During the design of data centers, professionals often face the question of raised floor systems versus the use of an overhead cable tray while designing cabling distribution and air handling systems. Twenty years ago, this wasn't even a discussion, as virtually all data centers used raised floor systems, although it has now become a heated debate. While a case can be made for both options, there are certainly many reasons raised floors have remained the industry standard in data centers across the United States.
After all, most design professionals and IT departments are already familiar with raised floors, and these systems offer more options for integrating infrastructure components as opposed to a data center built on a slab. Flexibility and scalability are only the beginning, though.
Flexibility and Scalability of Raised Floors
Most people who have been working in data centers for many years have seen all sorts of innovation in equipment, beginning with very large mainframes and disk drive memory machines which turned into routers, servers and tablets. Of course, the one thing that has remained the same is the use of raised floors as a platform.
Raised floor systems are incredibly easy to configure to accommodate changes and add-ons, with the flexibility for retrofits of next generation equipment into the existing space. Even with increasing density, raised floors continue to accommodate diverse heat loads.
Without a raised floor system, the power to the racks must be run overhead using a bus system, which is complicated for many reasons. These systems are often proprietary, costly and inflexible with few options. While a short in an under-floor power cord may take out one rack, the same short in a bus system may take out a whole feed and dozens of racks. Repairs and replacements are also a major burden.
Using an under floor plenum-based cooling system, however, makes it easy to implement extra overhead cooling when necessary, and repairs are much simpler as they require removing just a few raised floor tiles to access the space.
Cabling Issues
Raised floors offer a clear distribution path for cabling that doesn't require a ladder or special structural cable trays and ceilings. Overhead cabling requires accessing overhead sructures like ductwork and sprinkler heads, and this access and maintenance often requires many people and the use of a stepladder. Consider that the risk of accidental disconnection of cables is more likely with overhead cabling than under floor cabling.
When cables are run in a hot aisle, they may be run in the same space under a raised floor with the flexibility to end the cables anywhere necessary. This option also means that ceiling height and overhead obstacles like sprinkler systems are not issues. Raised floors make accessing cabling worlds easier, with the ability to access cables at any point in the under floor space by simply removing select raised floor tiles rather than a complicated system involving a handful of people and ladders.
Finally, raised floors offer build-in grounding grids to ground sensitive equipment, as well as water distribution lines for reduced risk in case of water leaks.
Airflow Issues
Adding dampers, integrated fans and perforated data center floor tiles makes raised floor systems the ideal platform for supplemental cooling devices as it optimizes airflow control on a rack-by-rack basis. Data centers will see the best airflow management by using hot/cold aisle containment, and there is simply no better way to implement this than aligning computer floor tiles into hot and cold aisles to contain air without the use of special structures or walls.
The use of perforated data center floor tiles allows you to concentrate cooling and airflow exactly where it needs to be, and areas that are running hot may be addressed by replacing a raised floor tile with a higher air flow version.
Appearance
Finally, many would argue that raised floor systems offer better aesthetics than overhead cable trays as well, as running cabling under the floor keeps an interior space neat and clean. Overhead wiring systems often run under light fixtures, casting shadows over work areas and cabinets, while running cables under the floor space keeps the entire data center bright, clean and neat.
While an argument can certainly be made for both overhead cabling trays and raised floor systems, raised floors remain the industry standard for a reason. They offer the flexibility, scalability and airflow management that is simply impossible with an overhead system, as well as a cleaner and safer environment that everyone can appreciate.
Raised Floor Information Center
