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6.4 Placing Electrical Systems and Communications Systems in Buildings

In order to achieve system flexibility and thorough integration between building architecture and engineering systems, a concept for the power and telecommunications infrastructure that supports the distribution of electrical and communications systems must be established during the architectural schematic design. The locations of vertical backbone pathways, horizontal pathways, closets, equipment rooms and utility entrance facilities for electrical and communications distribution equipment must be established before the architectural concept is finalized.

Electrical Closets. The spacing of electrical and communications closets in buildings is described in Chapter 3: Architectural and Interior Design, Building Planning, Placement of Core Elements and Distances.

Communications Closets. Communications closets shall meet the requirements of EIA/TIA Standard 569: Commercial Building Standard For Telecommunications Pathways And Spaces (and related bulletins). The location and size of communications closets are discussed in Chapter 3: Architectural and Interior Design.

Planning Grid, Floor Grid and Ceiling Grid. A common planning grid is to be used in all GSA buildings. Electrical and communications elements in floors and ceilings including lights, power, telephone and data are given precise locations within the planning grid. The relationship of this grid to wall placement, ceiling grids and location of mechanical and electrical elements is described in detail in Chapter 3: Architectural and Interior Design, Building Planning, Planning Grid.

Horizontal Distribution of Power and Communications. In new construction the building shall have raised access flooring. In buildings with access flooring, power circuits should be provided via conduit, modular wire distribution boxes and modular wire cable sets to flush floor receptacles. Communication cables can be laid exposed directly on the slab and grouped together in rows 3600 mm (12 feet) on center.

Power, data and telephone cables shall be grouped together in pathways that are separated into channels for each system. Independent channels are required in horizontal pathways for normal power, emergency power, mechanical, fire alarm, security, television and communications. The communications channel includes voice and data. Major zones within the facility should have horizontal distribution capacity for all seven categories described above. Horizontal pathways serving individual work stations must have at least three channels for power, voice and data. EIA/TIA Standard 569: Commercial Building Standard For Telecommunications Pathways And Spaces (and related bulletins) provides detailed requirements for communications pathways, including requirements for underfloor ducts, access floor, conduit, cable trays and wire ways, ceiling pathways and perimeter pathways. Provide at least 650 mm2 (1 square inch) of horizontal capacity for power and communications to office areas for every 10 m2 (100 square feet) of occupied area.

U.S. Courthouse, Kansas City, KS
U.S. Courthouse,
Kansas City, KS

The placement of outlets in walls or in the partitions of systems furniture should be avoided because of the difficulty it creates for future reconfiguration of the office space. This is true for both closed office and open plan concepts. Light switches likewise should be located on columns and the walls of fixed core elements, to the maximum extent possible.

Flat conductors, poke-through and/or power poles shall not be used in new construction.

These criteria apply to all occupiable area or net usable space in a GSA building but not to public paces or support spaces, which can be considered fixed elements and are not subject to frequent changes.

Vertical Distribution. Risers for normal power, emergency power and communications should be combined with other core elements to form compact groups and maximize usable floor space. The number and size of risers will depend on the systems chosen, but future flexibility should be an important criterion in the vertical layout as well. Electrical and communication closets shall be vertically stacked. Electrical closets shall have two capped 4-inch spare sleeves through the structural floor for future flexibility. Communications closets shall also have two capped spare sleeves in each closet. Vertical risers for normal power, emergency power, and communications should be aligned throughout the building to minimize conduit bends and additional cabling. Be aware of the requirements to locate fire alarm vertical risers remotely.

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