Technologies for Seismically Bracing MEP Equipment – Part 1
The core purpose of seismic bracing is to restrict horizontal shaking from an earthquake. All seismic braces ﬁrmly attach equipment to structural members of a building so that they move with the structure during an earthquake. This prevents the equipment from tipping over, falling from where it is suspended, or colliding with other objects.
Where the seismic bracing strategy is concerned, MEP equipment ﬁts into two general categories: heavy equipment and conduits. The strategy for bracing equipment in either of these categories is principally the same, whether it’s electrical, piping, or HVAC components.
Seismic bracing of HVAC, electrical, and other heavy equipment
Industrial HVAC and electrical systems are expansive, and they involve some large and heavy pieces of equipment. Examples include compressors, air handling units, fans, generators etc.
In practice, this means securing them to structural members so they can’t move. As per FEMA’s Installing Seismic Restraints for Mechanical Equipment (FEMA 412) and Installing Seismic Restraints for Electrical Equipment (FEMA 413) outline, heavy equipment like these can be installed in several ways, including:
- Rigid mounting to the ﬂoor or a pad
- Suspension from the ceiling
Clockwise from Top left :
- Steam Generator directly mounted on EFRSI Restrained Spring Isolator. Reinforced housekeeping pad secured by anchors.
- Axial Blower with EFTR Thrust Restraints suspended by EFSH Hangers and restrained by Easyﬂex-Zip Clip Seismic Wire Rope Kit.
- Large Transformer mounted on a EFSSB Base supported by EFRSM Restrained Spring Mounts and EFSS Seismic Snubbers.
- Large Multi Section Cooling Tower secured to steel base and beam supports using EFRSI Restrained Spring Isolators and EFSS Seismic Snubbers.
In an earthquake, equipment sitting on a surface (no matter how heavy) can shake, wobble, and tip over. The hangers for suspended equipment can experience signiﬁcant stress during an earthquake because of shaking, and the equipment itself may deform, collide with other objects, or fall from its mounting point. To prevent damage—by ensuring that the equipment moves with the building during an earthquake and can’t shift or tip over—seismic bracing is necessary. As FEMA 412 and FEMA 413 explain, this can involve:
- Bolting equipment directly to structural members
- Using steel shapes to ﬁx equipment to the structure
- Using bumpers to prevent the equipment from moving (when there is no risk of the equipment tipping over.
Vibration isolation systems may also be used to dampen the effects of shaking on equipment. These commonly take the form of heavy-duty springs.