A Statistical Methodology for Determination of Safety Systems Actuation Setpoints Based on Extreme Value Statistics

Table 2

Influence of the number of available detectors on the probability of missing a required trip.

Mean true detector reading	Instruments per Logic channel	Probability of trip [%]	Probability of Type 1 error [%]
0.90	1	0.0	0.0
	2	0.0	0.0
	4	0.0	0.0
0.95	1	0.1	0.2
	2	1.0	0.9
	4	4.7	2.0
0.98	1	2.8	4.4
	2	15.2	12.9
	4	45.4	17.7
0.99	1	6.2	10.3
	2	27.2	23.2
	4	66.7	18.3
1.00	1	12.4	20.0
	2	42.2	25.6
	4	83.0	12.4