You’re reading an outdated article. Please go to the recent issues to find up-to-date content.
Raised access flooring is becoming a more common feature in today’s commercial and institutional buildings. Long preferred in computer-intensive locations, access flooring is now being manufactured in finishes that fit into more upscale settings as well. For electrical contractors willing to take the time to work through some of the coordination issues required, access-floor installation can be less labor intensive and, potentially, more profitable than with standard designs.
Raised-floor systems offer building owners and tenants a number of advantages, including the ability to make wiring and cable changes more easily than with standard chase designs. Wire and cable are installed below easily removed floor tiles, often in modular, home-run-styled distribution schemes. Relocating power and data connections can be an easy, plug-and-play process, depending on the design.
Raised-floor approaches also can make for a more efficient use of electrical materials, an added benefit when sustainability is a goal. Standard commercial-office plans, for example, call for outlet boxes every 2 feet to provide power and data access if space is reorganized. Access flooring can eliminate the need for such saturation wiring, along with the resulting waste of wire and cable when spaces are reconfigured.
Additionally, for data centers or computer rooms, the plenum space created between the floor slab and the underside of the raised flooring can be used for forced-air distribution. Some access-floor products incorporate specialty diffuser tiles that can be positioned to serve hot-aisle/cold-aisle server arrangements, delivering cooler air directly where it is needed and using natural air-movement patterns to draw hot air up from server racks to ceiling-height return-air ductwork. Depending on how it’s implemented, this approach to air distribution can be more efficient than using ceiling vents and provide greater occupant control over space-conditioning settings, adding to its appeal among some green-building proponents.
Driven by data centers
Data centers and computer rooms remain the biggest markets for access-flooring makers, but you won’t find manufacturers complaining any time soon about their industry’s current reliance on a single building sector. They are busy enough keeping up with orders, as it is. Tate Access Floors, Jessup, Md., for example, has seen its business grow 25 percent in just the last year, according to Bill Reynolds, the company’s marketing and technical director.
According to Reynolds, “2008 is predicted to be as good as . And 2009 is looking good as well.”
Reynolds said interest also is increasing among owners and designers of other building types.
“There’s a common theme—they’ve got a desire for flexibility,” he said. “They know going in that their space will change. Or, from the developer’s side, they don’t know what tenants are coming in. They want systems that are flexible and adaptable.”
Electrical contractors also are beginning to see access-floor applications beyond traditional computer-room and data-center installations. Chicago-based Gibson Electric & Technology Solutions, for example, currently has several jobs underway where raised flooring is involved. Hyatt Corp.’s recently completed headquarters in Chicago uses access flooring throughout, according to Carmen Manno, a senior vice president with Gibson.
“We see more and more projects with it,” Manno said. “The initial idea made a lot of sense for the data and HVAC guys, but it’s also helped us be more competitive. It’s a lot easier for us to work on the floor, instead of on an 8- or 10-foot ladder.”
This is not to say, however, that installing wire and cable in underfloor plans doesn’t pose its own challenges. First, wiring plans must address adaptability goals if plug-and-play flexibility is on the client’s wish list. In these cases, modular distribution systems can create centralized connection points that can be accessed using flexible extender cables, where local codes allow.
“What you’re trying to avoid is one long home-run cable from the closet to your desk,” Reynolds said.
Some sort of cable-management plan also is critical, to ease both the initial installation and any future changes. In jurisdictions that don’t require conduit, it could be tempting to just drop in the wire or cable and close up the floor. However, such inefficient planning can create nightmares for clients and their electrical contractors down the road.
“A large percentage of the problems with downtime on a server can be attributed to the physical methods of routing the cables,” said Tim Place, president of Macoutah, Ill.-based cable-tray maker Cablofil. “And if it’s not planned out properly, you’re just asking for trouble. You should plan for potential growth and lay those pathways out in advance.”
