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Old 10th March 2009
Gear interested

I probably summon forth old demons here but after reading through this thread over and over again, I still cannot figure out that Paroc table in the initiator's first post of this topic..

Maybe I'm plain stupid or didn't pay enough attention in high school physics and math classes, but on Paroc website they have an equation which can be used to calculate the air flow resistance: AF = d/A*l

So for instance:
Thickness, d (mm) = 10
Air Permeability, l (m2/Pa s 10-6) = 5
now, having put those numbers in the formula, I get AF = 2 which is also presented in the table under Rs column.

But Airflow Resistivity, r (kPa s / m2) for the same numbers is 200

As I understand, this is the most important figure to look at when it comes to choosing a suitable wool / fiber for an absorption application, but how do I get that using the above formula and data?