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How Cable Management and Airflow Management Impact Each Other in Data Centers

How Cable Management and Airflow Management Impact Each Other - Cable Management Blog

Here’s the simple truth of the matter. Cable management can impact airflow management , and airflow should definitely inform the method, type, and execution of cable management. To understand how the two impact each other and what the best overall solution will be for your data center, it is important for use to take a look at cable management and airflow from a high level perspective.

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How Cable Management and Airflow Management Impact Each Other
Airflow is an Important Factor in Data Centers

The Goal of Airflow Management

So what is the goal of airflow management? The goals are twofold: preventing large variations in air temperature and air pressure. This means separating supply air mass and return air mass through design.

Just grouping cables together with a zip tie does nothing to facilitate this and can actually result in a serious disruption of airflow. What happens as a result? Lower fan efficiency, higher HVAC costs, potential changes in pressure, and even equipment damage or failure.

The current problem? Because more people are working from home or adopting the work from anywhere culture as a result of COVID, data centers are having to increase capacity, and they may not have additional floorspace to accommodate more server racks. Since conventional cable management can use up as much as 25% of rack space, this means that intelligently designed rack cable management is more important than ever.

Because of this it is important that cable management and airflow be looked at as an entire package. There are two areas of cable management in a data center: cable management in the room itself, essentially the cables that run between server racks, and rack cable management.

Cable Management in the Room

Of course, we must manage the cables that run between server racks, and they have to go somewhere. There are essentially two approaches, and both can create unique issues. They are running cables under the floor or running cables overhead.

Perhaps the most common is underfloor cabling where the underfloor space is also used for cool air transport. This is usually a very efficient method for separating supply and return air masses. However. When you put more holes in the floor, say to accommodate more server racks, the risk of “bypass air” or mixing the two airflows increases.

Why not just go with overhead cable management then? In some cases, this works exceptionally well, although there are budget and logistical obstacles. The height of the cable pathway is also often an issue.

Think of it this way. If your data center uses the underfloor space for air system management and not cable management, overhead pathways are fine. If they are placed too high though, the warm return air underneath can actually get too turbulent, resulting in a mix of the supply and return air. This created a temperature bypass.

But this bypass also can increase variations in pressure throughout the data center, causing the fans and other mechanisms to work harder. It’s a delicate balance.

Rack Cable Management

There are a lot of best practices and industry standards for airflow and cable management between servers, but often rack cable management falls into the “out of sight, out of mind” category. That’s a mistake, as cable management at this critical point can have a huge impact on airflow management.

While this seems like it should be common sense, the practice of good rack cable management seems to be hit or miss. As early as 2002, research done by Paul Artman, David Moss and Greg Bennett (Dell PowerEdge 1650: Rack Impacts on Cooling of High Density Servers) showed that poorly bundled cables, overloading cables on a horizontal lacing bar (particularly 1U configurations) could result in as much as a nine degree increase in component temperature.

This is a good argument for ZeroU rack cable managers and other more advanced techniques. Also, more data centers are moving to 23” or larger racks as opposed to the standard 19” racks, because equipment manufacturers are constantly increasing the computing power per U space. As a result there are more cables per rack. As cable bundles get larger, they also need more space between them to increase airflow.

For some components that possess a single fan intake side and hot-switchable components on the other, there is really only one path for cables to go. Careful cable management means not only ensuring that the fan intake is not blocked, but that there is an airflow egress as well. Often specialized chimney cabinets that allow air to enter both the front and the rear of the cabinet can be used for these applications.

The Effect of Poor Cable Management

Poor cable management, whether cables between server racks or rack cable management, will negatively impact airflow management. More than just the increased costs associated with HVAC systems, poor airflow can also lead to premature equipment and cable failures, overheating, and even increased downtime.

5 Ways Effective Cable Management Benefits Your Data Center - Cable Management Blog
A ‘Spaghetti Mess’ of cables blocks network rack airflow very effectively!

Since uptime is the most important metric to most data centers, cable management solutions need to be an integral part of any planned data center and prioritized expansion.

Devising a Comprehensive Solution

What’s the solution? The best path is to be proactive rather than reactive. Plan airflow management and cable management together as part of an overall data center plan. Be sure you and your staff have the right tools and materials. This not only includes the right racks and rack cable management tools like ZeroU rack managers and chimney racks where needed, but things like Velcro, wire tags, and even colored zip ties to keep things organized.

If you do have to do a sudden expansion due to increases in demands, bring in the whole team and listen to everyone’s ideas. Use industry best practices where possible, but understand that creative solutions and innovation may be necessary in extraordinary times.

Do you have questions about effective rack cable management, or do you need tools and supplies to get started? Contact us here at AnD Cable. We have the materials you need and the know how to help you select the best product for your situation.

WHITEPAPER – Understanding Stranded and Solid Conductor Wiring in Modern Networks

Understanding Stranded and Solid Conductor Wiring in Modern Networks - AnD Cable Products Whitepaper

An overview of the differences between stranded and solid conductor wiring, the properties of each and the best cable type to use in a variety of typical settings.

  • Types of Stranded and Solid Conductor Wiring
  • Comparison of Electrical Properties
  • Factors Impacting Attenuation / Insertion Loss
  • Choosing the Right Cable

About the Author

Louis Chompff - Founder, AnD Cable Products, Rack and Cable ManagementLouis Chompff, Founder & Managing Director, AnD Cable Products
Louis established AnD Cable Products – Intelligently Designed Cable Management in 1989. Prior to this he enjoyed a 20+ year career with a leading global telecommunications company in a variety of senior data management positions. Louis is an enthusiastic inventor who designed, patented and brought to market his innovative Zero U cable management racks and Unitag cabel labels, both of which have become industry-leading network cable management products. AnD Cable Products only offer products that are intelligently designed, increase efficiency, are durable and reliable, re-usable, easy to use or reduce equipment costs. He is the principal author of the Cable Management Blog, where you can find network cable management ideas, server rack cabling techniques and space saving tips, data center trends, latest innovations and more.
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