The need to optimize airflow in the data center is becoming increasingly important as heat load densities continue to rise above beyond the average 6 to 7 kW per rack.
While best practices like reducing cable congestion, using a hot aisle/cold aisle configuration or deploying a containment strategy are ideal ways to help manage passive airflow, cabinet doors play a key role.
And when it comes to choosing a cabinet, it’s important to look at all the features of the door.
There are two separate variables to consider that determine the air resistance characteristics of a cabinet door—perforation pattern and total perforated area.
The holes of the perforation pattern can be round, square or hexagonal, and their size and position determines the open percentage of the pattern. While a 63% open perforation pattern was once considered best practice, a 78% open perforation pattern is now becoming mainstream.
The other variable that should also be considered is the total perforated area, which is the area of perforation compared to the entire door, including the frame. For example, you may have a cabinet door that offers a 78% open perforation pattern. But if the perforated area is surrounded by a very thick frame, you might not be getting as much airflow as you think. In fact, because active equipment is designed to pull air in from all sides, not just straight, a thick frame on your cabinet door will restrict the airflow.
So both the perforation pattern and the total perforated area of the door need to be considered – while these two variables are independent of one another, it is the combination of both that impacts overall airflow.
And if you are deploying ducted air containment that requires a solid rear door, make sure it has continuous gasketing that provides a complete seal around the door perimeter to prevent hot air leakage.
The risk of using a higher open pattern perforation percentage is a weak perforated area that is easy to cut through and therefore a security threat. In addition, the total perforated area is limited by the structural needs of the door—a frame that is too thin or of weak material can cause a flimsy door. So when reviewing the quality of a cabinet door, you also need to consider the overall rigidity of the door.
Hinges also play a critical role in security and should not be accessible when the cabinet door is closed. They should also be secure enough to prevent forcing of the door on the hinge side. At the same time, hinges should allow doors to be easily removed by authorized personnel when needed and provide a 270-degree swing for end-of-row or stand-alone cabinets to prevent unsafe aisle blocking. For high security environments, another feature to consider is an access control option that requires cards or biometric information for access.
There is yet another point to consider—door shape. Not only does a bowed door offer an attractive curved shape for a sleek, high tech look for modern data centers, but it also offers more space in the front of the cabinet than a flat door.
While it may seem insignificant, the additional clearance provided by a bowed door is well suited for high-density patching environments. It eliminates concern that the door is placing pressure on the cables and preventing airflow. Options like dual-swing doors can also be ideal for cable management in high-density environments.
While it might seem like a stretch to find all of these features in a single cabinet door, the new doors on our Belden X-Series data center enclosures hit the mark with optimal airflow, strength, security and functionality—all in a simple yet sleek, durable and cost-effective design.
Mike Salvador is a 28-year industry veteran, living the challenge of operating efficient data centers, optimizing the performance of network devices and delivering highly available, highly agile, low-risk data centers. Mike served as Belden’s technical solutions manager from 2012 to 2015.