FEMA E-74 Reducing the Risks of Nonstructural Earthquake Damage

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6.4.7.3 Transformers

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Transformers may be dry-type or liquid filled; mounted on a floor, wall, or roof; and installed with or without vibration isolation.

Typical Causes of Damage

  • Transformers may slide, tilt, overturn, or fall. Vibration isolation hardware may be damaged.
  • Internal elements may be damaged by inertial forces.
  • Damaged electrical equipment may be cause electrical hazards and fire hazards. Transformer damage may result in power outages and business interruption.

Damage Examples

Photo of displaced rail mounted transformer at power plant.
Figure 6.4.7.3-1 Rail mounted transformer slipped off rails at power plant in Port-au-Prince in the 2010 magnitude-7 Haiti Earthquake; only one of six identical transformers was damaged (Photo courtesy of Eduardo Fierro, BFP Engineers).

Seismic Mitigation Considerations

  • Working around electrical equipment can be extremely hazardous. Read the Electrical Danger Warning and Guidelines in Section 6.6.8 of this document before proceeding with any work.
  • This type of equipment can be supplied with a structural steel base, shop welded brackets, or predrilled holes for base anchorage. For any new equipment, request items that can be supplied with seismic anchorage details.
  • See Section 6.4.1.1 for additional base anchorage details. Refer to Installing Seismic Restraints for Electrical Equipment (FEMA 413) for additional mounting configurations such as wall- and roof-mounting, or vibration isolation as well as general information on seismic anchorage of electrical equipment.

Mitigation Details

Seismic mitigation detail for transformers, for which engineering is required. One transformer is anchored directly through base to concrete slab and another is anchored to floor with the use of steel angles on each side. Consult an engineering professional for implementation.
Figure 6.4.7.3-2 Transformer (ER).

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Last Updated: 
04/30/2013 - 21:18