What is an OPA listing for HVAC equipment in California HCAI projects?

OPA stands for Office of Plan Approval - the HCAI (formerly OSHPD) process by which mechanical equipment is pre-approved for use in California licensed healthcare facilities. OPA-listed equipment has been reviewed and approved by HCAI for seismic compliance, typically through a seismic certification (IBC/CBC Seismic Zone 4 or equivalent shake-table test). Using OPA-listed equipment eliminates the need for project-specific seismic calculations for that piece of equipment. For non-OPA-listed equipment, a licensed structural engineer must provide seismic calculations specific to the installation location and building structure.

Do all California hospital HVAC units need seismic bracing?

Yes. All mechanical equipment installed in HCAI-regulated healthcare facilities must be seismically anchored or braced per CBC Chapter 13 and ASCE 7. This includes rooftop units, air handling units, fan coil units, exhaust fans, ductwork, and piping. The specific bracing requirements depend on the equipment weight, its location in the building (roof, ceiling, mechanical room), the facility's seismic design category, and whether the equipment is OPA-listed or requires project-specific engineering.

What is the difference between HCAI-1 and HCAI-2 mechanical requirements?

HCAI uses an occupancy classification system (HCAI-1, HCAI-2, HCAI-3) that affects the level of HCAI oversight and the seismic design requirements. HCAI-1 facilities (acute care hospitals, skilled nursing facilities) have the most stringent requirements - full HCAI plan review, field inspection, and OPA-listed or engineer-certified seismic support for all mechanical equipment. HCAI-2 facilities (clinics, medical offices) have less stringent requirements. The distinction determines the submittal package depth and the inspection frequency - always confirm with HCAI which category applies to your project before preparing the mechanical submittal.

What sway brace spacing is required for ductwork in California healthcare facilities?

HCAI follows SMACNA's Seismic Restraint Manual (ANSI/SMACNA 001) and ASCE 7 Chapter 13 for duct restraint. For rectangular ductwork over 6 inches in the largest dimension, transverse sway braces are required at intervals not exceeding 30 feet and within 6 feet of each turn, tee, or end. Longitudinal restraint is required every 40 feet. For round duct, similar spacing applies. All sway braces must be engineered for the specific duct weight and seismic zone. In HCAI-1 facilities, sway brace calculations must be submitted with the mechanical package and reviewed by HCAI before construction begins.

Healthcare · HCAI · Published 2026-06-03

HCAI seismic bracing requirements for mechanical systems: a California healthcare contractor's guide

California HCAI (formerly OSHPD) requires seismic bracing and anchorage for every piece of mechanical equipment installed in a licensed healthcare facility - from rooftop units to exhaust fans to ductwork. Getting the submittal package right the first time requires understanding OPA listings, sway brace spacing tables, and the HCAI plan review process. Here is the field-level guide that does not appear in the regulatory documents.

Mechanical engineering drawings for California HCAI healthcare facility seismic bracing submittal — HCAI mechanical submittals require seismic engineering documentation for every piece of equipment and duct system - a submittal package that Sierra Mechanical prepares as part of healthcare TI scope.

Why seismic requirements are different in California healthcare

California healthcare facilities are regulated by HCAI under the Alfred E. Alquist Hospital Facilities Seismic Safety Act. The seismic performance standard for healthcare is significantly higher than for standard commercial construction - acute care hospitals must remain operational after a major seismic event. This translates directly to mechanical systems: every piece of equipment, every duct run, every pipe system must be designed and installed to resist seismic forces and remain functional after a design-level earthquake.

HCAI enforces this through mandatory plan review and field inspection. Unlike a standard commercial mechanical permit where the inspector verifies code compliance at rough-in, HCAI reviews the complete seismic engineering package before approving construction. The mechanical contractor cannot begin work until HCAI issues plan approval. Submitting an incomplete or non-compliant seismic package triggers a correction cycle that typically takes 4–8 weeks per round.

OPA-listed vs. project-specific seismic engineering

The practical choice for every piece of mechanical equipment on an HCAI project: use an OPA-listed unit or provide project-specific seismic calculations.

