at stake for tube to header welds, since header entry is not likely. Considering the context of HG-360.1, and the presumed reasons for requiring deburring, it seems unreasonable to require deburring of tube holes for welded tube attachments. Tube to header attachments per Figure HW-731 sketch (y) are acceptable without deburring. -------------------------------------------------------------------------------50. Calculated Test Pressure - VIII Div1 Question: How do you determine the "New and Cold" MAWP of a Section VIII, Division 1 vessel. The owner wants to have the New and Cold MAWP included on the nameplate as well as the traditional MAWP. How is this determined, and why would the purchaser need this information? Response: The "New and Cold" MAWP is the value determined as the basis for a calculated test pressure as discussed in UG-99(c). It references the reader to Appendix 3, which defines a calculated test pressure as "the highest permissible internal pressure as determined by the design formulas, for each element of the vessel using the nominal thicknesses with the corrosion allowances included and using the allowable stresses given in Section II, Part D for the temperature of the test." In this case, the MAWP calculated for the most limiting component times the multiplier of 1.3 would be the basis for the calculated test pressure, and no stress ratio would be applied. The reasons for needing this information are unknown, but an educated guess would be for the purpose of conducting an acceptance pressure test upon the system after installation and connection to piping components. Often piping test pressures are limited by installed component MAWP, and the purchaser may want to minimize the limiting influence of the vessel MAWP on the system acceptance test. Be sure that the nameplate clearly indicates the different MAWPs as being either new and cold and operating values. Also remember that the marked MDMT is based upon the operating MAWP. -------------------------------------------------------------------------------51. - VIII Div 1 - Vacuum, RT- nameplate 1.Question: Is it acceptable to mark a vessel with a "FV" rating on the nameplate? The Manufacturer wants to know if putting "-15" (minus fifteen) was acceptable. Is it permissible to mark supplementary information on a nameplate?
Response: Marking a vessel rated for both internal and external pressure in a manner such as "MAWP 150 and FV at 400F" is a long standing industry practice, and acceptable. An alternative method is to mark it "MAWP 150 (INT)/15 (EXT) at 400F". Putting a negative pressure such as -15 on the vessel is so contrary to standard practice that I do not recommend it, as it might be too ambiguous. Supplementary information may be added to a nameplate by the Manufacturer, provided that the required information and formatting shown in Figure UG-118 is not interfered with. Such information should appear at the bottom of the nameplate. The only thing that should appear above the "certified by" is the National Board No. when so registered. 2. Question: What is the correct RT designator for a Section VIII, Division 1 U-tube heat exchanger shell per UG-116(e). Vessel has a seamless shell, seamless head on one end attached with a Type 2 weld joint that is fully radiographed, and a slip on flange on the other end attached by double fillet welds. Is this RT1 or RT4? Response: This is RT1. All butt welds in the vessel have been subjected to a full radiography, meeting the requirements of UW-11(a). This is the criteria of UG-116(e)(1) for RT1. 52. SAW welding procedure Changes, PQR requirements for Corrosion Resistant Overlay 1.Question: What is required to revise a SAW procedure to change from double welding a joint (with back gouging before welding the backside) to single welding using a ceramic tape backing? Is there a qualification issue here? Response: Joint design is not an essential variable, and neither is the addition or deletion of backing, so re-qualification of the WPS is not required to make this revision. Some revisions in the heat input may be required, such as adjusting the electrode diameter, amperage, and travel speed to get good burn through and fusion in a single pass. This would have qualification implications for an impact test qualified procedure. There are no qualification implications for welder performance. 2.Question: What is the correct interpretation of QW-404.37. The Manufacturer has a corrosion resistant weld metal overlay procedure qualified for the SMAW process using E309L electrode. He was wondering if the change in electrode designation from E309L to another alloy such as E316L would require a new PQR be prepared. The filler metals have the same A-No. and F-No., but QW-404.37 tends to indicate that for A-8 and A-9 weld metal analysis, a change of AWS classification requires re-qualification. Response: Yes this is a correct interpretation of QW-404.37. A change in AWS classification requires re-qualification. Flux trade name LINCOLN:760/Flux Type: ACTIVE 3. Question: One of my clients was told that the above type of flux is not allowed for Subarc welding because that it adds alloy? What is the correct answer? Response: Changing from an active to a neutral flux or vice versa requires re-qualification per QW-404.34. Fluxes that add alloying elements are acceptable once qualified under Section IX requirements. The variables addressing alloy fluxes are QW-404.10 and QW-
404.27, which are both essential variables. These are not normally addressed when fluxes t hat do not contain alloying elements are used. -------------------------------------------------------------------------------53. Inspection Openings - VIII Div 1 Question: What about the requirements for inspection openings per UG-46 in Section VIII, Division 1. The vessel in question is 42" ID, and 11 ft. long, with elliptical heads attached, that has only two 2 inch openings in the bottom head. Is this acceptable? Answer: This is an acceptable condition if the vessel is intended for non-corrosive service. If so, the data report needs to state "For Noncorrosive Service" in the remarks section per UG46(a)(4). -------------------------------------------------------------------------------54. - Root pass WPS - QW-200.4(b) Detail: Does a WPS for a root welding process qualified on a 3/8 inch coupon which is then to be applied in a 1 inch production base metal thickness weld meet the QW-200.4(b) requirements? Response: For a root process to be applied, it must meet the qualified base metal thickness ranges of QW-451, or have been qualified on a coupon at least 1/2 inch thick for unlimited base metal thickness applications. The example cited can be used as a root pass weld for metal up to 3/4 inch thick without additional qualification. The basis of this requirement is a phenomenon known as the "3D cooling effect". There is a fundamental difference between the heat dissipation rates in thin metals and thick metals. The difference occurs due to the available paths of dissipation within the base metal during welding. At thicknesses around 1/2 to 5/8 inch and less, the thickness of the material acts as a bottleneck to the flow of conductive heat in the metal. At greater thicknesses, the cross sectional area is great enough that the heat flux is not constricted and flows more freely, hence the 3D effect. Cooling rate has a great deal to do with fusion properties of welds, as well as the structures formed within the weld and HAZ. This is why impact testing requirements and qualified base metal thicknesses are based on the thickness qualified. -------------------------------------------------------------------------------54. - Boiler External Piping – design Question: How do you verify the adequacy of a spool piece design for a Section I boiler installation, with a MAWP of 600 psi and design temperature of 489F. Safety Valve settings are 570 and 595 psi? The spool piece consists of SA-106B seamless pipe with an ASME B16.5 Cl 600 flange on the inlet and a Cl 300 flange on the outlet. At issue is the acceptability of the Cl 300 flange, which is present to allow connection with the client's Cl 300 flanged valve in the steam system. Is this design adequate for the conditions cited? Response: Yes. The Cl 300 flange is good for 600 psi at 500 F, and the design requirement of B31.1 paragraph 122.1.2 (A.1) requires the design to have a value of "P" that is not less than the lowest set safety valve setting. Since this value is 570 psi, the flange is acceptable.
