Remember the days when process alarms required justification before installation? With wiring, panel boards, lights, pushbuttons, and installation, the cost per alarm could exceed $1,000 each. That was a compelling incentive to limit the number of alarms used in a control system.
With the advent of PLC/DCS and HMIs, it has become much easier to turn on alarms by merely doing so from within the control module software configuration. The cost is minimal, and there is no longer an incentive to minimize the number of alarms. Unfortunately, a programmer can fall into the mindset of “if in doubt, turn it on” during system setup. This approach quickly creates a new problem—nuisance alarms. An excellent example to consider is a modern PID loop that can include six or more alarm options:
- High High
- Low Low
- Setpoint Deviation (some systems have two deviations: high and low)
The problem is that this loop only needs two or three alarms configured. As a result, nuisance alarms become part of operators’ everyday life, no matter how new the facility or how cutting-edge the equipment.
The boy who cried wolf
This can cause several issues as operators constantly reset or ignore alarms that have no significance. More concerning, these alarms soon become “the boy who cried wolf” for everyone involved. When a serious issue eventually triggers an alarm, operators and engineers are conditioned to dismiss it without studying it closely. Ironically, the sheer number of nuisance alarms becomes a safety and downtime risk.
Often plant personnel assumes that fixing the problem is a massive undertaking and instead chooses to live with it. Fortunately, there is a better option.
A recent project success
Our customer’s system was only three months old on a recent project, but the alarm configuration was out of control. We started by reviewing an export of their alarm configuration along with their alarm philosophy documentation. By drawing on our experience with process control and alarm rationalization, we could get a head start on the new alarm configuration. Then we hosted a work session with a cross-functional customer team. Having people with daily operational and process knowledge experience in the room while going through each alarm and assigning priority was critical to our success. During this session, we also identified any “smart alarming” required and developed an implementation plan. Once implemented, the benefits were clear:
- A quieter control room
- Confidence from knowing that alarms have meaning
- Mitigated process and plant safety risks
- Less downtime due to clear actionable alarms.
Maintain alarms like other plant assets
Once a plant has its alarm configuration under control, the job is not finished. It takes a cross-functional team to maintain an optimal alarm configuration. Like other assets in the plant, alarms need to be maintained. We recommend using a tool such as Pareto Analysis to evaluate the alarms regularly.
If you are facing a nuisance alarm situation in your plant, keep these four points in mind:
- You are not alone. Alarms are rarely configured properly when control systems are installed, instead being simply “switched on” when processes go live. This is a brownfield and greenfield issue.
- Instead of being a programming issue, nuisance alarms are often the result of not having cross-functional team input when initially set up. Operator input is especially critical – they understand the daily operations of their processes, they are the ones who respond to alarms every day, and they must understand what that alarm means in order to maximize its value.
- Alarms need to be tied to operator action. For example, a “high tank level” alarm may need to have upstream changes made to the process (i.e., loop setpoints modified). Most modern control systems can also have consequences of inaction and suggested operator action as part of their alarm configuration.
- Developing and implementing an effective alarm configuration does not have to be a monumental task. By drawing on our process knowledge, we can help turn your alarms into a valuable, productivity, safety and maintenance asset.
It all starts with a conversation. One of our alarm rationalization engineers is ready to listen. Give us a call at 877-735-6905 or contact us online.