Insulation Layer

[toyboat13]

I am trying to make a protective casing for documents using high temperature ceramic or calcium silica fiber blankets. The document will be wrapped in the casing and placed into a furnace for 1350 F for 15 mins and will record internal temperature of the document. I am looking to mathematically find out how long it will take either fiber blankets to reach 350 F internally. The heat flow rate is given for each material and also the dimensions. The thickness of the blanket will be about 2 inches but can vary for .5 in to 2 in if needed.

Thank you

 

[IRstuff]

It's a transient analysis, but you can start with the heat transfer coefficient and specific heat to get an idea of the speed at which the material could heat up.

TTFN

FAQ731-376

 

[Compositepro]

Fireproof safes use an insulation that absorbs heat by releasing water vapor or something similar. If there is no thermal heat capacity in the safe, it takes very little energy to heat it to a high temperature, so even very good insulation is not very effective. Often plaster is used to fill the walls.

 

[toyboat13]

So basically the test will fail unless I apply a hydrated salt to said blankets. The hydrated salts should release a cooling water effect when heated, correct. Any other kind of chemicals should be added since just application of a fire retardent was only the one considered

 

[IRstuff]

Anything that has a solid-liquid phase transition within the deisred temperature range is a possibility.

I would suggest that you cut up a commercially available firesafe to get some ideas about how it's done with something that presumably has passed a similar test. You can get one for about $50 at Walmart or Costco.

TTFN

FAQ731-376