Panasonic Electric Works Nordic AB
MEW01351
Rev: -
Planning Instructions Fire alarm system EBL512 G3, V1.1.x
94
3.
The decision value has here reached the pre-warning level and
pre-warning is activated.
4.
The decision value is here below the pre-warning level and the
pre-warning is automatically reset.
16.4.3
Smouldering smoke algorithm
The smoke from a smouldering fire brings the sensor value to rise
very very slowly but not reach the fire alarm level. A smouldering
fire can last for hours and sometimes days. The smouldering smoke
algorithm will detect such a fire at an "early" stage.
The smouldering smoke algorithm is depending on and works in
parallel with the selected alarm algorithm, i.e. the smouldering smoke
algorithm can affect the pre-warning and fire alarm levels, see below.
If the decision value has been over the smouldering level for
7
minutes
(1-2 in the figure), the pre-warning and fire alarm levels will
be lowered:
- The pre-warning level will be lowered to a level right between the
original pre-warning level and the smouldering level.
- The fire alarm level will be lowered to a level right between the
original fire alarm level and the pre-warning level.
If the decision value has reached the pre-warning level, but not the fire
alarm level, after
additional 90 minutes
(2-4 in the figure), the pre-
warning and fire alarm levels will be lowered again:
- The pre-warning level will be lowered to the original smouldering
level.
- The fire alarm level will be lowered to the original pre-warning
level.
If the decision value continue to rise fire alarm will be activated (5 in
the figure).
The smouldering smoke algorithm will be aborted and the pre-
warning and fire alarm levels restored to their original values if:
- The decision value becomes lower than the smouldering level.
- The decision value, after the
90 minutes
, has not reached the pre-
warning level.
- The decision value, after the
90 minutes
and
additional 120
minutes
, has not reached the fire alarm level.
The smouldering offset can, for the whole system, be set in WinG3,
see chapter "Alarm algorithms", page 136.
