O&M Glossary

View a list of common terms used in building O&M practices.

Operations and maintenance (O&M) is an evolving field that includes new technologies (high performance and renewable energy) that require new maintenance procedures, "smart" technologies that increase the gathering and analysis of performance data, and federal and agency requirements that require more efficient and resilient operations. 

The Federal Energy Management Program offers the following information to provide agencies with clear explanations of challenges they may encounter and solutions on how to approach new procedures, capabilities, and policies.


Advanced Maintenance Approach: Reliability Centered Maintenance

Well-practiced operations and maintenance (O&M) is one of the most cost-effective methods for ensuring reliability, safety, resiliency, and energy efficiency. Good maintenance practices can generate substantial energy savings and should be considered a resource.

Modern and effective O&M programs rely on four basic approaches:

  1. Reactive/Corrective Maintenance: Fix/replace when broken
  2. Preventive Maintenance: Time-based actions
  3. Predictive Maintenance: Fix it before it breaks
  4. Reliability Centered Maintenance: A strategic combination of the previous three approaches coupled with root-cause analytics.

This best practice focuses on the fourth approach, reliability centered maintenance (RCM) and highlights the benefits of RCM in optimizing O&M program design and delivery. This best practice presents the process and development path, the elements of a successful RCM program, and cost effectiveness via two case studies. It builds on the previous maintenance approaches best practice which provides the groundwork for the optimization of maintenance by offering traditional definitions of the three basic types of maintenance approaches (reactive, preventive, and predictive) and offering the benefits and risks to each.

Reliability centered maintenance can be defined as:

A logical, structured process used to determine the optimal failure management strategies for any system based on the system's reliability characteristics (i.e., the reliability profile) and the intended operating context. RCM defines what must be done for a system to achieve the desired levels of safety, environmental soundness, and operational readiness at the best cost. 

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Applying Key Performance Indicators

Developing and applying key performance indicators (KPIs) is a valuable way for building owners and their O&M organizations to measure O&M performance and identify areas in need of improvement.

There is an ever-increasing number, variety, and complexity of KPIs related to O&M. These complexities can result in challenges in the selection of KPIs and/or limited usage by operations, maintenance, and facility managers. 

In general, a KPI can be defined as a numeric value used to measure and evaluate the progress toward a defined goal or objective. KPIs are typically generated by combining one or more relevant metrics into a mathematical relationship to express the performance, condition, or efficiency of a part, system, facility, or organization.

With the multitude of KPIs available, it becomes important to spend the time up front before selection to determine the balance between tactical and strategic KPIs, operational and financial KPIs, and those that help capture real-time performance while anticipating the future.

This best practice strives to present federal-sector-relevant KPIs, offer guidance on KPI selection and development, and provide an understanding of how to use KPIs for evaluating an O&M program. 

This O&M best practice provides information on: 

  • What KPIs are and how they are used
  • Commonly used KPIs
  • Criteria to apply when developing and/or selecting KPIs.

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Comprehensive O&M Programs

Operations and maintenance (O&M) is often thought of as an individual action, such as replacing an air filter or adjusting equipment schedules. However, to be effective, O&M needs to be addressed in a comprehensive and integrated manner that completes a series of functions and activities with the primary purposes of:

  • Operating all systems in a safe and efficient manner
  • Achieving/extending the system and equipment’s expected life 
  • Providing equipment and system availability and operability to meet user needs.

We recognize many of the actions and outcomes associated with O&M that are being performed in our buildings to meet our needs, including (but not limited to) heating and cooling building spaces during working hours; replacing burnt-out lamps to restore lighting levels; addressing water leaks and clogs to keep restrooms operational; testing standby generators regularly to ensure an ongoing supply of electricity during electrical outages; and continually operating renewable energy systems in a transparent manner to provide clean and sustainable energy to our sites. 

In the bigger picture, a comprehensive O&M program works to support successful, broader operational target outcomes at the site and agency levels. These often include:

  • Meeting mission requirements
  • Preserving asset value (and reducing capital investment requirements)
  • Realizing energy and water efficiency
  • Improving resilience
  • Achieving safe operations
  • Operating healthy buildings.

Behind these outcomes, both visible and strategic, is a comprehensive O&M program, as shown below. The top half represents the O&M program's functional components (e.g., operations, maintenance, engineering, training, and administration). The bottom half represents the O&M program's strategic components (e.g., O&M approaches, tools, existing building commissioning, and building optimization).

Donut chart with slices labeled after various components of an operations and maintenance plan.
FEMP's comprehensive O&M approach

This O&M best practice identifies and describes the key components of such a program including: 

  • Key functional and strategic components of a comprehensive O&M program
  • Roles and responsibilities of individuals and organizations supporting O&M delivery
  • Steps to include when implementing a comprehensive O&M program.

