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Seismic Rated Enclosures FAQ
General
When should I choose a seismic enclosure over a standard enclosure?
A- Choose seismic enclosures for areas that have a high probability of seismic activity. Seismic
enclosures may be required by building code or customer specifications. Specifications may
reference the NEBS GR-63-CORE document and require a NEBS Zone 3 or Zone 4 enclosure.
Does the use of a seismic enclosure guarantee that equipment will not be damaged during an
earthquake?
A- No. There is no way to predict the result of an earthquake. However, a non-seismic enclosure is
not designed to withstand the severe forces that a seismic enclosure is designed to handle. The
use of seismic enclosures/kits provide an extra level of defense against seismic damage. For
Telcordia GR-63 enclosures, it is an added assurance that an enclosure design has been tested
under simulated earthquake conditions. For IBC, it is an added assurance that an enclosure’s
concrete anchors have been calculated to withstand seismic loads. The IBC analysis does not
include or consider the structural integrity of the rack itself.
Does the use of a seismic enclosure eliminate the need to have a licensed professional engineer
provide guidance on placement and installation for enclosures?
A- No. A full seismic installation involving the placement and bracing of racks, cable runways, etc.
can only be designed by a licensed structural engineer familiar with the applicable codes. The
IBC kit involves the use of a structural engineer to “certify” the seismic installation has been
performed correctly to code.
Do seismic racks have a lower load-bearing capacity than non-seismic racks?
A- No. The specifications for non-seismic enclosures show the load-bearing capacity for nonseismic conditions, also called the static load. The rack is loaded to assure that the load will not
bend the enclosure, but the load is not placed in motion. The specifications for seismic
enclosures list the load-bearing capacity for seismic conditions, also called a dynamic load.
Although both values are listed as a weight limit, there is a difference. When you compare racks
for seismic installations, be sure to compare the seismic (dynamic) load. If you compare racks for
non-seismic installations, be sure to compare the non-seismic (static) loads. Most seismic racks
will have a higher non-seismic (static) load than a similarly sized non-seismic rack.
Is special installation hardware required for internal accessories in a seismic enclosure?
A- Yes. All seismic enclosures must be secured to the floor with a special seismic (heavy-duty)
anchor. Each anchor has very specific installation requirements for seismic installations.
Anchors used for IBC applications must be the anchor shown in the structural calculation packet
or have the same tension and shear load ratings.
Crenlo | 1600 4th Avenue NW | Rochester, MN 55901 | 507-289-3371 (phone) | 507-287-3405 (fax) | www.crenlo.com
Form No.12606.11.09
Why are seismic enclosures more expensive than non-seismic enclosures?
A- Seismic enclosures have more engineering design time than non-seismic enclosures and they
are also more difficult to manufacture because of the increased welding at tight tolerances. Any
necessary independent testing and certification also add to the cost of the enclosures/kits.
Why can’t Emcor’s Telcordia cabinet and IBC kits accommodate the use of casters and/or
levelers?
A- To pass the stringent Telcordia Zone 4 shaker table test, the rack must be firmly anchored to the
floor/test bed. Casters and levelers are the weakest area of the assembly and would most likely
fail under seismic (dynamic) loads. The IBC brackets are internal brackets and used with a
specified frame spacer. The use of casters/levelers would necessitate the use of a different
frame spacer or redesign to work properly. Additionally, the calculations will only work with the
frame sitting on the floor as the frame’s center-of-gravity would change if casters/levelers are
involved.
Specifically talking IBC
What is the Difference between Essential and Non-essential buildings?
A- There are 3 ways a building may be classified essential according to IBC.
a. The component is required to function for life-safety purposes after an earthquake.
b. Components containing hazardous materials.
c. The component is needed for continued operation of the facility or its failure could impair
the continued operation of the facility.
Every other scenario would be classified as non-essential.
Why doesn’t ESQ have a seismic kit?
A- ESQ does not have a seismic kit because of its already low static load rating. Additionally,
ESQ’s standard use of a pontoon base would necessitate a different design to meet IBC.
Where can I find the certification data for these kits?
A- On our website. www.crenlo.com/enclosures
Where can I get/buy anchors for the seismic kit?
A- Anchors may be obtained from Hilti or through their various distributers and sales partners.
I have an existing Emcor enclosure, can an IBC seismic kit be retrofitted to it?
A- Yes. A seismic installation will require access beneath the enclosure to install the concrete
anchorage, so in nearly all cases, the enclosure will need to be briefly unloaded.
What is the difference between IBC and UBC?
A- UBC (Uniform Building Code) was code maintained by the International Conference of Building
Officials (IBCO) used primarily on the west coast of the United States. In an effort to maintain a
single set of construction codes, UBC was combined with several other regional building codes to
form the International Building Code (IBC). The last revision of UBC was the 1997 version.
UBC’s assessed how “bad” the earthquake can be at a particular site by assigning a value of
Zone 1 through Zone 4. Starting in the year 2000, the IBC mapped the ground accelerations for
the entire USA. Specifying engineers must now reference these ground acceleration values in
specifications, not the old UBC Zones.
