MAN2285-9
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4.3
Alarm levels
Alarm levels and delays tab, Level subgroup
The value set in the Fire, PreAlarm and Aux functions in the Level subgroup is the relatively scaled bargraph
level at which the appropriate alarm is initiated on the detector. The Fire 2 level assigns an absolutely scaled
alarm level in % obs/m.
The Aux level is set by factory default at level 10 which means that this alarm will occur after the Fire alarm.
The default level settings for Pre-Alarm and Fire 1 are 6 and 8 respectively. The default setting for Fire 2 is
20% obs/m.
4.4
Alarm delays
Alarm levels and delays tab, Delay subgroup
The alarm delay is the number of seconds that an alarm level has to be continuously sensed before the alarm is
initiated. Each alarm level has a programmable delay of between 0 and 90 seconds. The default delay for each
alarm level is 5 seconds.
Note:
For FastSense 25 systems installed in accordance with AS1603 PT8 and AS1670 PT1, Alarm
delays should not be set to exceed 60 seconds.
4.5
ClassiFire override
Alarm levels and delays tab
This function has no current use on the FastSense 25 but are reserved for future expansion purposes.
4.6
Alarm factor
Alarm levels and delays tab
The detector sensitivity is set with this entry, which will also affect the probability of nuisance alarms. 0 = high
sensitivity, higher probability, 8 = low sensitivity, lower probability. The default alarm factor is 4.
The highest sensitivity setting is suitable for clean, environmentally controlled environments, e.g.
semiconductor manufacturing clean rooms where airborne pollutants are kept to an absolute minimum and the
least contamination is cause for alarm. Use of this setting in a busy machine shop would lead to relatively
frequent nuisance alarms due to the normal variation of atmospheric contamination and a lower sensitivity
setting is recommended. It is therefore important that the alarm factor chosen is suitable for the area to be
protected. When the appropriate alarm factor for the protected area has been set, nuisance alarms will be
reduced to an absolute minimum.
The following table gives suggested settings of ClassiFire alarm setting for different locations
Alarm
Factor
Sensitivity
Probability of Nuisance
Alarm
Suggested Protected Area
0
Extremely High Once per year
Semiconductor manufacturing clean
room
1
Once per 5 years
Computer room
2
Once per 10 years
Non-smoking office
3
Once per 50 years
Clean factory
4
Medium
Once per 1000 years
Warehouse
5
Medium
Once per 5,000 years
Warehouse with diesel trucks operating
6
Medium
Once per 10,000 years
Warehouse with diesel trucks operating
7
Low
Once per 20,000 years
Warehouse with diesel trucks operating
8
Low
Once per 100,000 years Warehouse with diesel trucks operating
