Nick Campey, national accounts manager, of Andrews Air Conditioning looks at the options available for hiring air conditioning units

With £millions worth of sophisticated IT equipment at stake, and a risk way beyond financial calculation in terms of business continuity, data centres are probably the most fragile air-conditioned environments in the commercial world.  Indeed, the fixed air conditioning systems specified for such applications are often extremely sensitive and advanced, with additional cooling capacity built in to the system to minimise the risk of equipment over-heating.  What’s more, most data centres have a standby system that will kick in if the main air conditioning units fail, reducing the risk still further.

The problem is, there is never a fail-proof system and failure to have a contingency plan in place can be extremely costly indeed, both financially and in terms of risk to a business’s reputation.  That’s because when a data centre goes down, huge amounts of data can be lost within hours, leaving the company with front of house issues as well as the problems associated with getting the data centre back up and running again. While the risk remains small, the pace of advancing technology means that many data centres may gain additional, increasingly sensitive equipment by stealth, making it easy to over-stretch the existing air conditioning installation. Add to this environmental factors such as periods of hot weather and fluctuations in data centre activity and it’s easy to see how issues can arise quickly and without warning.

The very fact that a rise in temperature can happen so quickly, and have such a devastating effect on equipment within a very small time frame is the reason that data centres need to have a contingency plan in place to counter the risk of air conditioning system failure.  An increase in temperature of just two or three degrees can cause irreparable damage within a few short hours, so companies managing data centres not only need to monitor the temperature accurately and regularly, they also need have a recognised process in place in case the data centre does begin to overheat.  For many companies, however, this process is often simply to pick up the yellow pages and contact the nearest equipment hire company.  While most hire specialists will do what they can to deliver suitable equipment to site as soon as possible and have it up and running quickly, there are no guarantees that they will be able to respond with the most appropriate kit within an acceptable time frame.  And when the damage to equipment in the average data centre can be measured in £100Ks per hour, a fingers-crossed-they’ll-have-the-air-con-units-we-need approach simply isn’t good enough.

Instead, an increasing number of companies are calling in HVAC hire specialists before the need for temporary air conditioning arises, so that they can be properly prepare if and when they do need help.  In this way, the hire specialist can complete site visits when the data centre is operating as usual and assess the cooling load, determining the areas that are most at risk and specifying the most appropriate kit to go in for a variety of scenarios.  This approach not only means that everyone knows the drill if there is a problem, giving the client peace of mind and the hire specialist a head start on installing the right kit in the best spot, it also means that there are no last minute snags on site.  For example, the site survey will cover any potential issues with access to the building or delivery restrictions, it will ensure that they have named contacts on the estates team and a full breakdown of where both the air con and the condenser units are to be positioned.

In general terms, there are two types of cooling units that are most suited to data centre environments: portable water-cooled ‘split’ air conditioning units or larger chiller units.  The PAC 22 6.5 Kw unit is by far the most commonly specified air conditioning unit for data centre applications because its condenser unit can be positioned up to 30m away from the cooling unit, ensuring that warm air is diverted well away from the data centre.  Indeed, for many fast turnaround data centre applications, putting several PAC 22 units in place is often the most flexible solution.  For more long-term hire requirements when significant chilling power is required, larger chillers may be more appropriate.  Offering multi megawatt chiller packages, these units are often sited outside the building with services routed through air handling units.

For some companies, even knowing what type of units their hire specialist will position where is not preparation enough for the level of risk involved.  They may choose to pay a ‘standby’ hire rate to reserve the relevant kit or even to have it on site in a dedicated ‘holding area’.  Paying for standby hire equipment they may never need may seem a little ‘belt and braces’ but, when the stakes are so high, data centre managers taking this approach are not only investing in thorough risk management but in peace of mind.