Testing and balancing measures and adjusts airflow and water flow to design values. Commissioning verifies that systems work together as intended, using functional performance tests. Equipment startup and checkout is a third, separate activity performed by the installing contractor. Independent agencies often perform TAB and commissioning, so the scope must name who does each and what deliverables are required.
- Startup, test and balance, and commissioning are three different activities. A scope that blurs them leaves gaps nobody notices until occupancy.
- Independent TAB and commissioning agencies are common. Name the agency, who hires it and who pays for retesting.
- Davinci performs startup and checkout of the equipment it installs. That is not the same as third-party TAB or an owner's commissioning agent.
- Functional performance tests need written sequences to test against. Seasonal testing may be needed when conditions during construction cannot exercise a system.
- The deliverable is documentation: reports, deficiency lists, resolution records and final sign-off.
Three activities that get mixed up
On many projects the same phrase, "test and balance," gets used to cover work that belongs to three different parties. Separating them in the scope is the simplest way to prevent a gap or a double charge.
| Activity | What it is | Typically performed by |
|---|---|---|
| Startup and checkout | Energizing and verifying that installed equipment starts, runs safely and meets basic operating parameters | The installing contractor, with manufacturer support where required |
| Testing and balancing (TAB) | Measuring and adjusting airflow and water flow, recording results against design | An independent TAB agency or a qualified party named in the contract |
| Commissioning (Cx) | Verifying systems meet the owner's project requirements through documented review and functional testing | An owner-selected commissioning agent or a designated team |
Davinci's mechanical, refrigeration and controls crew does the startup and checkout of the equipment Davinci installs. Test and balance by a third-party agency, and owner-side commissioning, are separate roles that the owner or general contractor must assign and confirm.
Name the party, the hiring chain and the access rules
A common failure is a scope that says "system shall be balanced" without saying who balances it. Fix it with four answers.
- Who performs the work: agency name or the qualification the owner requires.
- Who hires and pays the agency: owner, general contractor or mechanical contractor.
- What the mechanical contractor must provide: accessible equipment, open dampers, clean filters, set belts, working controls and a ready-for-balancing notice.
- Who pays for repeated visits when the system was not actually ready.
Specifications on public projects often require certification of the agency by a recognized body. Confirm the requirement in the documents. For bid-package reading, see public works HVAC bid scope.
Startup and checkout: what the installing contractor owns
Startup is the contractor's proof that the equipment works as installed. It comes before balancing, because an agency cannot measure a system that is not running correctly.
- Electrical readiness confirmed with the responsible party: voltage, phase and disconnects.
- Rotation, belt tension, alignment and lubrication checks on fans and motors.
- Refrigerant circuit checks: charge, pressures, superheat and subcooling readings recorded.
- Safety devices verified, including pressure cutouts, freeze protection and limit switches.
- Gas train and combustion checks where applicable, and condensate and drain testing.
- Controls point-to-point verification and confirmation that the sequence runs.
- Startup report with serial numbers, readings and photos.
Those records become the baseline for future maintenance. When the startup readings sit in an asset record such as the DaVinci Portal, later readings have something to be compared against.
What a TAB scope should require
A balancing agency measures supply, return and exhaust airflow at terminals and equipment, adjusts dampers, pulleys and drives, and reports results against design. On hydronic systems the same applies to pump and coil flow. The scope should state the standard of acceptance, such as a tolerance to design values, that the contract defines.
Report content
- Instrument list and calibration status.
- Design versus measured values by terminal, coil and equipment.
- Final damper, valve and drive settings.
- Deficiencies noted, with who is responsible for correction.
- Drawings or schedules marked with measured values.
Balancing is sensitive to later changes. After a tenant improvement or a controls upgrade, rebalance the affected zones and update the report.
Functional performance tests and seasonal testing
Functional performance tests (FPTs) force a system through its sequence and record what actually happens. They need a written sequence of operation, which is why an unclear sequence is a commissioning problem as well as a programming one. See building automation controls upgrade scope.
- Commissioning agent writes test procedures from the approved sequences.
- The mechanical and controls contractors prepare the system and confirm readiness.
- Tests run, with results recorded: pass, fail or not testable.
- Deficiencies are listed, corrected by the responsible party and retested.
- Final report shows resolution of each item and any open issues.
Seasonal testing matters because a building finished in a mild month cannot prove it handles peak cooling or winter heating. If the scope calls for deferred tests, state which ones, when they occur, who attends and how results are added to the record. Heating tests in a building commissioned during summer, and peak-cooling tests during a cooler season, are typical examples. Economizer and energy-code acceptance items should be confirmed against current Title 24 requirements.
Documentation that closes the job
The finish line for this scope is paper that the owner can use later. Without it, the building has equipment that works today and no proof of how it was set up.
- Startup reports from the installing contractor.
- Final TAB report, signed by the responsible agency.
- Commissioning plan, test procedures, completed FPTs and issues log.
- Updated sequences of operation and controls backups.
- Training records for operators and maintenance staff.
- Seasonal test schedule and results when deferred tests are required.
Contractor shall perform startup and checkout of the equipment it installs and shall deliver startup reports to Owner. Testing and balancing shall be performed by the independent agency named in the contract documents, and Contractor shall provide a written notice when systems are ready for balancing. Contractor shall participate in functional performance testing directed by the commissioning agent and shall correct deficiencies assigned to Contractor. Deferred seasonal tests shall be scheduled with Owner.