- The OPR records what the owner needs. The BoD records how the design team intends to deliver it.
- Both documents are the reference that commissioning tests and acceptance criteria are measured against.
- California energy and green building codes include commissioning provisions that depend on them for many nonresidential projects.
- The OPR belongs in predesign, and the BoD should be reissued at every design milestone.
- Measurable criteria, such as temperature bands, noise limits and uptime targets, are far more useful than general goals.
- Skipping these documents rarely saves money. It moves the cost into change orders and warranty disputes.
- What Are the OPR and BoD?
- How the Two Documents Work Together
- Formats and Levels of Detail
- Standards and Code Requirements
- Applications by Building Type
- Design Process and Deliverables
- Special Cases
- How to Specify and What Drives Cost
- Best Practices and Common Mistakes
- Where Budlong Delivers This
- Related Reading
- Frequently Asked Questions
Every building project begins with a set of expectations that live in people’s heads: how warm the clinic should be at 2 a.m., how quickly a laboratory must recover after a fume hood opens, how much downtime a tenant will tolerate. The Owner’s Project Requirements and the Basis of Design turn those expectations into written, testable statements. They are the backbone of a disciplined commissioning program and a quiet driver of better MEP engineering outcomes.
This guide explains what each document contains, how they connect to design milestones and code requirements, and how to avoid the habits that make them useless. It reflects the experience of a firm that has been engineering buildings in California since 1958. You can learn more about our company or review the disciplines we cover.
1. What Are the OPR and BoD?
The Owner’s Project Requirements
The Owner’s Project Requirements, usually shortened to OPR, is a written statement of the functional needs, performance targets and expectations the owner holds for a facility. It answers the question “what must this building do for us?” It is written in the owner’s language, not in the language of equipment schedules.
The Basis of Design
The Basis of Design, or BoD, is the design team’s response. It explains the design approach, the codes and standards applied, the assumptions behind load calculations, the systems selected and the reasons they were chosen. It answers the question “how will we deliver what you asked for?”
Why They Are Always a Pair
One document without the other leaves a gap. An OPR with no BoD offers no evidence the team understood it. A BoD with no OPR has nothing to be judged against. Together they give the commissioning authority a clear line from need to design to installed system.
2. How the Two Documents Work Together
A Document Trail From Predesign to Occupancy
The documents evolve as the project matures. In predesign, the owner and a facilitator capture goals and constraints. During schematic design, the engineers write the first BoD narrative. As drawings reach design development and construction documents, the BoD gains detail: design temperatures, airflow targets, electrical load summaries, and references to sequences of operation. During construction, the contractor’s submittals are reviewed against both. After turnover, operators use the final versions to understand why systems were configured as they were.
The Role of the Commissioning Authority
The commissioning authority, or CxA, reviews the OPR for clarity and testability, reviews each BoD update for alignment, and builds the commissioning plan from them. Many owners rely on an independent provider through new building commissioning services so that the reviewer has no stake in the design or the installation.
Feedback Loops
When the BoD departs from the OPR, the departure should be visible and approved. That feedback loop is the main benefit. A design team that cannot meet a requirement, perhaps because of budget, should say so in writing and let the owner decide, rather than quietly delivering something different.
Also Read: The Building Commissioning Process, Step by Step
3. Formats and Levels of Detail
Narrative, Matrix and Hybrid Formats
There is no single required layout. A narrative OPR reads like a project brief, grouped by topic. A matrix OPR lists each requirement in a row with an identifier, a measurable criterion, a priority and a verification method. Many teams use a hybrid, with a short narrative for context and a matrix for testable items.
Scaling to the Project
A twelve-room office renovation needs a concise OPR. A hospital wing or a laboratory building needs a longer document that is organized by department and by system. The test is whether a stranger could read it and know how to judge the finished work.
Comparing the Two Documents
| Attribute | Owner’s Project Requirements | Basis of Design |
|---|---|---|
| Author | Owner, often with facilitator support | Design team, led by the engineer of record |
| Purpose | State needs and success criteria | Explain how the design meets them |
| Typical content | Goals, occupancy, uptime, comfort, energy and maintenance expectations | Codes, design conditions, calculations summary, system descriptions |
| Update rhythm | Revised only by owner decision | Reissued at each design phase |
| Used by commissioning for | Defining acceptance criteria | Checking design review and test scripts |
A requirement that cannot be verified is a wish. Write each OPR item so that a test, a measurement or an inspection can prove it was met.
4. Standards and Code Requirements
ASHRAE Guidance
The commissioning process is described in documents from ASHRAE, including Guideline 0 for the commissioning process, Guideline 1.1 for HVAC&R systems and Standard 202 for the commissioning process of buildings and systems. These documents describe the OPR and BoD as core inputs and set out the role of each in the design review and testing steps.
