Section 192.63 - Marking of materials(a) Except as provided in paragraph (d) and (e) of this section, each valve, fitting, length of pipe, and other component must be marked as prescribed in the specification or standard to which it was manufactured.(b) Surfaces of pipe and components that are subject to stress from internal pressure may not be field die stamped.(c) If any item is marked by die stamping, the die must have blunt or rounded edges that will minimize stress concentrations.(d) Paragraph (a) of this section does not apply to items manufactured before November 12, 1970, that meet all of the following:(1) The item is identifiable as to type, manufacturer, and model.(2) Specifications or standards giving pressure, temperature, and other appropriate criteria for the use of items are readily available.(e) All plastic pipe and components must also meet the following requirements: (1) All markings on plastic pipe prescribed in the listed specification and the requirements of paragraph (e)(2) of this section must be repeated at intervals not exceeding two feet.(2) Plastic pipe and components manufactured after December 31, 2019 must be marked in accordance with the listed specification.(3) All physical markings on plastic pipelines prescribed in the listed specification and paragraph (e)(2) of this section must be legible until the time of installation.Amdt. 192-1, 35 FR 17660, Nov. 17, 1970, as amended by Amdt. 192-31, 43 FR 883, Apr. 3, 1978; Amdt. 192-61, 53 FR 36793, Sept. 22, 1988; Amdt. 192-62, 54 FR 5627, Feb. 6, 1989; Amdt. 192-61A, 54 FR 32642, Aug. 9, 1989; 58 FR 14521, Mar. 18, 1993; Amdt. 192-76, 61 FR 26122, May 24, 1996; 61 FR 36826, July 15, 1996; Amdt. 192-114, 75 FR 48603, Aug. 11, 2010; Amdt. 192-119, 80 FR 180, Jan. 5, 2015; Amdt. 192-124, 83 FR 58716, Nov. 20, 2018