1.1 This guide is intended to describe the physical and chemical characteristics of water to be used whenever critical purity is essential to the use intended in clinical, pharmaceutical, biophysical, biomedical, chemical, physical research applications, or a combination of these. This guide is not intended for use in preparing water for injectables. Generally, the appropriate use of this guide may include experiments involving tissue culture, chromatography, mass spectroscopy, or analysis where molecular quantities of impurities may be important.

1.2 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.