How to Permanently Reduce Operating Costs in Your Maintenance Department

How to Permanently Reduce Operating Costs in Your Maintenance Department

This guest blog post was written by Bryan Christiansen, founder and CEO at Limble CMMS. Limble is a mobile first, modern computerized maintenance management system application, designed to help managers organize, automate and streamline their maintenance operations..


Every organization that wants to stay competitive on the market has to strive to increase its profits. When it comes to the process industries, it is not rare that, in the search for higher profits, upper management often turns to reducing operational expenses.

Since most managers still look at maintenance only as a cost center, reducing operational costs in the maintenance department is often the first thing on their list. That puts a lot of strain on maintenance managers that are always under pressure to further optimize their maintenance operations.

While I would love to tell you that we discovered some hidden secrets you can use to reduce your maintenance costs, the reality is that there are no simple ways to permanently cut those costs down.


predictive maintenance, preventive maintenance, project management


I mean, you can always try to make some tweaks to your workflow and communication to save a few bucks. However, if you really want to see significant long-term cost savings, there are two sure-fire ways you should explore:

  1. Changing/adjusting your maintenance strategy
  2. Taking advantage of an appropriate maintenance software

Both approaches require a dose of clarification so let’s put everything in the right context.

Maintenance strategies designed to reduce operating costs

Basically all maintenance strategies, besides breakdown maintenance (run-to-failure maintenance), are designed to improve the efficiency and effectiveness of your maintenance activities which, in turn, leads to reduced operational expenses.

Despite that, a recent survey shows that there are still around 50 percent of plants that strongly rely on reactive maintenance as a part of their overall maintenance strategy. Now, I won’t say that reactive maintenance doesn’t have its place in your maintenance strategy, but it should only play a supporting role and leave the heavy lifting to more effective strategies which we will discuss here.

Preventive maintenance

If you look at the same research mentioned above, you will notice that preventive maintenance strategy is the most popular approach to maintenance. And that is not a coincidence. Over the years, it has been proven to have a great return on investment when implemented properly and the implementation process itself is more straightforward than any other proactive maintenance strategy.

Any business that operates on a larger scale should consider implementing a preventive maintenance strategy. Making a shift from reactive maintenance to preventive maintenance will take some time, but the benefits are numerous.

Conducting routine maintenance based on a quality preventive maintenance plan will:

  • reduce the number of emergency repairs since you will be able to discover and fix problems before a breakdown occur
  • reduce overtime labor cost as maintenance technicians will not need to stay late to fix a breakdown of a critical piece of equipment
  • increase overall productivity and extend the life of critical equipment

While preventive maintenance can be a great choice for any facility that has a trouble keeping their maintenance costs in check, here are some situations in which it could be your go-to solution:

  • you want to move away from reactive maintenance but you don’t have the resources for the large capital investment other maintenance strategies require
  • you want a straightforward maintenance strategy that isn’t too complicated to implement
  • you are willing to invest a few months to see the implementation go through successfully

Predictive maintenance

Preventive and predictive maintenance (PdM) share the same goals but the execution of each approach is quite different.

PdM aims at predicting equipment failure before it actually occurs. Predictions are not based on the average life cycles of machinery as with a scheduled maintenance strategy.

Some PdM strategies rely on physical inspection of the respective equipment but you can get best results by implementing a software system to monitor and track production facilities. By incorporating readings from different sensors and metering into a maintenance platform, you are able to predict potential failures and get insights into your equipment’s current working status which will help prevent unexpected breakdowns.

Properly implemented predictive maintenance will:

  • increase the lifecycle of your assets
  • minimize the number of both scheduled and unscheduled downtimes
  • increase uptime of your assets
  • allow you to more efficiently manage your maintenance team’s work

You should consider implementing predictive maintenance when:

  • you are willing to invest a moderate to large sum of money to get the project off the ground
  • have a moderate to large amount of time and resources to implement the strategy and properly train your employees
  • you have all the necessary data at your disposal or you are willing to wait a few months to gather enough data to actually start a predictive maintenance plan (you can shift to predictive maintenance only once you have enough data to generate actionable insights about your equipment; even if you use software to collect meter readings, it will take a while before the software is able to generate valuable and accurate reports)
  • want to have a complete control and insight about your assets
  • want to keep your parts inventory low (by predicting when you need to do certain repairs, you can order parts just before those repairs occur)
  • already did or have plans to invest in industrial IoT

Reliability-centered maintenance

Reliability-centered maintenance represents a very complex approach to maintenance. The main goal is to identify all possible failure modes of a machine and then draft a custom maintenance strategy for every piece of equipment.