-------------------------------------------------------------------------------55. Use of SA 36 - VIII Div 1 Question: What about the acceptability of SA-36 for use in fabricating pressure vessels? Some people have been questioning this, and pointing out that the Scope of the material is structural. Is there a problem with using this material? Response: This material is acceptable for use within the restrictions of Paragraph UCS-6 of Section VIII, Division 1. Question: Are there any restrictions on the use of SA-36 material in Section VIII, Division 1? Reply: The only restrictions on the use of SA-36 material is on plate called out in UCS-6(b) and specifically UCS-6(b)(4) of Section VIII, Division 1. These restrictions prohibit the use of such plate material where strength welding is applied and only for heads, shells, and nozzles which exceed 5/8 in. in thickness. There is no restriction on the use of SA-36 bar stock. Question: Is it permissible under the requirements of UCS-6(b) in Section VIII, Division 1 to use SA-36 plate material in thicknesses over 5/8 in. in the construction of welded covers, similar to that shown in Fig. UG-34 sketch (g)? Reply: No. In addition, there has been a recent action to remove the penalty applied to the allowable stress values for structural materials. There has been an error in Table 1A for the past 3 years with respect to SA-36 allowable stresses. It all started when Section II decided to publish the values unadjusted by the 0.92 quality factor, and then rely on General Notes to apply the factor for pressure applications. However, somewhere along the line the applicable note [currently G37] was dropped. Customers should use the values as published, and not apply the 0.92 factor, although Table 1-100 says it should be applied. The information supplied in Appendix 1 is for information only; code users should not have to review this material in order to figure out what allowable stress to use. This problem will finally be put to rest in the upcoming 2000 Addenda, when the 0.92 penalty factor will be deleted from Table 1-100, and dropped for all cases. -------------------------------------------------------------------------------56. Nozzle replacement - VIII Div 1 Question is about a "repair" replacing a NPS 1-1/2 coupling with a NPS 3 SCH 10 pipe stub in the head of a Section VIII, Division1 vessel. Head is 0.3125" thick. Vessel rated at 150 psi for -20 to 650F. Nozzle attachment detail per Figure UW-16.1 sketch (i). The concern is about the thickness of the nozzle being from a pipe stub, since it is not as heavy as a coupling, and the fact that a SCH 10 pipe was specified. Is there any problem with this? Response: Yes, the thickness will not meet the requirements of UG-45. The wall thickness needs to be either the same as the shell or head that it penetrates or Sch 40 (STD), whichever is less. Since SCH 40 for this size pipe is 0.216 inches, which is less than the head thickness, this is the minimum wall thickness needed. For the stated head thickness, this diameter of opening may be attached without reinforcement calculations unde the provisions of UG36(c)(3)(a), and the weld strength can be exempted from calculations per UW-
15(b)(2). Since this is a new opening size for the vessel and not a like-for-like replacement, it is an Alteration and not a Repair. -------------------------------------------------------------------------------57. DA Tank - small nozzle welds Inspector did a DA tank internal inspection and noted three nozzles were not full penetration welded. These three nozzles used a fitting that is fillet welded from the outside only with just a hole in the shell on the inside. Shouldn't DA tanks nozzles be full penetration and welded as such? I know the code allows the fillet type fitting, but isn't it good engineering practice to use full penetration type nozzle? Response: Fittings less than NPS 3 may be attached with a single fillet weld from the outside only per UW-16(f)(2). The welds may actually be quite small and still be acceptable. In addition, UG-36(c)(3)(a) permits these openings to be installed without having to evaluate them for sufficient reinforcement, and UW-15(b)(2) exempts them from weld strength calculations. Assuming that these "fittings" are in fact couplings, half couplings, threaded bushings or some other forged type of pipe fitting. If this is not the case (i.e.; the nozzles are pipe segments), UW-16(f)(2) cannot be applied. Pipe segments can only be attached with full penetration groove welds or double full fillet welds. Another potential problem is if they are too closely spaced. They must be spaced at a distance of not less than twice their average diameters (center-to-center) or they will be subject to some additional requirements. -------------------------------------------------------------------------------58. - NCRs - Section I and VIII Div 1 Question: What is an "NCR" in an ASME QC Program? (Ref: ASME Section VIII Div 1 Appendix 10-8, ASME Section I A-302.6) Answer: The ASME Code requires the Manufacturer to have a system for identifying and resolving nonconformances, but does not specify how to do so. The Code intentionally leaves this open to the Manufacturer to decide, since nonconformances may vary considerably from job to job. The nonconformance system shall be described in the Manufacturer's Quality Control Program, and shall be followed. Once a nonconformance has been identified on a NCR, this usually involves having the engineering department and/or manufacturing propose a resolution to the NCR. The NCR is reviewed for acceptance of the proposed corrective action by the QC Manager and AI, who are responsible for verifying Code compliance. There are typically three choices that apply to resolving a NCR. They are: 1. Scrap, 2. Rework, or 3. Use as is. For the instances cited, the proposed resolution should be to "use as is"; with the additional actions of either providing a marked up copy of the drawing or some other documentation of what was done differently than specified during production. Many firms use a "deviation" document. This document reports and documents a "one time" change to the drawing or specifications for a particular vessel or series of vessels, and documents approval of those changes. This becomes a permanent part of the job package. The NCR should also become a permanent part of the job package as well. Then, additional care needs to be taken to ensure that the Manufacturer's Data Report properly documents the specifications of the vessel. In the case of the actual head thickness, this is not an issue, since the minimum specified head thickness is recorded, not the actual thickness. A change in reinforcement material may need to be properly recorded on the Data Report (ie nozzle or shell), and calculations need to be adjusted to verify the suit ability of such a change.
-------------------------------------------------------------------------------59. WPS qualification with impacts Question: When impact tests are required to be added to an existing WPS, a new test coupon has to be welded for the impact testing. Does the new test coupon also have to have complete physical tests if all parameters fall within the limits of the original WPS? Response: No, the other mechanical testing is not required. If the coupon was welded following all the currently qualified essential variables merely to expand the qualification to include toughness applications, the impact test alone is sufficient to qualify the current WPS for toughness. The WPS should be revised to address the supplementary essential variables applied to the test weldment, and to reflect the new supporting PQR as well. Question: When a change is made in a Supplementary Essential Variable for work done according to a Section which specifies notch toughness tests, are tension, bend, and impact tests required or only weld deposit and heat affected zone impacts? Reply: When a change is made in a Supplementary Essential Variable for work done according to a Section which specifies notch toughness tests, all tests are not required to requalify the procedure. The second paragraph of QW-403.5 states: When a procedure has been previously qualified to satisfy all requirements other than notch toughness, it is then necessary only to prepare an additional test coupon using the same procedure with the plates only long enough to provide the necessary notch toughness specimens. If a previously qualified weld procedure has satisfactory notch toughness values in the weld metal then it is necessary only to test notch toughness specimens from the heat affected zone. Question: If a welding procedure has already been qualified to satisfy all requirements other than notch toughness and a new procedure is to be qualified without changing essential variables but incorporating additional supplementary essential variables, will it be necessary to prepare an additional test coupon using the new procedure, only to provide necessary notch toughness specimens? Reply: Yes. -------------------------------------------------------------------------------60. Section I - connection off water column, & B31.1 valve 1.Question about connections in a FTSM Section I boiler. Apparently a repair/installation company wants to put a steam connection on the water column in a dry cleaners. They want to install piping that would take the steam for warm-up purposes for some of the equipment in the store. Is this permitted? Answer: PG-60.30.4 and PG-60.3.8 are paragraphs that address connections for the water column. PG-60.3.4 discusses the piping sizes and states that "These connections shall be completely independent of other connections for any function other than water level indication". PG-60.3.8 states "No outlet connections, except for control devices... or
apparatus of such form as does not permit the escape of an appreciable amount of steam or water therefrom shall be placed on the piping connecting the water column or gage glass to a boiler". 2.Question: How do you determine the valve pressure rating for a blowoff B31.1 valve? Answer: Example: Per B31.1, paragraph 122.1.7(C.6), the pressure rating of the flange or valve must be increased by 25%. Therefore, for a blowoff line with a MAWP of 325 psi, the pressure rating must be greater than 406 psi (325 x 1.25=406). A 300# flange has a rating of up to 490 psi for blowoff piping. This would be ok for a water temperature up to about 486 F. This is based on the fact that the same class rating (300#) is acceptable for steam use up to 605 psi. The saturation temperature of steam at this pressure is about 486 F. The temperature of water at 406 psi is about 445 F. -------------------------------------------------------------------------------61. PWHT - placement of thermocouples VIII Div 1 Question: What are the requirements regarding the number of thermocouples for PWHT (postweld heat treatment) in accordance with UCS-56 of ASME Section VIII Div.1? When PWHT is to be carried out, the proper number of thermocouples shall be attached to the parts or vessel surface. How many numbers of thermocouples should be attached to the vessel in a furnace? Is it sufficient for furnaces to have been calibrated by qualification block attaching thermocouples with 15ft interval of len gth annually? Are four(4) or five(5) thermocouples in a furnace are sufficient for PWHT regardless of item size? Response: The only requirements for thermocouple placement are found in UW-40(c). It discusses the placement of thermocouples near the top, middle, and bottom of the charge, to ensure true metal temperature indication for all zones when more than one vessel is included in the oven charge. Referenced footnote 10 states that furnace gas temperature measurement is insufficiently accurate to use as a guide. It is intended that the time at temperature shall be based on the metal temperature, not the oven temperature, otherwise the PWHT will be ineffective. So, a specific number of thermocouples for a given oven charge is not specified. But, based upon the guidance of UCS-56, sufficient numbers of thermocouples need to be present to verify that the thermal gradient limitation of 250 F (139 C) within a distance of 15 feet (4.6 m) is not exceeded during the heating period [per UCS-56(d)(2)], and to ensure that the temperature difference between the highest and lowest temperatures of any parts being PWHT does not exceed 150 F (83 C) [per UCS-56(d)(3)]. -------------------------------------------------------------------------------62. In process inspection by the AI? - VIII Div 1 Question: Can the AI get by with "no" in-process inspections of a pressure vessel during fabrication? Answer: We do not believe that the intent of the Code is being met when an AI performs no in-process inspections. Yes, there are many items in UG-90(c)(1) which require the AI to "verify" that a Code requirement has been complied with, but which do not necessarily require an in-process inspection in every case. However, as a minimum there are some inspections that must always be performed, such as:
