I am currently adding insulation to my icebox. I am doing this in place,
because it is difficult to remove existing cabinetwork without wrecking it.

Basically, I will use sheet foam where I can get at surface - probably
polyisocyanurate with foil on it. Elsewhere, I will pour in urethane foam.

I am concerned about the flammability of these products. Are there
regulations for boats as there are for homes that require the foam to be
covered with a fire barrier? What is recommended?

My box will end up with 1/2" plywood as sheath on two sides. The back is a
large cavity with hull as outside. The front and bottom are exposed and
should probably be covered. The insulation has an aluminum foil, but I doubt
that provides any flame resistance. Thinking about just using 1/2" plywood -
Would this be acceptable to a surveyor?

GM

GM:

Rethink your foam choice.

Glacier Bay has a cool site at:
http://www.glacierbay.com/Instresult.asp

Here you'll ultimately conclude that anything but Extruded Polystyrene
(Dow "blue" Styrofoam Square Edge) is crap, because it falls apart or
absorbs moisture.

Mike Worrall
Los Angeles

Mike,

I have read their site, but went further and looked into the moisture
absorption of Polyisocyanurate. I think they overstate the problem -
probably to try and sell their vacuum panels.

According to the manufacturers, it absorbs very little moisture (way less
than the building codes require) but when it does, it reduces the R value to
80% of new and then stabilises . But, the R value quoted in the literature
already takes this into account. The reduction takes place mainly around the
edges if they are not sealed (often the case in house construction). The
aluminum foil (both sides) minimises moisture entry through the surface and
if the joints are well taped, this insulation should be fine. It does have a
better R value that the Blueboard and the aluminum foil acts so as to reduce
radiant heat transfer into the box. It is widely used to sheath houses under
the siding and once installed is there for good - Just like our iceboxes!

Besides, I am only adding to existing insulation and I already have the foam


But, you are right - Styrofoam would be fine, but it needs greater thickness
and I don't have much space.

GM

Rethink your foam choice.

Glacier Bay has a cool site at:
http://www.glacierbay.com/Instresult.asp

Here you'll ultimately conclude that anything but Extruded Polystyrene
(Dow "blue" Styrofoam Square Edge) is crap, because it falls apart or
absorbs moisture.

Mike Worrall
Los Angeles

You are right up to the last sentence. Nothing replaces thickness for
effectiveness except vacuum panels. If there is any way, add to the
thickness even if it means loosing interior volume.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"GBM" wrote in message
...
Mike,

I have read their site, but went further and looked into the moisture
absorption of Polyisocyanurate. I think they overstate the problem -
probably to try and sell their vacuum panels.

According to the manufacturers, it absorbs very little moisture (way less
than the building codes require) but when it does, it reduces the R value
to
80% of new and then stabilises . But, the R value quoted in the literature
already takes this into account. The reduction takes place mainly around
the
edges if they are not sealed (often the case in house construction). The
aluminum foil (both sides) minimises moisture entry through the surface
and
if the joints are well taped, this insulation should be fine. It does have
a
better R value that the Blueboard and the aluminum foil acts so as to
reduce
radiant heat transfer into the box. It is widely used to sheath houses
under
the siding and once installed is there for good - Just like our iceboxes!

Besides, I am only adding to existing insulation and I already have the
foam


But, you are right - Styrofoam would be fine, but it needs greater
thickness
and I don't have much space.

GM

Rethink your foam choice.

Glacier Bay has a cool site at:
http://www.glacierbay.com/Instresult.asp

Here you'll ultimately conclude that anything but Extruded Polystyrene
(Dow "blue" Styrofoam Square Edge) is crap, because it falls apart or
absorbs moisture.

Mike Worrall
Los Angeles

GBM wrote:
I am currently adding insulation to my icebox. I am doing this in place,
because it is difficult to remove existing cabinetwork without wrecking it.

Basically, I will use sheet foam where I can get at surface - probably
polyisocyanurate with foil on it. Elsewhere, I will pour in urethane foam.

I am concerned about the flammability of these products. Are there
regulations for boats as there are for homes that require the foam to be
covered with a fire barrier? What is recommended?

My box will end up with 1/2" plywood as sheath on two sides. The back is a
large cavity with hull as outside. The front and bottom are exposed and
should probably be covered. The insulation has an aluminum foil, but I doubt
that provides any flame resistance. Thinking about just using 1/2" plywood -
Would this be acceptable to a surveyor?

