Hello,

Tubes for tubular heat exchangers are available with minimum-wall-thickness (m.w.) or with average-wall-thickness (a.w.).

Problem:
A carbon steel heat exchanger shall be designed with seamless cold-drawn low-carbon steel tubes of the type SA-179 and U-stamped.

The material specification for SA-179 according ASME Section II, Part A, §1.1 covers minimum-wall-thickness only (this is also the case for SA 210, SA-213 austenitic tubes and others...).

Question:
Does a heat exchanger with a.w. carbon steel tubes fulfil the requirements of ASME VIII, Div. 1 if it is properly designed (i. e. calculated with the minimum possible wall thickness for a.w. tubes) or must the tubes yet ordered with m.w.?

For any hints thanks in advance!