UG-93(a)(1) The Inspector shall examine the Material Test Report or certificate of compliance and shall determine that it . UG-94 The Inspector shall inspect materials used in the construction UG-97 When conditions permit the Inspector shall perform an internal inspection, and he shall make an external inspection at the time of the hydrostatic test. UG-90(c)(1)(j) Making a visual inspection of vessel to confirm that the material identification numbers have been properly transferred. UG-90(c)(1)(k) Making a visual inspection of the vessel to confirm that there are no material with dimensional defects. This is not a complete list for Section VIII-1, but it does show that the Code mandates a minimum amount of in-process inspections. -------------------------------------------------------------------------------63. WPS for Dissimilar Thickness Joint Question: An ASME Code stamp holder called about a Welding Procedure Specification for a dissimilar thickness joint they were reviewing. The weld is a set-on [Figure UW16.1(a)] 20 inch diameter nozzle with 1.281 inch wall thickness to a shell with 1.812 inch wall thickness. Both base metal are P-No.1. The WPS assigned to weld the nozzle to shell joint has a maximum qualified base metal thickness of 1.5 inch. Is the WPS acceptable to use on this joint? Answer: No, the Welding Procedure Specification is not acceptable per QW-202.4. The welding procedure must have both base metal thickness, nozzle and shell, within its qualified range. Question: Is PWHT required for the same joint? Answer: They should determine the nominal thickness from UW-40(f), which is the greater of the nozzle groove weld size and fillet weld throat dimension, to evaluate whether PWHT is required. -------------------------------------------------------------------------------64. RT designator Section VIII Div1? 1.Question: This is regarding a vessel that has a smls pipe shell and smls (one piece) elliptical head. The girth was single spot RT examined at time of mfg and the nameplate was stamped RT-3. If the vessel is altered, can a spot be taken on the girth again (either single spot or double spot)and call it RT-2 as well as claim the increased joint efficiency to increase the MAWP as part of the alteration? Answer: RT-3 is the incorrect designation for the original vessel. The correct marking should be RT-2 if all the following are correct: 1. seamless shell and two seamless heads
2. Category B girth welds are Type 1 or 2, welded by a single welder, and combined length less than or equal to 50' 3. A single spot x-ray taken on one of the girth seams per UW-11(a)(5)(b) 4. Design Efficiencies: Shell Circumferential stress - E = 1.0 for Type 1, E = 0.9 for Type 2 Shell Longitudinal Stress - E = 0.7 for Type 1, E = 0.65 for Type 2, Seamless heads - E = 1.0 Although the joint efficiencies for longitudinal stress are less than 1.0, this will not control the design, since the longitudinal stress is one-half the circumferential stress when pressure is the only load. You don't describe the extent of the alterations, or whether it will require further RT. Assuming the answer is no further RT is required, then you can increase the MAWP for the vessel based on the information provided above; the nameplate and data reports should be corrected to RT-2, etc. 2.Question. A rolled and welded shell has seamless heads attached. The shell to head joints are given spot radiography to allow the heads to be calculated with E=1.0. What RT designator fits this situation? Response:2. RT-4 is the best fit. RT 3 does not apply, since the long seam is to be left as welded without examination. -------------------------------------------------------------------------------65. Lifting Lug calculations VIII Div 1 Background: During an ASME Joint Review for a "U" Certificate of Authorization it was noted by the ASME Team Leader that no calculation was made for the lifting lugs which were welded directly on the vessel wall. He pointed out that this is a Code deficiency in the light of paragraph UG-22, and asked the stamp holder to issue an NCR and prepare the calculation. Question: Does the Code require the calculation be made for lifting lug when it is welded directly on the vessel wall? Answer: ASME has previously issued the following interpretation for this si tuation: Interpretation: VIII-1-98-81 Subject: Section VIII, Division 1 (1998 Edition, 1998 Addenda); U-1(e)(2) Date Issued: September 10, 1999 File: BC99-373 Question: Are the calculations for lifting of the vessel considered a part of Code, Section VIII, Division 1, design calculations and required to be made available to the Authorized Inspector? Reply: No. When a lifting lug is welded directly to a vessel, the scope of the vessel ends with the attachment weld. The only time we would consider any reaction loads at the lug attachment point is during pressurized operation of the vessel, where t hese reaction loads may produce stresses which are additive to pressure induced stresses. However, if the lift lugs are solely used to move the vessel, then as stated by VIII-1-98-81, these are not Code mandated calculations. -------------------------------------------------------------------------------66. - VIII Div 1 - Opening Reinforcement Calculations
Question: Regarding a blind flange design: The C of A Holder submitted a design to their customer for review, and they rejected it based on incorrect reinforcement calculations. Looking over the customer's drawing for this vessel and cover; indeed they have an 2" NPT and 1/4" NPT spaced at 2.311", which is slightly closer than that permitted by UG-36(c)(3)(c), which is the sum of their diameters (2.625"). The C of A holder missed this, and did not run reinforcement calculations. Unless their cover plate is designed such that tr = tn, they should be able to satisfy reinforcement calculations for each opening using a smaller set of limits. Answer: This question is about exemptions from reinforcement calculations for small openings. Oil separators use a bolted blind flange for one of their closures. These blind flanges have several NPT fittings installed in them. The question deals with the application of the UG-36(c)(3) and UG-36(c)(3)(c) reinforcement exemption and spacing requirement for these small openings. If you look at the C of A holder's drawing, they would position a 1/4" NPT near a larger 2" NPT. The two openings are spaced too close to meet UG-36(c)(3)(c); however, calculations can be performed for the 1/4" NPT which would show it to be adequately reinforced. If this is done, then is there any need to perform reinforcement calculations for the 2" NPT, since the spacing requirement of UG-36(c)(3)(c) is for two UNREINFORCED openings, and we now only have one unreinforced opening, the 2" NPT? -------------------------------------------------------------------------------67. VIII Div 1 - production impact test? Situation: A vessel is being built to Section VIII-1. MDMT -50F Shell material is SA-350 LF2 1.63" nom. Flat head material is either SA- 516GR 70N Impact tested to -50 or SA-350 LF2[ 2" nom.] WPS is a combination (short circuiting GMAW and FCAW) and has been impact tested to 50 F Welding consumables are GMAW ER70S-2 and FCAW E71T-1 neither of which is impact test certified to -50 F. Question:. Are production impacts required to meet UCS-67? Answer: Based on the information presented, the Welding Procedure Qualification shall include impact tests of the weld and HAZ, since none of the paragraphs of UCS-67 provide an exemption. Specifically UCS-67(a)(2) does not waive qualifying the WPS with impacts since the welding consumable use was not classified by impact tests at the MDMT by the applicable SFA specification. Per UG-84(i)(2), once the WPS has to be qualified with impacts, then production impact tests are also required. The rules of UG-84(i) shall be followed regarding the production impact tests. -------------------------------------------------------------------------------68. Impact Test Exemptions for ERW Pipe
Except as exempted in UG-20(f), UCS-67(b) requires impact testing of Weld Procedure's of welds made without the use of filler metals if the weld exceeds 1/2" for all MDMT and when the weld exceeds 5/16" with MDMT colder than 50 deg F. Question 1) Does this apply to ERW Pipe supplied by a pipe manufacturer? If the answer is no, is this by ASME interpretation? Question 2) If the answer to question 1 is yes, how does a Certificate holder obtain certification of this? The below interpretation was the response: Interpretation: VIII-1-89-322 Subject: Section VIII, Division 1 (1989 Edition); UG-20(f) and UCS-67 Date Issued: January 9, 1991 File: BC90-683 Question: When material is exempted from impact testing by UG-20(f) of Section VIII, Division 1, must impact tests per UCS-67 be performed on the longitudinal welds of SA-53 ERW pipe in thickness up to and including 1 in.? Reply: No. The rational for this response is that when you purchase ERW pipe, you are essentially purchasing material; the vessel Manufacturer is not responsible for the autogenous weld. Also, UCS-67(b) would also not apply if UCS-66(a) or (b) were used to establish the impact test exemption. In my opinion the only time UCS-67(b) would apply is when the Manufacturer makes the weld himself. -------------------------------------------------------------------------------69. Section IX Welder Qualification using S numbers Question: Client is using A-36 for qualification of welders for use in ASME Code construction. Is this acceptable? Answer: Per QW-420.2 (last para), qualification interchangeability between P No's and S No's is acceptable i/a/w QW-403.18. This is an essential variable that applies to all welding processes in Section IX. QW-403.18 also references QW-423. QW-423.2 allows for welder qualification using any material (to a natl' or internatl' spec, e.g. DIN spec) as long as it meets the mechanical and chemical requirements of the target P or S No. Therefore, since Section IX allows for the interchangeability of P and S No's for welder qualification, use of A-36 is acceptable to qualify Code welders. The fact that the addenda year is not listed for the A-36 material is a moot point. The listing of a specification year and addenda is not a requirement for Section IX purposes as it is in the referencing book sections. Further, the wide latitude of acceptable materials used for performance qualification in Section IX confirms that the particular material does not have as much importance in the qualification as other variables do that confirm a welder's ability to make a sound weldment. -------------------------------------------------------------------------------70. VIII Div 1 - production impact test?
