IEEE 420-2001 pdf download IEEE Standard for the Design and Qualification of Class 1E Control Boards, Panels, and Racks Used in Nuclear Power Generating Stations
4.Design considerations
4.1 Human factors
The design/layout of the Class 1E control board, panel, or rack shall incorporate human factorsengincering principles (see IEEE Std 1023-1988 for further guidancc).
4.2 Seismic
4.2.1 General
The structure for a Class 1E control board, panel, or rack shall enable the equipment contained thereinto meet its essential performance requirements during and after the postulated design basisearthquake. The Class 1E control board, panel, or rack should be designed to minimize theacceleration levels to which the equipment must be qualified. In minimizing the acceleration levels.consideration shall be given to existing qualification levels of equipment. For further guidance seeANSI/TEEE Std 344-1987
In designing the control board, panel, or rack, considcration shall be given to the location of thcdevices mounted upon it or within it The desiener’s responsibility is to optimize the eflectiveness of thecontrol board, pancl,or rack as a suitable structure for mounted devices. The designer should alsoconsider location and availability of component mounting surface arcas for future modifications andadditions.
4.22 Other considerations
Provisions shall be included for mounting the control board, panel, or rack to its supporting structure.The interaction of the plant cable, raceway, and tubing systems entering and/or attached to the controlboard, panel, or rack shall be considered
Plug-in equipment,slide-mounted cquipment, or devices with access doors shall be provided withmechanical restraints, if needed, to maintain positional integrity.
All non-Class 1E devices within or attached to Class 1E control boards, panels, or racks shall bemounted to preclude degradation of Class 1E equipment or circuits. or both, beyond an acceptablelevel, as a result of a seismic event.
Where relative motion exists between equipment mounted on or in a control board structure, themaximum range of such motion shall be considered in the physical arrangement and designparameters for wiring and adjacent equipment, Wiring to equipment and termination devices shoulchave suficient slack or be installed in such a way that relative motion within the control board, panel.or rack does not cause failure.
4.3Independence
The gencral requirements for achicving clectrical independence of redundant Class lE cquipment andcircuits are contained in ANSI/IEEE Std 384-1992.
IEEE 420-2001 pdf download
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