Fire detection system
In order to reduce damage caused by fires,
it is essential that they are detected at an early stage. To that end, vessels
shall be required to provide means of detecting and declaring fire. Fires can
be detected by visually observing images of cameras installed on board or
directly during patrols. If you notice any signs of fire, the alarm of the fire
is activated, with the help of the nearest fire alarm manual sensor. Another
way to detect a fire is to install automatic fire alarm sensors. These sensors are
the main part of the automatic fire alarm and depend on the efficiency of the
entire system.
Fire alarm sensors are divided into four main groups:
Thermal fire sensors;
they are only appropriate for use where heat is the most
distinct feature of the possible fire. Smoke fire
sensors respond to the smoke present in the air.
These sensors usually work by measuring the change in infrared dispersion
caused by smoke. The main disadvantage of such sensors is that they can
mistakenly actuate under the influence of water vapor or room dust. Therefore,
they should not be installed in smoking and dusty rooms.
Flame fire sensors respond to a smouldering or open flame fire source. Therefore, they
are frequently installed where a fire can occur without prior, significant
smoke emission. The fire sensors are more effective than smoke and thermal
sensors, since they can detect the fire earlier because they crack into the
fire source before a significant amount of smoke is released or there is a
change in temperature.
Combined fire sensors contain a few different types of fire detection sensors. Most often it is a
combination of smoke and thermal sensors, thanks to which the fire signal
formed and sent to the fire alarm centre is more reliable than that of single
type sensors.
The overall efficiency of the ship's fire
protection system depends directly on the installation of a fire alarm system
on board based on fire detection sensors. Therefore, the type, quality and
quantity of fire sensors have been selected taking into account the
characteristics of the protected room (dust, smoke, temperature fluctuations,
humidity, and area), mainly determining the effectiveness of the fire fighting
system of the whole ship.
As an additional means of detecting fire,
hand-held gait detection sensors are mandatory on larger and passenger ships.
Most often these are small red, square boxes with a plastic or glass cap
covering the fire alarm activation button. These hand-held fire sensors are
installed in prominent and accessible places near the entrances to the premises,
the ends of the corridors, etc. Their installation sites are marked with
standard markings made of fluorescent material.
A fixed fire detection and fire alarm system shall be
installed for the protection of mechanisms and accommodation.
Fire alarm sensors for the protection of machinery premises
shall be fitted in:
- periodically unattended machinery spaces;
- machinery spaces in which:
- the installation of automatic and remote-control systems and equipment is permitted instead of permanent standby;
- the main propulsion and associated machinery, including major sources of electricity, shall be equipped with automatic or remote-control measures of varying degrees and shall be under the permanent supervision of the personnel on call at the control post facility.
In these rooms, the design of the fixed
fire detection and fire alarm system and the arrangement of fire detectors must
ensure that the fire is detected rapidly under any normal operating and
ventilation conditions necessary to maintain the ambient temperature within the
prescribed range. It shall be prohibited to install detection systems using
only thermal fire detectors in any premises other than those of limited height
where such systems are specially designed. The detection system shall activate
both audible and visual alarms, the signals of which must be clearly
distinguishable from those of signals other than fire warning systems; the
detection system equipment shall be located in a sufficient number of locations
to ensure that these alarms are audible and visible on the navigating bridge
and are heard and seen by the engineer in charge. If the navigating bridge is
not awake, the alarm shall be audible at the place where the crew member in
charge is on duty.
For the protection of residential and service
premises and control stations, all stairwells of the residential area, all
corridors and escape exits, fire sensors for the detection of smoke shall be
installed. It is necessary to consider the need to install a special purpose
detector for the detection of smoke in ventilation ducts.