For all components, including nozzles, COMPRESS automatically considers the rules of UCS-66 to obtain the coldest possible MDMT rating without the need for impact testing. COMPRESS follows the method outlined in Figure UCS-66.2.

COMPRESS applies UCS-66(c) for rating standard B16.5\B16.47 flanges to −-20° F, and applies UCS-66(b)(1)(b) to obtain a colder rating for the flange if the coincident stress ratio is less than 1.0.

For nozzles constructed as long weld neck flanges COMPRESS applies the foregoing rules to the "flange" portion of the LWN.

However, the attachment of the LWN to the shell is treated identically to that for any other nozzle construction: the rules of UCS-66 are followed for the corner joint as shown in Figure UCS-66.3 sketch (b). There is no technical justification why this joint should be treated differently for a LWN than for other types of nozzle necks. It is Codeware's interpretation that this joint for the LWN is to be treated under the Code rules for corner joints. This may result in the nozzle (LWN) being rated to a MDMT that is warmer than −20° F.

The warmest MDMT rating for all components and welds in the nozzle assembly governs the MDMT reported for the nozzle.