Using alarm suppression

摘要

One of the signs of an effective alarm system is that it presents alarms to the operator only when they are relevant and require their response (attention). This means the alarm system is able to track the state of the process in order to know when to present the alarm and when to suppress it. Transient plant conditions, use of different feedstocks, and unplanned process upsets make this a challenge for many process applications. Modern systems provide a powerful and easy-to-configure capability for suppressing alarms dynamically based on the state of the process and/or equipment (called automatic alarm hiding). It can be used, for example, to suppress alarms when equipment is out of service or in response to a compressor trip (which would otherwise lead to an alarm flood). Overloading the operator with stale (irrelevant) alarms or alarm floods can lead to increased operator stress, missed alarms, operator error, production losses, or worse. This article discusses how to implement designed alarm suppression (a form of advanced alarming) following the best practices and recommendations of the ISA standard ANSI/ISA-18.2-2009, Management of Alarm Systems for the Process Industries, as well as EEMUA 191, Alarm Systems: A Guide to Design, Management, and Procurement, and NAMUR NA 102, Alarm Management for Process Control Industries.