Um, Rick, you have again confused EPS and XPS. That is EPS on fire. EPS burns great, as it is made from PS soaked in benzene. XPS is not.

That video is unsourced bs from a long time ago. Every cold room would have an interior wall surface (often both sides) that is fire proof, typically stainless steel, and one wall missing to feed flame growth is silly. Cold rooms are sealed to keep cold in. Flames wont last long in them, and everything is cold.

Any building material will have ASTM fire ratings for buildings, as the XPS we have discussed does.

But yes. If one needs to reduce fire risk for boats, PVC is a better material than XPS.

Also, if you feel that oil slicks are a common enough, where you sail, to put your encapsulated in epoxy core at risk, then PVC is also a better material choice.

If these are very low risks for you and a lighter cheaper boat is more important, perhaps consider XPS, if it is available in the strengths you need.

On July 21, 2018 12:06:58 AM UTC, "Rick Willoughby rickwill@bigpond.net.au [harryproa]" <harryproa@yahoogroups.com.au> wrote:
|One of the key characteristics of XPS that has not yet been discussed
|is its chemical resistance. If used as a skin on a boat you would need
|to be very carful about complete encapsulation; never damaging the
|encapsulation and avoid the use of hydrocarbons in the boat as there
|will be inevitable spills that will find their way into any
|imperfection and eat out the core.
|
|Every marina I have seen has some oil film on it somewhere. So any
|external surface scratching or through-hull fitting is a potential
|source for ingress of hydrocarbon and chemical attack of the core.
|
|By comparison PVC foams have greater chemical resistance to common
|chemicals. When building there is no need to be cautious about the use
|of acetone for example.
|
|The greatest consideration for a boat building material in terms of
|ultimate safety is flammability. I give this aspect great weight. Any
|material that is not self-extinguishing has to be used with care.
|Again I would not like to have a boat skinned with a material that is
|highly flammable. The significance of the linked table should be taken
|into consideration;
|http://www.pvc.org/upload/images/Chart_26WEB_large.jpg
|<http://www.pvc.org/upload/images/Chart_26WEB_large.jpg>
|
|You can get fire retardants in XPS but it adds cost and the
|effectiveness is not well tested - or at least up to a few years ago
|when it was not given any value by insurers. Some insurers will not
|insure buildings that contain XPS or EPS panels. This video might
|influence where you will store the XPS sheets and the location of the
|area for building a vessel comprising large amounts of XPS.
|https://www.youtube.com/watch?v=bJAWPfZzIKY
|<https://www.youtube.com/watch?v=bJAWPfZzIKY>
|When heated the XPS gives off flammable vapour that will inevitably
|flashover and cause an intense fire.
|
|
|
|> On 21 Jul 2018, at 12:39 am, StoneTool owly@ttc-cmc.net [harryproa]
|<harryproa@yahoogroups.com.au> wrote:
|>
|> What are the Characteristics of Polystyrene?
|>
|> Now that we know what it is used for, let’s examine some of the key
|properties of Polystyrene. Polystyrene is typically (but not always) a
|homopolymer meaning that it is composed only of the monomer styrene in
|combination with itself. Depending on the type of PS it could be
|classified as a “thermoplastic” or a “thermoset” material. The name has
|to do with the way the plastic responds to heat. Thermoplastic
|materials become fully liquid at their melting point (210-249 degrees
|Celsius in the case of Polystyrene), but they begin to flow at their
|glass transition point (100 degress Celsius for PS). A major useful
|attribute about thermoplastics is that they can be heated to their
|melting point, cooled, and reheated again without significant
|degradation. Instead of burning, thermoplastics liquefy, which allows
|them to be easily injection molded
|<https://www.creativemechanisms.com/blog/topic/injection-molding> and
|then subsequently recycled. Thermoset plastics, by contrast, will not
|reliquify once they are “set” in solid form.
|>
|>