ASME Code Case 2877 details the design of heat exchangers using Vipertex® tubes.
This code case details the conditions that austenitic stainless steel welded tubes in which the external tube surface, internal tube surface, or both internal and external tube surfaces have a modified configuration. In general the following is included:
(a) The grades applicable to this include those detailed in ASTM A1098
(b) The maximum nominal diameter is limited to 1.50 in. (38 mm), and the maximum wall thickness is limited to 0.079 in. (2 mm)
(c) For determination of minimum wall thickness on textured tubing, a point-to-point micrometer shall be used. Alternately, tubing shall be supplied with plain ends and all measurements and proof testing taken in the plain end section of the tubing.
(d) The tubing shall be used for heat transfer equipment and shall be a straight length. When the tubing is used with tubesheets, the tubing shall have a plain end with untextured surfaces for the full length inserted within the tubesheet. The untextured surface would need to be both on the I.D. and the O.D.
(e) Proof tests to establish maximum allowable working pressure. The maximum allowable working pressure of any component part proof tested by this method shall be established by a hydrostatic test to failure by rupture of a full-size sample of such pressure part.