Seismic Rack Cabinets

Earthquakes are not limited to the state of California, nor are they infrequent. Seismic events take place every day throughout much of the continental United States. In many cases, millions of dollars worth of technology depend on the quality and installation method of the seismic rack that it is stored in. Most manufacturers of seismic racks and enclosures offer products that are marketed as offering “seismic protection”; however, there can be significant differences in the standards used to achieve those labels, and thus, major disparities in the level of protection that those products provide.

seismic enclosures

seismic rack cabients

Learn more about the differences between seismic ratings by downloading our Seismic Rating Comparison Chart, reading our White Paper or by clicking the tabs below.

Emcor Seismic Cabinets Information


IBC Enclosures
The International Building Code (IBC) is a set of guidelines which describe how to properly secure objects -in this case enclosures- so that they do not tip over and cause injury to anyone during an earthquake.
Telcordia GR-63 Enclosures
GR-63 describes the protection level of an enclosure. It requires an enclosure to provide a level of protection such that the equipment inside shall sustain operation without replacement of components, manual rebooting, (or) human intervention during an earthquake.

Historical Base

IBC Enclosures
Following the 1994 earthquakes in Los Angeles, during which more than 40 percent of the $80 billion in damages were non-structural, it became apparent that there was a need to create guidelines for securing objects  to the floors, walls or ceilings of buildings. In 2000, the IBC was created as a guideline to which businesses must adhere in order to receive funding from the Federal Emergency Management Agency (FEMA) in the aftermath of an earthquake.
Telcordia GR-63 Enclosures
In the years following AT&T’s monopoly lawsuit, a flood of competitive local exchange carriers arose, bringing a slew of new and varied network equipment to the once homogenous collection of AT&T equipment housed in central offices throughout the country. As a result, standardized network equipment were established to ensure network compatibility and uptime. What came to be were the NEBS requirements, of which, section GR-63 applies specifically to protecting equipment in the event of seismic activity.

Test Procedures

IBC Enclosures
The most common IBC test procedure uses a mathematical equation that compares potential seismic effects to objects mounted in a building. These calculations determine how the enclosure must be secured or installed in the building. A value called the “seismic design category” is assigned based on the building’s location. This is calculated based on the distance of the building to the anticipated location of an earthquake as well as the type of soil beneath the building, and on which floor and the type of floor the enclosure will be mounted. The building is also given an “importance factor” value, which is either 1.0 or 1.5. The essential value of 1.5 would require that the electronics continue to function in the event of an earthquake whereas the non-essential value of 1.0 would simply require the enclosure to remain standing. Crenlo currently offers a solution for non-essential buildings or 1.0.
Telcordia GR-63 Enclosures
To achieve GR-63 compliance, enclosure manufacturers turn to independent, third-party testing facilities. An enclosure is loaded to capacity and mounted on a shaker table. The shaker table then simulates an earthquake, shaking in every potential direction at varying levels of intensity up to the equivalent of an 8.3 earthquake. Accelerometers are attached to the enclosure to measure its vibration and sway during the test. In order to pass the test and achieve the seismic rating, the enclosure must not sway more than three inches in any direction and all components must remain operable during and after the test. This test is the same for every enclosure manufacturer, regardless of where that enclosure is going to be used or its intended purpose. Crenlo currently offers seismic rated enclosures that are GR-63 compliant.

The Maps

IBC Enclosures
In addition to viewing the entire continent as a series of potential seismic locations the specification “IBC” has resulted in maps that measure potential seismic activity within given locations relative to identified fault lines.  For localized seismic information The “IBC”  has maps which define the probability of earthquakes within 100-foot sections relative to fault line locations.

IBC Seismic Risk Location Map

Telcordia GR-63 Enclosures
A seismic zone map is based on a statistical compilation of the number and the magnitude of past earthquakes.  These maps show an indication of where the next earthquake is most likely to occur, how frequently they occur and their magnitude. There is NO direct correlation between seismic zone ratings and Richter scale recordings, although past experience shows the worst earthquakes occur in the higher rated seismic zones.

Telcordia GR-63 Seismic Zones Map


IBC Enclosures
Concrete expansion anchors are used to mount the rack to the floor. Anchor embedment depths will vary based on the floor type. When loading the rack, keep the center of gravity low. Ganged enclosures will produce a more stable installation than single racks.
Telcordia GR-63 Enclosures
This certification requires all racks to be secured in the same manner using concrete expansion anchors. When loading, keep the center of gravity low by placing heavier components toward the bottom of the enclosure. Ganged enclosures will produce a more stable installation than single racks.

Don’t see the seismic enclosure you’re looking for?

We offer design services and solutions to meet the needs of any seismic cabinet specification, from examining current product prints to completing new product development. You can count on our expert resources and engineering capabilities to support any stage of your project, from concept to production. For more information download our Capabilities Brochure.



Cobalt Cab Video
Crenlo Enclosure Video