Situation: A vessel is being built to Section VIII-1. MDMT -50F Shell material is SA-350 LF2 1.63" nom. Flat head material is either SA- 516GR 70N Impact tested to -50 or SA-350 LF2[ 2" nom.] WPS is a combination (short circuiting GMAW and FCAW) and has been impact tested to -50 F Welding consumables are GMAW ER70S-2 and FCAW E71T-1 neither of which is impact test certified to -50 F. Question:. Are production impacts required to meet UCS-67? Answer: Based on the information presented, the Welding Procedure Qualification shall include impact tests of the weld and HAZ, since none of the paragraphs of UCS-67 provide an exemption. Specifically UCS-67(a)(2) does not waive qualifying the WPS with impacts since the welding consumable use was not classified by impact tests at the MDMT by the applicable SFA specification. Per UG-84(i)(2), once the WPS has to be qualified with impacts, then production impact tests are also required. The rules of UG-84(i) shall be followed regarding the production impact tests.
-------------------------------------------------------------------------------71. Impact Test Exemptions for ERW Pipe Except as exempted in UG-20(f), UCS-67(b) requires impact testing of Weld Procedure's of welds made without the use of filler metals if the weld exceeds 1/2" for all MDMT and when the weld exceeds 5/16" with MDMT colder than 50 deg F. Question 1) Does this apply to ERW Pipe supplied by a pipe manufacturer? If the answer is no, is this by ASME interpretation? Question 2) If the answer to question 1 is yes, how does a Certificate holder obtain certification of this? The below interpretation was the response: Interpretation: VIII-1-89-322 Subject: Section VIII, Division 1 (1989 Edition); UG-20(f) and UCS-67 Date Issued: January 9, 1991 File: BC90-683 Question: When material is exempted from impact testing by UG-20(f) of Section VIII, Division 1, must impact tests per UCS-67 be performed on the longitudinal welds of SA-53 ERW pipe in thickness up to and including 1 in.? Reply: No. The rational for this response is that when you purchase ERW pipe, you are essentially purchasing material; the vessel Manufacturer is not responsible for the autogenous weld. Also, UCS-67(b) would also not apply if UCS-66(a) or (b) were used to establish the impact test exemption. In my opinion the only time UCS-67(b) would apply is when
the Manufacturer makes the weld himself.
-------------------------------------------------------------------------------72. Section IX Welder Qualification using S numbers Question: Client is using A-36 for qualification of welders for use in ASME Code construction. Is this acceptable? Answer: Per QW-420.2 (last para), qualification interchangeability between P No's and S No's is acceptable i/a/w QW-403.18. This is an essential variable that applies to all welding processes in Section IX. QW-403.18 also references QW-423. QW-423.2 allows for welder qualification using any material (to a n atl' or internatl' spec, e.g. DIN spec) as long as it meets the mechanical and chemical requirements of the target P or S No. Therefore, since Section IX allows for the interchangeability of P and S No's for welder qualification, use of A-36 is acceptable to qualify Code welders. The fact that the addenda year is not listed for the A-36 material is a moot point. The listing of a specification year and addenda is not a requirement for Section IX purposes as it is in the referencing book sections. Further, the wide latitude of acceptable materials used for performance qualification in Section IX confirms that the particular material does not have as much importance in the qualification as other variables do that confirm a welder's ability to make a sound weldment. 73. Internal Inspection Question from a Code stamp holder in regard to internal inspections. The QC Manager feels after carefully reviewing UG-90, that the requirement stated in UG90(l), "performing internal and external inspections and witnessing the hydrostatic or pneumatic tests (UG-96, UG-97, UG-99,UG-100, and UG-101)", does not infer that every vessel requires an internal inspection. The QCM believes the words provided in UG-90(c)(1) "some but not all, of the required inspections and verifications, which are defined in the applicable rules, aresummarized as follows", is where the QCM feels that there is reason toquestion the need for internals on each vessel manufactured at his facility. Response: The words from UG-90(c)(1) are referring to the list of activities (a, b, c, etc.) not really specific parts of the activities list. UG-90(c)(1)(a) through (n) are also just SOME of the activities that should be performed. If the AI feels that there should be other things checked then that is his/her prerogative. Also see UG-97(a), "When conditions permit entry into the vessel, as complete anexamination as possible shall be made before final closure." Internal inspections are a necessary option for the AI. Weld penetration, weld size, material condition, nozzle stick through etc. can only be verified by internal inspection. As the AI, he has the right to perform any inspections he deems necessary and the option to check inside the vessel is within this scope. Therefore because we recognize the importance, we have a hold point on the Vesse l Traveler for this inspection. -------------------------------------------------------------------------------74. Application of UCS-68(c) to UG-20(f) Detail:
When UG-20(f) is used for evaluation of impact test for P-No. 1 and Group 1 or 2 materials, the resulting MDMT without impact test is -20 F. If the PWHT other than that required by the Code is performed, can this resulting MDMT be further reduced by 30 F to -50 F per UCS-68(c)?
Reply: No, the words of UCS-68(c) say that the 30 F reduction may be given to the minimum permissible temperature from Figure UCS-66. You have to determine the impact exemption temperature per UCS to be able to apply UCS-68(c) to P-No. 1 materials.
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Question: The client has 1" think stainless steel. The client has no WPS qualified for over 3/4". He does have 2 WPSs - one GTAW and one GMAW qualified to 3/4" with/without backing. The question is can the 2 WPSs be used together to make this weld as long as neither process goes over 3/4"? Answer: This approach is called piggy backing of welding procedures which is not acceptable to Section IX,. The practice violates QW-202.2(a) and QW-451.1. -------------------------------- ------------------------------------------- -------------------------------------- ------------ ---
75. VIII-1 material marking and "piggy back welding" Subject: VIII-1, Required Marking of SA-53 Pipe Received in Cut Up Lengths : Question: An ASME Certificate Holder buys standard full length (6Meters) of SA 53 pipes from a suppli er with instruction that the pipe be divided (by the supplier)into the length required and that heat numbers be t ransferred onto each piece. It is their opinion that this meets the requirement of UG-77. Material certificates are providedin all cases and traceable to the material. The C of A holder verifies that the heat number areon all the cut pieces during receiving inspection. The heat number transferred satisfies theterm "coded marking" which is traceable to the MTR. However the customer commented it should satisfy the Section 24 of SA 53 for subdividing the pipe for sale and all the markings required by the material specification be transferred and the processor's marking or name be included in the marking. Since the C of A holder is not buying short length of pipe but a full length of 6M is this required?
Answer: 1. Section VIII-1 UG-94 and UG-93 take precedent over Section II part A when it comes to material marking and identification. For pipe, theminimum marking required is Specification and Type, Class and Grade, as applicable. So Paragraph 24 of SA-53 does not control the required marking. 2. Per UG-93(a)(2), Material Test Reports are not required for product form pipe. The pipe need only be marked with spec/type/class/grade. 3. New paragraph UG-77(c) permits a vessel Manufacturer to receive shapes/parts marked with a coded marking system from a supplier. How they trace the original required marking to the coded marking must be described in the Manufacturer's QC program. The procedure being used satisfies UG-77, UG-93 and UG-94. ------------------------------------------------------------------------------------------------------------------------------76. Calculating the MDMT - VIII Div1 Question: In calculating the MDMT on a vessel with the following conditions: 1) The joint to be calculated is a category B butt weld between a seamless head and a seamless shell. 2) The shell is curve-B and the head is curve-A and the shell is thicker than the minimum head thickness. 3) The shell has a lower allowable stress than the head. 4) The shell will be welded to a straight flange on the head. In calculating the ratio=trE*/(tn-c): A) Should the tr to be calculated be based on the longitudinal stress ? B) Should the lower allowable stress be used in this calculation ? C) Should the tn to be used be the greater thickness of the two ?
