Seismic Considerations
IBC & Telcordia GR-63
Earthquakes are not limited to the state of California, nor are they infrequent. Seismic
events take place every day throughout much of the contintential United States. In many
cases, millions of dollars worth of technology depend on the quality and installation
method of the rack that it is stored in.
Most manufacturers of 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.
There are two standards by which enclosures are deemed seismic.
Crenlo offers a solution for both.
Learn more about the differences between the two:
IBC
GR-63
The 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 describes the protection level of an
enclosure. It requires an enclosure to provide a level of
protection such that the equipment inside remains active
during an earthquake.
Our Solution:
Tie Down Kit for Emcor’s 10 Series or G-Series products.
Our Solution:
Fully Welded Enclosures with Tie Down brackets.
We see enclosures differently™
Seismic Considerations
International Building Code (IBC)
Definition
NEBS Telcordia GR-63 (Formerly Bellcore)
The International Building Code (IBC) is a set of guidelines which describe how
Telcordia GR-63 describes the protection level of an enclosure. It requires an
to properly secure objects -in this case enclosures- so that they do not tip over
enclosure to provide a level of protection such that the equipment inside shall
and cause injury to anyone during an earthquake.
sustain operation without replacement of components, manual rebooting, (or)
human intervention during an earthquake.
Historical Base
Architectural / Building Based
Telecommunication Equipment Based
Following the 1994 earthquakes in Los Angeles, during which more than 40
In the years following AT&T’s monopoly lawsuit, a flood of competitive local
percent of the $80 billion in damages were non-structural, it became apparent
exchange carriers arose, bringing a slew of new and varied network equipment
that there was a need to create guidelines for securing objects to the floors, walls
to the once homogenous collection of AT&T equipment housed in central offices
or ceilings of buildings. In 2000, the IBC was created as a guideline to which
throughout the country. As a result, standardized network equipment were
businesses must adhere in order to receive funding from the Federal Emergency
established to ensure network compatibility and uptime. What came to be were
Management Agency (FEMA) in the aftermath of an earthquake.
the NEBS requirements, of which, section GR-63 applies specifically to protecting
equipment in the event of seismic activity.
Test Procedures
Formulas are provided to determine seismic compatibility, however,
this can only be determined by knowing the specific building elements,
features, location, floor level, etc.
Specific test procedures are provided to determine seismic compatibility.
The test is comprised of a composite waveform that is synthesized from
typical earthquake (approx 8.3 on Richter scale).
The most common IBC test procedure uses a mathematical equation that
To achieve GR-63 compliance, enclosure manufacturers turn to independent,
compares potential seismic effects to objects mounted in a building. These
third-party testing facilities. An enclosure is loaded to capacity and mounted
calculations determine how the enclosure must be secured or installed in the
on a shaker table. The shaker table then simulates an earthquake, shaking in
building. A value called the “seismic design category” is assigned based on the
every potential direction at varying levels of intensity up to the equivalent of
building’s location. This is calculated based on the distance of the building to
an 8.3 earthquake. Accelerometers are attached to the enclosure to measure
the anticipated location of an earthquake, the type of soil beneath the building
its vibration and sway during the test. In order to pass the test and achieve
and a variety of other variables. The building is also given an “importance factor”
the seismic rating, the enclosure must not sway more than three inches in any
value, which is either 1.0 or 1.5. Essential buildings, such as hospitals are given
direction and all components must remain operable during and after the test.
a value of 1.5 due to the need for immediate uptime. Non-essential buildings are
This test is the same for every enclosure manufacturer, regardless of where that
given a value of 1.0. The essential value of 1.5 would require that the electronics
enclosure is going to be used or its intended purpose. Crenlo currently offers
continue to function in the event of an earthquake whereas the non-essential
seismic rated enclosures that are GR-63 compliant. Please see our catalog for
value of 1.0 would simply require the enclosure to remain standing. Crenlo
more information.
currently offers a solution for non-essential buildings or 1.0.
The Map
Very specific map that measure Short Period Spectral Response
Acceleration (Ss) – How bad an earthquake can be at specific site.
General map that shows the 5 seismic zones according the USGS survey
– The likelihood of a seismic event in a specific location.
In addition to viewing the entire continent as a series of potential seismic
A seismic zone map is based on a statistical compilation of the number and
locations, the specification “IBC” has resulted in maps that measure potential
the magnitude of past earthquakes. These maps show an indication of where
seismic activity within given locations relative to identified fault lines. For
the next earthquake is most likely to occur, how frequently they occur and their
localized seismic information the IBC has maps which define the probability of
magnitude. There is NO direct correlation between seismic zone ratings and
earthquakes within 100-foot sections relative to fault line locations.
Richter scale recordings, although past experience shows the worst earthquakes
occur in the higher rated seismic zones.
Installation and
Equipment Distribution
Installation of the enclosure as well as how the equipment is loaded in the
enclosure effect performance.
Installation of the enclosure as well as how the equipment is loaded in the
enclosure effect performance.
Concrete expansion anchors are used to mount the rack to the floor. Anchor
This certification requires all racks to be secured in the same manner using
embedment depths will vary based on the floor type. When loading the rack,
concrete expansion anchors. When loading, keep the center of gravity low
keep the center of gravity low. Ganged enclosures will produce a more stable
by placing heavier components toward the bottom of the enclosure. Ganged
installation than single racks.
enclosures will produce a more stable installation than single racks.
We see enclosures differently™
Emcor enclosures are designed and manufactured by Crenlo | 507-289-3371 (phone) I 507-287-3405 (fax) | www.crenlo.com
© 2011 Crenlo Cab Products, Inc. All Rights Reserved. Crenlo® and the Crenlo® Logo are registered trademarks in the United States [and various other countries] of Crenlo Cab Products, Inc.
© 2011 Emcor Enclosures, Inc. All Rights Reserved. Emcor®, and 10 Series® are registered trademarks in the United States [and various other countries] of Emcor Enclosures, Inc.
CRN.2060 10.11