Alarm management is the application of human factors (or ergonomics as the field is referred to outside the U.S.) along with instrumentation engineering and systems thinking to manage the design of an alarm system to increase its usability. Most often the major usability problem is that there are too many alarms annunciated in a plant upset, commonly referred to as alarm flood, since it is so similar to a flood caused by excessive rainfall input with a basically fixed drainage output capacity. However, there can also be other problems with an alarm system such as poorly designed alarms, improperly set alarm points, ineffective annunciation, unclear alarm messages, etc
The need for alarm management
Alarm management is usually necessary in a process manufacturing environment that is controlled by an operator using a Distributed Control System, or DCS. Such a system may have hundreds of individual alarms that up until very recently have probably been designed with only limited consideration of other alarms in the system. Since humans can only do one thing at a time and can pay attention to a limited number of things at a time, there needs to be a way to ensure that alarms are presented at a rate that can be assimilated by a human operator, particularly when the plant is upset or in an unusual condition. Alarms also need to be capable of directing the operator's attention to the most important problem that he or she needs to act upon, using a priority to indicate degree of importance or rank, for instance. A good example of this problem is from the old US sitcom MASH. A common scene was Radar O'Reilly slipping in a requisition for something that Hawkeye wanted in the stack of papers for Colonel Potter to sign. In much the same way, if alarms were unprioritized, the important ones can be mixed in with lower value nuisance ones.