Spectrex 20/20MPI - Commercial IR3 Flame Detector - Manual (Page 19)

Detection Sensitivity 7
3 Performance
➣ In this chapter…
Detection Sensitivity page 7
Cone of Vision page 9
False Alarms Prevention page 10
3.1 Detection Sensitivity
Detection sensitivity is the maximum distance at which the detector will
reliably detect a specific size of fire and typical type of fuel (standard fire).
3.1.1 Standard Fire:
A standard fire is defined as a 1 ft 2 (0.1m 2 ) gasoline pan fire with maximum
wind speed of 6.5 ft./sec (2m/sec).
3.1.2 Sensitivity Ranges:
The detector has four user selectable sensitivity ranges. For each range
there are two response levels.
 WARNING (Pre-alarm)
 ALARM
The detection distance, for the WARNING level, is approximately 10% higher
than the ALARM distance. Alarm response times for a standard fire at a
specified range are shown in Table 1.
Table 1: Alarm Response Time versus Range
10 20 30 40
Sensitivity Range – ft. (m) 33 (10) 65 (20) 100 (30) 140 (43)
Response Time (sec) 5 8 10 10
For some typical ambient conditions the Zeta parameter, as defined in
NFPA 72 for the detector, is 0.005 (1/meter).
Note: Zeta parameters may vary significantly with changes in temperature,
air pressure, humidity, visibility conditions, etc.