Infloor Wire & Cable Management

Advertising Supplement Provided By The Wiremold Company

Continuing Education

Learning Objective:
After reading this article, you will be able to:

1. Explain how wire and cable systems can lend flexiblity to an interior environment.

2. Describe the different considerations in selecting a system

3. Describe variations of infloor duct systems.

Increased workstation specialization means a "one size fits all" approach to providing wire and cable in open plan space is falling from favor. Instead, there is now a premium on systems that have the capacity and flexibility to meet all current and future workstation demands. At the same time, aesthetic considerations demand that the wire and cable infrastructure be as unobtrusive as possible.

In many new buildings, particularly those with open plans, infloor wire and cable management systems offer maximum efficiency and aesthetics. These fully integrated systems effectively manage complex data/communications requirements in environments where flexibility is a paramount concern. And, because these systems are located within or under floors and have flush or recessed power and data connections, they are practically invisible.

Infloor wire and cable management systems are particularly effective for large, open areas such as offices with modular partitions, schools, and retail stores. They can also be used to provide service to partitioned spaces, such as private offices, training centers, and conference rooms. These systems include:

• Underfloor duct
• Cellular and cellular deck systems
• Floor boxes
• Poke-thru devices
• Raised floor systems System Considerations

The location and capacity of infloor wire and cable management systems are critical concerns that ultimately depend on workstation requirements. In fact, the central importance of the workstation dictates that the selection of an infloor wire and cable management system begins at the workstation and works back toward electrical closets and telecommunications rooms.

Determine service requirements. Typical workstations require a minimum of five services: filtered, surge protected, isolated ground AC power; unfiltered AC power; LAN connection; internet connection; and telephone line(s). A growing number of workstations also need specialized services, such as video, and/or multiple monitors. Outlets and jacks may be built into modular furniture, attached to the surface of partitions, or located in the floor, independent of any furniture.

Determine system density. Cellular and duct systems are laid out in a grid pattern. Floor boxes, poke-thru devices, and raised floor systems are not constrained by a grid, though they are frequently installed in such a pattern. In all cases, infloor systems offer nearly unlimited flexibility to choose the density of service for a particular area. This density must be balanced against the project budget and the capacity of the wire and cable management system.

Locate distribution system. Since wire congestion is most likely to occur near service closets and in feeder runs, careful planning is needed to eliminate this concern. Dividing the area to be wired into zones can reduce the size of the feeder run by lowering the number of workstations it will be required to feed. Optimal placement of feeder runs also lowers wire pulling distance, reduces feeder size, and minimizes the amount of feeder required.

Infloor Wire & Cable Management Solutions

Cellular and cellular deck systems combine separate wire and cable channels in a single, unified infloor raceway that is encased in the concrete pour. If a building is of steel frame construction, a cellular deck system serves as part of the steel reinforcement for the slab, as well as a wire and cable management system. Both systems offer moderate to high capacity and options to meet all service density requirements. In order to maximize the benefits of these systems, close coordination is required between the owner, architect, electrical engineer, and structural engineer. Not only is this good design practice, but in the case of infloor distribution systems the specification channels themselves can differ. Deck systems are considered structural components and are specified through Division 5, while other infloor systems are specified through Division 16 (electrical). Infloor distribution products specified in multiple divisions should be coordinated with one another to ensure compatibility.

Underfloor duct systems offer support and security for power and data/communications wiring in reinforced concrete and steel construction. These duct systems have been employed with great success for decades and, although cabling has increased in volume and complexity, properly designed systems can accommodate even the most complex power, voice, data, and other wiring and cabling.

Available in a variety of sizes and configurations, underfloor duct systems provide separate channels for power and data/communications systems. Junction boxes facilitate cable pulling and allow cabling to be added or upgraded. Users access single points of service for workstations through low profile or flush service activations, which may be located anywhere along the duct run.

Trenchduct is a variant of infloor duct. The duct is set into concrete, but the removable cover is flush with the floor, providing ease of access and lay-in installation capability. Trenchduct is used in high-capacity applications and as a feeder system for other infloor wire and cable management systems.

Floor boxes are ideal for low-density, low-churn applications, and for providing cost-effective wire and cable management in open space areas. Single and multiple gang boxes are available. If the application is on-grade, a cast iron floor box or an approved on-grade stamped steel floor box may be needed. If the application is above-grade, a stamped steel or nonmetallic floor box may be appropriate. Floor boxes are available in both shallow and deep versions with a wide array of round and rectangular covers.

Poke-thru devices offer a high degree of design flexibility for open office space, since their placement is not constrained by partitions or by the grid pattern. Poke-thru devices are installed in core-drilled holes that enable wires and cabling to penetrate from plenum space below through the concrete slab. The only limitations are the presence of major structural components such as beams, and the rare instances where there is no available plenum space (since poke-thru devices require plenum access, they cannot be used in slab-on-grade applications). The UL fire resistance directory details the standard for poke-thru specifications as a "minimum of 2' on-center and not more than 1 insert per 65 sq. ft. of floor area in each span."

