OSHPD Generator Seismic Certification
Generators serving as emergency or alternate power in HCAI-jurisdiction facilities are normally Iₚ = 1.5 — they must function after the Design Earthquake. Where CBC §1705A.14.3 (OSHPD 1 & 4) or §1705.14.3 (OSHPD 1R, 2 & 5) requires Special Seismic Certification, that certification is demonstrated through a voluntary OSP listing or an HCAI-reviewed project-specific submittal, and is paired with a properly engineered isolator + snubber base and anchorage design.
Outside HCAI jurisdiction, seismic qualification requirements depend on the project's adopted building code, ASCE 7 edition, AHJ requirements, and equipment function. For projects that need generator anchorage engineering, see generator anchorage services. Our shake-table qualification of a 2,000 kW Cummins genset is summarized in the project record.
Two SSC compliance routes for HCAI generators
Where Special Seismic Certification is required for the genset, HCAI's published SSC FAQ states that project-specific submittals must include shake table test report(s) for the equipment, support and attachment calculations, installation drawings, and CBC labeling, approved by a California Structural Engineer before installation. There are two compliance routes — an existing applicable OSP, or a project-specific HCAI-approved SSC.
Existing applicable OSP
A current HCAI OSP listing that covers the genset model and the proposed installation conditions. Voluntary manufacturer preapproval of Special Seismic Certification, reusable across projects.
Learn more about Existing applicable OSPProject-specific HCAI-approved SSC
Where no applicable OSP exists, HCAI reviews a project-specific qualification package — shake table test report(s), support and attachment calculations, installation drawings, and CBC labeling, approved by a California Structural Engineer before installation.
Learn more about Project-specific HCAI-approved SSCSupporting engineering scopes
These scopes are not alternative certification pathways. They work together inside whichever SSC route applies, and they are not interchangeable approvals — anchorage calculations by themselves do not satisfy Special Seismic Certification of an active generator.
AC156 shake table qualification
The test substantiation behind either SSC route. The engine, alternator, controls, and the isolator/snubber base are tested as one assembly.
Supports, vibration isolators & snubbers
Engineered isolator + snubber selection sized for the genset's operating weight, CG height, and SDS at the project site — evaluated against the OSP's tested support conditions.
Attachment & anchorage calculations
PE/SE-stamped attachment and anchorage design for a specific genset on a specific pad. Required in both routes; not a substitute for SSC of active equipment.
Why isolator selection matters for generator OSP
An OSP applies to the tested assembly — engine, alternator, controls, and the isolator/snubber support conditions used during AC156. A substitution is not automatically disqualifying: HCAI PIN 55 §25(b)(i) allows spring vibration isolator and snubber supports at the same tested mounting locations, or at additional locations, using either the isolators identified in the OSP or alternate HCAI-approved cyclic-tested isolators whose capacities equal or exceed the applicable component seismic demands per ASCE 7 §13.3.
What matters is whether the proposed support falls inside the OSP's approval conditions. If it does not, additional HCAI review, a project-specific certification, or retesting may be required. A separate OPM covers preapproved seismic design of supports and attachments — it does not by itself extend or replace the equipment's SSC or OSP. We help packagers map OSP approval conditions to commonly spec'd isolator families before the submittal.
What we need to scope a generator cert
- Genset cut-sheet, dry/wet operating weight, and CG height
- Mounting: rigid skid, spring isolators, or housed restrained isolators
- Existing OSP/OPM number (if certifying a substitution)
- SDS at the project site (from geotech / structural engineer)
- Hospital project number and HCAI office (Northern / Southern CA)
- Sub-base fuel tank — included in the assembly or anchored separately?
Quote a generator cert in 24 hours
Send us the genset cut-sheet, weight, isolator model, and Ip designation. You'll have a scoped, itemized PE/SE-stamped proposal — typically within one business day.
