API RP 505:2025 Third Edition PDF
The purpose of this recommended practice (RP) is to provide guidelines for classifying locations Zone 0, Zone 1, and Zone 2 at petroleum facilities for the selection and installation of electrical equipment. Basic definitions given in the 2023 edition of NFPA 70, the National Electrical Code (NEC), have been followed in developing this RP. This publication is only a guide and requires the application of sound engineering judgment.
