This standard covers sodium polyphosphate, glassy, for use in water supply service. This material is also known as sodium hexametaphosphate, sodium tetrapolyphosphate, and Graham's salt. The main purpose of this standard is to provide purchasers, manufacturers, and suppliers with the minimum requirements for sodium polyphosphate, glassy, including physical, chemical, packaging, shipping, and testing requirements. The major revisions in this edition of ANSI/AWWA B502 include the following: The format has been changed to reflect current AWWA standard style; The acceptance clause (Sec. I.C) and definitions (Sec. 3) have been revised to approved wording; and Editorial revisions have been included throughout the standard.