Witnessing/Commissioning

Description 

The Witnessing and Commissioning Strategy defibnes the controleld and auditable process by which Mechanical, Electrical and Public Health (MEP) systems and the Building Management Systems (BMS) are functionally tested, proven and independently assured prior to handover.

The strategy sits within the integrated MEP technical assurance framework, following on from: 

  • MEP Scope (definition and intent)
  • MEP & BMS Level of supervision and site inspections (installation readiness and compliance)
  • Metering (measruement and monitoring capability)

Witnessing and commissioning:

  • Build upon completed supervision and site inspections 
  • Confirm that installed systems operate as designed
  • Demonstrate correct sequencing, interlocks, alarms and resilience modes
  • Provide objective evidence that systems are fit to be accepted into operation

Witnessing and commissioning do not constitute acceptance into maintenance; acceptance only follows after successfuly completion and handover.

Engagement

The Project Manager (PM) is responsible for establishing, coordinating and maintaining the Witnessing and Commissioning Strategy, in collaboration with:

  • Engineering Team. During the course of any project, it will be necessary to speak to the Head of Engineering, Property (Gavin Tang - ka-wing-gavin.tang@imperial.ac.uk) to agree on the Witnessing and Commissioning Strategy
  • Energy & Sustainability
  • MEP Design Consultant(s)
  • MEP & BMS Contractor (s)
  • Controls / BMS Engineers
  • Independent Validation Engineer
  • Maintenance and Operations Teams

For laboratory, research and critical infrastructure projects, engagement shall explicitly address: 

  • System criticality and resilience expectations
  • Enhanced witnessing scope and proving requirements
  • Sequencing to minimise operational and safety risk

Forms and Links

Approvals and Compliance Review

The Witnessing and Commissioning Strategy shall be agreed before completion of Stage 2 and shall not be fundamentally redefined thereafter. Commissioning activities shall not commence unless systems have been fully installed in accordance with approved design and verified as ready through MEP Supervision and Site Inspections. 

Witnessing shall demonstrate: 

  • Compliance with approved design intent and BESPR requirements
  • Correct functional operation, sequencing, interlocks, alarms and safety responses
  • Stable operation where a proving period is required

For BMS Systems: 

  • A 100% functional witness shall be completed by the Independent Validation Engineer
  • A representative sample witness (typically 10%) shall be undertaken by Imperial College London Controls Engineer
  • BMS graphics shall not be made live on the head end until witnessing is complete and approved 

Repeated Subsequent RIBA Stages 

RIBA Stage 2 
  • Identifying systems requiring commissioning and witnessing
  • Defining commissioning and proving expectations, including for laboratory and critical systems
  • Confirming key interfaces affecting commissioning (MEP, BMS, Fire, Metering)
  • Ensuring commissioning considerations inform RIBA Stage 4 technical design decisions
RIBA Stage 4 
  • Detailed commissioning and witnessing methodology
  • Definition of witnessing scope, sampling strategy and responsibilities
  • Alignment with detailed MEP and BMS design, BIM outputs, and control strategies
  • Confirmation of documentation, data and evidence requirements
RIBA Stage 5
  • Progressive commissioning of systems and subsystems (schedule to be agreed upon contractor(s) onboard)
  • Functional testing of controls, interlocks, alarms, safeties and resilience modes
  • Independent Validation Engineer witnessing, where applicable
  • Imperial witnessing
  • Functional commissioning and witnessing of metering, including verification of accuracy, segregration, resilience arrangements and live data integration within BMS/energy monitoring platforms

All activities shall be supported by complete, auditable commissioning and witnessing records.