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O-1 GENERAL
This Appendix provides alternative ultrasonic fracture mechanics based acceptance criteria that may be used for Code piping welds in lieu of those described in para.
136.4.6(b).
O-2 SCOPE
(a) The examination shall be conducted using auto- m a t e d o r s e m i a u t o m a t e d t e c h n i q u e s u t i l i z i n g computer-based data acquisition.
(b) The examination shall be performed in accordance with a written procedure approved by UT (Ultrasonic Testing) Level III personnel and conforming to the re- quirements of ASME BPVC, Section V, Article 4, Mandatory Appendix VIII and
(1) for Phased Array — ASME BPVC, Section V, Article 4, Mandatory Appendix V
(2) for Time of Flight Diffraction (TOFD) — ASME BPVC, Section V, Article 4, Mandatory Appendix III
(c) Procedure qualification shall meet the require- ments of ASME BPVC, Section V, Article 4, Mandatory Appendix IX.
O-3 EQUIPMENT
A mechanical guided scanner capable of maintaining a fixed and consistent search unit position relative to the weld centerline shall be used.
O-4 PERSONNEL
(a) Personnel performing nondestructive examination to the requirements of this Appendix shall be qualified and certified in the ultrasonic method in accordance with a procedure or program as described in ASME BPVC, Section V, Article 1, T-120(e) or T-120(f), and T-120(g).
(b) Setup and scanning of welds shall be performed by personnel certified as UT Level II or III (or by Level I per- sonnel under the direct supervision of Level II or III personnel).
(c) Interpretation and evaluation of data shall be performed by NDE Level II or III personnel.
(d) Personnel demonstration requirements shall be as stated in ASME BPVC, Section V, Article 4, Mandatory Appendix VIII.
O-5 EXAMINATION
(a) The initial straight-beam scan for reflectors that could interfere with the angle-beam examination shall be performed manually, as part of a previous manufac- turing process, or during the weld examination, provided detection of these reflectors is included in the demonstra- tion as required inpara. O-2(c).
(b) The examination area shall include the volume of the weld plus the lesser of 1.0 in. (25 mm) ortof the adja- cent base material. Alternatively, the examination volume may be reduced to include the actual heat-affected zone (HAZ) plus 0.25 in. (6 mm) of base material beyond the HAZ on each side of the weld, provided the extent of the weld HAZ is measured and documented.
O-6 DATA RECORDING
Data shall be recorded in the unprocessed form as speci- fied in ASME BPVC, Section V, Article 4, V-471.6. The data record shall include the complete examination area as specified inpara. O-5(b).
O-7 DATA ANALYSIS
(a) Reflectors exceeding the limits below shall be inves- tigated to determine whether the indication originates from a discontinuity or is a geometric indication in accor- dance with(b).
(1) For amplitude-based techniques, the location, amplitude, and extent of all reflectors that produce a response greater than 20% of the reference level shall be evaluated.
(2) For non-amplitude-based techniques, the loca- tion and extent of all images that have an indicated length greater than 0.16 in. (4.0 mm) shall be investigated.
(b) Ultrasonic indications of geometric and/or metal- lurgical origin shall be classified as specified in ASME BPVC, Section V, Article 4, T-481. Alternatively, other tech- niques or NDE methods may be used to classify an indica- tion as geometric (such as alternative beam angles and radiography). The method employed is for information only to classify the indication as geometric, and ASME B31.1 requirements for examination techniques are only required to the extent they are applicable.
O-8 DISCONTINUITY EVALUATION
(a) Discontinuity Dimensions. The dimension of each discontinuity shall be determined by the rectangle that fully contains the area of that discontinuity. (Refer to Figure O-8-1.)
(1) The length,ℓ, of the discontinuity shall be drawn parallel to the inside pressure-retaining surface of the component.
(2) The height,h, of the discontinuity shall be drawn normal to the inside pressure-retaining surface of the component.
(3) The discontinuity shall be characterized as a surface or subsurface discontinuity, as shown inFigure O-8-1.
(4) A subsurface indication shall be considered as a surface discontinuity if the separation (SinFigure O-8-1) of the indication from the nearest surface of the compo- nent is equal to or less than half the through-wall dimen- sion [hinFigure O-8-1, illustration (b)] of the subsurface indication.
(b) Multiple Discontinuities
(1) Discontinuous indications that are oriented primarily in parallel planes shall be considered to lie in a single plane if the distance between the adjacent planes is less than or equal to 0.50 in. (13 mm) or 0.5t, whichever is less.
(2) If the space between two indications aligned along the axis of weld is less than the height of the indica- tion of greater height, the two discontinuities shall be considered a single discontinuity.
