1.1 This specification covers standard dimensional requirements for obtaining, within practical limits, interchangeability in glass stopcocks (Note 1) with polytetrafluoroethylene (PTFE) plugs for ordinary laboratory and industrial applications. It covers dimensional interchangeability only and does not involve design characteristics of the item except where specified, nor does it involve physical or chemical characteristics of the material used. It does not cover glass stopcocks with glass plugs (Note 2) or stopcocks intended for use in high-vacuum work.

Note 1 - A stopcock is defined as consisting of a plug and barrel in assembled configuration.

Note 2 - Glass stopcocks with glass plugs are covered by Specification E675.

Note 3 - The dimensions pertaining to stopcocks were taken from the now obsolete Commercial Standard CS 21-58 of the U.S. Department of Commerce and Product Standard PS 28-70 published by the National Bureau of Standards.

Note 4 - Although glass is the most common material for stopcocks, other materials may be used as specified. Stopcocks constructed from glass shall be in accordance with Specifications E438 and E671.