Ongoing Commissioning and Monitoring-Based Commissioning (MBCx)

1. Introduction

Ongoing Commissioning (OCx) and Monitoring-Based Commissioning (MBCx) represent advanced strategies in building performance optimization, extending the traditional commissioning process beyond the initial occupancy phase into the operational life of a facility. While conventional commissioning ensures that new or renovated buildings and their systems are designed, installed, tested, and capable of being operated and maintained according to the Owner's Project Requirements (OPR), OCx and MBCx provide continuous oversight to sustain and enhance this performance over time. OCx is a broad term encompassing various approaches to continuous performance verification, whereas MBCx specifically leverages advanced data analytics and fault detection diagnostics (FDD) from Building Management Systems (BMS) and Energy Management Information Systems (EMIS) to identify and address operational inefficiencies proactively [1].

These methodologies are applicable to a wide range of project types, from large commercial and institutional buildings to industrial facilities, where complex HVAC, lighting, and control systems are critical for energy efficiency, occupant comfort, and operational reliability. Buildings with significant energy consumption, intricate system interactions, or those pursuing high-performance green building certifications are particularly well-suited for OCx and MBCx implementation.

The regulatory landscape increasingly drives the adoption of OCx and MBCx. Energy codes and standards, such as ASHRAE Standard 90.1, often mandate or incentivize continuous performance monitoring. Green building rating systems like LEED and WELL also incorporate requirements for ongoing commissioning, recognizing its role in achieving and maintaining high levels of sustainability and occupant well-being. These drivers underscore the growing recognition of OCx and MBCx as essential practices for ensuring long-term building performance and meeting evolving environmental and operational goals.

2. Standards and Requirements

The implementation of Ongoing Commissioning (OCx) and Monitoring-Based Commissioning (MBCx) is guided by various industry standards and green building certification programs, ensuring a structured and effective approach to continuous building performance optimization. These standards define the processes, roles, and documentation necessary for successful OCx/MBCx integration.

ASHRAE Standards and Guidelines

ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) provides foundational guidelines for commissioning processes, which are extended to ongoing and monitoring-based approaches:

• ASHRAE Guideline 0-2019, The Commissioning Process [2]: This guideline outlines the fundamental commissioning process for facilities, from pre-design through occupancy and operation. It serves as a comprehensive framework that can be adapted for OCx, emphasizing a systematic quality-oriented approach to verify that a facility and its systems meet the Owner's Project Requirements (OPR).
• ASHRAE Standard 202-2024, The Commissioning Process Requirements for New Buildings and New Systems [3]: This standard describes the commissioning process for new buildings and systems, defining roles, documentation, and procedures. While primarily focused on new construction, its principles are directly applicable to establishing the baseline for ongoing performance verification in OCx and MBCx.
• ASHRAE Standard 230-2022, Commissioning Process for Existing Buildings and Systems [4]: This standard specifically addresses existing buildings, providing requirements for commissioning activities from planning through initial ongoing commissioning. This is particularly relevant for retro-commissioning and the initiation of OCx programs.
• ASHRAE Guideline 0.2-2015, Commissioning Process for Existing Systems and Assemblies [5]: This guideline offers a detailed roadmap for improving the performance and sustainability of existing facilities through a systematic quality-oriented process, including planning, assessing, investigating, implementing, verifying, and documenting performance to meet defined operational requirements, which is central to OCx.
• ASHRAE Guideline 1.2-2019, Technical Requirements for the Commissioning Process for Existing HVAC&R Systems and Assemblies [6]: This guideline provides specific technical requirements for applying the commissioning process to existing HVAC&R systems, crucial for the detailed technical aspects of MBCx.

NEBB (National Environmental Balancing Bureau)

NEBB offers certification programs and procedural standards for various building systems, including commissioning. The NEBB Building Systems Technical Commissioning Procedural Standard provides comprehensive guidance for firms performing technical building systems commissioning, ensuring adherence to rigorous quality and performance verification protocols. While not exclusively focused on OCx/MBCx, its emphasis on detailed testing, balancing, and system verification forms a critical basis for the continuous monitoring and diagnostics inherent in MBCx [7].

AABC (Associated Air Balance Council) Commissioning Group (ACG)

The AABC Commissioning Group (ACG) is dedicated to the advancement of independent, third-party commissioning services. ACG provides certification for Commissioning Authorities (CxA) and publishes guidelines that promote a thorough and independent commissioning process. The ACG Commissioning Guideline describes the commissioning process and includes sample forms, specifications, and checklists, which are valuable resources for developing and implementing OCx and MBCx programs, particularly in ensuring the independence and technical competence of the commissioning team [8].

Green Building Certification Programs

Green building rating systems integrate commissioning as a fundamental component for achieving and maintaining high-performance buildings:

• LEED (Leadership in Energy and Environmental Design) [9]: Developed by the U.S. Green Building Council (USGBC), LEED includes several credits related to commissioning:

  • Fundamental Commissioning (EAp3) [10]: This is a prerequisite in LEED v4.1 (and earlier versions) for Building Design and Construction (BD+C) and Operations and Maintenance (O+M) rating systems. It requires the completion of basic commissioning process activities for mechanical, electrical, plumbing, and renewable energy systems, including the development of an Owner's Project Requirements (OPR), Basis of Design (BOD), and a commissioning plan. For OCx, a key requirement is to develop an ongoing commissioning plan during the occupancy/operations phase.
  • Enhanced Commissioning (EAc1) [11]: This is an optional credit that builds upon fundamental commissioning, requiring more extensive commissioning activities such as enhanced system testing, development of a systems manual, and a plan for ongoing commissioning. This credit directly supports the implementation of OCx and MBCx by incentivizing continuous performance verification.

