Computing detection delays in industrial alarm systems

False and nuisance alarms are major problems in the process industry. Techniques like deadbands, delay-timers, and filtering can significantly reduce these false and nuisance alarms. The down-side, however, is that using these techniques introduces some delay in raising the alarm (detection delay). In this paper, detection delays caused by deadband and delay-timer techniques are calculated using Markov processes. A design procedure is also proposed that compromises between detection delay, false alarm rate and missed alarm rate for an optimal configuration.