Place has seen the disasters that can result when such planning has been ignored. He tells of visiting one prospective client in a facility featuring a 3-foot-high raised-floor system. Over time, staff members had treated the under-floor space as an inexhaustible resource, to the point where floor tiles were actually bulging over heaps of tangled wire and cable.
“Less than 1 percent were actually active,” he said. Mining out the inactive material and organizing what was left became a months-long process.
Manno agreed that cable-management is critical in under-floor settings, and he said he has seen equally bad results when systems aren’t maintained. In one case, pedestal support arms were broken off to allow even more cable to be laid in an already over-full space.
“It was actually the cables holding the floor up,” he said.
Although the Chicago-area jurisdictions where Gibson Electric does most of its work generally require conduit for electrical distribution, Manno said the company counts on cable-tray systems for its low-voltage designs.
“Our low-voltage side uses a tone of the cable-management tray,” he said. “If there are multiple runs, there’s definitely cable management. If it’s not managed correctly, it’s a total rat’s nest.”
Steering clear of collisions
Planning also is required for the initial installation when raised flooring is involved. Otherwise, designs intended to improve efficiency can end up resulting in run-ins between the various building trades sharing the under-floor space.
In a typical installation, raised-floor systems are supported by pedestals spaced every 2 feet with heights ranging from 3 inches to 3 feet. Although pedestal locations are marked on the slab or subfloor before electrical and mechanical work begins, the pedestals, themselves, usually aren’t installed until other systems are laid out, Reynolds said.
Keeping the trades from interfering with each other can take some effort, however. Electrical and mechanical team members have to develop strategies from the outset to prevent placement conflicts between cable and wiring or ductwork, air-handling equipment, process piping and any required containment piping. Manno said Gibson Electric has moved from paper wiring and mechanical plans to 3D software to predict and prevent just such problems.
“It will let us know if we’ve got a collision,” Manno said. “That seems to be what everybody in Chicago is doing. Our coordination is a process, not just a markup with a red pen.”
Some electrical pros also consider the possibility of cross-interference between electrical and data cabling in such installations, if the systems aren’t adequately insulated or separated from each other. Manno said he hasn’t faced this situation because Gibson Electric works primarily in jurisdictions where conduit is required.
“We hear mixed results,” he said, noting that electrical design engineers may take varying approaches, as a consequence of these concerns, from running power lines under cable wireways to isolating the two systems completely.
For building owners and developers, the up-front planning along with added flooring-material expenses can result in a higher first cost over standard, slab-based flooring designs, although Tate’s Reynolds said higher flooring costs may be offset by resulting lower costs in other systems.
“It’s everywhere from a premium of $2 per square foot to a savings of $2 per square foot, to a net/net situation,” Reynolds said. “The bottom line is if you add up all of these offsets, you can realize some savings. We want people to look at this as an integrated-design solution, and part of this cost story is educating people to that.”
For example, ductwork may be reduced significantly when the under-floor space is used for air distribution. Also, in commercial settings, plug-and-play distribution designs could cut owners’ furniture budgets. With easily accessible power and data connections, there would be less need to purchase high-end wired cubicle systems. Instead, owners could choose less expensive, nonelectrified options.
Finally, Reynolds said electrical contractors’ labor expense could be reduced with the use of modular wire and cable systems. And Manno agreed that access flooring can cut electrical installation costs, even when the need for added planning is taken into account. Floor-height systems are simply easier to install than overhead alternatives, he said.
“We’ve found that we can be more competitive, and the overall cost has come down,” Manno said.
Manno added that he also sees ongoing maintenance-cost advantages for owners who have adopted raised-floor plans. With access flooring and modular wiring systems, he said an owner’s maintenance staff may be able to perform changes that would otherwise require a call to an electrical contractor.
“You spend more time up-front coordinating, but I think, in the long run, it’s time well spent,” he said. “It’s more serviceable. If it’s a plug-and-play situation, you pop a couple tiles in and out and pop [the outlet] into place.”
ROSS is a freelance writer located in Brewster, Mass. He can be reached at [email protected].