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MMY COMMISSIONINGCOMMISSIONING MADE SIMPLE
Primary Guide

Data Center Commissioning Levels 0–6 Explained

Commissioning levels provide a structured sequence of verification gates. Each level establishes defined activities, responsibilities, documentation, acceptance criteria and readiness requirements before the project proceeds to the next stage.

Commissioning levels are not the same as Uptime Institute Tier classifications. Levels describe how a facility is verified over time; Tiers describe the redundancy and topology of the design.

A strong data-center commissioning strategy should combine the practical Level 0–6 testing sequence with recognized commissioning-process principles:

Owner’s Project Requirements (OPR)Basis of Design (BoD)Commissioning PlanDesign ReviewsSubmittal ReviewsIssues LogFunctional Test ProceduresTrainingSystems ManualFinal Commissioning Report
Rationale

Why use commissioning levels?

01

Divide complex commissioning work into manageable stages

02

Establish measurable readiness gates

03

Clarify stakeholder responsibilities

04

Prevent incomplete systems from progressing prematurely

05

Improve traceability of testing and issue closure

06

Support reliable project scheduling

07

Provide visible status through commissioning tags

08

Create a structured evidence trail for the owner

Using level numbers alone does not guarantee quality. Each project still requires approved procedures, competent personnel, clear acceptance criteria, calibrated instruments, safety controls and complete documentation.

Status Indicators

The commissioning tag system

Tags are project-status indicators and should only be attached after the defined level has been completed, verified and accepted.

Level 0

No physical tag

Level 1

Red tag

Level 2

Yellow tag

Level 3

Green tag

Level 4

Blue tag

Level 5

White tag

Level 6

No physical tag

Typical information on a tag

  • Tag colour
  • Commissioning level
  • Equipment identification
  • System or location
  • Project reference
  • Completion date
  • Contractor or vendor sign-off
  • Designer or consultant sign-off, where required
  • Commissioning authority sign-off
  • Status and next-stage readiness
Level Detail
00

Level 0 — Design and Planning

Typical lead · Commissioning Authority

No tag

Purpose. Establish the commissioning strategy, technical requirements, team structure, programme and documentation before factory or site testing begins.

Form the commissioning team
Develop a responsibility matrix
Review the Owner’s Project Requirements (OPR) and Basis of Design (BoD)
Confirm the design is sufficiently complete
Conduct commissioning-focused design reviews
Review maintainability and testability
Conduct single-point-of-failure (SPOF) reviews
Define the commissioning process and level gates
Hold technical workshops
Establish commissioning meetings and reporting
Define factory testing requirements
Develop the commissioning plan
Develop commissioning specifications
Prepare checklists and testing procedures
Establish the commissioning schedule
Agree issue-classification and closure processes
Define document-control requirements
Plan temporary load banks and test instruments
Establish safety, LOTO and energization processes

Level 0 exit gate. Approved commissioning plan, defined responsibilities, agreed testing scope, approved documentation strategy and an achievable commissioning programme.

01

Level 1 — Factory Testing

Typical lead · Vendor / CxA Witness

Red tag

Purpose. Verify selected equipment at the manufacturer’s facility before it is shipped to site.

Factory Acceptance Testing (FAT)
Factory Witness Testing (FWT)
Equipment QA/QC inspections
Verification against approved submittals
Nameplate and rating verification
Visual and dimensional checks
Functional tests
Performance tests
Protection and control-logic checks
Alarm and interlock verification
Review of test-instrument calibration
Recording test results and observations
Deficiency tracking and closure
Approved FAT/FWT reports
Packaging, preservation and shipping checks

Level 1 exit gate. Factory tests completed, critical issues closed or formally accepted, approved reports issued and equipment released for shipment.

02

Level 2 — Delivery, Installation and Pre-Startup

Typical lead · Contractor

Yellow tag

Purpose. Confirm that equipment has been delivered without damage, installed correctly and completed all required static or dead testing before energization.

