This report establishes a methodology for the evaluation of gas detection devices and is the result of a critical investigation into the basic principles defining gas detector performance. A scheme is presented to evaluate the performance of a test sample of gas detectors based on the detector type and intended application. Test procedures, worksheets, test apparatus, glossary, and statistical methods for handling test data are given. In addition, evaluation standards and test parameters are identified. It is intended for this report to serve as a comprehensive framework for the eventual certification of all gas detectors for mine applications. A plan is proposed and recommended for the quantification and implementation of evaluation standards for gas detection device certification.