The purpose of these recommended practices is to provide
standard testing procedures for evaluating high-strength
proppants, that is, proppants stronger than silica sand.
API RP 60-1995 history
1995API RP 60-1995 Recommended Practices for Testing High-Strength Proppants Used in Hydraulic Fracturing Operations (Second Edition)
1989API RP 60-1989 RECOMMENDED PRACTICES FOR TESTING HIGH STRENGTH PROPPANTS USED IN HYDRAULIC FRACTURING OPERATIONS FIRST EDITION (WITHDRAWN)