Soils Are Not Classified Unless the "NV" and "NP" Boxes are Checked

Problem: LabSuite and CLSuite do not produce a USCS soil classification. Eventually the user discovers that checking the "NV" and "NP" boxes on the Atterberg test data entry screen causes the program to produce a USCS classification. Some users have contacted us asking for an option to automatically check the "NV" and "NP" boxes.

Explanation: ASTM D2487, which codifies the USCS soil classification system, requires that an Atterberg test be performed in order to classify most soils. Clicking on the "NV" and "NP" boxes is simply incorrect: you're telling the program that you ran the Atterberg test and that the LL and PL values could not be determined (i.e., because the groove closed on its own -- see §18.1.1 in the latest specification). Do not check these boxes unless you've actually run the Atterberg test or unless you know from prior experience with the soil that the LL and PL values could not be determined.

Solution: The requirement that the user enter Atterberg test data before a classification is produced is by design and is consistent with the ASTM classification standard. An Atterberg test must be performed to classify most soils; circumventing this requirement by clicking on the "NV" and "NP" boxes is a misuse of the software and will potentially produce invalid classification results.

Note: Version 1.x of the USCS classification package (produced between 1996 and 2005) would produce a USCS classification in the absence of valid Atterberg data: After warning the user that it would assume that the Atterberg results were 0, the software would proceed to produce a classification. This classification was technically correct only if the user had actually data indicating that the soil was NP. We cannot add a similar "automatically assume NV Atterberg data" into the current version of the software as it would allow the software to make baseless assumptions about the soil being tested.