{"id":14879,"date":"2019-03-19T11:00:22","date_gmt":"2019-03-19T19:00:22","guid":{"rendered":"https:\/\/www.palada.net\/index.php\/2019\/03\/19\/news-8628\/"},"modified":"2019-03-19T11:00:22","modified_gmt":"2019-03-19T19:00:22","slug":"news-8628","status":"publish","type":"post","link":"http:\/\/www.palada.net\/index.php\/2019\/03\/19\/news-8628\/","title":{"rendered":"Getting it Right – How Much Air Containment is Enough in Your Data Center?"},"content":{"rendered":"

Credit to Author: Victor Avelar| Date: Tue, 19 Mar 2019 18:00:10 +0000<\/strong><\/p>\n

This is a common question we\u2019ve heard enough times that we decided to test containment across a range of \u201cleakiness\u201d and came up with some practical guidance.<\/p>\n

You may have heard the term \u201cpercent leakage\u201d as a means of assessing the effectiveness of a hot or cold aisle air containment<\/a> solution. But what does this actually mean? How would you measure it or validate a particular claim in your own data center? Does this percent leakage spec correlate to your desired data center operating temperature range? You may be paying for a tighter tolerance than what is really needed. Or worse yet, paying for a \u201ctight\u201d solution that doesn\u2019t perform in practice as it did in a test lab. From reading this blog, you\u2019ll learn some practical metrics and practices you can take to ensure that your IT equipment stays cool and your energy bills low.<\/p>\n

What is \u201cpercent leakage\u201d?<\/h2>\n

I searched for containment-related documents that included the term % leakage and I found two loose definitions in that they weren\u2019t specific on the criteria. One is percent leakage as the open area (the holes) of a containment surface as a percent the total area. Do you include the racks in the surface area or only the containment structure? As well as top of racks? Is this with no IT equipment installed? This variable significantly changes the percent value.<\/p>\n

\"Hyperpod\"Another defines percent leakage as the amount of air that \u201cleaks\u201d as a percentage of air required by the IT equipment at a given pressure difference (deltaP) between the hot and cold aisle. By \u201cleak\u201d they mean air that either bypasses<\/em> the server or is over supplied through<\/em> the server. Furthermore, these documents specify percent leakage values of no more than 3%, less than 5%, etc.<\/p>\n

The variables when measuring percent leakage<\/h2>\n

On the surface, a percent leakage specification seems logical, but in practice, not so much. Imagine you just finished your containment project and you had to validate a percent leakage value. How would you practically validate that only 3% of the surface area was open? How would you validate that only 5% of air was bypassing the servers? How would you know if some of this \u201cbypass\u201d air was forced through the servers? What if you used a different number of racks than what the specification assumed? The leakage flow rate is directly proportional to the number of racks. Note that the racks tend to be the leakiest element in a fully contained pod. So, there\u2019s no point in installing containment that\u2019s significantly tighter than the racks.<\/p>\n

These metrics fail to provide a consistent basis for comparison across all pod configurations. Here are just some of the variables you\u2019ll find in a production environment that complicate a percent leakage validation:<\/p>\n