D) Should the reduction temperature be subtracted from the greater of the MDMT shown in Table UCS-66 for curve-A or curve-B material ?
Answer: UCS-66 requires you to evaluate EACH COMPONENT for its impact test exemption temperature versus its minimum design metal temperature. If you do not have a specified MDMT then the highest impact test exemption temperature may be used to avoid impact testing all of the components. The governing thickness for that determination is defined in UCS-66(a)(1) - (3). The governing thickness may or may not be based on a welded joint. So the ratio needs to be done for each component if the exemption temp per Figure UCS-66 determined for each component is warmer than your MDMT. So, to answer the questions: A) Should the tr to be calculated be based on the longitudinal stress? Ans: tr is based whatever you equation you used in Part UG (e.g. usually circ for cylinders) B) Should the lower allowable stress be used in this calculation? Ans: component only has one allowable (usually) C) Should the tn to be used be the greater thickness of the two? Ans: tn of the component being evaluated D) Should the reduction temperature be subtracted from the greater of the MDMT shown in Table UCS-66 for curve-A or curve-B material? Ans: reduction temperature is taken from the component. -------------------------------- ------------------------------------------- -------------------------------------- ------------ --
77. - Material Test Reports - EDI (Electronic Data Interchange)
The General Specifications in ASME Section II Part A, such as SA-6, SA-20, SA-480 have been revised to accept (EDI). Note: SA-530 was not revised to accept (EDI). Question: Is EDI acceptable per ASME Section VIII, Division 1, UG-93 (a)(1) where the supplier is transcribing information? The way I read SA-20 19.7, you still must have the original manufacturer's test report [the company that melted the steel] in addition to any subsequent test reports. The acceptance of EDI has not changed anything with regard to validation of an MTR. The definition of a Material Test Report in Appendix 3, including the statements concerning transcribing information are still valid when using EDI to report information. Answer: Lets look at this from a practical point of view. If a vessel Mfg. purchases plate material from a supplier, and the MTR reporting all the information required by the material specification is only on the supplier's letterhead, then one has to assume a) the material supplier is the material manufacturer who melted and produced the raw material and finished product; b) the supplier transcribed information from the material manufacturer. If it is not case a), then there must two pieces of paper [material certs] supplied with the plate; one from the material manufacturer, one from the material supplier. To just identify the material manufacturer on the Supplier's cert. does not meet the code. The test report printed from an EDI from the original material
manufacturer may not contain a logo, etc., but so long as the original manufacturer is listed on this printout, then it should be accepted. -------------------------------- ------------------------------------------- -------------------------------------- ------------ --
78. PWHT Question - ASME I Question: I recently found out strip chart recorders are required for all PWHT. I've had some instances in the past at various field sites, which is basically owner/user type facilities, where PWHT was done by the R Stamp Holder by logging the results every 15 minutes. I had approved the procedure. The stress relieving was done on tube to tube welds, and/or weld buildup, on the secondary superheater, P5b material tubes, with 5% chromium. Stress relieving was required due to greater than 3% Chromium. The whole superheater assembly in Boiler #2 has been replaced, so the subject tubes in this boiler are now gone. Where is it documented that strip chart records are required? I seen in the QC Manual where it references calibrated instruments, but it doesn't specifically require strip chart recorders. I try to make sure they are used now, but occasionally, an emergent job comes up that makes it difficult to go this route. I'm still not sure where it is written. Answer: There are numerous requirements in both I and VIII Div 1 that talk about controls for PWHT. Most people require a written procedure and since they do not want the AI to have to witness the PWHT then they require a chart. PG-90.1.11 is hard to verify if you do not have a chart. "Duties of AI are to " verify that all required heat treatments have been performed and are properly documented". I would not want to try to defend not having a chart to the ASME/NB team leader. This same requirement is in the NB rules for Commissioned Inspectors par 8.1 (q).
Interpretation: I-81-16 Section I, PW-39 Requirements for PWHT Subject: Date Issued: August 6, 1981 File:
BC-80-621
Question (1): If a time-temperature chart is utilized to satisfy the requirements of PW-39.3, must the chart also reflect the cooldown in a still atmosphere to 800°F? Reply (1): No. Question (2): If the answer to the first question is no, how is it demonstrated that the cooldown to 800°F has been achieved? Reply (2): The Manufacturer's procedure shall be such that it demonstrates compliance with PW-39.3. ------------------------------------------------------------------------------------------------------------------------------79. VIII Div 1 - UG-93 material marking Question: (1) A "U" stamp manufacturer purchased SA-106 pipes, they accepted these pipes according to UG-93(a)(2) without obtaining a Material Test Report or Certificate of Compliance. After
a few years, the manufacturer can not identify the edition of the specification to which the pipes were fabricated. In this case, can these pipes be used for Code vessel without test and recertification? Question (2) Can bolts be accepted if the marking requirements of UG-93(a)(2)or(3)are met. According to SA-193, Para.18, certification is required. Can the vessel manufacturer accept SA-193 bolts if material certification is not furnished ? Answer: 1) Yes 2) Yes Section VIII-1 only requires material certificates for plate material; all other product forms can be accepted at receiving if marked with specification, grade, type and class. However a lot (maybe even most) U stamp holders require MTRs for pipe for other reasons such as; * the final customer may ask for them * to verify their suppliers quality control identification system works (and pipe is shipped with just heat numbers and not full marking) * just to have extra insurance and traceability in case problems occur later or the material remnants are kept in stock for future use. -------------------------------------------------------------------------------------------------------------------------------
80. Boiler Parts and BEP Question 1: Are pipe spools built to Sect.I req'd to be "S" Part stamped? PG106.8.1 Are they req'd to be documented on P4 or can they be doc'd on a P4a? PG112.2.4, PG112.2.5, PG109.3 Reply 1: Generally boiler internal piping is considered a part of a completed boiler. As such, it SHOULD be recorded on a P-4 form and stamped as an S Part. However, there could be exceptions. The P-4A form is routinely used as form for fabricated piping, regardless if it is internal or external piping. It really doesn't matter much which form is used, as long as it IS recorded accurately. But I think the stamping does matter. If someone stamps them as Parts, they are then indicating they are not taking full design responsibility for the item. If it is NOT stamped as a part, then it indicates they are responsible for the design. Question 2: Are small bore parts in PG106.8.2 req'd to be doc'd on P4 or can they be doc'd on a P4a? Reply 2: In this context, they should be reported on a P-4 form. But as mentioned in Reply 1, there could be exceptions. The Code stamping exclusion in PG-106.8.2 is just a subset to the requirements in PG-106.8. Whatever reporting provisions apply to Parts in PG-106.8, they would also apply to small parts. Question 3: May boiler external pipe spools built to B31.1 within the Sect.I jurisdiction, be stamped "S"Part? PG109.1, PG109.3 Reply 3: No. BEP is to be stamped with either a PP or S stamp. Question 4: Re: making flat end closures in headers under a PP stamp. This is not permitted. PG-109.3 allows a PP stamp holder to fabricate cylindrical parts with a PP stamp if the parts are welded in accordance with PW-41. PW-41 clearly allows only circumferential welds and not so clearly allows attachment of connections to piping such as a weld-o-let. But it does not allow the attachment of a flat plate or end closure similar to that shown in fig PG31, sketch (g). We believe that the end closure weld is not a circumferential weld. It is a corner joint. And it is certainly not a butt weld.
Section I, as you are aware, has several inconsistencies. It is sometimes difficult to discern the exact rule when there are so many apparent contradictions. Our suggestion is that if you, or you customer, find areas where a resolution cannot be achieved because of apparent contradictions then send in an inquiry to the Committee for their interpretation.
