Floods of unnecessary alarms during plant upset and long lists of standing alarms, sometimes suppressed and often ignored have been closely linked in recent years with a number of high profile industrial accidents. Poor alarm handling contributes to operator stress, reduced plant safety, production loss and can lead to injury, loss of life and environmental damage.
When the cost “per alarm” associated with traditional hardwired annunciators was relatively high engineers naturally rationalised the number of alarms or events displayed. With the onset of powerful computer based systems it was easy & cheap to alarm and display everything without considering the useful purpose or operator capacity to manage this information. Effective alarm management mitigates against all these negative impacts.
Inspec’s approach when designing control systems is to apply industry best practice as captured in EEMUA Publication 191 ('Alarm Systems '" A Guide to Design, Management and Procurement').
Inspec can also provide Alarm Rationalisation of existing systems and our approach in this instance is to agree a strategy at the outset of the project. The strategy is likely to focus on worst offending alarms and areas or units of plant first before working down the levels of alarm frequency. The final rationalised system should have minimal critical alarms and only those that require operator intervention. All others should be either lower priority alarms or events only