• WELL Building Standard [12]: Administered by the International WELL Building Institute (IWBI), the WELL Building Standard focuses on enhancing human health and well-being through the built environment. While WELL does not have a specific commissioning credit in the same way as LEED, its Performance Verification process involves rigorous on-site testing and measurement of various parameters related to air, water, light, and thermal comfort to ensure that the building performs as intended to support occupant health and well-being. This continuous monitoring and verification align closely with the principles of MBCx, as it relies on data-driven insights to maintain optimal indoor environmental quality [13].

These standards and certification programs collectively emphasize the importance of a systematic, quality-oriented approach to commissioning, providing a robust framework for the successful implementation and sustained benefits of Ongoing Commissioning and Monitoring-Based Commissioning.

3. Process and Procedures

Ongoing Commissioning (OCx) and Monitoring-Based Commissioning (MBCx) involve systematic processes designed to ensure continuous optimal performance of building systems. While the specific steps may vary depending on the project scope and the chosen methodology, a general framework includes planning, implementation, and continuous optimization phases.

Step-by-Step Procedures for OCx and MBCx

1. Planning Phase:

   • Define Owner's Project Requirements (OPR) and Current Facility Requirements (CFR): Clearly articulate the owner's goals, operational needs, and performance expectations for the building and its systems. For existing buildings, this includes understanding current operational challenges and desired improvements.
   • Develop a Commissioning Plan: Outline the scope of work, team roles and responsibilities, communication protocols, schedule, and deliverables. This plan should specifically address the continuous nature of OCx/MBCx.
   • Establish Performance Metrics and Baselines: Identify key performance indicators (KPIs) for energy consumption, indoor environmental quality (IEQ), equipment run-times, and other relevant parameters. Establish baselines against which future performance will be measured.
   • Select and Configure Monitoring Tools: Choose appropriate Energy Management Information Systems (EMIS), Building Automation Systems (BAS), and Fault Detection and Diagnostics (FDD) software. Configure data points, alarms, and reporting functionalities.

2. Implementation Phase:

   • System Integration and Data Acquisition: Connect all relevant building systems (HVAC, lighting, power, etc.) to the EMIS/BAS for centralized data collection. Ensure data quality and integrity.
   • Baseline Performance Verification: Conduct initial performance tests and measurements to validate the established baselines and identify any immediate operational issues.
   • Develop FDD Rules and Algorithms: Configure the FDD software with rules and algorithms to automatically detect common faults, operational inefficiencies, and deviations from optimal performance. This may involve custom rules based on system specifics.
   • Initial Optimization and Corrective Actions: Address any identified issues from baseline verification and initial FDD analysis. Implement low-cost operational improvements and fine-tune system controls.

3. Continuous Optimization Phase:

   • Ongoing Monitoring and Analysis: Continuously collect and analyze data from building systems using EMIS/BAS and FDD tools. Regularly review performance dashboards and reports.
   • Fault Detection and Diagnosis: The FDD system automatically identifies potential faults, such as simultaneous heating and cooling, excessive run-times, or sensor malfunctions. Commissioning providers (CxP) or facility managers investigate and diagnose the root causes.
   • Prioritization and Implementation of Corrective Measures: Based on the severity and potential impact, prioritize identified faults and implement corrective actions. This may involve control adjustments, maintenance activities, or minor system modifications.
   • Measurement and Verification (M&V): Quantify the energy savings and other benefits achieved through implemented corrective actions. This involves comparing post-implementation performance against established baselines.
   • Reporting and Communication: Regularly report on building performance, identified issues, implemented solutions, and achieved savings to stakeholders. Maintain clear communication channels within the building operations team.
   • Continuous Improvement: Periodically review and update OPR/CFR, commissioning plans, FDD rules, and performance metrics to adapt to changing building usage, technology advancements, and evolving performance goals.

Checklists and Forms

Effective OCx and MBCx rely on structured documentation to ensure consistency and thoroughness. Examples of checklists and forms include:

• Pre-Design/Design Phase Checklists: For reviewing OPR, BOD, design documents, and commissioning specifications.
• Construction Phase Checklists: For verifying equipment installation, pre-functional checks, and functional performance tests.
• Functional Performance Test (FPT) Forms: Detailed procedures and data sheets for testing specific system components and sequences of operation.
• Issues Log/Deficiency Tracking Forms: To document identified faults, their severity, proposed solutions, responsible parties, and resolution status.
• Trend Log Review Forms: For systematic analysis of historical operational data from BAS/EMIS.
• Measurement and Verification (M&V) Reports: To document energy savings and other performance improvements achieved.
• Systems Manual and O&M Manual Review Checklists: To ensure comprehensive and accurate documentation for ongoing operations.
• Training Verification Forms: To confirm that facility staff have received adequate training on system operation and maintenance.

These documents are crucial for maintaining a clear record of the commissioning process, facilitating communication, and ensuring accountability throughout the continuous optimization cycle [14].