81. Section I - Use of SA-36 material Question: Customer called on the use of SA-36 plate as a flush patch and or plug in a power boiler. Is this acceptable in Section I construction or NBIC repairs? Answer: The only permitted usage in Section I is for stays, as referenced in PG-13. The stamp holder, claims it is acceptable and is listed in Section II Part D. They are correct that it is listed in II D, but it is only listed as bar stock for Section I. PG-13 is the only place in Section I that allows the use of SA-36 material and that is only for stay material. SA-36 material cannot be used for anything except stays in Power Boilers. Just because a material is listed in Section II D, that does not mean that it can be used indiscriminately. Section II D also limits the use of SA-36 in the notes. You are limited to the acceptable use as defined in the Construction Code. The ASME Boiler and Pressure Vessel Committee establishes rules to afford reasonably certain protection of life and property and to provide a margin for deterioration in service so as to give a reasonably long, safe period of usefulness. It is divided into Sections which determines the rules for the manufacture of the respective types of vessel. Section II is the Material Specification Section which specifies material which has been adopted by at least one of the other Sections of the Code. Section II does not a govern when determining what type of material is permissible for use in each respective Construction Code. It is only a list of adopted material which is acceptable in one of the other Codes. Each Section of the Code for construction will govern and adopt the material which is acceptable for construction to their rules. See ASME Section I, 2001 edition. First turn to the 'Forward' on the second page, viii, read the last paragraph on this page. You will get to a sentence that clearly states what we are discussing. "Not all materials included in the material specifications in Section II have been adopted for Code use. Usage is limited to those materials and grades adopted by at least one of the other Sections of the Code for application under rules of that Section. All materials allowed by these various Sections and used for construction within the scope of their rules shall be furnished in accordance with material specifications contained in Section II or referenced in Appendices A of ........" It goes on to say, "Materials covered by these specifications are acceptable for use in items covered by the Code Sections only to the degree indicated in the applicable Section. PG-5, page 5 simply states that all material that is subject to stress due to pressure shall conform to one of the specifications given in Section II. The last sentence in PG-5, "Specific additional requirements described in PG-5 through PG-13 shall be met as applicable. If you read PG-5 through PG-13 it outlines the specific type of materi al which is acceptable for use in the construction of boilers. It is broken down into each type of pressure part. You will clearly see that SA-36 is not an acceptable material for use in Section I.
82. NDE Level III qualification Question: The Level III of Company A has left the company, this Level III was qualified as Level III based on Experience ability ... The QCM is going to subcontract the Level III services to a Company B that has a U Stamp, the Level III of Company B is a Level III qualified by experience, ability and continuous satisfactory performance. Is this acceptable? Response: Yes, this Level III assignment is acceptable. There are some issues to be verified to ensure that all is well, however. Level III examiners are qualified to their employer's Written Practice. The Written Practice must be developed with SNT-TC-1A as a guide. The Edition of SNT-TC-1A at the time of the Level III qualification is the key. If this individual was qualified as a Level III under any Edition of SNT-TC-1A prior to 1992, it is acceptable for him to be qualified under experience. 1992 was when the requirement for qualification by written examination became effective. Once qualified, the Level III may be recertified based upon sustained satisfactory performance, regardless of the Edition of SNT-TC-1A in effect. All versions allow recertification by experience. Once his qualificati ons lapse. he comes under the requirements for initial certification again. It is important that the Manufacturer appoint the Level I II to act as their Level III by letter, and receive a letter accepting the appointment from the appointed individual. These should be kept on file by the Manufacturer. Copies of the Level III qualification records and current eye exams must be kept on file by the Manufacturer. The Written Practice for the subcontracted organization must be compliant with the current Code accepted Edition of SNT-TC-1A, which is the 1996 Edition with 1998 Addenda. It should be kept on file as well. Finally, the written procedure to be applied when performing radiography should be compliant with the current Edition and Addenda of Section V, Article 2, and also kept on file by the Manufacturer.
83. VIII Div 1 - UCS-66 - "GOVERNING" thickness for establishing MDMT? Question: Manufacturer is intending to weld a heavy series LWN flange (SA105 – Curve B) into a shell (SA516-70 Curve D). The flange does not qualify for the UCS66(C)(4) B16.5, – 20 F impact exemption due to its outside diameter. The flange neck is 3.875” thk and the shell is 2.0” thk. UCS66(a)(1)(b) states that the thinner of the 2 components should be used as the governing thickness. Does this mean that this lesser thickness, of 2”, should be applied to the Curve B material, which is actually 3.875’, or should it be applied to the Curve D material? Answer: Yes, you have interpreted the rules of UCS-66(a) correctly. When you go into Figure UCS-66, you use the so-called "GOVERNING" thickness for each material on either side of the joint. Therefore, for your example since UCS-66(a) says to use the thinner of the two components in a corner joint, the governing thickness would be 2". You would then go
to Curve B at 2" to assign an MDMT for the flange, and to Curve D at 2" to assign an MDMT for the shell. This part of the process is described in Fig UCS-66.2, Step 2 and Note (5). These 2 values of "raw" MDMT could then each be further modified by UCS-66(b) using the coincident ratio defined in Fig. UCS-66.1 when the ratio is less than one. 84. - Rods and Bars used as nozzles in VIII Div 1 vessels? Question: My AI says I cannot machine rod or bar to use as nozzles in my Section VIII Div 1 vessel! Why not? Answer: Your AI is correct, however there is a Code Cases (2148) that may allow it with some restrictions. If you look at UG-14 in VIII Div1 you will note the restrictions on the use of rod and bar and you will see that nozzles are not mentioned as one of the permitted applications. The purpose of the "rod and bar" Code Case is the perceived anisotropic properties (the worst case being laminations) of these product forms - that the properties are not the same in all 3 directions. Therefore, if a rod or bar is loaded other than along its axis, it may experience a premature failure. This case is exemplified by a rod that is bored out and exposed to internal pressure such that the hoop stress is not oriented along the axis of the bar. Side note: Other rod and bar Code Cases of interest (2155 - heads, 2156 shells)
85. VIII Div 1 vessel hydrostatically tested in the vertical position Background: An ASME VIII Div 1 fabricator is building small "UM" heat exchangers in which the tube side is made up of a coiled tube that penetrated the shell side shell wall with an inlet and outlet coupling. This coiled tube is less than 6 in. in diameter and contains water at 150 psi at 150 degrees Fahrenheit. Question: What about note 39 of Appendix W? This note states that if a vessel is hydrostatic tested in a vertical position this must be stated in the remarks section of the Data Report. The customer was asking why the Code required this? What is the purpose was for remarking on the Data Report if a vessel is hydrostatically tested in the vertical position? . What is the rationale behind this? If one were constructing a 200 ft. tower this might be information that would be of value to the end user. But the situation with this customer is that he builds a small vessel only 13 in. tall that does get tested in the vertical position. It does seem bizarre to have to state on the Data Report that such a small vessel was tested in the vertical position! Answer: You cite a perfect example of when a generic rule makes no practical sense at all, a situation when the nonmandatory generic guideline obviously has no structural significance and should, with the AI's agreement, be ignored. However, there are cases when the exception to the normal horizontal-position shop hydrotest is practical and is desirable for structural reasons, and of course for field assembly/construction situations it is necessary. In those situations, the fact that a vertical hydrotest test was conducted can be very useful information, information that could prevent a dumb mistake during future( post construction ) situations.
Accordingly, I think the guideline should stay. Besides, it probably prevents us from having to develop a guideline as to when the effects of a hydrotest head should be, and need not be, considered, a virtually impossible task. For applications involving very tall vessels it is important for the end user to know whether not such a vessel is tested in the vertical position. This is the problem with writing a generic rule to cover everything from pressure cookers to 200' long towers. 86. VIII Div 1 vessel Code boundary Question: A customer called looking for information regarding whether not the seal weld used to attach a threaded plug to a coupling in a pressure vessel would be considered a Code weld? Answer: The ASME Section VIII, Division 1 Code defines the pressure vessel boundary in the Introduction chapter, paragraph U-1(e). The purpose of this paragraph is to define the Code boundary for the vessel when it is stamped and certified by the Manufacturer. The general rules of thumb are as follows: Nozzles, couplings, necks, etc. and their attachment welds to the vessel are always considered part of the Code Vessel. When a nozzle or a coupling is connected to piping, the Code boundary ends at the weld prep of the nozzles or coupling. The weld is not considered part of the Code stamped vessel unless the vessel manufacturer wanted it to be. He would do this by indicating on his drawings and on the manufacturer's data report where he intended to end the Vessel boundary. In the case of a threaded plug being installed into a coupling and then seal welded, if this is done during the fabrication of the pressure vessel and prior to certification, then the threaded plug and weld are considered part of the Coded vessel. However, if the vessel is stamped and certified without the threaded plug installed, and this plug and seal weld are installed in the field, then the plug and seal weld come under the jurisdiction of the applicable piping Code such as B31.3. In either case the seal weld would be considered a Code weld in as much as the weld procedure and welder should be qualified to Section IX since both Section VIII and the piping Codes use Section IX to control all welding. The one difference is that if the threaded plug and seal weld were originally considered part of the pressure vessel when it was first constructed, then the activity of removing and reinstalling a welded plug could be considered a repair under the NBIC code and thus may involve the services of an NB Commisoned Inspector. To summarize all of the above, is the threaded plug seal weld a Code weld? Maybe. Should the seal welding of the threaded plug to the coupling be carried out with a Section IX qualified procedure and welder? Yes.
