ASTM B891/B891M : 19(2024)

1.1 This specification covers seamless and welded titanium and titanium alloy tubing on which at least part of the external or internal surface has been enhanced by cold forming for improved heat transfer. The tubes are used in surface condensers, evaporators, heat exchangers, coils, and similar heat transfer apparatus in diameters up to and including 1 in. [25.4 mm]. The base tube wall thickness is typically at least 0.049 in. [1.245 mm] average, but lighter gauge may be negotiated with the manufacturer.

1.2 Tubing purchased to this specification will typically be inserted through close-fitting holes in tubesheets, baffles, or support plates spaced along the tube length such as defined in the Tubular Exchanger Manufacturer’s Association (TEMA) Standard.2 The tube ends will also be expanded, and may then be welded. Tube may also be bent to form U-tubes or be coiled or otherwise formed, although tight radii may require unenhanced length for the bends.

1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the order. Combining values from the two systems may result in non-conformance. Within the text, the SI units are shown in brackets. The inch-pound units shall apply unless the “M” designation of this specification is specified in the order.

1.4 The following precautionary statement pertains to the test method portion only: Section 8, 9, 10, and S1 of this specification: This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International StandardDetails, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.