Short description
1.1 This guide covers methods for purging wells used for ground water quality investigations and monitoring programs. These methods could be used for other types of programs but are not addressed in this guide. 1.2 This guide applies only to wells sampled at the wellhead. 1.3 This standard describes seven methods (A-G) for the selection of purging methods. Method A-Fixed Volume Purging, Method B-Purging Based on Stabilization of Indicator Parameters, Method C-Purging Based on Stabilization of Target Analytes, Method D-Purging Based on Fixed Volume Combined with Indicator Parameter Stabilization, Method E-Low Flow/Low Volume (Minimal Drawdown) Purging, Method F-Well Evacuation Purging, and Method G-Use of Packers in Purging. 1.4 This guide offers an organized collection of information or a series of options and does not recommend a specific course of action. This document cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of this guide may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied without consideration of a project's many unique aspects. The word "Standard" in the title of this guide means only that the document has been approved through the ASTM consensus process. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.