Code Case 181 2m3t4a

NOTICE REGARDING CODE CASES OF THE ASME B31 CODE FOR PRESSURE PIPING

All B31 Code Cases in effect as of September 21, 2007 will remain available for use unless annulled by the B31 Standards Committee.

B31 CASE 178 CASES OF THE CODE FOR PRESSURE PIPING – B31 B31 Case 178 Providing an Equation for Longitudinal Stress for Sustained Loads in ASME B31.3 Construction Approval Date: May 6, 2005 This Case shall expire on May 1, 2008, unless previously annulled or reaffirmed

Inquiry: ASME B31.3 provides a description for determining SL for sustained loads. Is there an equation that may be used? Reply: It is the opinion of the committee that, in the absence of more applicable data and in accordance with para. 302.3.5(c), the following equation may be used to calculate SL for sustained loads.

S L = (| S a | + Sb ) 2 + (2St ) 2 where the definitions in para. 319.4.4 apply and, Sa = stress due to axial loads1 = Fa/Ap Fa = longitudinal force due to pressure2, weight, and other sustained loadings Ap = cross-sectional area considering nominal pipe thickness less the sum of the mechanical (thread or groove depth), corrosion and erosion allowances Sb = resultant, intensified bending stress3 due to pressure, weight, and other sustained loadings

Sb =

(Ii M i )2 + (Io M o )2 Z

Ii = in-plane sustained stress index4. In the absence of more applicable data, Ii is taken as the greater of (0.75ii) or 1.00 Io = out-plane sustained stress index4. In the absence of more applicable data, Io is taken as the greater of (0.75io) or 1.00 St = torsional stress3 due to pressure, weight, and other sustained loadings1 = Mt/2Z NOTES: 1

In the absence of more applicable data, Sa and St need not be intensified. B31 Case 178 continues on following page

B31 CASE 178

2

Fa includes the longitudinal force due to pressure P × Ai for piping systems that contain no expansion ts, where Ai = π × d 2 / 4 , and d is the pipe inside diameter considering pipe

3

4

wall thickness less allowances. For piping systems with expansion ts, it is the responsibility of the designer to determine the longitudinal force due to the pressure in the piping system. Z shall be based on the nominal section, less the sum of the mechanical (thread or groove depth), corrosion and erosion allowances. It is the responsibility of the designer to determine Ii and Io; in cases where these indices are based on stress intensification factors, it is the responsibility of the designer to determine ii and io for all components not explicitly addressed in Appendix D (e.g., elbows/bends/miters other than 90 degrees, base-ells, reducing elbows, crosses, etc.).

B31 CASE 180 CASES OF THE CODE FOR PRESSURE PIPING – B31 B31 CASE 180 Leak Testing of Subassemblies of Jacketed Piping for use in ASME B31.3 Piping Systems Approval Date: January 5, 2007

Inquiry: Does ASME B31.3 permit an alternate leak test for jacketed piping in which it is impracticable to visually examine the welded ts and connections for leaks in accordance with para. 345.2.2(a)? Reply: Visually observing the ts and connections during the leak test in accordance with para. 345.2.2(a) and 345.3.1 is not required provided all of the following conditions are satisfied: 1. The welded ts and connections are on the inner pipe of jacketed piping. 2. A leak test is performed that otherwise meets the requirements of para. 345.1 except visual examination of ts and connection in accordance with para. 345.2.2(a) and 345.3.1 is not required. 3. A sensitive leak test is performed in accordance with para. 345.8 to demonstrate leak tightness of welded ts and connections that are not visually examined during the leak testing requirements in 2 above.