This can be a daunting task for any business since you need to an in-depth analysis of hundreds, or even thousands, of pieces of equipment. Due to being an advanced maintenance strategy, RCM requires a regular collection of data from the machines, preventive and predictive maintenance measures, and regular basic inspection of all the equipment in place.

You can apply an RCM strategy for either small or large system but defining failure modes and differentiating between constituents of different systems may be hard. A business must define its business-critical production assets first, and only then assign priority to failure modes. An RCM strategy does not deal with functionality but reliability, so the proper categorization of assets is crucial.

An RCM might be a good solution when:

  • you have enough knowledge and experience to develop an effective RCM strategy
  • you are willing to invest a significant amount of time and money to complete the analysis and make the maintenance program
  • you want to have a clear strategy for every likely failure mode for the equipment you analyzed

Reducing maintenance costs

Every maintenance strategy has its pros and cons so choosing the one you should focus on can be a challenging task.

How do we know that one of the existing maintenance strategies isn’t superior to other across the board?

Well, the market is the one that ultimately decides which approach to maintenance is the most profitable. Since it is obvious that not all successful processing facilities have the same approach to maintenance, we can conclude that all strategies are still viable to one degree or another for your unique setup.   

In an ideal scenario, you would use a mix of these strategies to get the best possible results and minimize your maintenance costs.

However, the more realistic scenario is the one in which you are concentrating on employing one or two strategies. For example, you would put all important assets on your preventive maintenance plan list, while some non-essential equipment (which breakdown won’t have much of an impact on your production line) doesn’t have to be regularly maintained and can be fixed when/if the failure occurs

When all is said and done, choosing the right strategy (or a mix of strategies) is one of the best ways to minimize costs that occur in your maintenance department.

Reducing operational expenses with maintenance software

You probably already noticed that turning to more proactive maintenance strategy is close to impossible without the help of appropriate maintenance software. If you think about it, it is only logical.

An effective maintenance schedule HAS to be based on the accurate and reliable information. With so many moving parts, tracking all of the necessary information is simply impossible without a central hub of information that allows you to make data-driven plans.

Since the main purpose of every computerized maintenance management system (CMMS) is to provide you with invaluable and actionable insights you can use to optimize your entire maintenance process, it cannot be avoided when discussing the reduction of operational costs.

While a CMMS has basically the same key benefits as all of the strategies just discussed, there are some indirect (and often overlooked) cost reductions that come with it.

Efficiently scheduling maintenance work

Ability to easily report problems, quickly schedule maintenance work, add priority levels, track work in progress, assign and reassign technicians with a few clicks, etc., saves a ton of time for maintenance managers and ensures that the most important work is being done on time.

Optimizing your workflow

The faster flow of information between your maintenance team, improved response times, eliminating overtime labor costs, an easier cooperation of multiple maintenance technicians on bigger maintenance tasks, are just some of the ways you indirectly reduce maintenance costs by employing a capable maintenance software.

A plethora of statistical data

A tried and tested way to improve your operations on all levels of your organization is by making adjustments based on accurate statistical data and performance reports.

When it comes to maintenance, CMMS will enable you to look at things such as:

  • what maintenance work has been that and how much is that costing you
  • what is the overall performance level of your maintenance team
  • which assets are costing you the most and why
  • which one of your locations/facilities is performing the best an why

Long things short, making data-driven decisions is a solution to most of your problems.


A modern production facility or manufacturing plant encompasses thousands of individual components. Which of them should be subject to preventive maintenance and where you should apply a predictive approach? Do you need to stop your entire production line for scheduled maintenance or you can reduce costs by replacing specific components on a run-to-failure basis without bothering to halt production?

Applying the right maintenance strategy to decrease operating costs requires making informed decisions based on accurate information. This data should be processed to generate actionable insights that enable you to draft long-term strategies that will permanently reduce your operating costs.

A major tool in your maintenance strategy should be a software platform capable of producing insights that let you combine chosen maintenance strategies and deploy the best solution for every particular scenario.

Which maintenance strategy are you using at your facility? You think that one approach is vastly superior to others? Don’t hold it in, let us know in the comments below.