In general, poke-thru systems are most advantageous in structures where low churn rates are anticipated or where churn does not result in physical alterations. Among commonly installed wire and cable management systems, poke-thru devices typically have low initial installation cost. However, the cost to add or relocate a device is relatively high because of the need to drill a new hole, purchase a new device, and open the plenum space for installation.

Raised floor systems are sometimes the most cost-effective solution, especially when the highest levels of capacity and flexibility are required. With workstations requiring more voice and data services than ever, raised floors are no longer confined to computer rooms. Low-profile floors have significantly reduced the vertical space requirement for these systems. In addition to providing the physical space for wires and cables, raised floors provide the added advantage of convenient access to power and data/communications outlets that are housed in raised floor boxes.

In order to maximize the flexibility and cost benefits of raised floors, many designers are now also specifying manufactured wiring systems. A manufactured wiring system consists of factory-assembled connectors and modular cable assemblies that connect raised floor boxes to electrical and data/communications systems. If a box must be relocated it is a simple matter to unplug the cable set, move the box to a new floor cut-out, and plug the cable set back in. An estimated 45 to 55 percent of raised floor systems now employ a manufactured wiring system instead of conduit.

An Integral Infrastructure

Wire and cable management systems are part of an integral, building-wide infrastructure that is of critical importance to owners. The design team should work closely with client's technology managers to understand their data/communications concerns and meet their requirements in ways that will not compromise aesthetics. Infloor systems in particular must be considered early in the design process - rather than leaving it until later.

Such an approach maximizes flexibility and protects the original design against the unplanned intrusions that can result when wire and cable management is not addressed until late in the process. Even a well-designed network can fail to live up to expectations if it is locked into an inflexible, difficult-to-change cabling infrastructure. The accessible design of infloor wire and cable management systems enables them to support both operational and systems flexibility. Operation flexibility encompasses the day-to-day or month-to-month changes required for the workplace to keep pace with the functions being performed in it. Systems flexibility enables a facility to accommodate new or expanded communications technologies over the long term.

Accommodating Fiber Optics

The use of optical fiber cable in horizontal applications, frequently called fiber-to-the-desk, has focused attention on the effect of bend radius on system performance and the need to maintain a specified cable bend radius at all points of the cabling pathway.

The TIA/EIA and the American National Standards Institute (ANSI) have recently approved a bend radius standard for fiber optic cable. Of particular concern in selecting and installing cabling pathways is the new minimum bend radius standard for these cables:

1. 1.0" under no pull load.
2. 2.0" when subject to tensile loading up to the rated limit.

Not all wire and cable management systems offer a 2.0" bend radius. Since no one can be certain that the initial installation or any future changes will not require cable pulling, the installation and maintenance of cables may be severely limited by a pathway that does not maintain the bend radius that is required suitable for pulling fiber optic cable.

 

Case studies Poke-Thru Devices in New Corporate Headquarters The headquarters of Clayton Homes in Alcoa, Tenn., is a completely open environment with no enclosed offices at all. The owner needed the flexibility to provide power, voice, and data cabling to modular furniture in a way that doesn't detract from the appearance. The solution was high-capacity poke-thru devices that accommodate high-speed UTP cabling. Ninety-one of the poke-thru devices are connected directly to modular office furniture.

 

Case Study Flexible Solution for Bank Buildings Three new buildings on the corporate campus of First Union Corporation in Charlotte, N. C., had to be up and running quickly in order to maintain quality customer service. To speed installation and maintain flexibility, designers specified raised floors with a manufactured wiring system. The flexible connection between the distribution boxes and the raised floor boxes allows the Customer Information Center to change and expand.

Profile: The Wiremold Company

The Wiremold Company, headquartered in West Hartford, Conn., is a leading manufacturer of wire and cable management systems, power and data quality products, and data/communications connectivity systems. Rapidly evolving data/communications technology and the need for flexible workstations have increased the amount and complexity of wiring and cabling. At the same time, building owners demand improved aesthetics and lower life cycle costs. The Wiremold Company anticipated these changes and introduced the concept of integrated wire and cable management systems. Leading product lines include Walker" infloor systems, SpecMate' cable tray, the Interlink Cabling System, the Activate' Connectivity System, Wiremold" perimeter raceway systems, and Sentrex" power and data quality products.

The Wiremold Company has embarked upon an aggressive program of product development that focuses on customer needs. A top priority is to extend future-ready enhancements, such as bend radius support, across a broad range of wire and cable management systems.

The Wiremold Company has expanded its global sales, support, and manufacturing capabilities. Its strategically located staff is "on the ground" with a thorough understanding of construction techniques and local codes. Value-added services include product testing and securing appropriate country approvals, design engineering support, and on-site project coordination.

60 Woodlawn Street, West Hartford, CT 06110
Tel: 800-621-0049 Fax: 860-232-2062
Web Site: www.wiremold.com

Questions:

1. Where do you begin when selecting the location and capacity for an infloor wire and cable system?
2. Why would you divide the areas to be wired into zones?
3. What are the advantages of poke-thru devices?
4. When are raised floor systems the most cost-effective solution?
5. What areas are infloor wire and cable systems most effective for?
6. What is the bend radius to allow for in fiber-to-desk cable applications?