HCAI Building Classifications: OSHPD 1, 1R, 2, 3, 4 and 5

Every California healthcare building regulated by HCAI (formerly OSHPD) is assigned a building classification. That classification decides how much seismic performance the structure and its nonstructural systems must deliver — and whether the equipment you are installing needs OSP preapproval or a project-specific certification.

Classification comparison

OSHPD 1 vs OSHPD 2 — the distinction that matters most

OSHPD 1 buildings are general acute care hospitals. Under the Alfred E. Alquist Hospital Facilities Seismic Safety Act they must remain operational after a design earthquake, not merely standing. That drives an importance factor of I_p = 1.5 on essentially all designated nonstructural components, certified anchorage for mechanical and electrical equipment, and full HCAI plan review.

OSHPD 2 buildings are Skilled Nursing Facility (SNF) and Intermediate Care Facility buildings under HCAI jurisdiction. They are not assigned SPC ratings, and they are frequently — and incorrectly — described as an anchorage-calculations-only classification.

What the code says

The California Building Code carries HCAI special seismic certification requirements in two separately scoped provisions. Section 1705A.14.3.1 is scoped to OSHPD 1 & 4 and lists the systems requiring Special Seismic Certification — including emergency and standby power systems — together with that section's own exceptions. A parallel provision, 1705.14.3.1, is scoped to OSHPD 1R, 2 & 5 and requires Special Seismic Certification for life-safety components such as emergency and standby power systems.

What it means in practice

Certain OSHPD 2 equipment is subject to Special Seismic Certification. Anchorage design to the California Building Code and ASCE 7 Chapter 13 is still required, but it is a separate obligation from certification of the component itself. For SNF alternate source of power, review current HCAI Skilled Nursing Facility guidance — Advisory Guide A6, Alternate Source of Power for SNFs — alongside the applicable CBC §1705.14.3.1 provision.

Common mistake

Applying the ≤25 kW emergency generator exception to an OSHPD 2 project. The ≤25 kW exception shown in PIN 55 is within the OSHPD 1 & 4 provision (CBC §1705A.14.3.1). The separate OSHPD 1R, 2 & 5 provision (CBC §1705.14.3.1) specifically requires Special Seismic Certification for alternate-power systems including generators, and does not show that exception. HCAI Advisory Guide A6 likewise states that Special Seismic Certification is required for generators used as an alternate source of power for skilled nursing facilities. Equally, an OPM is not an alternative to Special Seismic Certification — it addresses preapproved seismic design of supports and attachments.

Project-specific considerations

An OSP is a voluntary preapproval, so an OSP listing is not automatically mandatory. Where Special Seismic Certification applies and no OSP covers the equipment, a project-specific certification path reviewed by HCAI is generally available. The 2025 California Building Standards Code took effect January 1, 2026 for applicable applications submitted or accepted on or after that date, and incorporates ASCE 7-22 for Chapter 13 nonstructural provisions. Per HCAI CAN 1-0, the code edition that governs your project depends on its application/acceptance date, so confirm which edition applies before relying on any exception list.

SPC ratings — structural performance

SPC (Structural Performance Category) describes how the building frame is expected to behave in a design earthquake:

• SPC-1 — significant risk of collapse; must be retrofitted or removed from acute care service.
• SPC-2 — does not meet current standards but is not judged a collapse risk.
• SPC-3 — expected to remain standing; may not be usable afterward.
• SPC-4 — expected to remain standing and repairable, with limited damage.
• SPC-5 — expected to remain fully functional; the long-term target for acute care.

SPC-4D explained

SPC-4D is the compliance path most California hospital owners are asking about today. It is an SPC-4 rating earned through HCAI's HAZUS-based structural evaluation and retrofit methodology rather than full conformance to current new-building provisions. A building rated SPC-4D is expected to remain standing and repairable after a design earthquake and may stay in acute care service past the SB 1953 2030 deadline.

Reaching SPC-4D does not exempt the building from nonstructural work. Equipment, piping, ductwork and emergency power still need code-compliant stamped seismic anchorage calculations and, for designated systems, HCAI OSP preapproval or project-specific certification. In practice SPC-4D retrofits generate a large volume of hospital equipment anchorage and seismic bracing submittals.

NPC ratings — nonstructural performance

NPC (Nonstructural Performance Category) rates the bracing and anchorage of everything that is not the frame — equipment, piping, ductwork, ceilings, communications, and emergency power. This is where most of our work lives:

• NPC-1 — minimal bracing of nonstructural systems.
• NPC-2 — bracing of communications, emergency power, and select systems.
• NPC-3 — adds bracing of critical piping, medical gas, and fire protection.
• NPC-4 — adds on-site water and holding, plus broader equipment anchorage.
• NPC-5 — full nonstructural compliance so services continue after an earthquake.

Raising an NPC rating almost always means producing stamped seismic anchorage calculations for existing and new equipment, plus hospital equipment anchorage details for the contractor.

How classification affects your submittal

1. OSHPD 1 / 1R / 4 / 5 — where Special Seismic Certification applies, it is demonstrated either by a voluntary HCAI OSP preapproval or by a project-specific certification reviewed by HCAI under CBC / ASCE 7-22 §13.2.3, usually backed by AC156 shake-table testing. An OPM (preapproval of seismic supports and attachments) and a PCS (preapproved prefabricated components and systems) are separate voluntary programs and are not generic substitutes for Special Seismic Certification. Check the OSP database before designing from scratch.
2. OSHPD 2 — stamped anchorage calculations to the California Building Code, plus Special Seismic Certification for life-safety components such as emergency and standby power systems under the CBC provision scoped to OSHPD 1R, 2 and 5. A voluntary OSP listing is one way to demonstrate it; a project-specific HCAI-reviewed certification path is the other. Anchorage calculations alone are support and attachment engineering — they are not Special Seismic Certification of the equipment.
3. OSHPD 3 — stamped anchorage calculations to the California Building Code, typically permitted through the local building department.
4. OSHPD 6 — chemical dependency recovery hospitals; scope of HCAI review follows the licensing and code provisions applicable to the specific building.

Related resources

• What does OSHPD mean? OSHPD vs HCAI
• OSHPD seismic requirements checklist
• HCAI seismic certification services
• Nonstructural component certification
• Free OSP database — search listings

Technical review: Ahmed Haider, Ph.D., PE· Last technically reviewed: September 1, 2026· General engineering information, not a substitute for project-specific review by the design professional or HCAI.