4. Instruments and Tools

Effective Ongoing Commissioning (OCx) and Monitoring-Based Commissioning (MBCx) rely on a combination of specialized instruments for data collection and verification, and sophisticated software platforms for continuous monitoring and analysis. The accuracy and reliability of these tools are paramount to identifying and resolving building performance issues.

Required Test Instruments

While much of MBCx relies on data from existing Building Automation Systems (BAS) and Energy Management Information Systems (EMIS), periodic field verification and diagnostic testing require specific instruments. These instruments must be properly calibrated to ensure accurate measurements:

• Airflow Measurement Devices: Anemometers (hot-wire, vane, thermal), capture hoods, and pitot tubes are used to measure air velocity and volume in ducts and at diffusers/grilles. These are critical for verifying HVAC system performance and ventilation rates.
• Temperature and Humidity Sensors: Digital thermometers, thermistors, thermocouples, and hygrometers are used to measure air and surface temperatures, as well as relative humidity. These are essential for assessing thermal comfort, system efficiency, and identifying issues like simultaneous heating and cooling.
• Pressure Measurement Devices: Manometers, differential pressure gauges, and pressure transducers are used to measure static and differential pressures across coils, filters, and fans, as well as duct static pressure. These help in diagnosing airflow restrictions and fan performance.
• Electrical Measurement Devices: Multimeters, clamp-on ammeters, power quality meters, and data loggers are used to measure voltage, current, power (kW), energy (kWh), and power factor. These are vital for assessing electrical system performance, motor efficiency, and overall energy consumption.
• Combustion Analyzers: Used for testing combustion efficiency of boilers, furnaces, and other combustion equipment, measuring parameters like O2, CO, and flue gas temperature.
• Light Meters: Used to measure illuminance levels in occupied spaces to verify lighting system performance and compliance with design standards.
• Infrared Cameras (Thermal Imagers): Used for non-invasive detection of thermal anomalies in building envelopes, electrical panels, and mechanical equipment, indicating insulation deficiencies, air leaks, or overheating components.

Calibration Requirements

All test instruments used in commissioning, including those for OCx and MBCx, must undergo regular calibration to maintain accuracy and traceability to national standards. Calibration frequencies typically range from annually to every two years, depending on the instrument type, manufacturer recommendations, and usage intensity. Documentation of calibration certificates is essential for quality assurance and compliance with standards such as ISO/IEC 17025. Organizations like NEBB and AABC often specify strict calibration requirements for their certified professionals and firms [7, 8].

Software

Software platforms are the backbone of MBCx, enabling continuous data acquisition, analysis, and fault detection:

• Building Automation Systems (BAS): The primary control system for HVAC, lighting, and other building services. BAS collects real-time operational data, which is then leveraged by EMIS and FDD tools.
• Energy Management Information Systems (EMIS): These platforms integrate data from BAS, utility meters, and other sources to provide comprehensive energy consumption and performance analytics. EMIS typically offer dashboards, reporting features, and benchmarking capabilities.
• Fault Detection and Diagnostics (FDD) Software: FDD tools use algorithms and rules to automatically identify operational anomalies, equipment malfunctions, and energy waste patterns from BAS/EMIS data. They can pinpoint specific issues, prioritize them based on impact, and often suggest corrective actions. Advanced FDD systems can learn building behavior and adapt their diagnostic capabilities over time.
• Data Visualization and Reporting Tools: These tools help in presenting complex operational data in an understandable format, facilitating decision-making and communication among stakeholders. They can be standalone applications or integrated features within EMIS/FDD platforms.

The integration of these instruments and software tools provides a powerful ecosystem for continuous performance monitoring, enabling proactive identification and resolution of issues, thereby sustaining and enhancing building efficiency and comfort over its lifecycle.

5. Acceptance Criteria

Acceptance criteria in Ongoing Commissioning (OCx) and Monitoring-Based Commissioning (MBCx) define the performance benchmarks and tolerances that building systems must meet to be considered operating optimally. These criteria are established during the planning phase, often derived from the Owner's Project Requirements (OPR), Basis of Design (BOD), and relevant industry standards. They serve as the basis for evaluating system performance, identifying deviations, and verifying the effectiveness of corrective actions.

Performance Benchmarks

Performance benchmarks are quantitative or qualitative targets that represent desired operational states. These can include:

• Energy Consumption Targets: Specific kWh/sq ft/year or BTU/sq ft/year for the entire building or individual systems, often benchmarked against similar buildings, design models, or historical data. These targets are crucial for assessing energy efficiency and identifying opportunities for savings.
• Indoor Environmental Quality (IEQ) Parameters: Setpoints and ranges for temperature, relative humidity, CO2 levels, and lighting levels in occupied spaces. These benchmarks ensure occupant comfort and health, aligning with standards like ASHRAE Standard 55 (Thermal Environmental Conditions for Human Occupancy) and ASHRAE Standard 62.1 (Ventilation for Acceptable Indoor Air Quality).
• Equipment Performance Metrics: Specific operational parameters for HVAC equipment, such as chiller kW/ton, boiler efficiency, fan static pressure, pump head, and motor amperage. These metrics indicate the efficiency and health of individual components.
• System Run-Time and Cycling: Optimal run-time schedules and acceptable cycling rates for equipment to minimize wear and tear and maximize efficiency. Excessive run-times or short cycling often indicate control issues or improper sizing.
• Occupancy Schedules and Setpoint Compliance: Verification that building systems adhere to programmed occupancy schedules and maintain appropriate setpoints during occupied and unoccupied periods.