About the Author
Bryan Christiansen is founder and CEO at Limble CMMS. Limble is a mobile first, modern computerized maintenance management system application, designed to help managers organize, automate and streamline their maintenance operations.

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ISA Executive Board Approves New Vision and Mission Statements

ISA Executive Board Approves New Vision and Mission Statements

This post is authored by Brian Curtis, president of ISA 2018.


I’m excited to announce that the ISA Executive Board, meeting earlier this month during the Spring Leaders Meeting in Raleigh, NC, USA, has approved new ISA vision and mission statements.

ISA’s new vision is to: Create a better world through automation. (This replaces: ISA sets the standard for automation by enabling automation professionals across the world to work together for the benefit of all.)

ISA’s new mission statement is to: Advance technical competence by connecting the automation community to achieve operational excellence. (This replaces: Enable our members, including world-wide subject matter experts, automation suppliers, and end-users, to work together to develop and deliver the highest quality, unbiased automation information, including standards, training, publications, and certifications.)



Why is this exciting? ISA now has mission and vision statements that are short, aspirational, and memorable. The previous iterations were too wordy and unwieldy, making it difficult for ISA members to concisely state why we exist and where we’re going, and for everyone else to understand why we exist and where we’re going. 

This is all part of an effort to better define our Society—both within our walls and beyond them—and take a hard look at our organizational mainstays, including our values, strategies, goals, and metrics. Stay tuned for updates as we hone our strategic focus, global brand recognition, and operational priorities.

As most of you well know, an essential, near-term priority is the IT infrastructure upgrade project. Funding for the project has been approved by the Executive Board and staff, consultants, vendors, and leaders are hard at work envisioning all the plans and steps that will be involved in this project.

The ultimate goals for the project include improved digital content delivery and user engagement, a personalized user experience, a mobile responsive environment, and a fully streamlined e-commerce process. ISA will be leveraging an open architecture built upon a Salesforce platform, adding overlays and applications based on best-in-breed solutions available in the market. We’ve hired a full-time project manager to oversee all aspects of the project, Leo Nevar, and he will be in RTP as a staff member for the duration of the work. Project plans, approaches, timelines, and milestones will be vetted and monitored by the ISA Executive Board.

I also want to take this opportunity to recognize the contributions of ISA and Automation Federation staff and volunteer leaders at two highly visible STEM (science, technology, engineering and mathematics) events that took place in April.

Approximately 350,000 people—mostly primary and secondary students and their families—attended the USA Science & Engineering Festival, 7-8 April in Washington, D.C. At the ISA/Automation Federation exhibit, hundreds of young people and their parents (assisted by ISA and AF volunteers) competed in a computerized game based on an actual industrial automation and control system. The game, powered by a programmable logic controller (PLC), demonstrated essential control panel design concepts and computer game programming.

Later in the month, 18-21 April, more than 15,000 students, ages 6-18, from 43 countries competed in three robotics competition championships and a LEGO® competition championship at the FIRST® Championship Houston. ISA and AF volunteers met with FIRST competitors and their family members to answer questions about career opportunities in automation and engineering.

Maintaining a strong presence at these premier STEM events is rewarding for all involved. ISA members who take part can reconnect to the excitement that ignited their own drive to pursue an automation career and, at the same time, inspire others to follow their path toward success in the profession.

While most STEM initiatives like these target students enrolled in elementary, middle and high schools, ISA also recognizes the need to better engage with those young people further down the educational pathway: new engineering school graduates—particularly those active in ISA student sections.

All too often, ISA student section members at engineering schools lose their association with ISA when they graduate and leave their student memberships behind.  ISA is exploring ways to help new college graduates maintain their connection to ISA as they enter the first stage of their automation and engineering careers. More to come on this in a subsequent column.

I’ll also be sharing with you any actions relating to the Executive Board’s review of recommendations from the ISA Globalization Task Force, which was established in 2016 by former ISA President Jim Keaveney. The task force was created to explore financially viable ways to improve ISA’s international growth and presence. Long-time ISA leader and current co-chair of the ISA99 Committee Eric Cosman presented the recommendations at the Spring Leaders Meeting.

I’m eager to provide you with more details on these and other promising initiatives in upcoming columns. As always, I thank you for your support of and contributions to ISA.