B31 Case 181‐2 (Approval Date: January 4, 2012)  Use of Alternative Ultrasonic Examination Acceptance Criteria in ASME B31.3    d) Personnel demonstration requirements Original Inquiry: Under what conditions and shall be as stated in ASME Section V, limitations may alternative UT acceptance Article 4 Mandatory Appendix VII. criteria apply in lieu of those described in para. 4) Examination 344.6.2 of ASME B31.3? a) The initial straight beam scan for reflectors that could interfere with the When specified by the owner, the ultrasonic angle beam examination shall be examination acceptance criteria included below performed (a) manually, (b) as part of a may be applied for welds in material greater previous manufacturing process, or (c) than or equal to 25mm (1.0 in.) in thickness1 in during the weld examination, provided accordance with ASME B31.3 provided the detection of these reflectors is included following requirements are met: in the demonstration as required in 1(c) above. 1) General/Scope: b) The examination area shall include the a) The examination shall be conducted volume of the weld, plus the lesser of using automated or semi-automated 25mm (1.0 in.) or t of adjacent base techniques utilizing computer based data metal. Alternatively, the examination acquisition. volume may be reduced to include the b) The examination shall be performed in actual heat affected zone (HAZ) plus accordance with a written procedure 6mm (0.25 in.) of base material beyond approved by a Level III and conforming the heat affected zone on each side of to the requirements of ASME Section V, the weld, provided the extent of the Article 4 Mandatory Appendix VIII and: weld HAZ is measured and documented. i) For Phased Array – ASME Section c) Scanning may be peformed at reference V, Article 4, Mandatory Appendix level provided the procedure V qualification was performed at reference ii) For Time of Flight Diffraction level. (TOFD) - ASME Section V, Article 5) Data Recording 4, Mandatory Appendix III Data shall be recorded in the c) Procedure qualification shall meet the unprocessed form with no thresholding. requirements of ASME Section V, The data record shall include the Article 4, Mandatory Appendix IX. complete examination area as specified 2) Equipment in (4)(b) above. A mechanical guided scanner capable of maintaining a fixed and consistent search unit position relative to the weld centerline shall be used. 3) Personnel a) Set-up and scanning of welds shall be 1 For wall thicknesses less than 25mm (1.0 in.), the performed by personnel certified as acceptance criteria stated in paragraph 344.6.2 of B31.3 Level II or III (or by Level I personnel shall be used. under the direct supervision of Level II personnel). b) Interpretation and evaluation of data shall be performed by Level II or III personnel. c) Examination personnel shall be qualified and certified following a procedure or program as described in ASME BPV Code, Section V, Article 1, T-120 (e), (f), (h) and (i).

B31 Case 181‐2 (Approval Date: January 4, 2012)  Use of Alternative Ultrasonic Examination Acceptance Criteria in ASME B31.3    dimension (h in Figure 1, sketch [b]) 6) Data Analysis of the subsurface indication. a) Reflectors exceeding the limits below b) Multiple Flaws shall be investigated to determine i) Discontinuous flaws that are whether the indication originates from a oriented primarily in parallel planes flaw or is a geometric indication in shall be considered to lie in a single accordance with 6(b) below. plane if the distance between the i) For amplitude based techniques, the adjacent planes is equal to or less location, amplitude, and extent of all than 13mm (0.50 in.) or 0.5t, reflectors that produce a response whichever is less. greater than 20% of the reference ii) If the space between two flaws level shall be investigated. aligned along the axis of weld is less ii) For non-amplitude based than the height of the flaw of greater techniques, the location and extent height, the two flaws shall be of all images that have an indicated considered a single flaw. length greater than 4.0mm (0.16 in.) iii) If the space between two flaws shall be investigated. aligned in the through-thickness b) Ultrasonic indications of geometric dimension is less than the height of and/or metallurgical origin shall be the flaw of greater height, the two classified as specified in ASME Section flaws shall be considered a single V, Article 4 Paragraph T-481. flaw. c) Alternatively, other techniques or NDE 8) Flaw Acceptance Criteria methods may be used to classify an indication as geometric (e.g., alternative Flaws shall be evaluated against the beam angles, radiography). The method applicable acceptance criteria of Table 1 employed is for information only to or 2, except that flaw length (l) shall not classify the indication as geometric, and exceed 4t, regardless of flaw height (h) ASME B31.3 requirements for or the calculated aspect ratio. examination techniques are only required to the extent they are applicable. 7) Flaw Evaluation a) The dimension of the flaw(s) shall be determined by the rectangle that fully contains the area of the flaw(s). (Refer to Fig. 1) i) The length, ℓ, of the flaw shall be drawn parallel to the inside pressure retaining surface of the component. ii) The height, h, of the flaw shall be drawn normal to the inside pressure retaining surface of the component. iii) The flaw shall be characterized as a surface or subsurface flaw, as shown in Figure 1. iv) A subsurface indication shall be considered as a surface flaw if the separation (S in Figure 1) of the indication from the nearest surface of the component is equal to or less than half the through wall