B- The IBC is much more stringent in how it applies the seismic forces to the component’s
anchorage resulting in a higher quality seismic installation.
Crenlo | 1600 4th Avenue NW | Rochester, MN 55901 | 507-289-3371 (phone) | 507-287-3405 (fax) | www.crenlo.com
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What does the IBC Map look like?
In an effort to simplify the choice of proper anchorage, the seismic map developed by IBC and the USGS
was grouped into the designations shown above by our structural engineering consultant. In each region
(low,moderate/high) the highest ground acceleration value was chosen to give the most conservative
results. Site specific engineering is required near the New Madrid fault and for any floor greater than 50%
of the building height. This was done as the loads on the concrete anchors become unacceptably high
and site-specific restraints would be necessary to meet code.
Who are our seismic competitors and what products do they offer?
A- Many enclosure manufacturers offer seismic rated products or tie-down kits, but the verbiage,
certification and information is not consistent.
a. Middle Atlantic – Has seismic brackets and documentation for each of its vertical
enclosures. Documentation claims that the brackets are certified to UBC, CBC, IBC,
ASCE and NFPA (certifications vary on enclosure and bracket type). PRODUCT IMAGE:
Middle Atlantic’s anchor kit brackets
i. Links:
1. Seismic Information Packet:
http://www.middleatlantic.com/pdf/wpseis.pdf
Crenlo | 1600 4th Avenue NW | Rochester, MN 55901 | 507-289-3371 (phone) | 507-287-3405 (fax) | www.crenlo.com
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b. Great Lakes - Offers a Seismic Anchor Kit and a “Seismic Zone 4 Enclosure” that
complies to GR-63-CORE at 1,000 lb. seismic weight capacity. The Seismic Anchor Kit
complies to 2003 and 2006 IBC. PRODUCT IMAGES:
Great Lake Seismic Zone 4 Enclosure
c.
Seismic Anchor Kit
i. Links:
1. Great Lake Seismic Zone 4 Enclosure:
http://www.werackyourworld.com/pdf/Spotlights/Seismic_Enclosure.pdf
2. Great Lakes Seismic Anchor Kit:
http://www.werackyourworld.com/international/products/accessories/cast
ers-and-levelers/seismic-anchor-kits/
APC – Offers a seismic option of their NetShelter enclosure as well as Bolt-Down Kit for
the NetShelter SX line. The Seismic enclosure is rated to GR-63-CORE and the BoltDown Kit meets 1997 UBC Zone 4 Seismic anchoring requirements. PRODUCT
IMAGES:
NetShelter VX Seismic Enclosure
NetShelter SX Bolt-Down Kit
i. Links:
1. NetShelter VX Seismic Enclosure:
http://www.apc.com/products/resource/include/techspec_index.cfm?base
_sku=AR2144BLK
2. NetShelter SX Bolt-Down Kit:
http://www.apc.com/products/resource/include/techspec_index.cfm?base
_sku=AR7701
Crenlo | 1600 4th Avenue NW | Rochester, MN 55901 | 507-289-3371 (phone) | 507-287-3405 (fax) | www.crenlo.com
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d. Damac – Offers “Seismic NEBS” (compliant to GR-63-CORE) and “Seismic UBC”
enclosure options. PRODUCT IMAGES:
Seismic NEBS GR-63 CORE Certified Cabinet
Seismic UBC Zone 4 Rated Cabinet
i. Links:
1. Seismic NEBS GR-63 CORE Certified Cabinet:
http://www.damac.com/catalog/cabinet-systems/seismic-nebs/seismicnebs-gr-63-core-certified-cabinet-78h-42u
2. Seismic UBC Zone 4 Rated Cabinet:
http://www.damac.com/catalog/cabinet-systems/seismic-UBC/seismicubc-zone-4-rated-cabinet-78h-42u
e. Other competitors with links to their seismic product offering(s):
i. Chatsworth: http://www.chatsworth.com/Products/Cabinet-and-EnclosureSystems/Seismic-Protection-Systems/
ii. AMCO: http://www.imsep.com/seismic_features.html
iii. Hammond: http://www.hammondmfg.com/C4CabinetSystem.htm
iv. Equipto: http://www.equiptoelec.com/seismic.htm
v. Optima: http://www.optimaeps.com/M_series.htm
vi. Bud: http://www.budind.com/view/Large+Cabinet+Racks/Seismic+Cabinet+Rack
vii. APW Mayville:
http://www.apwmayville.com/products/category_overview.aspx?categoryID=1048
viii. Hoffman:
http://www.hoffmanonline.com/product_catalog/product_detail.aspx?cat_1=34&c
at_2=2410&cat_3=99101&catID=102842&itemID=3648&searchFor=seismic
cabinets
ix. Martin International Enclosures, Inc.:
http://www.martinenclosures.com/whats_new.htm
x. Electrorack’s Barracuda line meets UBC Zone 4 ratings
Crenlo | 1600 4th Avenue NW | Rochester, MN 55901 | 507-289-3371 (phone) | 507-287-3405 (fax) | www.crenlo.com
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