87. VIII Div 1 UW-11(a)(5)(b) Background: ASME Section VIII Div 1 "U" stamp holder and their Authorized Inspector disagree on the requirements for spot examination of a Section VIII-1 vessel. The vessel has a 40 inch diameter, single wall, seamless head and 1/2 inch wall thickness for the shell and head. Total length of Cat A and B welds ~29 ft. All welding performed by one welder. Question: What is the number of RT spot examinations in order to use: E=1 for the head thickness calculation; E=.85 for the shell (hoop stress) calculation using type 1 joint?
Answer: A minimum of two 6-inch spot examination would be required: 1 for the quality factor UW-11(a)(5)(b) and 1 for the weld increment UW-11(b). Another issue is placement of the spot examination. The Code rules [UW-52(b)(3)] is very clear that the AI has this prerogative, unless the AI waived his prerogative, only then may the manufacturer designate the area to be examined. 88. Section I, PG-99, Application of Insulation Prior to Hydrostatic Test AI is having disagreement (difference of opinion) with a boiler "A" assembler about the quantity of insulation that is present during hydrostatic test of a boiler. ASME has issued past interpretations, with the most recent as follows: "Question: May portions of welded power boilers that do not contain longitudinal welded joints made with the addition of filler metal be covered with insulation or refractory prior to the hydrostatic test required by PG-99? Reply: Yes; however, the Authorized Inspector may require the hydrostatic test pressure to be maintained at the maximum allowable working pressure for an extended period of time, sufficient to assure there is no indication of leakage. The Authorized Inspector may also require the removal of insulation for cause." Note: The reason for specifying the longitudinal seams is that they are usually the higher stresses seams and more likely to fail. It is ultimately up to that AI, but if the "A" stamp holder insists on testing with insulation present on circumferential, nozzle, etc. seams, then a much longer hold time should be imposed, which is within the AI's right. Make it real long so you will definitely see a pressure drop if there is a leak. You should see all (or as many as possible) seams if you are the AI signing the Manufacturer ’s Data Report.
89. VIII Div 1 purpose of final pressure test Question: Our heat exchangers are built to ASME Section VIII, Division 1 Code requirements and hydrostatically tested to the requirements of UG-99. UG-99 does not state a time to hold the pressure vessel at the test pressure to check for leaks. Our standard hydrostatic test procedure states that we will hold the heat exchangers at the required test pressure for 15 minutes per test to check for any leaks. If a test greater than 15 minutes is required then after the initial 15 minute period at 1.3 test pressure ratio we drop the pressure to the maximum allowable working pressure for the remainder of the test period. Our position is that the 1.3 test pressure ratio is a deformation check and should not be held for extended periods of time. Can you describe the intention of UG-99 as far as the time that is required for the pressure test and the acceptance of our test procedure as described above. Answer: The purpose of the final pressure test [hydrostatic or pneumatic] is threefold: 1. It is first and foremost a safety test. It is the final opportunity to verify that there were no gross errors in design or construction of the pressure vess el.
Although VIII-1 does not specify the length of time that the vessel must be held at the test pressure, it is common that the vessel be maintained at the full test pressure for a least 10 minutes in order to allow the material to reach an equilibrium state, and to be able to determine if there is going to be any gross deformation. 2. It is a leak test for the purpose of verifying no leakage through any pressure boundary welds or any permanent gasketed joints. This inspection takes place with the vessel at a lower pressure equal to the test pressure divided by the pressure test factor [1.3 for hydrostatic test, 1.1 for pneumatic. 3. Finally by subjecting the vessel to a pressure equal to 1.3 times the MAWP, a small amount of stress relief occurs as well as some crack blunting. There have been numerous studies conducted which demonstrated the quantifiable benefits from subjecting a vessel to a pressure higher than its original design pressure for a short period time. In conclusion, for the purposes of conducting a final pressure test, holding the vessel at its test pressure for a period longer than 10 to 15 minutes adds no further value to the process. But at the same time considering the large design margin built into VIII-1, holding a vessel at the test pressure for a period of time longer than 10 to 15 minutes should have no detrimental effect for most pressure vessels. 90. VIII Div 1 impact test requirements for UG-11 manwa y assemblies. Question is in reference to a prefabricated manhole ring for an elliptical manhole. This ring is furnished to the vessel manufacturer with a cover as a completed item, per UG-11, for installation in a Section VIII, Division 1 vessel. The standard ring is formed from SA-675 Gr 70 3/4" x 4" bar material and the ring is welded and stress relieved prior to machining. This material appears to be a curve-A material and would require impact testing, based on the 3/4" thickness, for the standard -20 deg.F MDMT as a component. The ring would be welded to a 1/2" plate SA-516 Gr 70 shell and the shell would govern under UCS-66(a)(1)(b) for impact testing exemption. 1) Would the SA-675 bar require impact testing? 2) Should this ring be fabricated from SA-516 Gr 70 and be exempted under UG-20(f)? Answer: You said that this is a prefabricated manway ring under UG-11. So, per Figure UCS-66, Note (b)(4) it is Curve B. Also per UG-11 the parts would be supplied with pressuretemperature ratings [UG-11(c)(2) and UG-11(a)(1)] which probably say that it is good for 20F. The manufacturer of the rings most likely takes the value from Figure UCS-66 and then reduces it by 30F per UCS-68(c) because their PWHT is not required by Code but they do it anyway. If you manufactured the rings yourself out of SA-675, they would have to be impact tested. 91. B31 Socket Weld Fitting Fit-Up Gap Question : What is the rationale for mandating that a 1/16th inch gap be maintained when welding socket welded fittings to pipe per B31?
Answer: The purpose of the gap between the end of the pipe and the bottom of the socket weld fitting during fit-up is to ensure that any differential thermal expansion between the pipe and fitting will not place additional stress on the fillet weld. See following B31 interpretations on this subject, all of which state that the gap must exist during fit-up, but it need not be measured after welding.
Interpretation: (B31.1) 19-5 B31.1, 127.3.3(A), Gap Requirements for Socket Welds Subject: Date Issued: April 5, 1991
B31-91-002
File:
Question (1): Does Para. 127.3.3(A) require that the approximately 1/16 in. gap required during fitup exist after welding is completed? Reply (1): No. Question (2): Does ASME B31.1 require an examination, radiographic or otherwise, to verify that the fitup gap required by Para. 127.3..3(A) exists in the completed weld? Reply (2): No.
Interpretation: (B31.3) 10-19 ANSI/ASME B31.3-1984 E dition, Para. 327.4.2, Fillet and Socket Welds Subject: Date Issued: December 2, 1991
B31-91-039
File:
Question: Are socket weld joints with intimate contact before welding (i.e., zero gap) between the end of the pipe and the bottom of the socket weld fitting prohibited by the Code? Reply: Yes.
Interpretation: (B31.3) 16-06 ASME B31.3-1996 Edition, Para. 328.5.2, Welding Requirements - Fillet and Subject: Date Issued:
Socket Welds May 20, 1997
File:
B31-96-058B
Question: In accordance with ASME B31.3-1996 Edition, para. 328.5.2 and Fig. 328.5.2c, what is the minimum gap acceptable in a socket-welded joint after welding?
Reply: The 1/16 in. approximate gap shown in Fig. 328.5.2c is "before welding." The Code does not provide a gap dimension after welding.
92. Question: Where in the ASME Code are international materials listed? Answer: International materials are treated essentially no different than ASTM materials. (see Forward to the ASME Construction and Reference Codes ...." Revisions to material specifications are originated by the American Society for Testing and Materials (ASTM), and other recognized national or i nter national organizations and are usually adopted by ASME." The materials that ASME has accepted thus far are listed in: Section II, Part A on pages xxxvii and 1473-1475, Section II, Section II Part D on page 6 (lines 7 & 25), page 10 (lines 35 & 36), and page 14 (line 12 &13), Section I PG-6 (page 6, SA/EN-10028-2), Section IV Table HF-300.1 Note (19), Section VIII, Division 1 UCS-6(b) page 177 (SA/CSA-G40.21 38W) and Table UCS-23 page 303 (SA/EN 10028-2, 3 and SA/CSA-G40.21 38W) , and Section IX QW/QB-422 p. 110.