B31 Case 181‐2 (Approval Date: January 4, 2012)  Use of Alternative Ultrasonic Examination Acceptance Criteria in ASME B31.3    TABLE 1 Acceptance Criteria for Surface Flaws Weld Thickness Aspect Ratio, h/ℓ

0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50

25mm to 64mm (1.0 in. to 2.5 in.) h/t < 0.031 < 0.033 < 0.036 < 0.041 < 0.047 < 0.055 < 0.064 < 0.074 < 0.083 < 0.085 < 0.087

100mm to 300mm (3.9 in. to 11.8 in.) h/t < 0.019 < 0.020 < 0.022 < 0.025 < 0.028 < 0.033 < 0.038 < 0.044 < 0.050 < 0.051 < 0.052

General Notes: (a) t = thickness of the weld excluding any allowable reinforcement. For a butt t ing two having different thickness at the t, t is the thinner of the two thicknesses ed. If a full penetration weld includes a fillet weld, the effective throat dimension of the fillet weld shall be included in t. (b) Aspect Ratio (h/ℓ) used may be determined by rounding the calculated h/ℓ down to the nearest 0.05 increment value within the column, or by linear interpolation. (c) For intermediate thickness t (weld thicknesses between 64mm and 100mm [2.5 in. and 3.9 in.]) linear interpolation is required to obtain h/t values.

TABLE 2 Acceptance Criteria for Subsurface Flaws Weld Thickness Aspect Ratio, h/ℓ

0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00

25mm to 64mm (1.0 in. to 2.5 in.) h/t < 0.068 < 0.076 < 0.086 < 0.098 < 0.114 < 0.132 < 0.156 < 0.180 < 0.210 < 0.246 < 0.286

100mm to 300mm (3.9 in. to 11.8 in.) h/t < 0.040 < 0.044 < 0.050 < 0.058 < 0.066 < 0.076 < 0.088 < 0.102 < 0.116 < 0.134 < 0.152

General Notes: (a) t = thickness of the weld excluding any allowable reinforcement. For a butt t ing two having different thickness at the t, t is the thinner of the two thicknesses ed. If a full penetration weld

B31 Case 181‐2 (Approval Date: January 4, 2012)  Use of Alternative Ultrasonic Examination Acceptance Criteria in ASME B31.3    includes a fillet weld, the effective throat dimension of the fillet weld shall be included in t. (b) Aspect Ratio (h/ℓ) used may be determined by rounding the calculated h/ℓ down to the nearest 0.05 increment value within the column, or by linear interpolation. (c) For intermediate thickness t (weld thicknesses between 64mm and 100mm [2.5 in. and 3.9 in.]) linear interpolation is required to obtain h/t values.