Cybersecurity for O&M Systems

This best practice introduces and highlights cybersecurity best practices for O&M staff. This information is provided to educate and support awareness. This best practice does not address high-level cybersecurity related to information technology (IT) roles, but rather focuses on cybersecurity practices relevant to O&M roles.

As buildings become "smarter" or more connected, new technologies are entering the smart building ecosystem at a rapid pace to help reduce energy consumption, improve comfort, and provide real-time monitoring and control. Unfortunately, this progress and convenience also introduces new opportunities for information to be compromised. The consequences of a security breach can be significant and cyberattacks can severely impact an agency or organization's ability to execute its mission.

Ensuring that standing procedures or policies are followed regarding cybersecurity for O&M along with cultivating a climate of awareness can play a vital role in minimizing cyber risks. Cybersecurity is not solely the responsibility of an IT department. Successful cybersecurity is the responsibility of all staff, including O&M staff. A knowledgeable and well-trained staff can serve as the first line of defense against cyberattacks.

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Existing Building Commissioning Approaches

This best practice provides information on existing building commissioning (EBCx) and options for procuring EBCx services. 

EBCx is a systematic process for investigating, analyzing, and optimizing the performance of building systems by identifying and implementing low-cost/no-cost measures to ensure systems are fully functional in accordance with the building owner’s project requirements. EBCx ensures that building systems perform interactively to meet current facility requirements and provide tools to support the continuous improvement of system performance over time. 

According to the Energy Independence and Security Act of 2007 (EISA 2007, 42 U.S.C. 17001) and the Energy Act of 2020 (EA 2020, 42 U.S.C. 8253), there are three distinct approaches to EBCx compliance:

  • Retrocommissioning (RCx)
  • Recommissioning (ReCx)
  • On-going commissioning (OCx, also known as monitoring-based commissioning, MCx).

EBCx is a comprehensive term defining a process that encompasses the more narrowly focused variations commonly used in the industry. This information focuses on the heating, ventilation, and air conditioning (HVAC) and HVAC controls systems that drive the energy and water use at the facility. 

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Healthy Building O&M

This best practice outlines the existing resources and actions for operating and maintaining a building to promote occupant health while considering energy efficiency. "Healthy building" refers to the physical attributes of the building and "indoor environmental quality" describes the conditions inside the building. 

In addition to the goal of improving energy performance, a focus on the importance of worker health and productivity continues to increase. Successful building performance requires balancing the indoor environmental quality (IEQ) and the energy performance of a building. Both IEQ and energy performance depend on building systems and their O&M. While there is a common misconception that health and energy priorities conflict, there actually are many strategies that can positively impact both energy and health.  

Currently healthy building practices primarily focus on design and new construction, and O&M in existing buildings is typically a secondary consideration. By incorporating appropriate O&M best practices with knowledge of the unique characteristics of a building, planning and prioritization, and response to changing conditions, facility personnel can improve the health outcomes for occupants while balancing other obligations such as energy, resilience, and costs.

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Integrating and Analyzing Building Information to Support O&M

This best practice serves to clarify the processes, tools, and actions recommended for integrating and analyzing building information data to make it actionable for a functioning O&M program. Analyzing building information data involves a progression from data to information, and from information to action. The analysis and resulting outcomes can be very powerful tools that lead to improved operational efficiency and economic performance.

Today's buildings are experiencing a challenging relationship between sophistication and complexity. This sophistication-complexity tradeoff has many potential benefits, with many falling into the category of improved operational efficiency. However, potential downfalls can result from a lack of training, insufficient relevant analytical skills, and/or data-driven information overload. To make the best use of these building system improvements, site staff should have access to system training and the relevant tools that allow data to be transformed to actionable information.

This best practice starts with common taxonomy and definitions, followed by the technologies that provide the data and its format(s), and finally useful paths, techniques, and tools to analyze and make use of these sources; relevant case studies are referenced as well.

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Maintenance Approaches

Well-practiced O&M is one of the most cost-effective methods for ensuring reliability, safety, resiliency, and energy efficiency. Good maintenance practices can generate substantial energy savings and should be considered a resource.

Modern, effective O&M programs rely on four basic approaches: 

  1. Reactive/corrective (includes run-to-failure) O&M: Fix/replace when broken
  2. Preventive O&M: Time-based actions
  3. Predictive O&M: Fix it before it breaks
  4. Reliability-centered O&M: A strategic combination of the previous three approaches. 

This best practice discusses the first three approaches and their relevancy in O&M program development.

Understanding the predominant O&M approaches is a critical first step to developing a high-functioning O&M program. This starts with characterizing your program and looking for opportunities and risks within your current function. Improving the balance between reactive, preventive, and predictive approaches will improve the overall health of your O&M program.