About the Author
Brian Curtis, I. Eng., LCGI, is the Operations Manager for Veolia Energy Ireland, providing services to Novartis Ringaskiddy Ltd. in Cork, Ireland. He has more than 35 years of experience in petrochemical, biotech, and bulk pharmaceutical industries, specializing in design, construction management, and commissioning of electrical, instrumentation, and automation control systems. He has managed complex engineering projects in Ireland, England, Belgium, the Netherlands, Italy, and Germany. A long-time ISA member, Curtis has served on the ISA Executive Board since 2013, the Geographic Assembly Board (2012 – 2015), and the Finance Committee (2013 – 2017.) He was Ireland Section President and Vice President of District 12, which includes Europe, the Middle East, and Africa. Curtis has also been active on several Society task forces, including Cybersecurity, Governance, and Globalization-related committees. He received the ISA Distinguished Society Service Award in 2010. He is the Former President of Cobh & Harbor Chamber of Commerce (2013-2015) and Former Chairman of the Ireland Southern Region Chambers (2015-2016) and is an active member of the Ireland National Standards Body, ETCI.

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A version of this article also has been published at ISA Insights.

Using OPC Technology to Support the Study of Advanced Process Control

Using OPC Technology to Support the Study of Advanced Process Control

This post is an excerpt from the journal ISA Transactions. All ISA Transactions articles are free to ISA members, or can be purchased from Elsevier Press.



Abstract: OPC, originally the object linking and embedding (OLE) for process control, brings a broad communication opportunity between different kinds of control systems. This paper investigates the use of OPC technology for the study of distributed control systems (DCS) as a cost effective and flexible research tool for the development and testing of advanced process control (APC) techniques in university research centers. Co-simulation environment based on Matlab, LabVIEW and TCP/IP network is presented here. Several implementation issues and OPC based client/server control application have been addressed for TCP/IP network. A nonlinear boiler model is simulated as OPC server and OPC client is used for closed loop model identification, and to design a model predictive controller (MPC). The MPC is able to control the NOx emissions in addition to drum water level and steam pressure.

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Top 5 Upfront Project Considerations for Effective Risk Management

Top 5 Upfront Project Considerations for Effective Risk Management

This post was written by Diane Trentini, vice president of marketing and sales for COMET Informatics LLC. Diane serves on the board of directors for the Control System Integrators Association.


When a system integrator finds a new opportunity to provide services—a new client, a revolutionary application, a troubleshooting issue that no one else has solved—we get really excited! We live for problem solving.

Industrial industry system integrators must be brave to face new frontiers. For example, when working on chemical plant process improvements, site visits may uncover safety issues, including poor maintenance, hazards, and undertrained employees. I remember a past project where I saw a metal rod jammed in the “alarm acknowledge” button automatically overriding alarms as they came up. This was remediated, but taught me that “risky” means different things to different people.

Safety risks deservedly take center stage, but all aspects of business present risks. Even operating at “steady state” has its own risks. But when you need to grow, upgrade, or improve operations, there are new risks to consider.

Risk management is part of operating a manufacturing facility and running a control system integration firm. The Control System Integration Association best practices states, “Risk is the potential loss resulting from a future event. For risk to exist, there must be an identifiable loss and uncertainty of that loss occurring.”

Owners and operators of manufacturing plants need to understand threats, vulnerabilities, and associated risks to their production systems. Issues include operational complexity, maintenance of legacy systems, evolving supply chains, competitive pressures, connections with enterprise resource planning systems and the Internet, remote access, and cybersecurity. Threat sources come from technical situations, infrastructure, and internal and external individuals—some with motives for sabotage and crime or even industrial espionage and terrorism.

Control system integrators work with clients to help manage client risk priorities, while also considering their own risk management at the project and corporate level. The process for identifying and assessing risk is undertaken at the beginning of a project, typically during proposal development where risk factors are identified and quantified with decisions made to accept the risks, plan accordingly, work with the potential client to mitigate risks, or to decline the project because it presents unnecessary or unacceptable risk. Failure to follow good practices here can place the company, as a whole, at risk.