h

h 

S < 0.5h  (a) Surface Flaw 

(b) Surface Flaw 

h

S > 0.5h (c) Subsurface Flaw

Figure 1: Surface and Subsurface Indications

CASES OF THE CODE FOR PRESSURE PIPING - B31

ASME B31.3 CASES B31 CASE 184 Use of Ultrasonic Examination of Welds as an Alternative to Radiographic Examination in ASME B31.3, Chapter IX Approval Date: 10/29/2009 This Case shall expire upon the publication of ASME B31.3–2010 Edition. Inquiry: Under what conditions and limitations may ultrasonic examination of welds be used as an alternative to radiographic examination for ASME B31.3–2008 Edition, Chapter IX piping systems? Reply: It is the opinion of the Committee that ultrasonic examination of welds may be used as an alternative to the radiographic examination specified in ASME B31.3–2008 Edition for Chapter IX piping systems, provided that the requirements specified in paras. K341.4.2 and K342 and Table K341.3.2 be modified as follows, and that the requirements of a new para. K344.6.3, shown below, be met: K341.4.2 Radiographic and Ultrasonic Examination (a) All girth, longitudinal, and branch connection welds shall be 100% radiographically examined, except as permitted in (b) below. (b) When specified in the engineering design and with the owner’s approval, ultrasonic examination of welds may be substituted for radiographic examination where Ťw ≥ 13 mm (½ in.). (c) In-process examination (see para. 344.7) shall not be substituted for radiographic or ultrasonic examination of welds. NOTE: Ťw = Twbar K342 EXAMINATION PERSONNEL Paragraph 342 applies, except that personnel performing and evaluating results of ultrasonic examination of welds shall be qualified and certified UT Level II or III in accordance with ASNT SNTTC-1A, AC (ASNT Central Certification Program), or -189 (Qualification and Certification of Nondestructive Testing Personnel). Qualification of these personnel shall also be by written examination. K344.6.3 Welds. The method for ultrasonic examination of welds shall be as specified in the ASME BPV Code, Section V, Article 4 and Section VIII, Division 3, KE-301 and KE-302, except that (a) Performance demonstration shall be required. (b) The employer’s written practice for UT personnel qualification shall meet ASNT SNT-TC-1A, AC, or -189. The recommended guidelines in SNT-TC-1A, AC, or -189 shall be required. (c) Written procedure in accordance with Section V, T-421.1 shall be required. (d) Procedure qualification in accordance with Section V, T-421.1 shall be required. REVISED TABLE K341.3.2: See Page 2.

B31 CASE 184 CASES OF THE CODE FOR PRESSURE PIPING - B31 ASME B31.3-2008

Table K341.3.2

(08)

Acceptance Criteria for Welds Criteria (A-E) for Types of Welds, and for Required Examination Methods [Note (I)] Type of Weld

Methods Type of Imperfection

Visual

Crack lack of fusion Incomplete penetration Internal porosity Slag inclusion or elongated indication Undercutting Surface porosity or exposed slag inclusion Concave root surface (suck-up) Surface finish Reinforcement or internal protrusion GENERAL NOTE:

X X X

X X X X X

Ultrasonics or Radiography

Girth Groove

Longitudinal Groove [Note (2)]

Fillet [Note (3)]

Branch Connection [Note (4)]

X X X X X X

A A A B C A A D E F

A A A B C A A D E F

A A A NA NA A A NA E F

A A A B C A A D E F

X

X = required examination; NA = not applicable; ... = not required. Criterion Value Notes for Table K341.3.2 Criterion

Symbol

A B

C

Measure Extent of imperfection

Zero (no evident imperfection)

Size and distribution of internal porosity

See BPV Code, Section VIII, Division I, Appendix 4

Slag inclusion or elongated indication: Indications are unacceptable if the amplitude exceeds the reference level, or indications have lengths that exceed Individual length < 19 mm (Yo in) 19 rom (% in.) < 57 mm (2~ in.) t" > 57 mrn (2Y. in.)

t.

6mrn~~

Cumulative length D

Acceptable Value Limits [Note (5)]

1;

