This document provides requirements and guidance of the Independent Safety Assessor for Railway Systems Accreditation Program that SCC operates and is a companion to ISO/IEC 17020. It outlines unique Canadian requirements of the SCC Accreditation Program for Independent Safety Assessors (ISAs) that carry out independent safety assessments of the suitability and application of both the risk management process and its results for changes to a Railway System, and that carry out independent assessments of system assurance processes for a Railway System.