What is all the fuss about alarms?

posted Jun 27, 2013, 6:39 AM by Niels Jensen   [ updated Jun 27, 2013, 7:25 AM ]
In recent years we have gotten an updated EEMUA guide on the design, management and procurement of alarm systems and also new ISA standard on Management of Alarm Systems for the Process Industries. Both of these documents recommended, that an individual operator is not exposed to more than 300 alarms per day. But what does 300 alarms per day mean?

300 alarms per day means we are asking an operator to solve potentially 300 unique problems each day. That is 12½ unique problems per hour or approximately 1 new problem every 5 minutes! Who in the world can be expected to cope with that kind of a workload? I am pretty sure that I can't. Unless many of the alarms require little or no analysis - and hence in my view should be handled by the automatic process control system (DCS or SCADA) - the requirements of the recent standard and guideline are in my view insane. Even half these numbers could be too much - just imagine an engineer having to work on a new problem every 10 minutes?

I recall being introduced to a very closely managed approach to alarms on my first job as a computer process control engineer - computer applications engineers, we were called - with a major Canadian integrated oil company. The general philosophy was, that computer process control applications should not generate any alarms, and they should cope with situations such as an online analyzer not being available due e.g. to calibration by the instrument technician without any bothering of the operator. Only when the measurement was unavailable for an extended period should the computer control application hand the situation over to the operator.

I recall days when there was less than one alarm every hour. We were using Honeywell's PMX II process control  computers on which is was very easy to implement alarms both on the TDC 2000 image points and on the computer control points. However, that did not result in a large number of alarms because, an alarm required the process engineer to specify the required operator action. Alarms hence were being managed - even without an alarm management application.

So what has happened since these early days of process control computers in the 1980's? My guess is that in many companies the process engineer has been eliminated as a filter of alarms implemented on the DCS or SCADA. This has allowed e.g. equipment vendors to implement alarms on turbines at major power plants - alarms without any required operator action. This should be stopped!

I believe articles such as Kevin Patel's "Managing the Alarms That Manage You" are treating the symptoms in stead of the root cause of too many alarms. However, the ISA standard does provide facility owners with a framework for managing alarms during the whole plant life cycle, just like all other aspects of plant operations.

Comments