B31.3 Para. 323.2.2 Lower Temperature Limits, Listed Materials, items (a), (b), and (e) states that impact testing of the base metal is not required if the design minimum temperature is warmer than or equal to the temperature listed in the Min. Temp. column of Table A-1 and in Table 323.2.2.
For B31.3 analysis, CAESAR II compares your specified minimum metal temperature to the lower temperature limits defined in Table A-1 and Figure 323.2.2A of B31.3. The software provides an output report of this comparison and a warning if the lower B31.3 limit is exceeded or is undetermined. The CAESAR II material database contains the Table A-1 Min. Temp. values, which are the letter designations of A, B, C, or D as defined in Figure 323.2.2A for carbon steel.
Adapted from: B31.3 - 2018, Process Piping, Fig. 323.2.2A, Minimum Temperatures Without Impact Testing for Carbon Steel Materials.
The material database also contains non-B31.3 letter designations of O through Z for minimum temperatures of other materials.
The software automatically checks MDMT for any element using the B31.3 or B31.3 Ch.
IX piping code when running Error Check 
. All defined operating temperatures (T1-T9), the piping system’s ambient temperature, and the element’s pipe thickness are checked against the material’s minimum temperature.
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If an operating temperature is above the MDMT, then the status is OK.
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If any operating temperature is below the MDMT, then impact testing is required, and the status is Impact.
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If the material does not have the MDMT specified (or no curve is defined), then NA is listed in the report for MDMT, and the status is Unknown.
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If the element’s pipe thickness falls outside the ranges specified in Fig. 323.2.2A, then NA is listed in the report and the status is Unknown.
The results are displayed into the MDMT Report tab of the Errors and Warnings dialog box, and also in the Miscellaneous Data report in the Static Output Processor.
If the status on any element is set to Impact or Unknown, a warning displays. You should then check the materials or operating conditions.
Example Warning
Example Report
