Everything You Need to Know about Raised Access Floors
Everything You Need to Know about Raised Access Floors
02 Jun, 2013
What Type of Access Floor Should I Choose?
If only it were that simple. There are now many types of raised access floors to choose from.
Back in the old days, things were a lot simpler. Heck, there was usually only one game in town and your choice was often made for you.
We live in a different world today. You have more choices, and you need to be more educated than ever.
So, how do you choose the right access floor for your building?
The type of raised access floor you need depends on several factors:
Application type (data center, retail, office, etc.)
Cooling System/Air Distribution Setup
Cabling/Wiring Needs (Including routing and distribution/delivery)
Weight & Load Capabilities
If you have made it this far, we assume you already know you need an access floor. Raised floors are useful for creating pathways for piping, wires, cable, conduit and airflow. If you would like to know more about the benefits of an access floor, please check out our article on how it can change the way you work. Otherwise, let's skip the sales pitch on why you need a raised floor, and we'll get into the nuts and bolts of what type you really need.
Access Floor Applications
Before diving in to specific information about raised access floors, it would be wise to note which types of applications would benefit from a raised floor:
Traditionally, many architects, property managers and building owners and operators have been reluctant to utilize a raised floor in an office space. This is likely due to a few reasons, but the most common reason is that many of these professionals are used to the traditional raised floor types that are often several feet high. While quite practical in industrial applications, commercial buildings cannot afford to lose several feet of floor to ceiling height.
A low profile floor, as the industry defines it, is a floor less than 6" in height, with the purpose of organizing cables, wires and conduit. Due to the low height of the floor, under-floor airflow is not a concern or option.
A standard/traditional access floor is anything higher than 6". Standard heights are usually 12" or more, with some floors reaching 6 feet or higher. These floors allow under floor cable management as well as airflow.
Standard raised floors are often found in industrial or institutional settings. They are rugged, heavy duty and provide ample space for wires, cables and piping. However, the drawback of this is flexibility and ease of use. And raised floors are used; they don't just sit there doing nothing!
If your needs are such to justify this type of system, you likely have outside contractors or highly-trained in house personnel who can service the heavy duty systems that reside in the floor.
Perhaps the biggest limitation of traditional floors is they do not provide easy access to the wires, pipes and cables below the floor. If you want to mange your wires and cables, you have to pull several access floor panels (usually weighing 35+ lbs. each). But don't pull too many floor panels at once, because the entire raised floor can lose stability; a major problem when your floor is several feet off the ground!
While some low profile access floors are lighter-weight than their big brothers, they still have great strength ratings (as you will see below). Some of their main advantages are they take up less ceiling height and they are much easier for onsite personnel to use.
There are no heavy panels to lift. There is no concern about falling through an opening three, four or more feet down.
The trade off of course is there is less underfloor height. If you are running a big 8" Chilled Water line under the floor, you're better off with a traditional access floor with panels, pedestals and stringers.
But if you are running electrical conduit and data cables for, say, an office space, a library or a retail store, a low profile floor may be exactly what you need.
Floor Height
The height of your raised floor will be determined in part by your need for underfloor space, combined with available ceiling height and budget. While taller floors may cost more, the additional cost may be surprisingly lower than you thought.
Traditional Raised Floor with Underfloor Air Distribution
During the concept and design stages, the height of your raised floor will be determined based upon the amount of cabling, wiring and piping to be installed under your floor, as well as any underfloor air distribution you may need.
For example, if you plan to have underfloor air distribution in a data center environment, your mechanical engineer should be able to tell you how much floor height you need for effective airflow.
Typical heights are 24"-48", but this is based upon several factors, not least of which is the type of air handler, fan (centrifugal vs. backward curved) and any type of air containment system implemented.
Your access floor height should be sufficient so that, once you subtract out the space used by wires, cables and piping, you are still left with sufficient floor height for air distribution.
This is one of the biggest points that needs to be made, so we will talk about it some more. The floor height is often determined by the design team early on in the process, with other trades vying for space.
A project design team usually sees better results when the absolute maximum height is known up front, and the actual floor height can be a dynamic value that may change as the electrical, mechanical and IT teams have their input.
