When a commercial building does not perform — spaces will not hold temperature, ventilation is short, energy bills run high, or controls fight themselves — the record almost always leads back to commissioning. Commissioning is the process meant to catch these problems before occupancy. When it is skipped, shortcut, or left undocumented, the gap is not just an operational headache; it is a standard-of-care question that attorneys, owners, and insurers eventually have to answer. This article explains what the standard of care requires in commercial HVAC commissioning and how commissioning failures become evidence.
What Is Commissioning, and Why Does It Exist?
Commissioning, abbreviated Cx, is a quality-assurance process that verifies and documents that building systems are designed, installed, tested, and able to operate in conformance with the owner's stated needs. It exists because complex HVAC systems rarely work correctly on the first try. Equipment gets installed to the wrong schedule, dampers are wired backward, control sequences are programmed from generic templates that never matched the design, and sensors are left uncalibrated. Commissioning is the structured discipline that finds and corrects those defects before they become the owner's problem.
It is important to understand that commissioning is a process spanning the life of a project, not a single visit at the end. It begins in design with the definition of intent, continues through construction with installation verification, and concludes with active testing and turnover. An expert reviewing a troubled project asks a simple question: did that process actually happen, and is there a record proving it?
The Governing Framework
The standard of care for commissioning is not a matter of opinion. It is anchored in published standards and in project-specific documents that define what "correct" means for a given building.
- ASHRAE Guideline 0 and Standard 202 (the Commissioning Process) — The American Society of Heating, Refrigerating and Air-Conditioning Engineers publishes the foundational documents that define the commissioning process across every project phase, including the roles of the commissioning authority, the required deliverables, and the sequence of verification activities. These documents are the recognized description of how commissioning is supposed to be performed. See the ASHRAE standards and guidelines library.
- ASHRAE Standard 90.1 and the energy code — The energy standard imposes commissioning requirements for HVAC and related systems above defined size thresholds, and those requirements are adopted into law through the energy code in most jurisdictions. When a project subject to these provisions has no commissioning record, the omission is both a code issue and a standard-of-care issue. See ASHRAE Standard 90.1 and the mechanical provisions in the International Code Council model codes.
- Owner's Project Requirements (OPR) and Basis of Design (BOD) — The OPR is the owner's written statement of what the building must do: temperature and humidity targets, ventilation expectations, redundancy, energy goals, and operating hours. The BOD is the design team's explanation of how the design satisfies the OPR. Together they are the project-specific yardstick. Commissioning measures the installed building against these documents, so a project that never produced a defensible OPR has no clear benchmark for what success even means.
The Commissioning Process and Functional Performance Testing
A properly executed commissioning process moves through recognizable phases. In design, the commissioning authority reviews the OPR and BOD and confirms the design is capable of meeting them. During construction, installation is verified through prefunctional checklists that confirm equipment is present, correctly installed, and ready to be tested. The decisive phase is functional performance testing.
Functional performance testing is the active, documented verification that equipment and control sequences actually perform across their full range of operating modes, including startup, staging, economizer operation, occupied and unoccupied modes, and failure conditions such as loss of power or a failed sensor. A functional test does not merely confirm that a rooftop unit turns on. It confirms that the unit responds correctly when the sequence of operations calls for it to modulate, stage, or fail safe — and it records the measured result against the expected result. Testing, adjusting, and balancing of airflows and water flows feeds into this phase, and the process closes with a systems manual and operator training so the building can be run as intended.
What the Standard of Care Requires of a Commissioning Authority
The standard of care is the degree of care, skill, and judgment that a reasonably competent commissioning authority would exercise on a similar project under similar circumstances. In practice, meeting it means several things. The commissioning authority must establish and work from a documented OPR. It must follow a written commissioning plan traceable to ASHRAE Guideline 0 and Standard 202. It must actually perform functional testing rather than accept installer assurances. And it must produce a commissioning record — checklists, test scripts, measured results, issues logs, and a final report — that a third party could later review and understand.
