Mineral Wool- Compression vs density

When you look at mineral wool in general there are several different densities. 2 or 2.5 pound density is used in roofing or sound attenuation (SAFB) 8 pound density is used in exterior assemblies and neither of those are appropriate for firestop applications.  

If you look at the product data sheet the product needs to show that it was tested to ASTM E814 for firestop penetrations or ASTM E1966 for fire rated joints. If it was tested to ASTM E119 or UL 263, that just means it was used in a fire rated wall, as insulation but not as firestop.  

Here is what often happens, the crews insulating the walls see a large block out and they just stuff it with 2.5 pound SAFB because they are told to fill the wall cavity. If you are running crews doing insulation, please tell them to avoid those banks of conduits or large openings for pipes or conduits because those will need to be firestopped and they will require either 4 pound or 6 pound density material.  

Now, for those of you who think all mineral wool is the same