Tolerances

Tolerances define the permissible deviation from the established performance benchmarks. They acknowledge that perfect adherence to setpoints or benchmarks is often impractical and allow for minor fluctuations within acceptable limits. Establishing appropriate tolerances is critical to avoid nuisance alarms while still capturing significant performance deviations. Examples include:

• Temperature Setpoint Deviation: A common tolerance might be ±1-2°F (±0.5-1°C) from the desired space temperature setpoint.
• CO2 Level Deviation: Tolerances for CO2 levels might be set to ensure they remain below a certain threshold (e.g., 800-1000 ppm above ambient) to maintain good indoor air quality.
• Pressure Differential: Acceptable ranges for pressure drops across filters or coils, indicating when maintenance (e.g., filter replacement) is required.
• Energy Consumption Variance: A percentage deviation (e.g., ±5-10%) from the energy consumption benchmark before an alert is triggered.

Documentation Requirements

Comprehensive documentation of acceptance criteria is essential for transparency, accountability, and the long-term success of OCx/MBCx programs. Key documentation includes:

• Owner's Project Requirements (OPR): A detailed document outlining the owner's functional requirements for the building and its systems, including performance expectations and acceptance criteria.
• Basis of Design (BOD): A document that explains how the design meets the OPR, including design assumptions, calculations, and the rationale behind system selections. The BOD should clearly state the intended performance and how it will be achieved.
• Commissioning Plan: This plan details the acceptance criteria for each system and component, outlining the methods and procedures for verifying compliance.
• Functional Performance Test (FPT) Procedures: Detailed test scripts that specify the expected performance, measurement points, and acceptable tolerances for each test.
• Measurement and Verification (M&V) Plan: Outlines the methodology for quantifying energy savings and other performance benefits, including the acceptance criteria for successful M&V.
• Systems Manual: A comprehensive document providing detailed information about the building's systems, including their intended operation, maintenance procedures, and performance criteria. This manual is a living document that should be updated as systems are optimized.

By clearly defining and documenting these acceptance criteria, OCx and MBCx programs can effectively monitor, evaluate, and ensure that building systems consistently operate at their intended performance levels, delivering sustained energy efficiency, comfort, and operational reliability [10, 13, 14].

6. Roles and Responsibilities

Successful implementation and ongoing management of Ongoing Commissioning (OCx) and Monitoring-Based Commissioning (MBCx) require a clear definition of roles, responsibilities, and qualifications for all involved parties. The collaborative nature of these processes necessitates effective communication and coordination among diverse stakeholders.

Key Roles and Their Functions

• Owner/Client: The ultimate decision-maker and beneficiary of the OCx/MBCx process. The owner defines the Owner's Project Requirements (OPR), approves the commissioning plan, provides necessary resources, and ensures the long-term commitment to continuous optimization. Their active involvement is crucial for success.
• Commissioning Provider (CxP): The central figure responsible for leading, planning, coordinating, and managing the commissioning team. For OCx/MBCx, the CxP oversees the continuous monitoring, analysis, and verification activities. The CxP ensures that the building systems operate according to the OPR and identifies opportunities for ongoing improvement. The CxP often acts as an independent third party to ensure objectivity.
• Facility Manager/Operations and Maintenance (O&M) Staff: These individuals are critical to the day-to-day success of OCx/MBCx. They are responsible for implementing corrective actions, performing routine maintenance, operating the building systems, and providing feedback on system performance. Their knowledge of the building's operational history and practical experience are invaluable.
• Building Automation System (BAS) Specialist/Controls Contractor: Responsible for the proper functioning and programming of the BAS, including data acquisition, control sequences, and alarm management. They play a key role in configuring the system to support MBCx data collection and FDD capabilities.
• Energy Management Information System (EMIS) Specialist/Data Analyst: Responsible for managing the EMIS platform, analyzing performance data, developing custom reports, and supporting the FDD process. They translate raw data into actionable insights for the CxP and O&M staff.
• Design Team (Architects, Engineers): While primarily involved in the initial design phase, their input is important for OCx/MBCx, especially when design intent needs clarification or when system modifications are considered. They establish the Basis of Design (BOD) which informs the OPR.
• Contractors (Mechanical, Electrical, Plumbing): Responsible for the proper installation and initial setup of building systems. Their adherence to specifications and quality workmanship during construction lays the groundwork for effective OCx/MBCx.

Qualifications

Personnel involved in OCx/MBCx should possess appropriate qualifications and experience:

• Commissioning Provider (CxP): Typically requires extensive experience in building systems design, construction, and operation, along with specialized training and certification in commissioning (e.g., ACG Certified Commissioning Authority (CxA), ASHRAE Building Commissioning Professional (BCxP), NEBB Certified Professional). Independence from the design and construction teams is often a key requirement to ensure unbiased oversight [8].
• Facility Manager/O&M Staff: Should have a strong understanding of building systems, controls, and energy management principles. Ongoing training on new technologies and OCx/MBCx processes is beneficial.
• BAS/EMIS Specialists: Require expertise in control systems programming, network integration, and data analytics platforms.

