This document provides requirements for the application of basic and well-tried safety principles and conditions for possible fault exclusions. This document provides guidance for the design and the validation of mechanical, pneumatic, hydraulic, and electrical systems for the safety-related parts of a control system (SRP/CS) designed in accordance with ISO 13849-1:2023. NOTE Additional requirements for programmable electronic systems, including embedded software, are given in ISO 13849-1:2023, Clause 7, and IEC 61508.