Risk identification and assessment includes the review of commercial terms, pricing, technical skills, available resources, service supplier qualifications, scope definition, safety issues, and deliverables. The following are five important areas to assess during initial project definition:

Technical risk

  • poorly defined project scope
  • undefined or poor acceptance test criteria
  • undertaking technical challenges beyond current skill sets
  • selection of unqualified or inexperienced service suppliers or subcontractors
  • unreasonable constraints, including schedule expectations and resource availability
  • undefined or poorly defined project deliverables: these risks are particularly important for projects governed by a regulatory body

Financial risk

  • failure to estimate appropriately causing a project overrun
  • failure to use good change management causing an overrun
  • poor project management resulting in poor cash flow
  • undertaking work for clients with a poor credit rating and an inability to pay

Insurance and indemnification risk

  • providing a proposal with inadequate terms and conditions
  • accepting contracts with one-sided or unfair terms and conditions

Commercial contractual risk

  • failure to appropriately handle confidential client information or intellectual property, opening up the possibility of financial loss claims by the client
  • failure to formally hand ownership of project deliverables to the client
  • failure of project team to understand contractual commitments

Safety risk

  • failure to come to an agreement on a health, safety, and environmental plan for project
  • failure to meet OSHA 29 CFR 1910.119 process safety management requirements, if required
  • failure to meet other regulatory agency safety standards that apply, including Department of Defense, Department of Energy, FDA, and the Bureau of Alcohol, Tobacco and Firearms

In the case of the chemical plant example, one of the risks is employees accepting a risky environment and not acknowledging dangers. It can be easy to miss threats or assume that someone else is going to watch out for them. Clear roles and responsibilities are essential.

Done properly, risk management allows project goals to be met and supports success. Consideration for project risk means that both parties—the client and the integrator—will look back on the project knowing it added value to both their companies.

About the Author
Diane Trentini is vice president of marketing and sales for COMET Informatics LLC. Previously she was vice president of marketing and sales for Optimation Technology, Inc., responsible for defining, improving, and managing processes in support of sales and marketing. She has 30 years of systems integration and software engineering experience. She serves on the board of directors for the Control System Integrators Association.


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A version of this article originally was published at InTech magazine.


How Much Risk Can Safety Alarms Reduce?

How Much Risk Can Safety Alarms Reduce?

This post was written by Charles Fialkowski, CFSE, a safety systems specialist for Siemens; Luis Garcia, CFSE, senior process safety consultant for Siemens and chair of ISA’s tank farm committee for the ISA84 Safety and Security Group; and Nicholas P. Sands, CAP, P.E., an ISA fellow, the ISA vice president of standards and practices, and a process control engineer working in DuPont’s Kevlar and Nomex businesses.


ISA defines an alarm as an audible or visible means of indicating to the operator an equipment malfunction, process deviation, or abnormal condition requiring a timely response. A safety alarm is essentially the same thing, but with the added metric of performance, or in layman’s terms, “how much risk can it reduce?” Risk reduction is generally measured in orders of magnitude (10, 100, 1000, etc.) If a company’s process hazard analysis (PHA) identifies and estimates a specific process hazard may be present every 10,000 years, yet there is a target of 100,000 years, it is easy to understand the company needs to reduce the risk by one order of magnitude (10) to reach this target. In general, it is a good practice for plant owners and operators to rigorously identify all potential risk-reduction layers to lessen the burden placed on their dedicated safety instrumented systems (SISs). The industry has been struggling with alarm management issues for decades, but adding the ability to quantify the amount of risk reduction is introducing additional challenges.

The newly revised ANSI/ISA-18.2-2016, Management of Alarm Systems for the Process Industries, states in its scope that the standard specifies general principles and processes for the life-cycle management of alarm systems based on programmable electronic controller and computer-based human-machine interface (HMI) technology for facilities in the process industries. It covers all alarms presented to the operator through the control system, which includes alarms from the basic process control systems, annunciator panels, packaged systems (e.g., fire and gas systems, and emergency response systems), and safety instrumented systems.” It provides a framework for the successful design, implementation, operation, and management of alarm systems in a process plant.

risk, safety, industrial automation, manufacturing, industrial standards, alarm management, process industries

In addition, ANSI/ISA-84.91.01, Identification and Mechanical Integrity of Safety Controls, Alarms, and Interlocks in the Process Industry, was released in September 2012, with the intent of establishing “a procedure to identify the process safety functions that utilize instrumentation to maintain safe operation in the process industry. In this standard, these functions are implemented by safety controls, alarms, and interlocks.”

As part of the continuing evolution of ISA-18.2, a series of ISA18 technical reports (TRs) is being developed to help alarm management practitioners put the requirements and recommendations of ISA-18.2 into practice. If you are interested in contributing your knowledge and experience to the TR development effort—and in gaining from the knowledge and experience of your professional colleagues at the same time — contact ISA18 co-chairs Nicholas Sands or Donald Dunn.


