Ongoing Commissioning (OCx)  



Ongoing Commissioning (OCx) provides the means and process to optimize and sustain building performance on an ongoing basis through investigating, analyzing, and monitoring the performance of building systems. As a continuation of the commissioning process typically implemented following NCCx or EBCx, OCx verifies that a facility continues to meet current and evolving Current Facility Requirements, or CFR (OPR for new construction). OCx also facilitates the improvement of building and system performance for efficiency and environmental conditions as the CFR and system technologies change.

Since OCx activities can occur throughout the life of the facility; some of these will be close to continuous in implementation, and others will be repeated, either scheduled or unscheduled, as needed. Manual OCx may be conducted as a non-automated operation usually conducted by a CxP and/or Cx team or by trained building operations and maintenance staff. Increasingly, however, monitoring-based commissioning (MBCx) uses a meter-level or system-level automated data gathering and analytics process.

  • Manual OCx must be conducted with enough frequency and detail to prevent building system degradation over time, based on priority and probability of degradation, with the most frequent items completed at least monthly. Manual OCx includes the engineering and onsite activities to identify, implement, and verify measures for improvement. These are usually integrated into the operations and maintenance functions and include system testing and utility monitoring.

  • Monitoring Based Cx (MBCx) includes the use of automated technology in the form of stand-alone software, an extension to a facility building automation system (BAS), or native functions of the BAS. Building systems and environmental monitoring equipment can also be integrated into the process.

    An Energy Management and Information System (EMIS) is an automated tool used to provide data collection and analysis for MBCx, but the EMIS does not include the engineering and onsite activities to identify, implement, and verify measures for improvement. The OCx process integrates the data and automated reporting results into a planned OCx implementation process that maintains and improves facility performance and ultimately profitability.

stock photo of two workers in hard hats and high viz vests in a wareshouse looking at a tablet

There are many benefits of ongoing commissioning as outlined below.
Photo Credit: Autodesk, Construction Cloud

Ongoing Commissioning Benefits and Goals

OCx sustaining maintenance and optimization activities take advantage of opportunities to save energy, reduce maintenance costs, extend the life cycle of building equipment, and improve operational and environmental performance. As shown in the Building Commissioning Handbook, Third Edition, benefits include:

  • Energy cost savings
  • O&M savings
  • Fewer comfort complaints from building occupants
  • Extended equipment life
  • Reduced risk of system failure
  • Reduce cost of downtime for research, revenues from production, etc.
  • Avoided cost of damage due to unplanned shutdown
  • Increased safety
  • Improved indoor air quality
  • Avoided cost of temporary emergency measures and temporary equipment for critical applications

Ongoing Commissioning Process

OCx includes and extends similar processes to both new construction and existing building commissioning, and is sequenced in three phases: Planning, Implementation, and Sustaining.

As listed more specifically in Building Commissioning: The Process, readers can see that OCx key project requirements and related commissioning activities are similar to those of any commissioning project, whether new construction or existing building commissioning. These include: identifying project requirements and establishing goals, scope, budget, roles, plans, schedules, investigation, analysis, implementation, testing and verification, documentation, and training.

Planning Phase
The Planning Phase may begin during new construction, or in parallel with Existing Building Commissioning, and if OCx is sought, in order to forecast and minimize the OCx budget for personnel and technical/technology requirements. Thus, if the intent is to eventually use OCx, the processes should be planned for and included in the NCCx and/or EBCx planning and application.

During the Planning Phase, a qualified CxP familiar with the tools and process of OCx should be engaged to lead the project team through all phases. The role of the CxP is substantial at the beginning, and is subsequently minimized, or even phased out entirely, as building operations personnel take over the Sustaining Phase.

Similar to developing the OPR, the Planning Phase includes defining and documenting the OCx goals and objectives. The Owner and CxP will also conduct a preliminary cost-benefit analysis to determine if implementing OCx meets the Owner's desired return on investment and building performance requirements.

In the case of an existing building, the CxP will assess current building system conditions to develop baseline measurements, conduct a gap analysis of the existing technology infrastructure, and perform an analysis of the facility CFR in order to plan for future technology use and desired performance requirements. Findings from these analyses will also be used to make necessary corrective system adjustments, possibly through EBCx, prior to implementing OCx.

The Owner and CxP select the individuals who will represent different aspects of building performance and occupants' needs in the delivery process. When OCx is going to use automated systems, the team must include internal staff and professionals responsible for IT, acquisition of software technology and systems integration, along with facility operations personnel who will ultimately be responsible for the OCx process.

The result of the Planning Phase is a formalized, agreed-upon OCx Plan for implementation, including training for future project management and personnel activities.

Implementation Phase
Implementation begins with preparation of a Diagnostic Plan, including itemized tasks and activities assigned to project team members, followed by project execution.

The Diagnostic Plan, developed early in the Implementation Phase, is an outline of commissioning activities to be performed, and tools needed to satisfy the project monitoring and evaluation goals, prior to the setup of data monitoring systems. This enables the OCx team to set up consistently identifiable data monitoring points, frequency of data trends, alarm/notification priorities, infrastructure needs, and reporting systems. The Diagnostic Plan defines diagnostic tasks, and includes lists of required data and information that will be needed to accomplish the diagnostic tasks.

In cases where an EMIS is not being implemented as part of the OCx project, the Diagnostic Plan would specify the means that the project team will use to monitor performance of building systems, using available equipment readings and, where possible, the BAS. It would also include the planning and implementation of additional monitoring systems and testing equipment needed in the facility.