Delivery inspection
Damage and preservation checks
Equipment identification
Installation verification
Drawing and specification compliance
Workmanship inspection
Torque verification
Cable continuity and insulation-resistance testing
Earthing and bonding verification
Point-to-point wiring checks
Pipework pressure testing
Cleaning and flushing
Rotational and alignment checks
Sensor and instrument installation
Calibration-certificate review
Pre-functional checklists
Safety and access verification
Outstanding-work review
Energization-readiness review

Level 2 exit gate. Installation complete, static testing accepted, safety controls established and equipment approved for energization or startup.

03

Level 3 — Energization and Startup

Typical lead · OEM / Contractor

Green tag

Purpose. Safely energize and start individual equipment and systems, validate settings and establish stable operation.

Approved energization permit
LOTO and safety controls
Equipment energization
OEM startup
Phase rotation and voltage checks
Equipment settings and setpoint validation
Protection-setting verification
Alarm and trip checks
Control-panel checks
Local and remote operation
BMS or EPMS point verification
Initial sequence checks
Operational adjustments
Baseline operating-data collection
Startup report
Issue and observation closure
Level 4 readiness review

Level 3 exit gate. Equipment operates safely and stably, settings are documented, critical startup issues are closed and the system is ready for functional testing.

04

Level 4 — Functional Performance Testing

Typical lead · Commissioning Authority

Blue tag

Purpose. Verify that individual equipment and complete systems perform according to the project requirements, approved control sequences and design intent.

Approved functional test scripts
Normal operating-mode testing
Standby and redundant-mode testing
Automatic and manual operation
Alarm, trip and interlock testing
Sequence-of-operation verification
Failure and recovery scenarios
Changeover and transfer tests
Load and performance testing
Capacity verification
BMS, EPMS and controls verification
Trending and data analysis
System optimization
Test-result documentation
Issue retesting and closure
Operator training
Level 5 readiness review

Data-center examples

• UPS normal, battery and bypass modes

• Generator start and load acceptance

• ATS source transfer and retransfer

• Chiller and pump lead-lag operation

• Cooling-unit failover

• Control and communication failures

• Power-path redundancy

• Equipment response at partial and full load

Level 4 exit gate. All required modes, interlocks, sequences and performance criteria are verified, with no unresolved issue preventing integrated testing.

05

Level 5 — Integrated Systems Testing

Typical lead · Commissioning Authority

White tag

Purpose. Demonstrate that electrical, mechanical and control systems operate together under realistic load, transition and failure scenarios without unacceptable interruption to critical operations.

Integrated test-script development
Technical workshops and scenario reviews
Approved safety plans and permits
LOTO and emergency-response planning
Load-bank strategy
Temporary cable and instrument planning
Calibration verification
Resource and vendor scheduling
Testing under realistic operating load
Utility-supply failure scenarios
Generator and UPS transition testing
Redundant electrical-path testing
Cooling-plant failure and recovery
Pump, chiller and cooling-unit failover
Controls and communication failures
Heat Load Testing (HLT)
Environmental trending
Electrical power-quality monitoring
Integrated alarm verification
Facility-team participation
Issue logging, retesting and closure
Final IST/HLT reports
Completion of operations training

Level 5 exit gate. Integrated performance has been demonstrated, critical failure scenarios have passed, results are documented and the facility is ready for controlled handover.

06

Level 6 — Closeout, Turnover and Handover

Typical lead · Owner & CxA

No tag

Purpose. Complete commissioning documentation, close issues and transfer the verified facility to the owner and operations team.

Final commissioning documentation
Approved test reports
As-built drawings
O&M manuals
Warranties and spare-parts information
Final site walkdown
Final installation and condition inspection
Issue-log closure
Verification of final settings
BMS and EPMS trend records
Completion of training
Systems Manual
Deep cleaning where required
Lessons-learned workshop
Closeout meeting
Final Commissioning Report
Formal handover and acceptance

Level 6 exit gate. Documentation is complete, systems and settings are verified, training is concluded, agreed issues are closed and formal handover is accepted.

