ANCHOR EQUIPMENT PROPERLY
Protecting Your Property from Earthquakes
FEMA
April 2008

To control the vibrations created by heavy equipment, many property 
owners install such equipment on spring-loaded platforms or mounts 
known as vibration isolators. Isolators are designed to absorb the 
vibrations created by the normal operation of the equipment, but not 
the excessive movement that can occur during an earthquake. 
Earthquake forces, coupled with the weight of the equipment, can 
stretch the isolator springs beyond their ability to rebound. As a 
result, the isolators can fail, equipment can be overturned, utility 
line connections can be broken, and workers may be injured. 

In earthquake hazard areas, anchoring equipment directly to the floor 
or another suitable part of the building is preferable to mounting 
equipment on vibration isolators. If isolators are used, they should 
be securely anchored and they should be equipped with “snubbers.” 
Snubbers limit the motions resulting from normal operation of the 
equipment and prevent the equipment from moving beyond the limits of 
the springs during earthquakes. 

[Begin illustration]
This illustration shows a vibration isolator mount equipped with 
snubber for use in earthquake hazard areas. The snubber limits motion 
of equipment during an earthquake.
[End illustration]

BENEFITS OF UTILIZING THIS MITIGATION STRATEGY

* Helps to prevent the failure of isolators, which can result in 
equipment overturning

* Helps to prevent broken utility line connections

* Helps to prevent injuries to occupants

TIPS 

Keep these points in mind when you anchor heavy equipment: 

* The multi-purpose isolator system shown in the figure is designed 
to absorb equipment vibrations resulting from normal operations and 
to prevent excessive motion during an earthquake. Systems of this 
type can be used for newly installed equipment and as replacements 
for existing isolator systems that do not include snubbers or other 
restraints. 

* Equipment mounted on vibration isolators must be able to move 
freely. Be sure to use flexible connections wherever utility lines, 
piping, and ductwork are attached to the equipment. 

* Before anchoring equipment to floors or walls, make sure they are 
strong enough to resist earthquake forces. 

* Tall pieces of equipment with narrow bases are more likely to 
overturn during earthquakes and will therefore need additional 
anchoring. 

* Equipment suspended from the ceiling must also be braced to resist 
earthquake forces. 

* The equipment manufacturer or dealer may be able to provide or 
recommend mounting methods and hardware for use in earthquake hazard 
areas. 

ESTIMATED COST 

The cost of anchoring a piece of heavy equipment will depend on its 
size, weight, location, and operation; the type and number of utility 
lines connected to it; and the anchoring method used (e.g., rigid 
connectors or vibration isolators). 

OTHER SOURCES OF INFORMATION 

FEMA 74, Reducing the Risks of Nonstructural Earthquake Damage: A 
Practical Guide, Third Edition, September 1994, 
http://www.fema.gov/library/viewRecord.do?id=1574. 

FEMA 547, Techniques for the Seismic Rehabilitation of Existing 
Buildings, February 2007, 
http://www.fema.gov/library/viewRecord.do?id=2393. 

To obtain copies of FEMA documents, call the FEMA Publications 
Warehouse at 1-800-480-2520 or visit FEMA’s Library online at 
http//:www.fema.gov/library.