Ceiling tile thermal resistance

[Clymber]

I am trying to calculate the thermal resistance of a ceiling tile + insulation. The construction is a standard acoustic ceiling tile of known resistance plus 12" of R30 insulation.

Here's the question:
Is the insulation value independent of thickness? In other words, whether I have 2" or 12" of insulation, is the total thermal conduction resistance value the same?

I should know this, but it's too early Monday morning.

TIA.

 

[vpl]

This reads a bit like you're running into a local building code...

Yes, thickness does make a difference, as does material. Here's a link to a table that the Tennessee Valley Authority put out, on average thicknesses of different materials to obtain an R30 insulation:

http://tva.apogee.net/res/reinrva.asp

Now the question is whether the specification meant for you to get one 12" thick piece of R30 insulation, or to combine thinner batts (or boards) of R30 insulation and come up with 12" with a much higher insulation value. If it's the latter, then you add the resistances together (so if you're using urethane foam, you could have an insulation that have an R60 value!)

What you really need to do is to go back to whomever gave you the requirement and ask what s/he really wants.

Patricia Lougheed

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