Nde based on piping class

=n ANSI B31.3: 341.4 Extent of Required Examination Piping Class

Description

Clause

Normal Fluid Service.

Process

341.4.1 Examination — Normal Fluid Service.

Category D Fluid Service.

Utility

Severe Cyclic Conditions.

Cyclic conditions defined by Engineering

341.4.3 Examination — Severe Cyclic Conditions. (b) Other

Highly toxic

M341.4 Extent of Required Examination

Cat. M

(1) Not less than 5% of circumferential butt and miter groove welds shall be examined fully by random radiography in accordance with para. 344.5 or by random ultrasonic examination in accordance with para. 344.6.

341.4.2 Examination — Category D Fluid Service. 341.4.2 Examination — Category D Fluid Service. Piping and piping elements for Category D Fluid Service as designated in the engineering design shall be visually examined in accordance with para. 344.2 to the extent necessary................

Examination. All circumferential butt and miter groove welds and all fabricated branch connection welds comparable to those shown in Fig. 328.5.4E shall be examined by 100% radiography in accordance with para.

344.5, or (if specified in the engineering design) by 100% ultrasonic examination in accordance with para.

344.6.

(1) The random radiography/ultrasonic examination requirements of para.

341.4.1(b)(1) apply except that at least 20% of circumferential butt and miter welds and of fabricated lap and branch connection welds comparable to those shown in Figs. 328.5.4E and 328.5.5 sketches (d) and (e) shall be examined.

Cat. K

High Pressure

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 Tw ≥ 13 mm (1⁄2 in.). (c) In-process examination (see para. 344.7) shall not be substituted for radiographic or ultrasonic examination of welds.

Extend 0f Volumetric NDE 5%

RT

0%

No requirement

UT

Visual only Not applicable

No requirement

Not applicable

100% or (if specified in the engineering design)

20%

Not applicable

100%

Not applicable

When specified in the engineering design and with the owner’s approval

341.4.1 Examination — Normal Fluid Service.

(1) Not less than 5% of circumferential butt and miter groove welds shall be examined fully by random radiography in accordance with para. 344.5 or by random ultrasonic examination in accordance with para. 344.6.

344.6.2 Acceptance Criteria.

A linear-type discontinuity is unacceptable if the amplitude of the indication exceeds the reference level and its length exceeds (a) 6 mm ( ¼ in.) for Tw ≤ 19 mm ( ¾ in.) (b) Tw/3 for 19 mm < Tw ≤ 57 mm (2¼ in.) (c) 19 mm for Tw > 57 mm

B31 Case 181‐2 (Approval Date: January 4, 2012) Use of Alternative Ultrasonic Examination Acceptance Criteria in ASME B31.3 Original Inquiry: Under what conditions and limitations may alternative UT acceptance criteria apply in lieu of those described in para. 344.6.2 of ASME B31.3?

PETRONAS TECHNICAL STANDARDS MANUAL SHOP AND FIELD FABRICATION OF PIPING PTS 31.38.01.31 DECEMBER 2010 4.3.4 Ultrasonic examination (UT) Ultrasonic examination may replace radiography in accordance with ASME B31.3, para. 341.4.1. If ultrasonic examination is applied, automated computer enhanced data acquisition is required to obtain a permanent record of the full weld to demonstrate the absence, or not, of linear type discontinuities with amplitudes exceeding the reference level.

Ultrasonic examination is limited by the local geometry near the welds. The use of ultrasonic examination shall not affect the random and independent selection of the welds for examination.

Keyword: ..enhanced data acquisition is required to obtain a permanent record of the full weld to demonstrate