California Energy and Green Building Codes
California’s Building Energy Efficiency Standards, published by the California Energy Commission, include nonresidential commissioning provisions that call for an OPR, a BoD, design review, a commissioning plan, functional testing and a final report. CALGreen contains a related commissioning section for qualifying nonresidential buildings. Thresholds and exceptions change between editions, so confirm the adopted edition before setting scope. Our Title 24 checklist for new construction and the CALGreen MEP guide explain how these provisions fit into the wider code picture. Model codes are published by the International Code Council.
LEED and Other Rating Systems
Rating systems treat commissioning as a prerequisite and reward enhanced commissioning with extra credit. Both rely on a documented OPR and BoD. See our summary of LEED commissioning requirements for how the credits are structured.
State Agency Projects
Public schools reviewed by the Division of the State Architect and hospitals reviewed by the Department of Health Care Access and Information add their own plan review and inspection rules. The OPR and BoD should anticipate those requirements. Our DSA process guide and HCAI guide cover the review paths.
| Source | What it asks for | Where the OPR or BoD matters |
|---|---|---|
| ASHRAE commissioning documents | Defined process with owner requirements and design intent | Core inputs to every phase |
| California energy standards | Commissioning for qualifying nonresidential systems | Compliance documentation |
| CALGreen | Commissioning for larger nonresidential buildings | Verification of installed systems |
| LEED | Fundamental and enhanced commissioning | Prerequisite and credit documentation |
| State agency review | Plan review and field inspection | Early alignment of criteria |
5. Applications by Building Type
Healthcare
Hospitals carry the most demanding OPRs: pressure relationships, air change rates, redundancy, emergency power transfer times and infection control. The OPR names these as measurable criteria, and the BoD cites the ventilation standard and the essential electrical system rules behind the design. Large campus work, such as the Baldwin Park central plant, depends on this clarity because plant outages touch every patient room.
Laboratories and Life Sciences
Labs need requirements for face velocity, air change rates, exhaust redundancy, pressurization and process utility quality. Owners often overlook future flexibility, so a good OPR also states how much adaptability is expected when research programs change.
Education and Public Buildings
Schools and campuses focus on acoustics, ventilation, operations by small maintenance teams and long equipment life. The OPR sets the expected maintenance staffing so that the design does not produce systems the staff cannot serve.
Aviation, Transit and Hospitality
Terminals, hotels and transit buildings run nearly continuously. Requirements cover guest comfort, noise at the room level, response after outages and energy goals. Programs such as terminal expansion at LAX show how large public owners write requirements that span many contractors.
Multifamily and Senior Living
Residential projects rely on OPRs that address unit-level comfort, domestic hot water delivery, corridor ventilation and long-term repair costs. Our portfolio shows the range of building types we support, from small tenant spaces to large campuses.
Need Help Writing an OPR?
Our engineers and commissioning specialists can facilitate the workshop, draft the OPR and prepare the matching BoD for your next project.
6. Design Process and Deliverables
Step 1: Gather Needs in Predesign
Interview the people who will own, operate and occupy the building. Capture business goals, hours of use, comfort expectations, space adjacencies, maintainability, sustainability targets and budget limits. Record where stakeholders disagree so the owner can resolve it early.
Step 2: Convert Needs Into Criteria
Translate statements such as “quiet classrooms” into criteria such as a maximum background noise level and a test method. Assign each item an identifier and a priority. The commissioning authority can then map each one to a verification step.
Step 3: Draft the First BoD
At schematic design, the engineers describe the design approach by discipline. The mechanical narrative covers system type, zoning and load assumptions. The electrical team documents service capacity, backup power and spare capacity. Plumbing and fire protection narratives address water use, hot water and suppression approach.
Step 4: Update at Each Milestone
At design development and construction documents, the BoD adds calculations summaries, equipment selection basis and sequence references. Review comments are logged and closed. The HVAC design team should be able to point to the load and ventilation basis behind every major piece of equipment.
Typical Deliverables
- OPR with criteria, priorities and verification methods
- BoD narrative per discipline with design conditions
- Design review comments and a closed-out issues log
- Commissioning plan referencing the OPR and BoD
- Functional test scripts and a final commissioning report
Also Read: How Early MEP Coordination Reduces Rework
7. Special Cases
Design-Build Delivery
In design-build, the contractor and designer share a contract, so the owner’s voice can get lost. The OPR becomes the contract-level statement of success, and the BoD is often the first deliverable the owner can formally accept. Build review and approval gates into the agreement.
Renovations and Existing Buildings
Existing conditions complicate everything. The OPR should describe what must be preserved, what can be replaced and what performance gap the work is meant to close. Where a building has no records, a condition survey comes first. For performance gaps in occupied buildings, compare the approach with retro-commissioning.
Phased and Fast-Track Projects
When construction starts before design is complete, the BoD becomes a series of packages. Keep a master document that records which version applies to which package so that early work does not conflict with later decisions.
