How High Should Your Access Floor Be?

You're standing on the threshold of the building.

Behind you, red-brown dirt covers everything. Skinny trees are propped up by string and wooden stakes. The sky is blue and clear. The beep of a forklift ruins the moment.

In front of you, a new building, every surface covered in drywall dust. Otherwise, the interior is pristine.

Countless meetings, conference calls and issuing last-minute addenda made this moment possible, and it was all completely worth it.

You get everything you wanted. Your department gets everything it needs. Business is good and the customers who visit will certainly be impressed by the design.

You take a step forward and remember the conversations about the raised floor.

Should it be two feet high? "No," someone says. "We need at least three feet."

"I saw another site recently and their floor was only 6 inches high." "Well I've seen a floor that's six FEET high."

That meeting was beginning to sound like a children's book.

Other pressing matters were brought up and somehow, someone decided the access floor should be a foot high. It seemed like a good compromise. After all, one person said, a foot was the industry standard. At least one architect nodded in agreement.

Your first stride onto the floor should have been perfect, but choosing the right access floor had been too damned hard.

It was a painful step.

How You Get Forced Into Someone Else's Standard

Architects and engineers have hard jobs, there's no doubt about it. But as a cost and time-saving measure, many aspects of a building are reused from project to project.

Why layout a new conference room when the CEO wants his office to have custom features that take more time to design?

Why bother with the height of the raised floor when the electrical engineer has to figure out the new video conferencing network schematic? Just specify the standard raised floor and call it a day.

And it works. For some people. Some of the time.

If you have visited our website before, you know we are passionate about access floors. We believe they can completely change the way business professionals work. So when we hear about a "one-size-fits-all" design being considered, a huge red flag goes up in our office.

It's not that architects and engineers are doing it wrong (who are we to judge?) But there certainly is a better way.

(Ok, we admit, some of them do it wrong. But that's for another post!)

Are you a "standard" company? Do you follow the herd? If you do, you won't for long; you'll be out of business!

I'm willing to bet you work for an exceptional company. Whatever industry you're in, there's something unique about your go-to-market strategy. I'm willing to bet again that a lot of it has to do with your people and your processes.

If so, you shouldn't be forced to work in an office that was designed for a regular company, and you shouldn't manage cables like everybody else does.

How High Should You Aim? (Just High Enough)

If you aren't pumping cold air under your floor, why do you need several feet of space down there?

After all, you're just running wires and cables under the floor because you don't want the hassle of running them overhead.

If this describes your building (and this includes 99% of all buildings), you don't need a tall raised floor.

So how high is high enough? Two to three inches should be enough for the majority of all users.

Keep in mind, the lower the floor, the easier maintenance will be, and the less ceiling height you will waste.

If you want some hard data on how many cables you can fit into a low profile access floor, take a look at the test we performed at our office.

In reality, though, it usually comes down to how you are managing and distributing the cables, and not the raw amount of cables you can cram under a floor.

The limiting factor is usually access points: How are your users accessing the cables? Through a cable grommet? An in-floor electrical box?

When choosing a floor, pay special attention to how the wires will be distributed and terminated. No matter how high the floor is, if you still have to run a patch cable on top of the carpet from a cubicle to the nearest power box, you are losing the cable mangement benefits you paid for.

Underfloor Airflow

This is a complex topic, and is deserving of its own article. As luck would have it, ASHRAE (American Society of Heating, Refrigeration and Air-Conditioning Engineers) has done just that!

If you want some light weekend reading, go ahead and pull out your trusty copy of the 2011 ASHRAE Handbook - HVAC Applications, and turn to section 19.9 (Air Distribution).

If you have better things to do, like watching the grass grow, let me highlight some important pitfalls you should watch out for:

• Airflow Inlet Delivery Concerns
• Pressure Variations
• Height of Raised-Floor Plenum
• Collision or merging of airstreams
• Flow disturbance caused by underfloor blockages

If you know you absolutely need underfloor air distribution, you're probably running a data center and are well aware of these drawbacks.

At Netfloor USA, we have standard access flooring products that are used for data centers. These floors are often several feet high and allow plenty of space for cold air to flow.

If you are on the fence, and aren't sure you want to give up the option of underfloor air distribution, please consider this quote from ASHRAE 19.10:

Often, the underfloor plenum is used for cables, electrical conduits and pipes. These obstructions in the plenum can interfere with airflow. When determining plenum depth, below-floor obstructions must be considered.

In order to take that little gem and apply it to your specific application, you need to hire a mechanical engineer who specializes in data centers. But the general idea is that you need leave enough room for proper airflow after you have subtracted the space used by everything else, like pipes and cables.

It seems like common sense, but I've seen far too many facilities with virtually zero space left for airflow. They often contacted me because they were experiencing airflow issues. I'd like to think of myself as somewhat of an expert, but it doesn't take a rocket scientist to see the mess of cables is blocking airflow.

Here's the bottom line for airflow and raised floors. If you can avoid it, you should. Once you eliminate underfloor airflow, you've eliminated the need for a tall raised floor. You've entered the world of: cable management flooring (cue dramatic music).

Follow the Crowd (But Do Your Own Thing)

99% of the buildings in the U.S. (and the world, for that matter), aren't data centers and don't need underfloor air distribution.

And that is a huge area of growth for cable management floors: normal, everyday buildings with some computers, communications equipment and power requirements. These are buildings with people in them, not computers.

Many facilities managers, designers and operators are realizing the ease of operations afforded by low-profile, cable management floor.

The cool thing about low profile floors is they fit in so well with the rest of your building. They only take up a few inches of height. You can build walls on them. You can put cubicles and bookshelves on them. There're a variety of floor finishes from bamboo to terrazzo to marble (and simple carpet, if you're a vanilla type person).

So just how high should your floor be? If you're using the right type of floor, it no longer matters.

Do you need help on your next design? Want to know what type of floor we would recommend for you? Give us a call (866-986-2661), email or use the contact form and let's see how we can help you!