Independence Requirements

For many commissioning projects, particularly those pursuing green building certifications like LEED, the CxP is required to be independent of the design and construction teams. This independence ensures objectivity in verifying system performance against the OPR and BOD, preventing potential conflicts of interest. While direct employment by the owner is generally acceptable, the CxP should not be directly involved in the design or installation of the systems being commissioned. This separation of roles is crucial for maintaining the integrity and credibility of the commissioning process, especially in the continuous oversight provided by OCx and MBCx [9, 10].

7. Documentation

Comprehensive and accurate documentation is a cornerstone of effective Ongoing Commissioning (OCx) and Monitoring-Based Commissioning (MBCx). It provides a historical record of system performance, operational changes, and corrective actions, which is invaluable for continuous optimization, troubleshooting, and compliance. The documentation requirements extend throughout the building's lifecycle, from initial planning to ongoing operations.

Required Forms, Reports, and Submittals

• Owner's Project Requirements (OPR): This foundational document, developed at the project's outset, clearly defines the owner's functional requirements for the facility and its systems. It includes performance expectations, environmental conditions, budget, schedule, and sustainability goals. For OCx/MBCx, the OPR is a living document that may be revisited and updated to reflect evolving operational needs.
• Basis of Design (BOD): Prepared by the design team, the BOD explains how the design addresses the OPR. It details design assumptions, system selections, and the rationale behind engineering decisions. The BOD is critical for understanding the intended operation of systems during OCx/MBCx.
• Commissioning Plan: This document outlines the scope, goals, team roles, communication protocols, schedule, and specific tasks for the commissioning process. For OCx/MBCx, it includes details on continuous monitoring strategies, data analysis methods, FDD implementation, and reporting requirements.
• Pre-Functional Checklists (PFCs): Used during the construction phase to verify that equipment is properly installed, connected, and ready for functional testing. PFCs ensure that basic installation requirements are met before more complex testing begins.
• Functional Performance Test (FPT) Reports: Detailed reports documenting the execution and results of functional tests for individual systems and components. These reports verify that systems operate according to the OPR and BOD under various conditions. For OCx/MBCx, FPTs establish a baseline of performance.
• Issues Log/Deficiency Tracking Log: A critical document for recording all identified deficiencies, non-conformances, and operational issues throughout the commissioning process. It tracks the status of each issue, responsible parties, and resolution dates, ensuring that problems are addressed in a timely manner.
• Interim Commissioning Reports: Periodic reports summarizing the progress of commissioning activities, identified issues, and their resolution status. These reports keep stakeholders informed during the implementation phase.
• Final Commissioning Report: A comprehensive document summarizing the entire commissioning process, including a narrative of activities, a list of resolved issues, outstanding items, and recommendations for ongoing operation and maintenance. For OCx/MBCx, this report often includes recommendations for establishing or enhancing continuous monitoring programs.
• Systems Manual: A detailed guide for facility operators, providing comprehensive information on all building systems. It includes system descriptions, operational sequences, maintenance procedures, troubleshooting guides, and performance data. The Systems Manual is essential for effective ongoing operation and is a key reference for OCx/MBCx activities.
• Operations and Maintenance (O&M) Manuals: Manufacturer-provided manuals for all installed equipment, detailing installation, operation, maintenance, and troubleshooting procedures. These are crucial for the O&M staff and for understanding equipment limitations during MBCx analysis.
• Measurement and Verification (M&V) Reports: Documents quantifying the energy savings and other performance benefits achieved through OCx/MBCx activities. These reports compare actual performance against established baselines and provide data-driven evidence of ROI.
• Training Records: Documentation of training provided to facility staff on the operation and maintenance of commissioned systems, including any specialized training for EMIS/FDD platforms.

Record Retention

Effective record retention is vital for the long-term success of OCx/MBCx. All commissioning documentation, including reports, forms, test data, and correspondence, should be systematically organized and stored in an accessible format. Digital archiving is often preferred for ease of access, searchability, and integration with building information modeling (BIM) or facility management software. The retention period should align with regulatory requirements, warranty periods, and the expected lifespan of the building, typically extending for the entire operational life of the facility to support continuous improvement and future retro-commissioning efforts [14].

8. Cost and ROI

Ongoing Commissioning (OCx) and Monitoring-Based Commissioning (MBCx) represent an investment that yields significant returns through improved building performance, reduced operating costs, and extended equipment life. Understanding the typical costs and the potential return on investment (ROI) is crucial for justifying these initiatives.

Typical Costs

The costs associated with implementing OCx and MBCx can vary widely depending on the building's size, complexity, existing infrastructure, and the scope of the commissioning effort. Key cost components include:

• Initial Setup Costs: This includes the cost of commissioning services for planning, system assessment, and initial optimization. It may also involve upgrades to existing Building Automation Systems (BAS), installation of additional sensors, or implementation of Energy Management Information Systems (EMIS) and Fault Detection and Diagnostics (FDD) software. These costs can range from $0.30 to $1.00 per square foot for existing buildings, with more complex systems or significant infrastructure upgrades potentially higher.
• Software Licenses and Maintenance: Annual fees for EMIS and FDD software licenses, as well as ongoing support and maintenance contracts.
• Commissioning Provider (CxP) Fees: Ongoing fees for the CxP to perform data analysis, diagnose faults, recommend corrective actions, and verify implemented measures. These can be structured as a fixed annual fee, a percentage of identified savings, or a combination.
• Facility Staff Training: Investment in training O&M staff to effectively utilize EMIS/FDD tools and participate in the continuous commissioning process.
• Corrective Action Implementation: Costs associated with implementing recommended operational changes, control adjustments, or minor equipment repairs. Major capital improvements are typically outside the direct cost of OCx/MBCx but may be identified as a result of the process.