~

~~~~

t .. in any 12 t.. weld length

Depth of surface concavity

Wall Thickness, mm (in.)

Depth of Surface Concavity, mm (in.)

Two

1.5 e1t6) ~ 3 (Va) > 51 (2) $ 4 (%2) and total t thickness including weld reinforcement

S 13 (%) > 13 CV2) and

"Z

E

Su rface rough ness

$

$

51 (2)

Tw

$ 12.5 f.Lm (500 f.Lin.)

Ra (see ASME B46.1 for definition of

roughness average, Ra )

F

Height of reinforcement or internal protrusion [Note (6)] in any plane through the weld shall be within the limits of the applicable height value in the tabulation at the right. Weld metal shall be fused with and merge smoothly into the component surfaces.

Wall Thickness, Tw , mm (in.)

External Weld Reinforcement or Internal Weld Protrusion, mm (in.)

$13 eh) > 13 (%) and $ 51 (2) > 51 (2)

$ 1.5

e1t6)

~ 3

(Va)

$4

Wd

NOTES: (1) Criteria given are for required examination. More stringent criteria may be specified in the engineering design. (2) longitudinal welds include only those permitted in paras. K302.3.4 and K305. The radiographic criteria shall be met by all welds, including those made in accordance with a standard listed in Table K326.1 or in Appendix K. (3) Fillet welds include only those permitted in para. K311.2.2. (4) Branch connection welds include only those permitted in para. K328.5.4. (5) Where two limiting values are given, the lesser measured value governs acceptance. Tw is the nominal wall thickness of the thinner of two components ed by a butt weld. (6) For groove welds, height is the lesser of the measurements made from the surfaces of the adjacent components. For fillet welds, height is measured from the theoretical throat; internal protrusion does not apply. Required thickness tm shall not include reinforcement or internal protrusion.

132 Copyright © 2008 by the American Society of Mechanical Engineers. No reproduction may be made ofthis material without written consent of ASME.

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B31 CASE 185 CASES OF THE CODE FOR PRESSURE PIPING – B31

ASME B31.3 CODE CASE 185 Title: Use of Standard Helium Leak Test for a Vacuum-only Piping System (Paragraph 345) Approval Date:

December 22, 2009

Inquiry: Under what circumstances does ASME B31.3 permit the use of helium mass spectrometer leak tests performed under a vacuum as a substitute for the leak test requirements specified in ASME B31.3, para. 345? Reply: In the opinion of the Committee, the qualified helium leak tests under vacuum conditions in the ASME BPV Code, Section V, Article 10, Appendix V and Appendix IX are acceptable substitutes for the testing requirements identified in para. 345 of ASME B31.3 provided the following conditions are met: 1. The piping system is expected to operate only under vacuum (i.e., sub-atmospheric pressure) conditions. 2. Any leakage into the piping system that could result in an internal reaction (e.g., combustion or explosion) that increases the pressure above atmospheric shall be prevented. 3. All system ts and connections shall be leak tested. Piping welds and ts to be tested shall be uninsulated and exposed, and shall not be primed, painted or otherwise coated. 4. Helium leak testing is performed at vacuum conditions sufficient for the mass spectrometer helium leak tests of ASME BPV Code, Section V, Article 10, Appendices V and IX, or at pressures below 10 millibars absolute (<1% of atmospheric pressure), whichever is lower. 5. ASME B31.3, para. 345.2 applies, except for the minimum “10 min” leak test period, the leak test pressure requirements and the limitation of the need for access for jacketed piping to “visual access.” Para. 345.3 also applies, except for the leak test pressure requirements. All other inspection, examination and records requirements of ASME B31.3 Chapter VI must still be satisfied (i.e., paras. 340, 341, 342, 343, 344 and 346). 6. Written procedures shall be qualified, in accordance with BPV Code, Section V, Article 10. 7. Test personnel shall have training and certification consistent with ASME B31.3, para. 342.

Page 1 of 2

B31 CASE 185 CASES OF THE CODE FOR PRESSURE PIPING – B31

8. Test reports, including records of personnel qualifications, shall meet the requirements of ASME BPV Code, Section V, Article 10, Item T-1091 and shall be retained for at least five years. 9. Options of the ASME BPV Code, Section V, Article 10 test methods, which allow the engineering design to modify specified requirements of the Appendix V and Appendix IX test methods (such as acceptability limits for system leak tightness), may only be exercised so as to make these requirements more sensitive or more conservative. 10. The use of the vacuum leak test instead of the pressurized leak test of ASME B31.3, para. 345 shall be specified in the engineering design and shall be accepted by the Owner. ____________________________________________________________________

Page 2 of 2

B31 CASE 188 Minimum Hydrostatic Test Pressure for ASME B31.3, Chapter IX (Para. K345.4.2) Approval Date: October 8, 2012

Inquiry: For piping in Chapter IX High Pressure Fluid Service, may a minimum hydrostatic test pressure for components and welds other than that specified in para. K345.4.2 be used? Reply: In the opinion of the Committee, the following equation may be used to calculate the minimum hydrostatic test pressure for piping in Chapter IX High Pressure Fluid Service: PT = 1.25PRr where P = internal design gage pressure PT = minimum test gage pressure Rr = ratio of ST/S for pipe or components without established ratings = ratio of the component pressure rating at the test temperature to the component pressure rating at the component design temperature for components with established ratings S = allowable stress value at component design temperature (see Table K-1) ST = allowable stress value at test temperature 1 Case 188.doc