Seismic Design Category

The Seismic Design Category is of great importance to everyone involved with MEP systems because it will determine whether seismic restraints are

required or not, and if they qualify for exemption. Generally the structural engineer is responsible for determining the seismic design category for a project.

Seismic Design Category depends on:

• Occupancy Category

• Long and Short Period Mapped Spectral Accelerations Parameters (SD1 and SDS)

• Site Class

There are six seismic design categories that vary from A, the least stringent seismic restraint requirement to F, the most stringent,level of restraint required.