Specifying Equipment Racks for Seismic Environments
March 17, 2009
The below information was taken from an article in Equipment Protection Magazine, written by Alan Taft, CPI Sr. Product Manager. Download the entire article in PDF format.
On any given day, per the National Earthquake Information Center (NEIC) our earth experiences approximately 25 earthquakes with a magnitude of 2.5 or above on the Richter scale
The highest risk areas within the United States are Hawaii, the entire west coast including the southern region of Alaska, the area around St. Louis, Missouri, the border between Utah, Idaho, Wyoming and Montana and areas around Charleston, South Carolina. Internationally, the west coast of Central and South America, Japan and the islands in the western Pacific Ocean south of Asia and east of Australia, central and western China, the area around Afghanistan, Turkey, Greece and southern Europe are the highest risk areas. Data centers built within these seismically active environments require specialized equipment and racks with special mounting specifications.
The commonly accepted standard test to certify compliance of a rack with zone 4 seismic events is defined by Section 4.4, “Earthquake, Office Vibration and Transportation Vibration” of Telcordia® Technologies, Inc. GR-63-CORE Network Equipment Building Systems (NEBS) requirements for Physical Protection. Seismic equipment racks are typically designed to secure 500 pounds (227 kg) with some models available up to 1000 pounds (454 kg) of evenly distributed equipment.
The chart above is from an actual GR-63-CORE test on a Chatsworth Product, Inc. (CPI) seismic rack (the Seismic Frame® Two-Post Rack). It depicts the amount of rack side-to-side deflection observed over the test period. The maximum deflection allowed per GR-53-CORE is +/- 3.0 inches of rack movement from its original position. The chart shows the actual tested deflection at only 1.0 inch, which is well within the NEBS maximum allowed specifications.
This video shows the above rack being tested.
It is vitally important that hospitals and critical data centers have equipment that has been seismically rated and installed per the manufacturer’s and Structural Engineers recommendations. It is equally important to ensure that the rack is properly mounted within the particular building. Fasteners and anchors with a high shear and high tensile strength rating should be selected to secure the racks. When mounting to concrete floors it is extremely important to choose seismically rated floor anchors that have been rated to support the load of the rack, equipment and overhead cable pathways.
Download the entire article to get full details on the following key areas:
- Cable Management and Pathways
- RMU Markings
- Screws or Cage Nuts
- Rack Height / Widths
- Electrical Boxes
- Shelves / Trays
- Cable Fingers
- Vertical Power Strips
CPI's Seismic Frame® Two-Post Rack meets the criteria listed above. If you have comments or questions about the information in this article or seismic concerns, please leave a comment using the “Comment” link below.