Session Type: Paper
In this paper session, industry experts will discuss the handling of alarm management in conjunction with DCS migration or expansion projects. Such projects provide great opportunities to review and improve alarm system performance, but many companies struggle to do this well. There is much to be learned from the case studies that will be presented.
Many facilities are in the process of or planning to migrate their existing control systems to the latest and greatest offering from several OEM’s. The economic justification is usually based on one or more of the following necessary replacement and improved profitability. Notably absent from the typical economic justification is improved alarm system performance.
Companies will invest significant money and assign critical resources to support control system migrations. But why do they migrate the good and bad aspects of existing control systems? Typically, the focus is on duplicating existing functionality so everything works as it did before. Sure, you may have a new High Performance HMI (HP HMI) that is ASM compliant, but the underlying operator information is unchanged.
Many plants have active alarms in the system that are ignored because they are associated with units that are not running or units that operate under conditions where the alarm is not a concern. Many common nuisance alarms (e.g., recurring alarms) distract operators and cause them to ignore the alarms, due to a unit operating closely to a defined limit or “chattering”.
There are many benefits derived from a properly performing alarm system, which have been well documented by ISA and others in numerous publications. The Alarm Management Lifecycle is defined in ANSI/ISA–18.2–2009 – Management of Alarm Systems for the Process Industries series of standards, which is the culmination of many years of detailing and disseminating Alarm Management Best Practices.
System migrations should never be treated as a replacement in kind. Migrate the good; get rid of the bad.
Commissioning and starting an industrial facility is costly and complex. While a new refinery built in the 1970’s had only 2000 instruments, a similar modern facility has five to ten times as many. To cope with this growing complexity, automation professionals increasingly rely on control strategy templates. This delivers manageable control systems to Operations to help them run the plant in a safe and cost effective way.
Despite the increase in the use of templates, alarm suppression designs have often not followed this approach. This case study takes a look at the alarm management problems at an industrial complex through a significant capacity expansion and follows the deployment of alarm suppression strategies developed from templates.
A large petrochemical manufacturer had implemented many successful alarm management projects throughout the years, but their experience during a more recent DCS migration project serves as a good example of what can still go wrong. Although the steps for good alarm management were followed, the resulting alarm system was virtually unusable for several weeks following cutover. This presentation explains what alarm problems were encountered, the contributing factors that led to those problems, and what you can do to prevent this from occurring in your control system. It is always better to learn from the pain experienced by others instead of repeating those errors yourself!