TS 13145

TS 13145 addresses the practice used when a test method derives its assigned value from measured values through a formula. In this context, consistent test method tolerances matter because they help define how much variation is acceptable and how the calculated result should be interpreted within a controlled testing framework.

Purpose of test method tolerances

From a general technical perspective, a test result is not always a single directly observed reading. In many methods, the reported value is calculated from several measurements, corrections, or derived inputs. A tolerance framework helps align repeatability, measurement uncertainty, and the acceptable bounds of the calculated result. This standard focuses on the practice used when developing such methods.

What the scope means in practice

The standard is concerned with the development approach for test methods that produce assigned values by formula, rather than with any one product category or instrument. For users, the key issue is not only how measurements are taken, but also how the resulting value is defined and judged. Its ASTM D 4356 basis places it in the broader context of applying statistical methods to test results.

• It applies to test methods where the assigned value is calculated from measured values.
• It supports a consistent way to think about acceptable variation between methods and results.
• It belongs to the broader use of statistical methods in test method development and evaluation.
• It frames how the calculated outcome is to be interpreted, rather than describing a single test procedure.