IEEE Std 628 pdf free download

IEEE Std 628 pdf free download.Criteria for the Design, Installation, and Qualification of Raceway Systems for Class 1E Circuits for Nuclear Power Generating Stations.
4. Design
4.1 General
4.1.1 Material selection
In the design and installation of raceway systems, consideration shall be given to the relative structural
integrity of aluminum versus steel when subjected to heat from postulated fires.
NOTE—Flexible conduit may not accommodate relative displacement in all installations. For additional guidelines pertaining to raceway systems, see Annex B.’
4.1.2 Structural integrity
Raceway systems for Class 1 E circuits are not Class I E per IEEE Std 308T1; 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.l and UL6, 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 he manufactured to requirements that support the 10 CFR 50 Appendix B calculations, which show the structural integrity of the seismic raceway system for Class 1 E circuits.
As a minimum, the design shall adhere to the basic requirements of this standard and of IEEE Std 384Th1. 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.
The design of raceways shall accommodate the installation of qualified fire stops where raceways penetrate a fire barrier. For additional fire considerations, see IEEE Std 690Th1.
4.2 Separation criteria
4.2.1 Design requirements
The design requirements for physical independence and separation of raceways containing Class IE circuits are contained in IEEE Std 384.
4.3 Grounding
Metallic raceways shall be electrically continuous and electrically connected to the station ground grid in accordance with IEEE Std 665Th1.
4.4 Raceway identification
Raceways shall be marked in accordance with the requirements of IEEE Std 384; embedded conduit shall be marked at all access points.
4.5 Raceway system protection
Raceway systems in hazardous areas shall be designed in accordance with IEEE Std 384.
4.6 Environmental considerations
The selection of materials used for raceway systems and the finishes required shall be based on the environmental conditions expected where the raceway systems are installed. To meet the requirements for combustible gas control, materials for raceway systems to be installed in containment shall be selected with due consideration to minimizing the generation of hydrogen gas following a design basis event (Regulatory Guide 1 .7 [B5j).’ For additional guidelines pertaining to environmental considerations for raceway systems, see Annex B.IEEE Std 628 pdf download.