SPC -4D is a Structural Performance Category that is part of the 2019 California Building Standards Code, which allows noncompliant buildings to go past the 2030 seismic compliance deadline.

Retrofitting SPC-1/SPC-2 buildings to the highest standard, SPC-5, would essentially require existing buildings to meet current code. This can be prohibitively expensive in most cases, and impossible in some others. Rather than requiring SPC-1 and SPC-2 buildings to retrofit to SPC- 5, now such buildings can retrofit to SPC-4D. SPC-4D allows retrofit to a structural standard that is equivalent similar or comparable to SPC-4 buildings, which are already approved to provide acute care services beyond 2030.  SPC-4D is a voluntary program that will primarily be used to retrofit SPC-2 buildings. The retrofit work will need to be completed by 2030 to allow acute care services to remain in the existing noncompliant buildings beyond the statutory deadline of 2030. It contains no milestones or other due dates. SPC-4D projects can be submitted to OSHPD now.

Both hospitals and their communities will benefit from SPC-4D. Hospitals that may benefit are those that have older SPC-1 and SPC-2 buildings that are in the center of their campus and surrounded by newer hospital buildings, and removal of such buildings from service could result in the communities’ loss of a General Acute Care hospital. Where older buildings cannot be easily replaced or retrofitted to current code, such buildings may be able to retrofit to the SPC-4D standard. Particularly those facilities with SPC-1/SPC-2 buildings in areas of low seismicity, including many rural parts of California, may find retrofitting to SPC to SPC-4D a cost-effective option.


Figure showing SPC-2 buildings in the 2016/2019 California Building Codes can meet SPC-4D requirements, which are equivalent to the 1980 California Building Code,  rather than SPC-5 requirements.  Use of either the 1980 California Building Code of ASCE 41-13 are permitted for design of the retrofit.  Prior codes allowed SPC-2 building to retrofitted only to SPC-5 requirements.

SPC-4D Upgrades#

The SPC-4D upgrade requires submittal of multiple projects to the Seismic Compliance Unit and the Building Safety Section of FDD. See the flowchart below (click to enlarge) for the recommended order of submittals of projects to FDD.

Process flow. see transcript on downloadable pdf version next.

Flowchart showing SPC-4D upgrade process

OSHPD/FDD Process for Material Testing and Condition Assessment for SPC-4D projects#

For questions or comments related to the SPC-4D Regulations, please eMail the Seismic Compliance Unit.