NEWSHEET13
MARINE VESSEL PROTECTION
Other Fire Protection & Heat Detection Newsheets
Fire Risks on board Military, Commercial and Petro-Chemical sea going vessels and those on Marine leisure craft may be assessed as completely different from each other. What IS common to ALL is the obvious risk to life and cargo from a fire and the limited escape options available to crew and passengers when at sea. What may be less obvious is that a tried and tested detection concept exists which is able (in many applications) to detect an overheat condition pre-combustion stage and therefore PREVENT a fire ever developing!
The “protection” system referred to above is LINEAR HEAT DETECTION- a local overheat detection system, the un-interrupted operation and rapid response times of which will not be adversely affected by conditions one would expect to find onboard marine vessels.
The most “traditional”Application for linear heat detection on leisure craft, is the protection of an inboard engine bay :– where oil or fuel leaks onto hot surfaces are more common than many believe or care to admit admit.- but which statistics support.
The installation of a linear heat sensor cable around the engine bay will provide a cost effective early warning of an overheat condition, and / or rapid detection of any flash fire situations. This detection signal may be used via suitable outputs from a dedicated control unit to automatically operate an installed extinguishing system, or alert those on board smaller craft so that necessary actions can be taken to manually extinguish the fire.
On larger commercial and military sea going vessels the same risk may be protected by linear heat detection in a similar manner – but in this case it is almost always associated with an automatic extinguishing system.
Depending on the purpose for which the vessel was originally designed and is currently operated, linear heat detection should be considered and specified for any combination of the following additional risks:
GENERATORS
ELECTRICAL SUPPLY CABLE PROTECTION
ELECTRICAL CONTROL CUPBOARDS
FUEL DISTRIBUTION LINES
STORAGE HOLD
CAR DECK.
The advantage a detector – installed at the EXACT point of risk, and not some distance away at the most convenient roof/ceiling height – can offer an end user / owner or operator should not be underestimated! Neither should the features and benefits offered by DIGITAL linear heat detection systems over their analogue, fibre optic, pneumatic competitors. Two such features/benefits are:-
• The ability to alarm at a pre-determined temperature REGARDLESS OF THE INSTALLED LENGTH EXPOSED TO THE OVERHEAT/FIRE.
• “Distance Read” Indication option – a visual indication of the exact location of the alarm signal (particularly advantageous for overheat detection where no visible flame will exist).
Any claims of “recoverability” or on site alarm adjustment by analogue systems should be carefully assessed. An overheat or incipient fire condition will ALWAYS be a localised event – resulting in only a short length of linear heat sensor cable being exposed. Resistance averaging systems would require a temperature far above sensor cable material destruct temperatures before it will provide an alarm signal – therefore it is not recoverable. In many cases, Site adjustment of alarm temperature levels can only be made where installed lengths of sensor cable or ambient temperatures are reduced.
OVERHEAT and FIRE risks are major considerations, but many operators are rightly as concerned with WATER or FLUID LEAK risks as they are with those presented by fires………………………
In addition to providing a low cost, low maintenance overheat / fire detection system, a similar cable based (or fixed point probe option) WATER and / or OIL leak detection system is available. This includes the capability of monitoring, detecting and signalling leaks during a period in which they may be safely corrected / repaired , but which may otherwise remain undetected. There have been repeated reports of commercial and military vessels experiencing such leaks – which at best may result in irreparable damage to goods, machinery or materials being transported by the ship.
FLUID LEAK DETECTION systems are cost effective, easy to install, many are recoverable (once the water/oil has been removed and the sensing cable allowed to dry) and are simple to design and install to provide pre-alarm and alarm signals if necessary as an indication of a progressively worsening situation.
The “two stage alarm” configuration can either take the form of two separate sensing cables each installed at different heights - typically around a ships hold, or can be a combination of sensing cables and point detection probes where specific high risk areas have been identified.
It is recognised that the LINE TYPE DETECTION systems – whether for OVERHEAT, FIRE or LEAK monitoring, would on larger vessels form an integral part of a complete protection system which would include the more familiar “spot” type detectors (for cleaner areas), manual call points and audible alarm signalling devices – all linked to a Central Control Panel. Integration with such control systems can be simply, rapidly and cost effectively achieved either by direct connection or via dedicated interface units. Alternatively – as with smaller leisure marine craft – line type detection can be provided as “stand alone” systems.
For further information , please contact PROLINE PROTECTION SYSTEMS Ltd @
Email:- proline@linedetect.com
Tele:- +44 8452 602 702
Fax:: +44 8452 602 902
or visit: www.lineardetection.com