(3) If the space between two indications aligned in the through-thickness dimension is less than the height of the indication of greater height, the two indications shall be considered a single discontinuity.
O-9 DISCONTINUITY ACCEPTANCE CRITERIA Discontinuities shall be evaluated using the applicable criteria ofTables O-9-1,O-9-2, andO-9-3. Regardless of discontinuity height or aspect ratio, discontinuity length shall not exceed 4t.
Surface Indications
(c) Subsurface Indications
(a) (b)
S [Note (1)]
S [Note (2)]
2d
2a a
l
t t
l
t l
l
a
NOTES:
(1) S≤ 0.5h.
(2) S> 0.5h.
Discontinuity h/t ℓ
Surface 0.100 or less 0.25 in. (6.4 mm) or less Subsurface 0.286 or less 0.25 in. (6.4 mm) or less GENERAL NOTES:
(a) tis the thickness of the weld excluding any allowable reinforce- ment. For a butt joint joining two members having different thick- nesses at the joint,tis the thinner of the two thicknesses joined. If a full-penetration weld includes a fillet weld, the effective throat dimension of the fillet weld shall be included int.
(b) A discontinuity is considered rejectable if its dimensions exceed theh/tvalue or the ℓ value in this Table.
Table O-9-2 Surface Discontinuity Acceptance Criteria for Weld Thickness 1.0 in. (25 mm) and Over
Aspect Ratio,h/ℓ
Maximumh/tfor Weld Thickness 1.0 in. (25 mm)
to 2.5 in.
(64 mm)
Over 2.5 in.
(64 mm) to Under 3.9 in.
(100 mm)
3.9 in.
(100 mm) to 11.8 in.
(300 mm)
0.00 0.031 See Note(1) 0.019
0.05 0.033 See Note(1) 0.020
0.10 0.036 See Note(1) 0.022
0.15 0.041 See Note(1) 0.025
0.20 0.047 See Note(1) 0.028
0.25 0.055 See Note(1) 0.033
0.30 0.064 See Note(1) 0.038
0.35 0.074 See Note(1) 0.044
0.40 0.083 See Note(1) 0.050
0.45 0.085 See Note(1) 0.051
0.50 0.087 See Note(1) 0.052
GENERAL NOTES:
(a) tis the thickness of the weld excluding any allowable reinforce- ment. For a butt joint joining two members having different thick- nesses at the joint,tis the thinner of the two thicknesses joined. If a full-penetration weld includes a fillet weld, the effective throat dimension of the fillet weld shall be included int.
(b) The aspect ratio (h/ℓ) used may be determined by rounding the calculatedh/ℓ down to the nearest 0.05 increment value within the column, or by linear interpolation.
(c) Regardless of discontinuity height or aspect ratio, discontinuity length shall not exceed 4t.
NOTE: (1) For intermediate thicknesses,t[weld thicknesses between 2.5 in. and 3.9 in. (64 mm and 100 mm)], linear interpolation is required to obtainh/tvalues.
Aspect Ratio,h/ℓ
Maximumh/tfor Weld Thickness 1.0 in. (25 mm)
to 2.5 in.
(64 mm)
Over 2.5 in.
(64 mm) to Under 3.9 in.
(100 mm)
3.9 in.
(100 mm) to 11.8 in.
(300 mm)
0.00 0.068 See Note(1) 0.040
0.10 0.076 See Note(1) 0.044
0.20 0.086 See Note(1) 0.050
0.30 0.098 See Note(1) 0.058
0.40 0.114 See Note(1) 0.066
0.50 0.132 See Note(1) 0.076
0.60 0.156 See Note(1) 0.088
0.70 0.180 See Note(1) 0.102
0.80 0.210 See Note(1) 0.116
0.90 0.246 See Note(1) 0.134
1.00 0.286 See Note(1) 0.152
GENERAL NOTES:
(a) tis the thickness of the weld excluding any allowable reinforce- ment. For a butt joint joining two members having different thick- nesses at the joint,tis the thinner of the two thicknesses joined. If a full-penetration weld includes a fillet weld, the effective throat dimension of the fillet weld shall be included int.
(b) The aspect ratio (h/ℓ) used may be determined by rounding the calculatedh/ℓ down to the nearest 0.05 increment value within the column, or by linear interpolation.
(c) Regardless of discontinuity height or aspect ratio, discontinuity length shall not exceed 4t.
NOTE: (1) For intermediate thicknesses,t[weld thicknesses between 2.5 in. and 3.9 in. (64 mm and 100 mm)], linear interpolation is required to obtainh/tvalues.
MANDATORY APPENDIX P