(Most) Access Floors Should Be Short - Especially If You Have No Under-Floor Air
I can't tell you how many data centers I've been in that have a 12"-24" floor, because that is a standard minimum for air distribution, yet the floor is completely full of wires, cables and pipes!
Obviously, these data centers have serious cooling issues that are usually exacerbated by adding more cooling units.
The underlying issue is insufficient floor height and lack of proper airflow..
So, we cannot stress enough the importance of proper design! However, if you have an existing space, and you are experiencing some of these issues, there are still some things you can do to improve your data center (or other space) performance.
You may wish to investigvate renovation work, which includes increasing the height of a floor while reusing the existing floor panels. It may also include refurbishing existing access floor panels.
Low Profile, Cable Management Floor (no air, cables only)
One of the biggest trends in building design and operations is the use of low profile access floors. These are floors from 1.5"-6" high that allow for simple, effective cable management, without the need for concrete trenching or overhead cable management. CISCA has recently adopted new terminology that defines "Cable Management Access Flooring" as a seperate building product than traditional access flooring.
If you don't need underfloor air distribution (usually for large, industrial applications like data centers, electrical rooms or production lines) you probably don't need a traditional access floor, which could be 2 feet or higher.
Many industries outside of data centers are now using low profile floors to simplify cable management; industries like the retail industry, command/control centers, call centers and even traditional office space.
Another benefit of these lower floors is the built in cable management trenches and variety of integral electrical floor boxes. This technology takes an otherwise cumbersome job and turns it into a simple plug and play affair.
Panel Material
Raised floor panels vary in construction materials, depending on your application. The standard panel type has been concrete-core, steel panels for quite a long time, but there are more options today. Your choices include:
Concrete core steel panels
Hollow steel panels
Bare concrete panels
High strength polypropylene panels
Wood panels
For traditional access floors, cement core, steel panels are by and large the industry standard, and the biggest variable is the weight rating. This type of panel is also available on low profile access floor, so if you have a weight concern but still want a lower profile floor, this may be your solution.
Hollow steel panels are also available in traditional and low profile floors. While their load ratings may not match those of traditional steel and concrete panels, you may be surprised with how strong they are, despite their lightweight and easy handling characteristics.
However, for low profile access floors, high strength polypropylene panels may be used in many instances. The benefit of such panel construction is drastic weight savings, easier handling and less environmental impact.
Some super low profile floor designs (cable management flooring), do not rely on 4 pedestals at the corner of each panel.
Instead, these panels rest directly on the subfloor, utilizing a number mini pedestals per panel. Panels of this type have a high crush rating, while being lightweight and easy to handle.
A Final Note on Panel Construction
You may have noticed I mentioned the actual weight of a panel being heavy or lightweight, and are wondering why it matters? After all, once the floor is installed, it doesn't matter how heavy the panels are, right? Well, not exactly. Your building is constantly in flux, and your electrical distribution system is no exception.
When you get right down to it, raised floor panels are picked up and moved far more often than one might imagine.
Whether it's a contractor running more conduit or piping, or it's one of your own in-house technicians running new data cabling, you want the floor panels to be as lightweight and convenient as possible, while meeting the weight and load capacities for your specific application.
But you don't always need to purchase floor panels with the highest weight rating. We often design solutions where light traffic areas are built with standard 1,000-1,500 pound panels, and more critical areas are built with 2,000-2,500 pound panels.
Critical areas could be designated pathways, where you know bulky equipment will be moved in and out of the space.
They could also be areas where heavy equipment will be permanently located, potentially eliminating additional support such as equipment floor stands.
Additionally, for seismically active regions, further support may be required to achieve a high seismic rating. This could be additional pedestal anchors as well as additional support structure connecting the pedestals, stringers and floor panels.
Navigating through all of the options can be tricky. Between PSI ratings, load bearing capability, crush strength, rolling tests and more, it's hard to know which panel is right for your application.
More Than the Sum of the Parts - Cable Management Floor Is a Big Part of Your Building!
You should know that the rating of an access floor is more than the load rating of its panels. A system is only as strong as its weakest link, so pay close attention to your needs, and design a system where all the components are selected to meet your requirements.