Energy Savings and Payback Periods

The primary driver for OCx and MBCx is often energy savings, which can be substantial and lead to attractive payback periods. Studies and real-world case studies consistently demonstrate significant energy reductions:

• Average Energy Savings: Research by Lawrence Berkeley National Laboratory (LBNL) and other organizations indicates that existing building commissioning, including OCx and MBCx, typically achieves energy savings ranging from 5% to 15% in commercial buildings, with some projects realizing even higher savings [1, 15]. For example, the combination of EMIS with an MBCx process has been shown to reduce building energy waste up to 15 percent [1].
• Non-Energy Benefits: Beyond energy savings, OCx/MBCx delivers numerous non-energy benefits that contribute to the overall ROI:
  • Improved Occupant Comfort and Productivity: Optimized HVAC and lighting systems lead to better indoor environmental quality, reducing occupant complaints and enhancing productivity.
  • Extended Equipment Life: Proactive identification and correction of operational issues reduce wear and tear on equipment, extending its lifespan and deferring capital expenditures.
  • Reduced Maintenance Costs: Early detection of faults prevents minor issues from escalating into costly breakdowns, leading to more efficient and planned maintenance.
  • Enhanced System Reliability: Consistent monitoring ensures systems operate reliably, minimizing downtime and disruptions.
  • Better Documentation and Institutional Knowledge: The process generates comprehensive documentation and improves the O&M staff's understanding of building systems.
  • Compliance with Green Building Standards: Helps achieve and maintain certifications like LEED and WELL, which can enhance property value and marketability.
• Typical Payback Periods: Due to the significant energy savings and operational benefits, OCx and MBCx projects often have very attractive payback periods, typically ranging from 1 to 3 years. In many cases, the energy savings alone can offset the implementation costs within this timeframe, making it a financially sound investment for building owners and operators [1, 15].

For instance, a study on existing building commissioning found a median payback period of 1.1 years for retro-commissioning projects, with median energy savings of 16% [15]. While these figures are for retro-commissioning, the continuous nature of OCx and MBCx ensures that these savings are sustained and often improved upon over time, providing a continuous positive ROI.

9. Common Challenges

While Ongoing Commissioning (OCx) and Monitoring-Based Commissioning (MBCx) offer substantial benefits, their successful implementation and sustained effectiveness can be hindered by several common challenges. Recognizing these obstacles and developing strategies to overcome them is crucial for maximizing the value of these processes.

Typical Problems Encountered and How to Resolve Them

1. Lack of Owner Commitment and Resources:

   • Problem: Without strong commitment from building owners or management, OCx/MBCx initiatives may lack the necessary funding, staffing, or long-term support to be effective. This can lead to a focus on initial cost rather than long-term savings.
   • Resolution: Emphasize the clear financial benefits and ROI through detailed cost-benefit analyses and case studies. Educate owners on the non-energy benefits, such as improved occupant comfort, extended equipment life, and enhanced asset value. Integrate OCx/MBCx into overall asset management strategies and capital planning.

2. Poor Data Quality and Integration:

   • Problem: Inaccurate, incomplete, or inconsistent data from Building Automation Systems (BAS), meters, or sensors can undermine the effectiveness of MBCx. Lack of integration between different systems can also create data silos and hinder comprehensive analysis.
   • Resolution: Implement robust data validation protocols. Invest in proper sensor calibration and maintenance. Prioritize interoperability during system upgrades or new installations. Utilize data cleansing tools and establish clear data governance policies. Consider phased implementation, starting with critical systems and expanding as data quality improves.

3. Inadequate Staff Training and Expertise:

   • Problem: Facility staff may lack the necessary training or expertise to operate complex EMIS/FDD software, interpret data, diagnose faults, or implement corrective actions. This can lead to identified issues remaining unresolved.
   • Resolution: Provide comprehensive training programs for O&M staff on EMIS/FDD platforms, control strategies, and the principles of OCx/MBCx. Foster a culture of continuous learning. Consider engaging external commissioning providers (CxP) to mentor internal staff and transfer knowledge.

4. Resistance to Change and Organizational Silos:

   • Problem: Resistance from O&M staff, IT departments, or other stakeholders due to fear of new technology, increased workload, or perceived threats to existing roles. Organizational silos can prevent effective collaboration between different departments.
   • Resolution: Involve all stakeholders early in the planning process. Clearly communicate the benefits of OCx/MBCx for all parties. Establish cross-functional teams and foster a collaborative environment. Highlight how technology can augment, rather than replace, human expertise.

5. Complexity of Building Systems and Controls:

   • Problem: Modern buildings often feature highly complex and interconnected systems, making it challenging to understand their interactions, diagnose subtle faults, and optimize performance without specialized tools and knowledge.
   • Resolution: Utilize advanced FDD software capable of handling complex system interactions. Employ experienced CxPs with deep knowledge of building systems and controls. Develop detailed systems manuals and O&M procedures to aid in understanding and troubleshooting.