OPA-listed equipment has been pre-approved by HCAI through the Office of Plan Approval process. The equipment manufacturer submits seismic test data (typically a shake-table test to ICC AC156 or equivalent), HCAI reviews and approves, and issues an OPA number. On the project submittal, the mechanical engineer simply references the OPA number - no project-specific structural calculation required for the equipment itself.

Non-OPA-listed equipment requires a licensed structural engineer (SE) to calculate the seismic forces on the specific equipment at its specific installation location, design the anchorage, and stamp the drawings. This adds engineering cost and HCAI review time. For one or two pieces of non-OPA equipment on a large project, this is manageable. For a project with ten non-OPA pieces, the SE cost and correction cycle risk becomes significant.

Practical recommendation: Specify OPA-listed equipment wherever available. For rooftop HVAC units, Carrier, Trane, Daikin, and Lennox maintain OPA listings for most commercial product lines. Verify the specific model's OPA listing at hcai.ca.gov before specifying - OPA listings expire and must be current at permit submission.

Sway brace requirements for ductwork

HCAI applies SMACNA's Seismic Restraint Manual (ANSI/SMACNA 001) and ASCE 7 Chapter 13 for ductwork restraint. The key parameters:

Transverse sway braces - required for rectangular ductwork over 6 inches wide: maximum 30-foot spacing, within 6 feet of each direction change (elbow, tee, offset), within 6 feet of each end cap or air handling unit connection.
Longitudinal sway braces - required every 40 feet of duct run length. Every duct run anchored to the building structure at the terminal point.
Combined braces - at duct direction changes, a single brace can provide both transverse and longitudinal restraint if designed to resist forces in both directions.
Weight threshold - rectangular duct under 6 inches in both dimensions and round duct under 6 inches diameter may be exempt from sway brace requirements in some HCAI-2 occupancies. Confirm with the structural engineer.

All sway brace hardware (threaded rod, concrete anchors, duct attachments) must be listed or submitted with load calculations. The most common submittal deficiency: the contractor specifies Hilti or Simpson anchor types without providing the pull-out and shear capacity data for the specific concrete substrate at the project. Include anchor manufacturer's technical data sheets (TDS) for each anchor type in the submittal package.

Pre-submittal checklist that cuts HCAI review cycles

HCAI correction letters on mechanical submittals most commonly cite these missing items. Address every one before initial submission:

OPA listing verification - print and include the current OPA certificate for every OPA-listed piece of equipment. Do not reference OPA numbers without the certificate.
Equipment mounting details - structural drawings showing the anchorage detail for every piece of mechanical equipment, stamped by an SE licensed in California.
Sway brace layout plan - floor plan showing the location of every transverse and longitudinal sway brace for each duct run.
Sway brace schedule - table listing each brace location, rod size, attachment hardware, and calculated seismic load.
Anchor TDS - technical data sheets for every concrete or structural steel anchor used, with the applicable load capacity table highlighted.
Installer qualifications - some HCAI projects require that sway brace installation be performed by SMACNA-certified installers or inspected by a special inspector. Confirm requirements with HCAI at the pre-application conference.

Working with Sierra Mechanical on HCAI projects

Sierra Mechanical has performed mechanical scope under HCAI jurisdiction for California healthcare operators including Sutter Health, Kaiser Permanente, UC Davis Health, and Dignity Health. Our C-20/C-43 crews are experienced with HCAI field inspection requirements - roughed-in work is inspection-ready before we call for inspection, not after.

For healthcare GCs building submittal packages, see our companion guide on OSHPD HCAI mechanical submittal checklist for California healthcare TI for the full plan check documentation list. General contractors evaluating mechanical subcontractors for HCAI projects should review our guide to choosing a mechanical subcontractor in California - and specifically ask candidates how many HCAI plan approvals they have obtained and whether they have an active SE relationship for seismic engineering.

Request a bid at sierramechcorp.com/contact or call (916) 638-8605.

Code references: CBC Chapter 13; ASCE 7-22 Chapter 13; ANSI/SMACNA 001 Seismic Restraint Manual. HCAI OPA listings verified at hcai.ca.gov.