There are several reasons for data center managers to perform a routine inspection of their subfloor plenum. Even though the subfloor plenum is often hidden from the day-to-day field of vision, it is vital to understand what may be happening under the raised floor that can cause unwanted downtime. It is similar to the idea of routinely “checking under the hood” of an automobile. It’s a good idea to inspect things that are not normally seen that will ensure the continuous and uninterrupted operation of your car. When inspecting the engine compartment, one should visually inspect belts, filters, fluid levels, and look for any signs of maintenance that may be needed.

Regular Inspections
Likewise, the same holds true for the data center’s subfloor plenum. A regular inspection will help facility managers understand the condition of their data center’s subfloor plenum so they can take corrective action if needed. So how often should a facility manager inspect the subfloor plenum, and what should they be looking for?

Recommended Frequency
We recommend that the subfloor plenum be inspected on a quarterly basis, but at least once per year at a minimum. There are several things managers should look for when performing an inspection. One of the first things we recommend is inspecting the raised floor support structure. Repairs and maintenance should be performed for any pedestal or stringer that is missing, broken, or leaning. Sometimes, an uneven floor panel can be the result of a larger issue in the foundation and may need to be addressed by an engineer.

Through Holes
Another area to keep an eye on is the firewalls around the perimeter of the data center. Look for any holes that may be allowing air to escape or contamination to enter your plenum. Even worse, in the event of a fire, penetrations in the firewall will allow smoke and fire to pass into the data center. Holes should be sealed with the proper fire-stop product. The product you select should be dictated by the size of the hole and the local fire code.

In addition to holes in the perimeter walls, look for unnecessary cutouts and holes in raised floor panels. These holes allow cool supply air to by-pass servers and create inefficiency in your cooling system. Use brush floor grommets to seal small holes. Fire-rated foam may be used for larger holes. Also, look for any unnecessary airflow panels or grates. If they are not cooling a specific cabinet, then replace the airflow panel or grate with a solid raised floor panel.

CRAC Units
Another area to inspect is under CRAC units. The presence of liquids can be an indication that corrective maintenance needs to be performed. Also, look for accumulating dust and debris in that may be harmful to servers if it becomes airborne. CRAC unit drive belts have been known to create a sticky black dust when out of alignment. This can be a serious problem for servers and other sensitive equipment.