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MAN3038-2
DISCOVERY PRODUCT GUIDE
At the other extreme, response mode 5 will be suited to more dusty or smoky environments such as loading
areas where diesel forklift trucks are operating. Response mode 3 is a general-purpose setting for which the
response is similar to that of the corresponding XP95 detector.
It will be seen, then, that it is often more useful to think of particular response modes being suited to different
environments rather than simply having different sensitivity to fire. Table 9 shows response modes for
Discovery detectors that are considered suitable for different environment types. Any of those identified as
suitable should give acceptable performance. The recommended detector/mode combinations will give the
best available performance from Discovery.
Time-related systems
Discovery detectors are particularly useful for installations in which it is desirable to set different detector
response characteristics at different times of the day because of changes in the environment. For example, if
an industrial process generates smoke or fumes during working hours and the area is clean at other times
the optimum response mode will be different at different times of the day. Outside working hours the
sensitivity can be switched to a higher level to maintain maximum protection.
The Discovery multisensor is especially suitable for time-related systems. Because its response can be
switched from a pure heat response to a sensitive multisensor smoke response, it can be optimised for very
clean or dirty (smoky) environments. However, if mode switching between heat and smoke (or multisensor)
modes is used, it is important to remember that the area coverage in the heat-only mode is less than that of
the smoke or multisensory modes.
The detector spacing must therefore be
based on the heat detector
spacing of
the relevant standard.
Optical
Multisensor
Ionisation
CO/Heat
CO
Heat
Overheating/thermal
decomposition
Very Good
Very Good
Poor
Very Poor
Very Poor
Very Poor
Smouldering/glowing
combustion
Good
Good
Moderate
/Good
Excellent
Excellent
Very Poor
Flaming combustion
Good
Good
Very Good
Moderate
Poor
Poor
Flaming with high
heat output
Good
Very Good
Very Good
Very Good
Moderate
Moderate
/Good
Flaming – clean
burning
Very Poor
Moderate
/Good
Poor
Moderate
/Good
Very Poor
Moderate
/Good
Table 8 – Relative Performance of Detectors in Test Fires
Table 9 – Discovery Response Mode Selection Grid