93. VIII Div 1, UG-10 and identical ASTM material Question: An ASME VIII Div 1 "U" stamp holder wants to know if they have to issue a nonconformity (NCR) referencing "UG-10" for materials that are coming in to their shop certified as "A" (ASTM) and not "SA" (ASME), which was how the y were ordered? Answer: The QC manual should be followed closely as there may or may not be an NCR required depending upon the how the Manual is written. An NCR would be one way to document the situation and corrective action taken. For "A" verses "SA" materials, the word "identical" is the key. UG-4 states that the "SA" and "SB" material for Section VIII, Div. 1 construction are listed in Section II, Part A or B. The Foreword and Appendix A of Section II, Part A pretty much says that material produced under an ASTM Specification may be used in lieu of the corresponding ASME Specification as listed in Appendix A. This means IF the ASTM material specification that is listed on the MTR isidentical with the one in Appendix A (specification year needs to be listed on the MTR to verify this) then there is no need for "recertification" under UG-10. Recertification really means something was done to verify the acceptance of the material - besides just scribbling on the MTR or marking an "S" in front of the "A" on the material. An additional note: the exceptions that ASME has taken occur in more than 95% of the materials. Looking at Appendix A they have taken exception to something in a lot of specifications - mostly corrections that ASTM hasn't gotten around to yet. 94: VIII Div 1 - UW-16(c) - Nozzle attachment welds, full penetration? Question:
According to UW-16(c), when complete joint penetration cannot be verified by visual inspection or other means permitted in this Division, backing strips or equivalent shall be used with full penetration welds deposited from one side. Besides visual inspection and RT, are there other means permitted by Code to verify full penetration? When it's not possible to verify complete joint penetration and if GTAW welding is used for root pass of the joint, does it meet Code requirements, and can the welding groove be made by gas cutting? If neither use of backing strip or GTAW is used for root passes of the joints, can we accept it through proper fit-up inspection? Answer: Besides visual and RT you may be able to use UT. Although, due to the configuration (corner joint), it is not clear how useful RT and UT will be. There is really not any other method of verifying complete penetration of this joint. Using a specific welding technique cannot guarantee complete penetration. Visual inspection, either direct or indirect (e.g. mirror, boroscope, fiber optics, etc), is the best method of examination to insure complete penetration. One main reason for the verification of the full penetration joint is that the Code does not want a crack left on the inside of the vessel. This is a high stress concentration area and an area where corrosion will begin. There is nothing in the Code that tells you how to make the weld groove. UW-9(b) states that "the dimension and shape of the edges shall be such as to permit complete fusion and complete penetration." UW-31(a) states that "when plates are shaped by oxygen or arc cutting, the edges to be welded shall be uniform and smooth and shall be freed of all loose scale and slag accumulations before welding." So the Code does not specify the method of cutting but does require that the edges be machined so that they provide a clean surface for the welding.
95: Titanium not reported as an unspecified element as required by SA-20 par. 7.1.1.1 Background: The 2002 Addenda to ASME Section II A of SA-20 SPECIFICATION FOR GENERAL REQUIREMENTS FOR STEEL PLATES FOR PRESSURE VESSELS (referenced by numerous plate material specifications), Table 1 requires Titanium to be reported on the Material Test Report. Question: How can material be accepted if Titanium is not reported as an unspecified element on the MTR as required by SA-20 par. 7.1.1.1? Answer: For right now, the only user options are Appendix A of ASME II A and Code Case 2053 (For Materials in Inventory Sections I, IV, and VIII Div 1 and 2). Code Case 2053 must be noted on the Manufacturer's Data Report. CC 2053 expires 11-28-03.
96: ASME Section I - difference between tube and pipe Question: May a SA-335 Seamless Ferritic Alloy Steel Pipe for High Temperature Service be used for boiler tube? This material is listed in PG-9.1. Answer: There is nothing in Section I that would prohibit the use of a pipe specification material in a "tubing" application. In most cases, the only real difference (other than the title of the specification)
between "pipe" and "tube" material is the tolerance's that are listed in the respective specification and PG-9. As general boiler industry practice, if the primary application for the material is heat transfer then it is usually considered to be "tubing" and the equation from PG-27.2.1 is used to calculate the thickness. If the primary purpose is fluid conveyance with relatively little or no heat transfer function then it is "piping" and the equation in PG-27.2.2 is used. These paragraphs make no mention of an appropriate material to be used. In fact, both sets of equations use the same variable, t, for the minimum required thickness. I've attached an Interpretation that discusses the definition of "piping" and "tubing" that may help. It is important to note that "pipe" and "tube" are material product forms and "piping" and "tubing" are applications or functions. note: see below interpretation.
Interpretation: I-86-25 Subject: Section I, PG-27.2, Wall Thickness of Pipe and Tube Date Issued: June 23, 1986 File:
BC81-713, BC83-289, BC83-669, BC84-230
Question: Under what circumstances do the equations under PG-27.2.1 (for tubing) and PG--27.2.2 (for piping) apply? Reply: The formulas in ASME Section I, PG-27.2.1, for tubing, are intended primarily for applications such as boiler tubes, superheater and reheater tubes, or economizer tubes in which groups of such tubular elements are arranged within some enclosure for the purpose of transferring heat to or from the fluid within the tubes. For this heat transfer function, the tubular elements ordinarily do not need fittings or valves. When the function to be performed is mainly the conveying of a pressurized fluid from one location to another, with little or no intentional heat transfer, the formulas in PG27.2.2 should be used. The elements commonly used for this purpose are called piping. The standard piping sizes are available with matching sizes of fittings (tees, elbows, etc.) and valves to facilitate the installation of piping systems to direct and control the flow.
97: UG-99 - Hydrostatic test pressure - VIII Div 1 Question from a stamp holder about the difference between UG-99(b) and UG-99(c). The customer has asked for a test based upon UG-99(c). What is the difference? According to UG-99 of ASME SEC.VIII, Hydro test press(Ph) is calculated as the f ollows; 1. HYDRO. TEST PRESSURE(which at every point in vessel for internal pressure) P(hydro) = 1.3 x M.A.W.P(or D.P) x Ratio St : Stress Value At Test Temperature per each material Sd : Stress Value At Design Temperature per each material Ratio : St / Sd 2. The User spec. is "the test pressure shall be at least 50% higher than design pressure." P(hydro) = 1.5 x D.P x Ratio or P(hydro) = 1.5 x D.P Answer: We will assume that you intend to Code stamp the vessel, and therefore the answer is based on meeting all of the Code requirements.
1. The minimum hydrostatic test pressure is given in paragraph UG-99(b), and is equal to 1.3 x MAWP x STratio [STratio is the lowest ratio, considering all of the materials used in the construction of the pressure vessel, of the stress value S for the test temperature on the vessel to the stress value S for the design temperature.] The MAWP is the pressure listed on the nameplate and is equal to or greater than the design pressure. Any additional pressure due to the static head of water that exists during the test is not included in the determination of the test pressure. 2. Paragraph UG-99(c) provides an option to conduct a hydrostatic test based on a calculated pressure which considers the vessel in new and cold condition. In this case, the test pressure is normally higher than the value provided in paragraph UG-99(b). Conducting a hydrostatic test based on calculated test pressure requires an agreement between the user and the manufacture, and the AI has the right to review the calculations used to determine this calculated test pressure. 3. Per UG-99(d) there is no upper limit on test pressure and Section VIII, Division 1. However the Inspector has the right to reject the vessel if he observes any permanent distortion of the vessel following the test. 4. If you choose to conduct the pressure test per your customer's specification, you should perform the calculations required by UG-99(c) and determine the Code " calculated test pressure " based on new and cold conditions. If the test pressure required by the customer's specification (1.5 x design pressure) is greater than the calculated test pressure given by UG-99(c), then you should calculate the actual stress in the pressure vessel during the test and compare this to the yield strength of the material, to ensure that there will be no permanent distortion of the vessel.
98: Section I power boiler hydrostatic test water temperature Question: PG-99, ASME Section I requires that pressure tests required be conducted using water at a temperature not less than 70oF. We use hot water above 70oF but we don't keep the temperature above 70oF during pressure tests because of ambient temperature. 1) May pressure tests required by PG-99 be conducted using water at a temperature less than 70oF during pressure tests ,if we use hot water above 70oF ? 2) Why does Code require using water at a temperature not les s than 70oF? Answer: PG-99 is clear that the water temperature shall be no less than ambient temperature, and in no case less than 70 degrees F. Interpretation I-95-27 (included below) supports the existing Code words. There are a couple of reasons for the minimum temperature. It is believed that the 70oF would keep the metal temperature above the range where brittl e fracture could occur since Section I does not have the same minimum design metal temperature as those in that Section VIII. A second possible reason is that using a temperature below ambient or 70oF (the warmer of the two) could result in condensation on the metallic surfaces which could conceal small leaks. It is often common practice when boilers are installed on-site in cold regions (or in cold shops) that a secondary boiler or heat exchanger is used to provide the boiler with warm water for hydrostatic testing purposes. Interpretation I-95-27 Subject:
Section I, 1992 Edition, PG-99, Pressure Testing of Completed Boiler Using Water at Ambient Temperature