I have seen far too many customers that were sold on a high load bearing panel, without regard to the rest of the system. That 2,000 lb rating doesn't mean much if the understructure won't support it.
I've also seen raised floor designs where heavy equipment was placed on the floor, exceeding the weight limits. A good example of this is a customer who wanted to install a UPS (Uninterruptible Power Supply) on their floor (another brand).
The UPS weighed about 8,000 pounds, and each panel had a 2,000 pound rating. Since the UPS cabinet rested, at some point or another, on 4 different panels, they thought everything was fine (4*2,000=8,000).
Unfortunately, the load was distributed unevenly, and did not account for rolling loads of moving the UPS, or what would happen when work was done nearby, requiring the removal of panels.
The UPS installation didn't go very well, and a third party was called in in to provide a floor that could handle the weight, and then some.
We have no problem building walls, cubicals, partitions, etc. on top of a Netfloor USA Raised Access Floor. Really. We do it all the time. (Some manufacturers shy away from this, but since our floors are part of your entire infrastructure, it seems silly to have too many special requirements that limit what you can do.)
So you know what cable trays are, right? Cable trays, wire trays, cable baskets; they're all names for the same thing: metal trays that hold cables and wires. Usually found suspended from the ceiling or hidden underneath a tall raised floor, cable trays are a good way to run (route) wires and cables.
There's nothing wrong with cable trays in a raised access floor. As a matter of fact, most data centers you come across use cable trays. There's just one problem with that (when we're talking about ANY building or facility that is NOT a data center)
There are some unique cable tray designs out there. You might think "It's just a metal tray, how special could it be?" And you're right, in a way. But there are flexible cable trays that you can easily bend and turn however you want them.
But again, you need a lot of overhead space to make those turns.
If you are designing or building a space where you can't have obnoxious-looking cable trays hanging from the ceiling, and putting them in a really tall raised floor isn't an option, you should consider a low profile access floor. No raised floor cable tray systems required!
With a cable management access floor system, there are built-in, modular cable raceways (which will take the place of cable trays). There can be in-the-floor electrical and data boxes. And perhaps the best part: You (and your customers and employees) never see it! It's under the floor, out of sight.
For decades, IT and facilities managers have been installing tall raised access floor, then installing cable trays and raceways under the floor. The problem with this method is it requires more materials and labor. (Not to mention taking up a lot of floor to ceiling height.
There is an easier and less expensive way: Low profile (short), cable management access floors. Whew, that's a mouthful! But saying its long name is the hardest part about using these types of access floors! They're easy to deploy and simple to maintain.
These modern access floors have built-in cable management raceways.
Just put your put your electrical and data wires into the cable raceway (cable tray) and you're almost done!
This one may surprise you! Traditionally, access floors have been a permanent part of the building structure. You use anchors and/or adhesive to hold the pedestals down, layout the floor panels, and put heavy and expensive equipment on top. That equipment runs 24/7 without a day off for years and years.
(Have you asked your landlord or building manager if they will even allow you to install a standard access floor; the anchors and adhesives can turn into major deal-breakers!)
The chances of removing all of that equipment and ripping out the floor are usually low, so the floor usually stays where it is. It's often fairly expensive to remove the panels, pedestals and stringers, so they are often abandoned or sold for scrap.
However, with the advent of low profile access floor, (also known as "Cable Management Access Floor") the industry has redefined what an access floor is and what it can do for you.
Of course we feel that our products are the best fit for most solutions, but no one is forcing you to choose one type of floor versus another. And, of course, our focus is on cable management first, raised floors second.
If you want a quick video guide to help learn some of the differences between some of our floors, this video is a great place to start. If you'd rather read about the differences in our low profile flooring products, this guide is what you'll want to check out first.
Your business needs are always changing, and a cable management floor makes it easy to re-route, re-deploy and grow with your business. Many of our customers have used one of our floors for several years, and due to company growth, have had to move to a new, larger location.
Yes, a low profile floor can be depreciated, but it can be reused, too!
An access floor can be a major asset to you and your organization, but you need an experienced vendor partner looking out for your best interests. Regardless of any product specifications or claims, make sure you have a trusted team member working on your behalf!
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