UL 2351 Standard PDF

UL Standards - The length of the ref- erence standards shall be determined by the pipe manufac- turer, and they shall have the same specified diameter and thickness as the product being inspected. Reference standards shall contain machined notches, one on the inside surface and one on the outside surface, or a drilled hole, as shown in Fig. 1, at the option of the pipe manufacturer. The notches shall be parallel to the weld seam, and shall be separated by a distance sufficient to produce two sepa- rate and distinguishable signals. The 1fi8-in. [3.2-mm] hole shall be drilled through the wall and perpendicular to the surface of the reference standard as shown in Fig. 1. Care shall be taken in the preparation of the reference standard to ensure freedom from fins or other edge roughness, or distortion of the pipe.

NOTE 6 - The calibration standards defined in 11.1.3 are convenient standards for calibration of nondestructive testing equipment. The dimen- sions of such standards are not to be construed as the minimum sizes of imperfections detectable by such equipment. 11.1.4 Acceptance Limits - Table 3 gives the height of acceptance limit signals in percent of the height of signals produced by reference standards.UL pdf Imperfections in the weld seam that produce a signal greater than the accept- ance limit signal given in Table 3 shall be considered a defect unless the pipe manufacturer can demonstrate that 2010 SECTION II, PART A SA-53/SA-53M the imperfection does not reduce the effective wall thick- ness beyond 121fi2% of the specified wall thickness.

11.2 Seamless Pipe - As an alternative to the hydro- static test, and when specified by the purchaser, the full body of each seamless pipe shall be tested with a nonde- structive electric test in accordance with Practices E 213, E 309, or E 570. In this case each length so furnished shall include the mandatory marking of the letters "NDE." Except as provided in 11.2.6.2 it is the intent of this test to reject pipe with imperfections which produce test signals equal to or greater than that of the calibrati