Fiberglass versus steel in fire resistance

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jsc7

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Apr 18, 2017
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I have seen some pretty scary videos concerning the flammability of fiberglass. Are steel boats a much safer fire risk than fiberglass boats, or is it a minor difference?
 
Depends on the boat and all the installed systems and materials.
 
Yes and no. The dangers of vehicle fires in the more broad sense is the paint, soft goods and "bolt ons" if you will.

Steel hulls and superstructures (properly built and protected) tend to be a more recognizable shape but will still lean toward a total loss. Fiberglass boats like FF's Uniflite "Lucy" (for sale btw) can be built to a fire resistant resin specs.

As is always the case the devil is in the details.
 
Either way, at about the 3 minute point of a fire, the interior of the boat will be trashed by flame and smoke. Small advantage to the steel boat that may better resist flames traveling through the cabin bulkheads.
 
OAK has a USCG burn rate of 100 .

Std GRP has a burn rate of 500 .

FR resin for the USCG and military has a burn rate of 100.

With a slight loss of strength (-2%) FR resin can be had at a burn rate of 10.

This is used for ducts in factories.

The hassle with FR resin although it is self extinguishing , the resin when burned can be poisonous to breath..

The usual cost difference when I was building boats was 2c a pound.

Like most items on a boat, if the first owner does not demand it , its not there.
 
As noted above, the 'fire load' is the real issue. That is, the stuff on board that burns. Same as in buildings. The interest in fire resistance of the structure has more to do with the safety of the occupants than in the structure itself. The time ratings given to structural components are for the amount of time you have to escape or to fight the fire. The ratings are determined by standard tests and thus may bear little resemblance to performance 'in the field' (maintenance, installation, etc.)

Fire safety has infinitely more to do with design and installation of components, maintenance, storage, care by the occupants than it does in the material of the structure.
 
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