GM



No, there are no regulations or standards for pleasure boats that
require them or parts of them to be fireproof. If the boat is
fiberglass, the resin is about as flammable as anything you can think
of....

Then there's cushion foam, synthetic upholstery, all that wood.

Evan Gatehouse

On 2006-04-06 15:07:21 -0400, "GBM" said:

I am currently adding insulation to my icebox. I am doing this in place,
because it is difficult to remove existing cabinetwork without wrecking it.

Basically, I will use sheet foam where I can get at surface - probably
polyisocyanurate with foil on it. Elsewhere, I will pour in urethane foam.

I am concerned about the flammability of these products. Are there
regulations for boats as there are for homes that require the foam to be
covered with a fire barrier? What is recommended?

My box will end up with 1/2" plywood as sheath on two sides. The back is a
large cavity with hull as outside. The front and bottom are exposed and
should probably be covered. The insulation has an aluminum foil, but I doubt
that provides any flame resistance. Thinking about just using 1/2" plywood -
Would this be acceptable to a surveyor?

GM

Might also want to rethink the use of polyisocyanurate foam as it
produces extremely toxic gases in the case of even a small fire.

"dog" wrote in

GM

Might also want to rethink the use of polyisocyanurate foam as it
produces extremely toxic gases in the case of even a small fire.


Dog - All foams are flammable and produce gases when burning. That is why I
was asking about types of fire barriers. Polyiso has some advantages and
disadvantages when exposed to fire - See:
http://www.pima.org/technical_bulletins/tbull105.html

In production boats, the icebox foam is usually encased with a thin layer
of glass/resin - not much of a fire stop. Adding 1/2" of plywood apparently
gives you about 10 minutes minimum before fire reaches foam.

Other foam on the boat, such as in the berth cushions is likely a bigger
hazard when burning than any foam around the icebox. We, and likely many
other boaters, have a heater located on a wood bulkhead, within a few feet
of a foam filled berth cushion!

GM

On Fri, 7 Apr 2006 11:48:25 -0400, "GBM"
wrote:


"dog" wrote in

GM

Might also want to rethink the use of polyisocyanurate foam as it
produces extremely toxic gases in the case of even a small fire.


Dog - All foams are flammable and produce gases when burning. That is why I
was asking about types of fire barriers. Polyiso has some advantages and
disadvantages when exposed to fire - See:
http://www.pima.org/technical_bulletins/tbull105.html

In production boats, the icebox foam is usually encased with a thin layer
of glass/resin - not much of a fire stop. Adding 1/2" of plywood apparently
gives you about 10 minutes minimum before fire reaches foam.

Other foam on the boat, such as in the berth cushions is likely a bigger
hazard when burning than any foam around the icebox. We, and likely many
other boaters, have a heater located on a wood bulkhead, within a few feet
of a foam filled berth cushion!

Hi,

If plywood is not enough then a layer of intumescent paint or coating
will give more fire resistance.

cheers,
Pete.

Well, Pete, if you mean the paint should not be aroused before application,
I can't help.

The older skyscrapers used oak to protect the steel beams from fire. (I got
several tours of the Tribune Tower in Chicago and was amazed that it seemed
to be built with wooden beams. Wrong, that was just the fire proofing.)
The World Trade Center tried a foam coating, but it got blown away.

Roger

http://home.insightbb.com/~derbyrm

"Pete C" wrote in message
...
On Fri, 7 Apr 2006 11:48:25 -0400, "GBM"
wrote:

If plywood is not enough then a layer of intumescent paint or coating
will give more fire resistance.

"Pete C" wrote

Hi,

If plywood is not enough then a layer of intumescent paint or coating
will give more fire resistance.

cheers,
Pete.

Pete,

I have heard of those paints and they would probably help - But are they
readily available at Home Depot etc?

My current icebox, has no plywood over the insulation. All it has, is a thin
layer of glass and resin that encapsulates the foam. Many boats are like
this.

Seems strange that when modifying boat, we go to lengths to solve problems
that the original builders ignored!

Plan is to use 3/8" or 1/2" plywood just to protect the insulation from
physical damage. If it helps stops a potential fire, so much the better!
But, by that time, the rest of the boat will likely already be on fire.

GBM