The scope of this latter standard is to address instrumentation classified as process safety safeguards by “the authority having jurisdiction” (typically the owner/operator or local regulatory agency) and to establish requirements for its mechanical integrity, including inspection and testing and documenting the inspection/test results. It is specific to process safety. As illustrated in figure 1 from the ANSI/ISA-84.91.01 standard, the term “safety alarm” is recognized as an element of process safety, and in many cases, it may be the same alarm that is also covered in the ANSI/ISA-18.2 standard—so which standard would apply and why?

Figure 1. Safety controls, alarms, and interlocks relationship to the PHA

A process alarm may be categorized as safety control alarms and interlocks (SCAI), as defined in the ANSI/ISA-84.91.01 standard. This diagram was important to help identify all the different safeguards that “might” be claimed by the owner/operator as a layer to reduce risk. These safeguards must be identified during the PHA of the process.

Alternatively, ANSI/ISA-18.2 defines a safety alarm as an alarm that is classified as critical to process safety or the protection of human life. Safety alarms are placed in a highly managed alarm class that have additional requirements throughout the standard.

Furthermore, the scope of the standard clearly indicates that alarm systems serve to notify operators of abnormal process conditions or equipment malfunctions. It may include both the basic process control system (BPCS) and the SIS, each of which uses process conditions and logic to generate alarms.

Therefore, a “safety alarm” is an alarm as per ANSI/ISA-18.2 that can be considered a SCAI as per ANSI/ISA-84.91.01.

Risk-reduction credit

The next question is, how much risk-reduction credit could one take for a safety alarm? Are there limits to the amount one could claim for the operator being able to step in during a critical process situation and effectively bring the process back to a safe state? Imagine a situation where a process hazard event occurred and was not originated by the BPCS. As a result, designers and reliability engineers decided to take one order of magnitude (10) risk-reduction credit for their BPCS. Also, because they identified another independent set of sensors connected to the BPCS, for alarming that same condition, they all agreed to claim another order of magnitude (10) risk reduction. Thus between its basic process control function and its alarm function, the BPCS is now providing two order-of-magnitude (100) risk-reduction credits. Could this be considered a good practice?

Sure, designers could try to argue that the BPCS they are using provides robust technology that includes independent and diverse operations to maintain their claim that two orders of risk-reduction credit would be justified. But we also must consider the human element that resides within this protection layer and that two orders of magnitude (100) in this case might be the recommended maximum limit in the amount of credit taken.

One might also argue that if the safety alarm was connected to separate and independent sensors, had a dedicated HMI alarm panel, and was programmed with a safety certified safety control system capable of meeting safety integrity level 3 (SIL 3), they could justify taking even more risk-reduction credits. Yet many designers, with reason, do not feel comfortable with this approach. It has been the center of ongoing debates about where we draw the line on overstretching the claims of safety alarm performance.

Considering that most process safeguards are “dormant” in the sense that they would react only when predetermined process hazard conditions are present, it is the owner/operators’ responsibility to ensure that their performance is available at all times. IEC 61511-1, second edition, Functional safety – Safety instrumented systems for the process industry, gives requirements for the specification, design, installation, operation, and maintenance of a SIS, so that it can confidently achieve and maintain each safety instrumented function’s performance level (e.g., SIL).

The human factor

Although this process has been well understood for years, it is not possible to predict or calculate human performance, only to estimate it. With humans (by definition required to react-operate in the presence of an alarm), there are variables that cannot be accurately measured or taken into account in operation environments. Although there is guidance and “good practices” that avert fatigue and stress, questions such as Does the operator have enough time to react to this alarm?” become critical. Could a designer confidently evaluate risk based on the premise that given 100 opportunities, the operator would fail only once reacting to an alarm and manually taking the plant to a safe state?

ANSI/ISA-18.2 provides guidelines on how to design and manage the whole life cycle of alarm systems. Follow the standard and utilize the ability of the modern BPCS to deploy advanced process graphic HMIs, which incorporate muted color schemes that are clear, simple, and well-arranged to reduce stress and eliminate unnecessary distractions to the operator.

Figure 2 shows example metrics from ANSI/ISA-18.2. It is based on rates necessary for the operator to detect an alarm, navigate within the control system to the relevant data, analyze the situation, determine and perform proper corrective actions, and monitor the situation to ensure the alarmed condition is successfully handled. Yet these are averages that indicate there could be moments when the rates are much higher. Using key performance indicators is a good methodology to obtain real values and optimize them.

