Process selection Guidance Standard

Probabilistic sampling, which lies in the core of the DQO process, is based on a random sample location selection strategy. It produces data that can be statistically evaluated in terms of the population mean, variance, standard deviation, standard error, confidence interval, and other statistical parameters. The EPA provides detailed guidance on the DQO process application for the... 

The critical parameter in the discussion of reference standards is the process of qualification. FDA guidance on this topic states that A non-compendial standard should be thoroughly characterized to assure its identity, strength, quality and purity. 3 It is therefore left to the pharmaceutical firm to establish thorough characterization for the ARS of each NCE. The overall qualification process for an ARS includes characterization of the material, proper form selection, and assignment of purity. Some general considerations in this process include... 

An effective conceptual site model is essential for the identification of risk-based and non-risk remedial action objectives. The conceptual model should identify source areas complete, potentially complete, and incomplete exposure pathways and receptors. In addition, the conceptual model should identify contaminants, affected environmental media, and specific areas within the affected environmental media to be addressed by the selected remedial action. Although a conceptual model should be developed prior to initiation of the risk-based remedy selection process, the conceptual model should be updated as needed during the remedy selection process to reflect any changes in the understanding of the site. ASTM (2003), Standard Guide for Developing Conceptual Site Models for Contaminated Sites, provides guidance for the development of an effective conceptual model. 

The selection of the optimum prefilter/membrane combination is best done experimentally on the user s process stream. The manufacturers give some guidance as to which prefilters should be used for a given membrane pore-size, but unfortunately, there is no standard rating system for prefilters. 

Harmonizing with international standards is a particularly timely effort as the Canadian Standards Association (CSA) undergoes the revision process for its CSA Z94.1 standard. As a companion to the product-performance standard, the ISEA Head Protection Group intends to create a companion user s guide that will covers topics such as proper product selection, service-life, care and other guidance information. 

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