Does the tubing need to have an ASTM stamp or logo imprinted stating it is seamless copper?
The ASTM standards that address the manufacture of the different types of copper tube allowed for fuel gas distribution do not require that the tube carry the ASTM logo or stamp, or standard designation. These standards do outline specific product identification requirements for copper tube made to these standards. This generally includes marking of the tube to include the type of tube (K, L, M, ACR, etc.), name or trademark of the manufacturer, or both, and the country of origin. Depending on the type and temper of the tube, and the standard to which it was made, this marking may be in the form of a permanently incised mark, a painted or inked label, or both. Regardless of the form of the mark, each must include the required information and are repeated throughout the length of tube at regular intervals (no more than every 18 inches for the incised mark or 3 feet for the painted label). The painted/inked marks also give an indication of the tube type by the color of the label: green f