6. Lack of Clear Roles and Responsibilities:

   • Problem: Ambiguity regarding who is responsible for specific tasks within the OCx/MBCx process can lead to missed opportunities, delayed actions, or unresolved issues.
   • Resolution: Clearly define and document roles, responsibilities, and communication protocols for all team members, from the owner to the O&M staff. Use RACI (Responsible, Accountable, Consulted, Informed) matrices to clarify involvement in key activities.

7. Difficulty in Quantifying ROI:

   • Problem: Accurately measuring and verifying energy savings and other benefits can be challenging, making it difficult to demonstrate the value of OCx/MBCx and secure continued investment.
   • Resolution: Implement robust Measurement and Verification (M&V) plans based on recognized protocols (e.g., IPMVP). Use EMIS tools with strong M&V capabilities. Regularly report on achieved savings and non-energy benefits to stakeholders to build confidence and support [1, 14, 15].

Addressing these challenges proactively through careful planning, stakeholder engagement, continuous training, and the strategic use of technology can significantly enhance the success and long-term impact of OCx and MBCx programs.

10. Case Studies or Examples

Real-world applications of Ongoing Commissioning (OCx) and Monitoring-Based Commissioning (MBCx) consistently demonstrate their effectiveness in improving building performance, reducing energy consumption, and enhancing operational efficiency. These case studies highlight the tangible benefits and diverse scenarios where OCx/MBCx can be successfully implemented.

Representative Scenarios and Specific Outcomes

1. Large University Campus - Sustained Energy Savings:

   • Scenario: A large university implemented MBCx across several academic and administrative buildings to address escalating energy costs and improve system reliability. The campus utilized an advanced EMIS integrated with their existing BAS to monitor HVAC systems, lighting, and plug loads.
   • Outcome: The MBCx program identified numerous operational inefficiencies, including simultaneous heating and cooling, overridden setpoints, and scheduling errors. Through continuous monitoring and corrective actions, the university achieved an average 12% reduction in energy consumption across the commissioned buildings within the first year, translating to significant annual cost savings. The program also led to a 20% decrease in HVAC-related occupant complaints due to improved thermal comfort and indoor air quality [16].

2. Medical Office Building - Rapid Payback and Enhanced Comfort:

   • Scenario: A medical office building sought to optimize its HVAC system performance to ensure a comfortable and healthy environment for patients and staff, while also reducing operating expenses. They implemented an MBCx program focusing on their variable air volume (VAV) systems and central plant.
   • Outcome: The MBCx initiative quickly identified issues such as improperly calibrated sensors, leaky VAV boxes, and inefficient chiller sequencing. By addressing these issues, the building achieved a 15% reduction in energy use and an impressive payback period of just 0.5 years on their MBCx investment. Beyond energy savings, the improved system control led to more stable indoor temperatures and enhanced occupant satisfaction [17].

3. Commercial Office Tower - Proactive Maintenance and Extended Equipment Life:

   • Scenario: A multi-story commercial office tower implemented MBCx to move from reactive to proactive maintenance, aiming to extend the lifespan of its critical HVAC equipment and reduce unexpected breakdowns. The MBCx system continuously analyzed data from chillers, boilers, and air handling units (AHUs).
   • Outcome: The FDD capabilities of the MBCx system detected early signs of equipment degradation, such as increasing motor current in an AHU fan and declining heat exchanger efficiency in a chiller. Proactive maintenance based on these insights prevented potential equipment failures, saving the building owner an estimated $50,000 in emergency repair costs and extending the operational life of key components by several years. The building also maintained consistent energy performance, avoiding the typical degradation seen in unmonitored systems [18].

4. Retail Chain - Scalable Energy Management:

   • Scenario: A national retail chain with numerous stores implemented a standardized MBCx program across its portfolio to manage energy consumption centrally and ensure consistent operational performance. The program leveraged cloud-based EMIS and FDD platforms.
   • Outcome: The MBCx program enabled the retail chain to identify and rectify common operational issues across multiple locations, such as lighting left on after hours and HVAC systems running unnecessarily during unoccupied periods. This resulted in an average 8% portfolio-wide energy reduction, contributing to significant annual savings. The standardized approach also streamlined energy reporting and compliance efforts, demonstrating the scalability of MBCx for distributed building portfolios [19].

These case studies underscore that OCx and MBCx are not merely theoretical concepts but practical strategies that deliver measurable financial and operational benefits across various building types and scales. The continuous nature of these processes ensures that these benefits are sustained over the long term, adapting to changes in building usage and external conditions.

11. FAQ Section

Here are some frequently asked questions regarding Ongoing Commissioning (OCx) and Monitoring-Based Commissioning (MBCx):

Q1: What is the primary difference between traditional commissioning and Ongoing Commissioning (OCx)?

A1: Traditional commissioning typically focuses on verifying that a building's systems are designed, installed, and operating correctly at the time of substantial completion and initial occupancy. It's a finite process. Ongoing Commissioning (OCx), however, is a continuous process that extends throughout the operational life of the building. It involves continuous monitoring, analysis, and optimization to ensure sustained performance, adapt to changes, and identify and correct operational drift over time.

Q2: How does Monitoring-Based Commissioning (MBCx) differ from general Ongoing Commissioning (OCx)?

A2: MBCx is a specific type of OCx that heavily relies on advanced data analytics and automated Fault Detection and Diagnostics (FDD) software. While OCx is a broader term for continuous performance verification, MBCx specifically leverages data from Building Automation Systems (BAS) and Energy Management Information Systems (EMIS) to automatically identify operational inefficiencies and potential faults, enabling a more proactive and data-driven approach to optimization.

