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Part 2: Commissioning: Best Way to Ensure Data Center Reliability
By Sunny Puri and Michael Kuppinger
August 2009 -
While energy efficiency is important today, reliability still is the most important factor in data center design. The design of the Allstate data center fused both goals into a single solution.
The highly reliable infrastructure design eliminates any single points of failure and employs total redundancy where necessary. The initial load of the mechanical system is 2N redundant with multiple distribution pathways to the end equipment. With three chillers installed but only two needed to operate the load on day one, equipment redundancy accounts for potential failures and maintenance needs. The 2N electrical system, which employs three generators for a load that is less than or equal to two generators on day one, provides for both future expansion and potential emergencies with fully redundant, multiple pathways to the equipment.
Both the data center’s mechanical and electrical systems were designed with space and infrastructure provisions that make it easy to add additional components as the data center’s load grows and technology evolves. Modularity was imposed, leaving empty spaces to accommodate new equipment, including two additional UPS systems, one additional generator and one additional chiller. The rationale for designing the data center in this way was straightforward: It would not only save Allstate money in the short term by not installing unnecessary equipment, but also cuts costs down the road by accounting for expansion and greater infrastructure needs upfront.
As the economy fell into recession, however, equipment prices dropped, and Allstate decided to install all equipment prior to initial move in. Even with installation of additional components, the project came in 4 percent under budget.
Achieving no single point of failure in either the mechanical or electrical system infrastructures not only promotes reliability within the data center, but also allows the facility to function without its utility feed should the need arise. The facility was fashioned with an on-site water well and generators that allow it to subsist completely on its own in the event of a disaster for at least 72 hours before needing to be refueled.
Contrary to popular belief, facility design doesn’t end where construction begins. Instead, cutting edge systems need to be commissioned to assure proper efficiency and operation prior to opening day. MEP systems were tested before computer equipment entered the building to assure operability. Load banks were brought in to simulate demand, and the utility was allowed to fail, requiring the elevation of back-up generators. Another test introduced a large amount of heat into the space, uncovering potential leakage from one space to another. Running the UPS system and batteries eliminated any unwanted surprises, while an integrated systems test evaluated the data center’s mechanical and electrical systems simultaneously to measure overall impact on the facility when both single and multiple components failed at once.
As is customary, a third-party commissioning agent followed up with similar testing on behalf of Allstate as well, providing another check on the facility’s systems prior to occupancy.
Sunny Puri, P.E., LEED AP, vice president, Environmental Systems Design, has over 10 years of design and commissioning experience in the mission critical and data center environment.
Michael Kuppinger, P.E., senior vice president, Mission Critical and Technology Group, Environmental Systems Design, has over 20 years of data center experience. Kuppinger is a past president of the 7x24 Exchange, Lake Michigan Region Chapter.
LEED Gold Data Center?
Part 1: Allstate Aims for Improved Reliability and Flexibility with New Data Center
Part 3: Data Center Operations Require Increasing FM, IT Collaboration