Do the "flexible approach", performance based measurement system (PBMS), and/or Methods Innovation Rule (MIR) change the way prescriptive language is interpreted when encountered in SW-846 methods?
The following statement from the Disclaimer for SW-846 provides specific guidance for interpretation of must, should, etc.:
"EPA generally does not intend these methods to be overly prescriptive. The words "shall," "must," or "require" are used to indicate aspects of the method that are considered essential to its performance, based on sound analytical practices (e.g., an instrument must be calibrated before use). In contrast, the words "should," "may," or "recommend" are used to provide guidance on aspects of the method that are useful but not essential. This flexibility does not apply to those Method Defined Parameters where the analytical result is wholly dependent on the process used to make the measurement."
Other caegory: MIR & MDPs, PBMS & Flexible Approach