Implementation Phase execution consists of conducting the Diagnostic Plan activities, technology installation, testing and verification, personnel training and coordination, in order to:

  • Establish and maintain baseline/benchmarks and comparison metrics
  • Conduct newly revised hands-on preventive maintenance training
  • Provide technology application training and system access to qualified staff
  • Enable building performance tracking, data acquisition, analytics, and corrective actions
  • Interface with building operations and maintenance functions to maintain and improve performance.
  • Define and distribute actionable communication/coordination methods and procedures
  • Schedule periodic process review
  • Plan for the implementation of system improvements and implementation of new technologies as they evolve.

Sustaining Phase
The first order of business in the Sustaining Phase is to review the facility Systems Manual and create or update a Facility Guide. The purpose of the Facility Guide is to establish and maintain criteria for systems performance and a normal routine for reviewing building mechanical, electrical and lighting systems. The Facility Guide is normally included in the Systems Manual. The CFR, OCx Plan, and Diagnostic Plan can supplement the Facility Guide. The Guide can also include attached sections or references for field observation, calibration, operating instructions, and maintenance tasks for O&M Personnel.

The Sustaining Phase includes the following initial and ongoing activities:

  • Update CFR, OCx, and related OCx process documents
  • Turn over commissioning activities to facility operations staff as defined by the OCx Plan
  • Integrate with and improve regular preventive maintenance
  • Coordinate diagnostic information with facility activities
  • Coordinate activities of preventive maintenance personnel with the OCx team
  • Document and correct performance anomalies
  • Monitor and report results of documented corrective actions
  • Initiate and continue training technical and operations staff as necessary

OCx training, similar to all training to sustain facility performance, is based on the systems' sequences of operation, the operations guide and the O&M manuals as the primary sources of information. Further technical and technology application training for OCx includes content that familiarizes the staff and/or other involved parties with the navigation and features of the technology product(s) and advanced tasks required to use and apply data analytics. BCxA training plans, agendas and instructions and Commissioning for Existing Federal Buildings provide useful tools for conducting hands-on EBCx training.

OCx Team Selection and Management

The OCx Team is composed of professionals and stakeholders who drive the project to completion and sustain the program. The specific roles and responsibilities of the team will change depending on the phase of the OCx project, the facility needs (CFR), and Owner's programs. An experienced CxP should be retained early in the OCx process to assist in the program planning and management. The Owner and their teams must be trained and involved throughout the process for maximum benefits. The chart below, from the BCxA Ongoing Commissioning Best Practices, describes core team roles by phase.

Table 1: (Source: BCxA Ongoing Building Commissioning Best Practices. By permission (

Role Planning Phase Implementation Phase Sustaining Phase
Commissioning Provider (CxP)
  • Update/document CFR
  • Develop OCx Plan
  • Organize OCx Team and set expectations
  • Perform condition assessment
  • Overall lead for Phase
  • Develop and provide Diagnostic Plan
  • Design and support technology implementation
  • Perform Data and analytics review for Master List of Findings
  • Transition OCx to standard operations
  • Perform Periodic review and update of CFR and OCx Plans
Systems Integrator (SI)1
  • Review OCx Plan and OCx goals and objectives
  • Perform technology gap analysis
  • Identify technology requirements
  • Design and manage technology implementation
  • Manage technology solution upgrades and updates as required by periodic CFR and OCx plan changes
    Owner (OCx Champion)
    • Support overall OCx initiative and priority within organization
    • Communicate key OCx project goals and objectives
    • Review OCx Plan for acceptance
    • Communicate CFR/review CFR for updates
    • Support timeline and resource requirements for implementation
    • Review Master List of Findings and approve applicable corrective actions
    • Maintain CFR
    • Engage CxP periodically for ongoing updates to OCx Plan
    • Review OCx results and approve corrective actions for ongoing sustained facility performance
    Owner's IT Representative1
    • Identify Owner security and IT requirements for technology system design considerations
    • Review design and validate implementation of technology solution
    • Support networking and communication requirements in line with Owner security and IT network requirements
    • Maintain network, communication, and security requirements for technology solution
    Facility and BAS Manager
    • Communicate CFR/review CFR for updates
    • Support technology gap analysis for identification and utilization of existing BAS capabilities
    • Support/manage BAS system requirements for data collection and management per the OCx Plan
    • Act as Overall lead for ongoing Sustaining Phase
    Building Operators & Engineers
    • Inform the condition-assessment effort
    • Identify key opportunities for OCx
    • Review and verify Master List of Findings
    • Support corrective actions
    • Incorporate OCx process into Preventive Maintenance Plan
    • Implement OCx process into stable operations
    Technology Provider(s)1
    • Provide OCx team with system capabilities and requirements for OCx Plan consideration
    • Implement technology solution at the direction of the CxP and Systems Integrator
    • Provide ongoing license and solution requirements as applicable to ongoing data management and analytics requirements
    Technology Maintenance Staff1  
    • Support execution of technology system for data management and analytics
    • Maintain technology system firmware and upgrade requirements

    1 Technology related roles and responsibilities are dependent on the specific software and hardware tools used for OCx and are part of the OCx team as required by the technology solution identified for the project.


    Additional Resources

    See the Additional Commissioning Resources page for more information.

    End Notes

    i  ASHRAE definition: Systems Manual: A system-focused composite document that includes the design and construction documentation, facility guide and operation manual, maintenance information, training information, commissioning process records, and additional information of use to the Owner during occupancy and operations.

    ii  ASHRAE definition: Facility Guide: A basic building systems description and operating plan with general procedures and confirmed facility operating conditions, set points, schedules, and operating procedures for use by facility operations to properly operate the facility.