Q3: What are the main benefits of implementing MBCx in an existing building?

A3: The main benefits of MBCx in existing buildings include significant energy savings (typically 5-15%), reduced operational and maintenance costs due to proactive fault detection, extended equipment lifespan, improved indoor environmental quality (IEQ) and occupant comfort, enhanced system reliability, and better compliance with green building standards. It transforms reactive maintenance into a more strategic, predictive approach.

Q4: Is MBCx only for large, complex buildings, or can smaller facilities benefit?

A4: While MBCx is often associated with large, complex commercial and institutional buildings due to their intricate systems and higher energy consumption, smaller facilities can also benefit. The scalability of EMIS and FDD technologies means that solutions can be tailored to various building sizes. For smaller facilities, the focus might be on more targeted monitoring of critical systems or leveraging cloud-based, more affordable MBCx platforms.

Q5: What role does the facility staff play in a successful MBCx program?

A5: Facility staff play a crucial role in MBCx. They are the primary implementers of corrective actions identified by the MBCx system and commissioning provider. Their deep understanding of the building's daily operations, equipment, and occupant needs is invaluable. Active participation in training, providing feedback on system performance, and collaborating with the commissioning team are essential for the long-term success and sustainability of the MBCx program.

12. Internal Links

• HVAC Glossary
• HVAC Commissioning
• HVAC Controls
• HVAC Energy Auditing
• HVAC Measurement & Testing

References

[1] FacilitiesNet. (2018, September 10). How To Implement Monitoring-Based Commissioning. Retrieved from https://www.facilitiesnet.com/buildingautomation/article/How-To-Implement-Monitoring-Based-Commissioning--17961
[2] ASHRAE. (2019). Guideline 0-2019, The Commissioning Process. Retrieved from https://www.ashrae.org/technical-resources/bookstore/commissioning
[3] ASHRAE. (2024). Standard 202-2024, The Commissioning Process Requirements for New Buildings and New Systems. Retrieved from https://www.ashrae.org/technical-resources/bookstore/commissioning
[4] ASHRAE. (2022). Standard 230-2022, Commissioning Process for Existing Buildings and Systems. Retrieved from https://www.ashrae.org/technical-resources/bookstore/commissioning
[5] ASHRAE. (2015). Guideline 0.2-2015, Commissioning Process for Existing Systems and Assemblies. Retrieved from https://www.ashrae.org/technical-resources/bookstore/commissioning
[6] ASHRAE. (2019). Guideline 1.2-2019, Technical Requirements for the Commissioning Process for Existing HVAC&R Systems and Assemblies. Retrieved from https://www.ashrae.org/technical-resources/bookstore/commissioning
[7] NEBB. (n.d.). Building Systems Technical Commissioning Procedural Standard. Retrieved from https://www.nebb.org/disciplines/building-systems-commissioning/
[8] AABC Commissioning Group (ACG). (n.d.). Commissioning Guideline. Retrieved from https://www.commissioning.org/commissioningguideline/
[9] U.S. Green Building Council (USGBC). (n.d.). LEED credit library. Retrieved from https://www.usgbc.org/credits
[10] U.S. Green Building Council (USGBC). (n.d.). Fundamental Commissioning (EAp3). Retrieved from https://www.usgbc.org/credits/new-construction-core-and-shell/v5/eap3
[11] U.S. Green Building Council (USGBC). (n.d.). Enhanced Commissioning (EAc1). Retrieved from https://www.usgbc.org/credits/new-construction-core-and-shell-schools-new-construction-retail-new-construction-healthc-173
[12] International WELL Building Institute (IWBI). (n.d.). WELL Building Standard. Retrieved from https://www.wellcertified.com/
[13] International WELL Building Institute (IWBI). (n.d.). WELL Certification. Retrieved from https://www.wellcertified.com/certification/v2/
[14] Lawrence Berkeley National Laboratory. (2017). MBCx Plan Template. Retrieved from https://betterbuildingssolutioncenter.energy.gov/sites/default/files/attachments/MBCx%20Plan%20Template_June%202017_Final-1.pdf
[15] Nadel, S., & Greenberg, S. (2023). Using Monitoring-Based Building Commissioning to Achieve Substantial Energy, Demand, and Emissions Savings. ACEEE. Retrieved from https://www.aceee.org/sites/default/files/pdfs/using_monitoring-based_building_commissioning_to_achieve_substantial_energy_demand_and_emissions_savings_-_encrypt.pdf
[16] Natural Resources Canada. (n.d.). Existing Building Commissioning Case Study Series. Retrieved from https://natural-resources.canada.ca/energy-efficiency/building-energy-efficiency/energy-efficiency-existing-buildings/existing-building-commissioning-case-study-series
[17] Boland. (n.d.). Case Study: Medical Office. Retrieved from https://www.boland.com/post/case-study-medical-office
[18] CMTA. (2023, June 7). The Simple Truth about Monitoring-Based Commissioning. Retrieved from https://www.cmta.com/news/monitoring-based-commissioning
[19] InSite Intelligence. (2025, June 3). Unlocking the Power of Monitoring-Based Commissioning (MBCx). Retrieved from https://www.insiteintelligence.com/optimize-buildings/unlocking-the-power-of-monitoring-based-commissioning-mbcx/