Figure 2. Example alarm performance metrics

When considering the performance of “safety alarms,” it is implied that the failure of the operator to react propagates to a dangerous condition. IEC 61511-3 did provide guidance on claimed levels of performance with respect to alarms, as shown in figure 3.

Figure 3. Typical protection layer (prevention or mitigation) PFD

In practice

Safety alarms facilitate taking credit for the action of an operator to take the plant to a safe condition. They are defined by ANSI/ISA-18.2, and as SCAI by ANSI/ISA-84.91.01. Safety alarms should be considered in the PHA and included in the IEC 61511 safety life cycle and managed per the ISA-18.2 life cycle.

Other points to consider when evaluating your safety alarms performance are:

  • ISA-18.2 requires monitoring the alarm system performance. Two common metrics, shown in figure 2, are the average alarm rate per operator in alarms/hour and the percent time in flood per operator, or the percent of time the operator has more than 10 alarms in 10 minutes. These metrics are one way to approximate the stress on the operator. An average alarm rate of less than six and a percent time in flood less than one might indicate an unstressed operator, whereas an alarm rate greater than 12 or a time in flood greater than five might indicate a stressful condition for the operator. In the latter case, it may not be appropriate to take any risk reduction for the response to any alarm. If the alarm system performance is not monitored, it might not be appropriate to take any risk reduction for a response to an alarm. These are cases where the risk reduction factor for safety alarms is one.
  • ISA-18.2 states that an independent HMI may be necessary for safety alarms. Some of the most common safety alarms do have an independent HMI (e.g., the light outside the entrance to an analyzer shed indicating a potentially fatal environment inside the room, or horns indicating the detection of a toxic gas with a response of evacuating the area). These safety alarms, when well designed, can provide the potential risk reduction factor of 100, a failure of one per 100 opportunities.
  • The actual risk reduction can still be limited by human-factor considerations, which is different from SIS design. An independently indicated safety alarm may not be affected by the average alarm rate and percent time in flood, but the percent of false alarms and the time in alarm can decrease the effectiveness of the alarm. The spurious trip rate of SIF does not affect the PFD, but as the false alarm percentage increases from 0 percent toward 50 percent, the operator loses confidence in the safety alarm. The operator response decreases toward zero. While the time in trip of an SIF does not impact the PFD, as the time in alarm increases, the operator becomes accustomed to the safety alarm state as normal (known as normalization of deviance), and the operator response decreases. Individual alarm monitoring is needed to maintain the alarm effectiveness, or the risk reduction factor can be reduced to one.

Safety alarms have potential as effective layers of protection, with the possibility of a risk reduction factor of up to 100. In practice, that risk reduction factor is difficult to achieve. In fact, there may be facilities where alarm system performance or individual alarm performance would indicate that no risk reduction should be taken.

About the Authors
Charles Fialkowski, CFSE, has been a safety systems specialist for more than 20 years, with a focus on burner management (BMS), fire and gas, and high-integrity pressure protection solutions. He is a voting member of the ISA84 committee and an ISA course developer and instructor for SIS and BMS. Fialkowski received his electrical engineering degree from Oklahoma State University and is currently the director of process safety with Siemens Industry, Inc.

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Luis Garcia, CFSE, has been a specialist for more than 20 years, with several publications in the Americas, Europe, and Australia. As a member of ISA, he chairs the tank farm committee for the ISA84 Safety and Security Group. Garcia is a process safety course developer, and he teaches several courses in process safety in two languages. Garcia graduated from Liverpool University, U.K., with a BEng in metallurgy and material science. He graduated from San Joseph Technical College in Argentina as a mechanical engineer, and he is currently the senior process safety consultant for the Americas with Siemens Industry, Inc.

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Nicholas P. Sands, CAP, P.E., is an ISA fellow, the ISA vice president of standards and practices, and a process control engineer working in DuPont’s Kevlar and Nomex businesses. Sands is co-chair of ISA standards and practices committee ISA18 working on alarm management, secretary for the IEC 62682 committee, and was involved in the development of the certified automation professional program. Sands’ path to instrumentation and control started when he earned his B.S. in chemical engineering from Virginia Tech.

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A version of this article originally was published at InTech magazine.


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