At A Glance

Level comparison table

LevelStagePrimary ObjectiveTypical LeadMain EvidenceTag ColourReadiness Outcome
0Design and PlanningEstablish strategy, requirements, team and documentation before testing begins.Commissioning AuthorityApproved commissioning plan & specificationsNo tagProgramme and scope agreed
1Factory TestingVerify selected equipment at the manufacturer’s facility before shipment.Vendor / CxA WitnessApproved FAT / FWT reportsRed tagEquipment released for shipment
2Delivery, Installation and Pre-StartupConfirm correct delivery, installation and completion of static/dead testing.ContractorPre-functional checklists & static test recordsYellow tagApproved for energization
3Energization and StartupSafely energize and start equipment, validate settings and establish stable operation.OEM / ContractorStartup reports & baseline dataGreen tagReady for functional testing
4Functional Performance TestingVerify equipment and systems perform to approved sequences and design intent.Commissioning AuthorityCompleted functional test scriptsBlue tagReady for integrated testing
5Integrated Systems TestingDemonstrate electrical, mechanical and controls operate together under realistic failure scenarios.Commissioning AuthorityFinal IST / HLT reportsWhite tagReady for controlled handover
6Closeout, Turnover and HandoverComplete documentation, close issues and transfer the verified facility to the owner.Owner & CxAFinal Commissioning Report & Systems ManualNo tagFormal handover accepted
The Sequence

A continuous verification flow

1

Design and Plan

2

Factory Verify

3

Install and Inspect

4

Energize and Start

5

Functionally Test

6

Integrate and Stress Test

7

Handover

Issue management, documentation, safety and stakeholder coordination continue across all levels.

Questions

Frequently asked questions

What are the data-center commissioning levels?
Commissioning (Cx) levels are a structured sequence of verification stages — from Level 0 design and planning through to Level 6 closeout and handover. Each level defines specific activities, responsibilities, documentation and acceptance criteria that must be satisfied before work progresses to the next stage.
Are commissioning levels the same as data-center tiers?
No. Commissioning levels describe how a facility is tested and verified over time. Uptime Institute Tier classifications (Tier I–IV) describe the redundancy and topology of the design. A project can follow the Level 0–6 sequence regardless of its tier.
Who manages each commissioning level?
Leadership shifts by stage: the Commissioning Authority (CxA) drives planning, functional and integrated testing; vendors lead factory tests; contractors lead installation; OEMs lead startup; and the owner and operations team take ownership at handover.
When should the commissioning authority become involved?
As early as possible — ideally during Level 0, while the design is still developing. Early CxA involvement enables design and SPOF reviews, a well-formed commissioning plan and testable acceptance criteria before construction begins.
What is the difference between Level 4 and Level 5?
Level 4 (Functional Performance Testing) verifies individual equipment and systems against their sequences. Level 5 (Integrated Systems Testing) proves that electrical, mechanical and control systems work together under realistic load and failure scenarios without unacceptable interruption.
What is a commissioning readiness gate?
A readiness gate is a defined checkpoint at the end of each level. Work only proceeds once the level’s activities are complete, evidence is documented, and critical issues are closed or formally accepted — preventing incomplete systems from advancing.
What do commissioning tag colours mean?
Tags are project-status indicators applied only after a level is completed and accepted: Level 1 red, Level 2 yellow, Level 3 green, Level 4 blue and Level 5 white. Levels 0 and 6 use no physical tag.
Can a project use Level 1–5 instead of Level 0–6?
Yes. Some programmes number stages differently or fold planning and closeout into adjacent activities. What matters is that the same verification intent — planning, factory, installation, startup, functional, integrated and handover — is covered with clear gates.
What documents are required for commissioning?
Typical documents include the OPR, Basis of Design, commissioning plan, design and submittal review records, checklists, functional test procedures, issues log, test reports, training records, Systems Manual and the Final Commissioning Report.
When is a data center ready for handover?
When integrated testing and critical failure scenarios have passed, documentation is complete, final settings are verified, training is concluded and agreed issues are closed — allowing formal handover to be accepted by the owner.

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