As the program develops, these three approaches become optimized in a defined way specific to your site, buildings, systems, and equipment. This optimization is generally referred to as reliability-centered maintenance and is discussed in the O&M best practice, An Advanced Maintenance Approach: Reliability Centered Maintenance.

Read more about the maintenance approaches best practice.

OMETA: An Integrated Approach to Operations, Maintenance, Engineering, Training, and Administration

The operations, maintenance, engineering, training, and administration (OMETA) concept defines the elements of an O&M program that makes use of a holistic approach and considers all elements of supporting infrastructure as integral parts of the larger system.

A functional O&M program is one of the most cost-effective methods for ensuring a facility's reliability, safety, energy efficiency, and overall resiliency. By looking at the whole system, including how functional areas interact, the opportunities for improvement, and the outcomes across multiple organizations, there will be a greater potential for significant and lasting impact.

From an O&M perspective, most facilities, plants, and systems requiring operational actions and infrastructure upkeep will have some representation of the following five functional areas:

  • Operations: Functional procedures and actions to enable a facility, process, or system
  • Maintenance: Necessary upkeep and repair of a system and its components
  • Engineering: Activities related to the design, monitoring, and improvement of a system and its components
  • Training: Providing the necessary information and education for a system operation and improvement
  • Administration: Functional area providing control of goals and resource needs.

The OMETA construct was developed to stem a noticeable trend in poorly developed and performing O&M programs that resulted in detrimental effects on system lifespan and efficiency. The concept acknowledges advances in data collection/availability, control system prevalence, and the continued need for the human interface to assure efficiency. 

The OMETA criteria are best applied as a site characterization protocol leading to an integrated facilities strategy. This protocol can be implemented as a stepwise process outlined in the best practice.

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Prioritizing O&M Actions

This best practice outlines a general process that departments follow when prioritizing O&M actions

Effectively utilizing the available resources is key to any field of management, and for facilities management personnel, this task involves prioritizing O&M actions. This is particularly relevant to the federal sector, as managers for public facilities have historically faced limited or inadequate budgets for O&M activities. However, resources are typically limited even in ideal circumstances, and effective prioritization is necessary in order to optimize the use of these resources.

This best practice provides resources to assist federal facilities (and energy) managers in improving their prioritization of O&M activities. While these managers are currently setting effective priorities for their O&M activities, this best practice will help them succeed in their stewardship of federal buildings by aligning terminology and processes used across various organizations as well as accelerating the propagation of more effective O&M management. If O&M actions are not adequately prioritized in preparation for emergency situations, the facility could fail in its mission.

The fundamental three-step process for prioritizing O&M actions is summarized below and detailed in the best practice.

  1. Establish an O&M vision.
  2. Assess and adjust O&M activities.
  3. Invest in proactive maintenance.

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Re-tuning Buildings

Building Re-tuning™ is a systematic, data-driven process that aims to identify and correct operational inefficiencies and problems to reduce energy consumption through the Building Automation Systems (BAS) at no-cost or low-cost.

The goal of Re-tuning is to optimize the operation of equipment and systems throughout the year to adjust to the actual demand. Not only that, the data collected is used to achieve the optimum equipment/system operation based on four basic principles:

  • If you don't need it, turn it off
  • If you don't need it at full power, turn it down
  • Mitigate simultaneous heating and cooling
  • Reduce infiltration and outdoor air.

For facilities with BAS and minimal recommissioning (ReCx) or retro-commissioning (RCx) needs, Re-tuning may allow the facility managers to comply with the commissioning requirements of Energy Information and Security Act of 2007 Section 432 (EISA 432).

Re-tuning offers additional benefits through the process of optimization that ReCx/RCx may not provide. Re-tuning efforts with federal agencies has resulted in:

  • Building energy savings typically ranging from 5% to 25%
  • Energy cost savings on the order of $0.185/sf-year with a corresponding simple payback of 0.3 to 3.5 years 
  • Thermal comfort, through correction of faults, and making airside systems responsive to specific zone demands.

The re-tuning process optimizes the energy-efficient operation of facilities/systems and aims to provide the "right" amount of heating, cooling, and ventilation throughout the year without compromising the occupant’s comfort or zonal needs.

The Re-tuning process can be used to verify that equipment operation meets the design intent and current operational needs and/or to identify the area of O&M needs that is related to control components, such as valves/actuators, etc. If O&M needs are minor, the process satisfies the requirement set by EISA 432. 

This best practice discusses the basic principles of Re-tuning and its benefits, as well as Re-tuning as a subset of ReCx/RCx to address low-cost/no-cost operation and maintenance (O&M) needs. Common Re-tuning measures are presented along with a method for assessing if the building is a good candidate for a Re-tuning project.

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