Mission Critical Earthquake Preparedness
December 07, 2018
New San Francisco data center underscores value of right enclosure specification.
For the first time since the early 2000s, a new colocation data center is planned for San Francisco. The 240,000-sq-ft campus at 400 Paul Avenue is expected to be developed into a premier data center property in a joint partnership between fifteenfortyseven Critical Systems Realty and infrastructure fund firm CIM.
Given the space and power constraints in the city, it is unlikely there will be another one in the next 10 years, according to fifteenfortyseven.
There are unique architectural and engineering challenges when building in a seismically active city like San Francisco, and with California’s Net Zero energy goals by 2030, the stakes are even higher.
Seismic areas require specific building codes and installation guidelines to ensure, primarily, the safety of people, but also the protection of expensive equipment. Add the fact that San Francisco has one the most expensive commercial real estate square footage in the country, with prices ranging from $600 to as high as $1,200 according to the San Francisco Center for Economic Development, and you have an expensive and challenging endeavor.
How can architects and designers guarantee they are specifying the right infrastructure elements, while making the best use of valuable real estate space? How will the colocation’s tenants ensure their space is not only compliant to California’s strict building codes, but also deploying the most amount of equipment in their leased space? Finally, how will the facility’s owners reap the most benefits from their rack space rental?
Here are a few important considerations to answer these questions:
SPECIFYING AN INFRASTRUCTURE FOR 10 YEARS DOWN THE ROAD
The California Building Code (CBC) requires that a licensed structural engineer design the components, supports, and attachments for nonstructural building components, such as equipment racks. This means an engineer defines the exact installation hardware, placement, and materials that attach the rack to the floor and, if necessary, how it will be braced overhead. The design must also include a calculation to determine the seismic load of the rack. With this design, any rack can be used in a seismic area.
FIGURE 1. Reputable manufacturers put their seismic cabinet through a shaker table test, as per Telcordia Technologies GR-63-CORE standards. Seismic testing includes a series of physical shaker table tests during which a loaded cabinet is placed through simulated 8.3 magnitude earthquake conditions.
However, the penalty may be a greatly reduced equipment load if you do not select a rack specifically designed for seismic applications. Racks that are specifically designed for seismic applications are more expensive than non-seismic racks, but they generally have higher load ratings and can be filled with equipment, whereas with non-seismic racks, multiple racks are needed to hold the same amount of equipment.
Additionally, many data centers in seismic areas choose to use an ISO base-isolation board under a row of cabinets, but this could be a real problem, says Steven Bornfield, senior data center consultant at Chatsworth Products.
“Because they’re designed to work on a roller base, they only help in earthquakes that move sideways. If you are in a zone with faulty waves that move upward and downward, you won’t get what you expect out of it,” he explains.
Most manufacturers only publish the static equipment load of their racks and cabinets in product specifications. Static loads range between 1,500 pounds to 3,500 pounds per rack, but it is important to remember that the static equipment load only provides the value for how much the rack can safely hold when still. It does not consider the effect of vibration on the rack. Seismic equipment load is calculated based on code requirements.
Racks specifically designed for seismic applications have heavily braced frames to resist side-to-side, front-back, and up-down motion. Reputable manufacturers load-test these racks on a shaker test table that simulates a seismic event to demonstrate rack performance, and verify their load claim.
The rack has to survive the test with no structural damage. Several standard shaker tests are available, but traditionally, rack manufacturers use the Telcordia Technologies GR-63-CORE, Section 4.4 test for rack and rack-mount equipment, as the video at http://bit.ly/2zqdjB8 shows.
COMPLYING WITH ENERGY EFFICIENCY CODE
The added challenge with data centers in California is Title 24 from the CBC, which specifically requires data centers to include some form of aisle containment as a way to save energy.
FIGURE 2. Here are a few key features to look for in a good seismic cabinet: high seismic load rating, wide range of thermal and cable management accessories, pre-drilled top attachment points for mounting overhead pathway and bracing, primary, and secondary anchorage points to provide flexibility in anchoring the cabinet to the floor, as well as OSHPD OPM design.
The benefits of airflow containment in data centers have been increasingly acknowledged by state and federal governments as a way to mitigate energy consumption in one of the most energy-consuming environments. When air recirculates and bypasses freely in the facility, server inlet temperatures change inadvertently, which not only damages equipment over time, but also takes away from cooling capacity. The way to alleviate this is to fully separate supply and return air with hot aisle, cold aisle, or cabinet-level containment.
Taking airflow containment into account is an important money-saving step when specifying and selecting a data center cabinet in California.
Suggestion: Shop around for seismic enclosures that enable proper airflow containment practices. Door perforation, enclosure width, and compatibility with airflow management accessories are important design elements to consider.
MISSION CRITICAL DATA CENTERS
Some facilities, such as hospitals and fire and police stations, are considered essential and are required to continue operation even after an earthquake. In California, hospitals and health care facilities must be certified by the Office of Statewide Health Planning and Development (OSHPD). OSHPD certification is based on requirements from the CBC as well as ASCE 7-10, Minimum Design Loads for Buildings and Other Structures, developed by the American Society of Civil Engineers (ASCE), which provides guidelines and specific calculations to prevent nonstructural components from sliding or overturning in the event of an earthquake.
Depending on the type of product, an OSHPD Special Seismic Certification Preapproval of Manufacturer’s Certification (OPM) may be required. OPM defines the product and installation practices that meet the most stringent requirements of the model code. If you are in the market for a seismic rack for a health care facility or tenant, use OSHPD’s OPM at http://bit.ly/2hQGTIx to short list a few of your favorite racks. Then, compare the details to find the highest seismic load. For permitting approvals outside of California, a local engineer makes the recommendation.
A SIGHT TO BEHOLD
When completed, fifteenfortyseven states, the two-story, tilt-up construction data center will provide a highly secure, scalable, and robust site with 24 megawatts of power capacity, delivered from dual power feeds via underground ducts from separate PG&E transformers, over 15 fiber networks delivering over 40 service providers from diverse paths to short list, and some of the most pristine space for tech support and office in the region.
In a city with limited space such as San Francisco, architects, engineering, tenants, and facility owners should invest on seismic-rated cabinets that can safely carry high equipment loads of as much as 1,500 pounds while meeting building, design, and energy efficiency codes.
By Raissa Carey, CPI Technical Writer
This article was originally published on the December 2017 issue of Mission Critical Magazine.