The through-line is documentation. A commissioning authority who verifies a system but leaves no record has, for evidentiary purposes, not verified it at all. The standard of care is not satisfied by good intentions or by a system that happens to work; it is satisfied by a defensible process that was performed and recorded. This is the same principle that governs the broader standard of care in HVAC and mechanical systems, applied to the specific discipline of commissioning.
The Most Common Commissioning Failures
Certain failure patterns recur across troubled commercial projects. Recognizing them early tells an attorney or adjuster where the evidence is likely to be:
- Never tested. The commissioning scope was in the specification and may even have been paid for, but functional performance testing was never actually performed. Equipment was energized, the building was occupied, and no one exercised the control sequences under real conditions.
- Checklist-only. Prefunctional checklists were completed and signed, creating the appearance of commissioning, but the active functional testing that the process requires never happened. A signed checklist confirming an installation is not a substitute for a test proving performance.
- Undocumented. Some testing occurred, but there is no test data, no issues log, and no final commissioning report tying results back to the OPR. Without the record, the work cannot be verified and cannot be defended.
- Deferred and abandoned. Testing was postponed — often because a season, a load, or a tenant fit-out was not available at turnover — and then never completed once the project team demobilized. Seasonal functional tests for heating or cooling modes are a frequent casualty.
- Sequences never verified. The control programming was accepted as delivered by the controls contractor, with no independent confirmation that the installed sequence of operations matched the design intent. Misconfigured controls can run for years, quietly wasting energy and undermining comfort.
How Commissioning Gaps Become Evidence
In construction-defect and performance disputes, the commissioning record — or its absence — is often the most efficient path to the truth. When an owner alleges that a building never performed, the first documents an expert requests are the commissioning plan, the OPR and BOD, the prefunctional and functional test records, the issues log, and the final Cx report. Where those documents exist, they show what was tested, what failed, whether the failures were corrected, and whether anyone signed off on performance that was never demonstrated.
Where they do not exist, the absence is itself probative. A missing commissioning report on a project that specified or was code-required to have one is direct evidence that a step in the standard of care was skipped. When a defect later manifests — short ventilation, unstable controls, humidity problems, equipment cycling — the expert can connect that defect to the specific verification that would have caught it and did not occur. That chain, from an unperformed test to a foreseeable and preventable failure, is what turns a commissioning gap into a defensible opinion a court can act on.
For owners and their counsel, the practical lesson is to preserve and produce the full commissioning file early, and to retain an expert before systems are modified or rebalanced. Once a building has been repaired or retro-commissioned, the original as-turned-over condition — the thing the commissioning process was supposed to document — can no longer be observed directly.
Frequently Asked Questions
What is HVAC commissioning?
Commissioning, often abbreviated Cx, is a quality-assurance process that verifies and documents that HVAC and related building systems are designed, installed, tested, and operating in conformance with the Owner's Project Requirements. It is a process, not a single inspection, and it runs from design through occupancy.
What standards define the standard of care for commissioning?
The governing framework includes ASHRAE Guideline 0 and ASHRAE Standard 202, which define the commissioning process, together with the commissioning provisions of ASHRAE Standard 90.1 and the energy code. The Owner's Project Requirements and Basis of Design are the project-specific benchmarks against which performance is measured.
What is functional performance testing?
Functional performance testing is the active, documented verification that equipment and control sequences perform correctly across their full range of operating modes and failure conditions. It goes beyond confirming a unit powers on; it exercises the sequence of operations under realistic and abnormal conditions and records the results.
How do commissioning failures show up in litigation?
Commissioning gaps surface as missing or incomplete Cx reports, checklists signed without underlying test data, functional tests that were deferred and never completed, and control sequences that were never verified. The absence of a defensible commissioning record is itself evidence that a required step in the standard of care was skipped.
Is commissioning legally required on commercial projects?
On many commercial projects it is. ASHRAE Standard 90.1 and the energy provisions adopted through the International Energy Conservation Code impose commissioning requirements above defined system thresholds, and most commercial specifications call for commissioning independently of code. Whether required by code or by contract, an unperformed commissioning scope is a breach of the contracted standard.