Structures and equipment installed in Data Centers located in seismically active regions must be designed to protect the operating equipment in the event of an earthquake. There are two standards by which enclosures are deemed seismically qualified. Telcordia Technologies GR-63-CORE Network Equipment Building Systems (NEBS) requirements and the International Building Code (IBC). These standards are used to achieve the seismic certification to comply with specific code requirements.
Clark Testing’s seismic laboratory provides seismic certification for BELCORE GR-63-CORE or Telcordia GR-63-CORE. During the test, an enclosure is loaded to its capacity and mounted to Clark’s Tri-axial seismic shaker table. The shaker table simulates an earthquake, shaking in three directions (one direction at a time) at varying levels of intensity equivalent to an earthquake in a particular seismic zone — Zone 1 is the least intense; Zone 4 is the most intense.
Clark lab technicians install instrumentation including accelerometers and strain bolts to the enclosure to measure important parameters of the seismic test. The accelerometers measure the speed and direction of the test equipment and the strain bolts measure the structural load changes of the test component. In order to pass the test and achieve the seismic rating, the enclosure must not sway more than 3 inches in any direction and all components must remain operable during and after the test.
The Seismic table at Clark Testing is capable of performing seismic testing on large packages up to 20,000 lbs. at 1g ZPA. The table can achieve 3g’s ZPA up to 10,000 lbs. & 5g’s for lower weight. The table has three (3) independent servo hydraulic actuators with 38,000 lbs. force +/- 5” stroke with peak acceleration of 15g – 18g.
Seismic enclosure standards are often specified in terms of the earthquake risk zones. As shown in the seismic map, zones vary from 0 to 4 – with the zone 0 designating no substantial risk. Zones 3 and 4 are generally viewed as regions where Seismic enclosures are needed.