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Old 06-23-2011, 09:51 AM   #9
Scraping Paint
City: Fort Lauderdale
Vessel Model: CHB 48 Zodiac YL 4.2
Join Date: Oct 2007
Posts: 3,804
Fire Suppression

GonzoF1 wrote:I'm curious why you would need fire suppression with engine shutdown with a diesel engine.
*The agents used in automatic fire suppression systems extinguishes the fire by interrupting the combustion process. They prevent oxygen combining with the fuel, they don't cool the burning material like water and they don't smother it like foam or some other agents.

If the engine room ventilation is open and the engine is running when the agent is released, most of it may just go through the engine and out the exhaust without extinguishing the fire. Boats with those systems that do not shut down the engine and shut the ventilation dampers before discharging agent into the engine room are regularly lost to engine room fires.*Marine casualty*reports are filled with examples.

If the engine room is not kept sealed tightly until it cools, the fire is very likely to reflash when the agent is diluted by fresh air. If you have one of those systems and it does work, don't be in a hurry to open the hatch to see what went wrong.

BTW, diesel has more energy per unit of volume than gasoline and while it is not as likely to cause an explosion, it is far better*for starting fires and keeping them burning.

-- Edited by RickB on Thursday 23rd of June 2011 09:53:11 AM
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