PE/SE stamped • Hundreds of California hospital projects since 2008
How the requirement is scoped by facility type
Special Seismic Certification is the underlying code requirement, and it is scoped separately for HCAI building classifications. CBC §1705A.14.3 applies to OSHPD 1 and 4 (acute care), while a parallel §1705.14.3 applies to OSHPD 1R, 2 and 5. The ≤25 kW emergency generator exception sits inside the OSHPD 1 and 4 provision and must not be generalized to an OSHPD 2 skilled nursing project. HCAI Advisory Guide A6 addresses generators used as an alternate source of power for skilled nursing facilities.
The three routes are not interchangeable. SSC is the requirement. OSP is a voluntary manufacturer preapproval route to demonstrate it — HCAI states the OSP program is limited to components that require SSC per CBC §1705.14.3, §1705A.14.3, or ASCE 7-16 §13.2.2 / 7-22 §13.2.3. A project-specific submittal reviewed and approved by HCAI is the alternate route where no applicable OSP exists. Anchorage calculations, OPM listings, and PCS listings are separate engineering scopes and are not substitutes for SSC of active equipment.
Engineering review required: facility classification, generator duty, and the code edition governing your project determine whether SSC applies to a specific genset. Confirm against the current CBC provision, PIN 55, and Advisory Guide A6 for your project's submittal date before relying on any exception.
PANACHE ENGINEERING estimate as of September 2026. These are our engineering fee and schedule ranges, not HCAI-published values. Actual cost and schedule vary with equipment scope, whether testing is required, laboratory availability, HCAI review and back-check cycles, redesign, and the number of models, sizes and mounting configurations covered.
Frequently asked questions
- Do emergency generators need OSHPD seismic certification?
- Where the California Building Code requires Special Seismic Certification (SSC) for the component, yes. Generators serving as an emergency or alternate power source in HCAI-jurisdiction facilities are normally designated Ip = 1.5 under ASCE 7-22 §13.1.3, and CBC §1705A.14.3 (OSHPD 1 and 4) or §1705.14.3 (OSHPD 1R, 2 and 5) is what triggers SSC. SSC is the underlying requirement. An OSHPD Special Seismic Certification Preapproval (OSP) is a voluntary manufacturer preapproval route to demonstrate it; where no OSP applies, HCAI accepts a project-specific submittal approved by a California Structural Engineer, which per HCAI's SSC FAQ includes shake table test report(s), support and attachment calculations, installation drawings, and CBC labeling. Project anchorage calculations alone do not replace SSC of an active generator when SSC is required. The ≤25 kW exception appears in the OSHPD 1 and 4 provision only — do not apply it to OSHPD 2; HCAI Advisory Guide A6 addresses generators used as an alternate power source for skilled nursing facilities.
- Can I swap vibration isolators on an OSHPD-certified generator?
- Not necessarily. An isolator substitution must be evaluated against the specific OSP and current HCAI requirements. HCAI PIN 55 §25(b)(i) provides that spring vibration isolator and snubber supports shall be at the same mounting locations as tested, or at additional locations, using either the tested isolators identified in the OSP or alternate HCAI-approved cyclic-tested isolators whose capacities equal or exceed the component seismic demands per ASCE 7 §13.3. PIN 55 also allows certain limited product changes without retesting when they stay within the test and approval limits and do not materially alter the certified configuration. If the proposed change falls outside the OSP approval conditions, additional HCAI review, a project-specific certification, or retesting may be required. A separate OPM does not by itself extend or replace the equipment's SSC or OSP.
- What's the typical lead time for a generator OSP?
- PANACHE ENGINEERING estimate as of September 2026 — not an HCAI-published schedule. Our engineering effort for an OSP where new AC156 testing is required typically runs 14 – 30 weeks, with the laboratory test program itself adding 6 – 16 weeks of scheduling and execution inside that window. A project-specific anchorage package for a one-off install is much faster, typically 1 – 3 weeks. HCAI review and back-check duration is outside our control and varies by workload and submittal quality.
Related guides in this topic hub
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