Modular and Prefabricated Work
Factory-built systems should be tested at the factory and again after installation. The OPR can require that both sets of results be delivered. Coordinate those test records with the installation schedule so nothing is retested without need.
When the design changes, change the BoD the same week. A stale design basis is worse than none, because testers will trust it.
Owners Without a Facilities Team
Developers who sell or lease on completion still benefit. The OPR can capture the expectations of the end user, and the BoD becomes a record the next owner can rely on.
8. How to Specify and What Drives Cost
Writing the Requirement Into Contracts
Specify the OPR and BoD as deliverables in the design agreement, with named milestones and a right of owner review. Add commissioning specifications to the construction documents so that contractors know their responsibilities. Where requirements affect budget, ask the design team to confirm the cost effect at each milestone through a cost estimate that follows the same criteria.
Choosing a Facilitator
Look for a team with relevant building experience, a record of resolving conflicts between owner needs and budget, and the independence to report honestly. Providers of building commissioning typically offer this facilitation.
What Drives Cost
| Cost driver | Why it matters | How to control it |
|---|---|---|
| Project complexity | More systems require more criteria and more review | Prioritize requirements by risk |
| Number of stakeholders | More interviews and more conflicts to resolve | Name a single owner decision maker |
| Late start | Rework when drawings conflict with needs | Begin in predesign |
| Rating system targets | Added documentation and testing | Align the OPR with certification goals early |
| Frequent change | Repeated updates to both documents | Use a change log and approval rule |
Also Read: Commissioning vs Retro-Commissioning Explained
9. Best Practices and Common Mistakes
Practices That Work
- Hold a facilitated workshop and invite operators, not only executives.
- Use measurable language, with units and tolerances where possible.
- Link each OPR item to a design response and a test.
- Run the BoD alongside energy modeling so efficiency goals are tested before equipment is purchased.
- Store the documents where operations staff can find them years later.
Mistakes to Avoid
- Writing the OPR after design begins, so that it only restates the drawings.
- Filling it with general terms such as “efficient” or “reliable” that cannot be verified.
- Letting the BoD go stale after schematic design.
- Treating the documents as paperwork for a certification rather than a decision tool.
- Leaving out the operations team, who inherit the building.
Testing and Long-Term Maintenance
Functional testing proves the installed systems match the documents. Seasonal testing catches problems that only appear under heating or cooling extremes. After occupancy, ongoing checks can confirm performance remains consistent with the OPR. Our article on commissioning and building performance describes how this stage supports long-term results. Federal guidance on building performance is available from the U.S. Department of Energy, and measurement science resources come from the National Institute of Standards and Technology.
- The OPR defines success and the BoD explains the plan to reach it.
- Start the OPR in predesign and keep every requirement verifiable.
- Reissue the BoD at each phase and log every departure from the OPR.
- California codes and rating systems reference both documents for many nonresidential projects.
- Independent facilitation and review improve clarity and reduce rework.
10. Where Budlong Delivers This
Budlong supports owners across Los Angeles, Ventura, Orange, San Bernardino, Riverside and Santa Barbara counties from offices in Glendale, downtown Los Angeles, Camarillo and Fremont. Local teams know the plan check habits of nearby jurisdictions and utilities.
11. Related Reading
12. Frequently Asked Questions
What is the difference between the OPR and the BoD?
The OPR states what the owner needs the building to do and how it should perform. The BoD is the design team’s written response, explaining the systems, criteria and assumptions chosen to meet those needs.
Who writes the Owner’s Project Requirements?
The owner is responsible for the content, but it is usually drafted with help from a commissioning authority, an owner’s representative or the lead design engineer, after interviews with facility staff, operators and end users.
When should the OPR be started?
Start it in predesign, before the architect and engineers begin schematic design. An OPR written after drawings exist tends to describe what was drawn rather than what the owner actually needs.
Is an OPR required by California code?
For many nonresidential projects, yes. The Title 24 energy standards and CALGreen both contain commissioning provisions that call for an OPR and a BoD, with thresholds that depend on building type and size. Confirm the adopted edition for your project.
How long should an OPR be?
Length should follow project complexity. A small tenant improvement may need a few pages, while a hospital or laboratory may need a long document organized by system, department and performance criterion.
Does the BoD need to be updated after the design is finished?
Yes. The BoD should be revised at each design phase and again when significant changes occur during construction, so the commissioning team always tests against the current design intent.
Can the OPR change during the project?
It can, but changes should be deliberate. Record each revision with a date and an approver, and have the design team document the cost and schedule effect before the change is accepted.
What does it cost to prepare these documents?
Cost depends on project size and complexity, and on whether a commissioning authority facilitates the process. Most owners find the effort modest compared with the rework it helps prevent.
How do the OPR and BoD help with LEED certification?
Fundamental commissioning prerequisites in LEED call for an OPR and a BoD, so these documents are a direct input to certification. They also support energy and indoor air quality targets.
