IEEE Std 628-2020 pdf download – lEEE Standard Criteria for the Design, Installation, and Qualification of Raceway Systems for Class 1E Circuits for Nuclear Power Generating Stations.
4.1.2 Structural integrity Raceway systems for Class 1E circuits are not Class 1E per IEEE Std 308TM; however, they shall be designed to seismic Category 1 requirements to prevent failure during a seismic event. Documentation requirements for the raceway system shall be in accordance with Clause 7 of this standard. Individual components (conduit, tray, etc.) within the raceway system are a subset of, and distinguished from, the raceway system. Those individual components shall meet the industry standard requirements (i.e, Certificate of Conformance to ANSI C80.1 and UL 6, see 4.7) necessary to support the structural and seismic calculations. Standard industry practice has allowed different requirements for conduit as to cable tray. All materials shall be manufactured to requirements that support the 10 CFR 50 Appendix B calculations, which show the structural integrity of the seismic raceway system for Class 1E circuits. As a minimum, the design shall adhere to the basic requirements of this standard and of IEEE Std 384TM. This will help ensure that the raceway system is designed to perform its functions, and not degrade the safety functions of adjacent safety-related systems during and after experiencing all conditions postulated to occur in its environment. Clearances with respect to other systems shall be established and provided to help ensure that movement due to loads and load combinations (see 4. 10.1) will not affect the integrity of the raceway system. Relative displacement of the raceway system to other systems, equipment, or structures shall be considered in the design of raceway systems. The raceway supports shall be designed to accommodate differential settlement and deflections between structures. 4.1.3 Layout Raceways shall not be located close to heat sources unless cables are selected or derated for the highest expected ambient temperature. Longitudinal expansion of raceways shall be considered in areas with varying temperatures.