ASHRAE: Best Practices for Environmental Monitoring of Humidity and Temperature

Jessica Ciesla
July 18, 2019

Data centers now consume an estimated 1.8 percent of electricity within the United States. As energy consumption has risen, so too have the associated costs. These costs, coupled with the fact that approximately 30 percent of data center servers are either idle or underutilized, have resulted in unnecessary expenses that could have been mitigated with the right environmental monitoring best practices. These best practices include monitoring temperature and humidity in accordance with ASHRAE 90.4. 

What Is ASHRAE 90.4 ? 

In its simplest forms ASHRAE 90.4 is a new standard that is designed to help data centers effectively monitor temperature and humidity levels so that downtime is reduced, and enhanced efficiencies can be introduced. This standard focuses on the use of on-site and off-site renewable energy. It uses both Mechanical Load (MLC) and Electrical Loss (ELC) to better determine the maximum allowable values for climate zones. At its core, ASHRAE 90.4 helps data center managers understand when they are undercooling their machines and operating at detrimental humidity levels, so that power utilization can be enhanced for the entire data center. 

What Are The Best Practice Approaches For Monitoring Temperature And Humidity Within A Data Center?

It's no secret that data center servers need to be operated within the temperature safe zone. Unfortunately, in an era when an overheated server can cause tens of thousands of dollars of damage during a period of downtime, far too many managers choose to undercool their data centers. The financial irony is that if data centers were only one degree closer to the temperature safe zone, then they could save an estimated four percent on energy costs.

Instead of using solely PUE levels as the designated standard, data center managers should take the time to check ASHRAE T.C. 9.9 for the servers' optimal operating temperatures. ASHRAE standards recommend that there are three sensors per rack. These sensors should be mounted at the top, middle, and bottom of the rack to more effectively monitor the surrounding temperature levels. In the case of a hot or cold aisle, the use of a sensor at the back of the cabinet could provide valuable insights, which could further dictate the most effective air flow containment strategies for each aisle. Finally, if managers want to further reduce downtime and improve efficiencies, then they should also track rack cabinet exhaust metrics, server temperatures, and internal temperatures. The latter readings can help a response engineer more effectively address issues in real-time before they cause a costly outage. 

As part of ASHRAE best practices, data center managers should also monitor humidity levels. Just as high temperatures can increase the risk of downtime, so too can high humidity create increased levels of condensation and thus a higher risk of electrical shorts. Conversely, when humidity levels drop too low, data centers are more likely to experience Electrostatic Discharge (ESD). To mitigate the latter issues, ASHRAE best practices state that managers should avoid uncontrolled temperature increases that lead to excessive humidity levels. Humidity levels within server rooms and across the data centers should stay between 40 percent and 60 percent Relative Humidity (rH). The latter range will help to prevent ESD, lower the risk of corrosion (due to excessive condensation), and prolong the life expectancy of equipment. 

Install Temperature Sensors Today To Effectively Monitor Humidity And Temperature

Implementing ASHRAE best practices is made easier with the right temperature sensors and intelligent PDUs. Raritan's Intelligent PDUs and environmental sensors are designed to monitor temperature and humidity levels throughout the entire room and at individual servers. Through real-time alerts and remote on / off capabilities, the right temperature sensors and intelligent PDUs can help data center managers lower the risks of outages, reduce energy costs, maximize profits, and mitigate environmental risks. Contact a Raritan team member to discover the ideal environmental monitoring tools for your data center.

To learn more, visit us here.