sound transmission

huangyhg

sound transmission
i've got an electrical engineer telling me that his refridgeration room on the elevated mezzanine level needs to have solidly grouted cmu walls to reduce sound transmission.  they're also crying about headroom below the mezz, too.  my mezzanine steel framing is already rather deep due to the required live loads.  and they will only get deeper with a solid cmu wall and l/600 deflection limits.
now, he said he'd like to get a 12" cmu wall.  i think a 12" metal stud wall with batt insulation would be a better option, at least structurally.  does anyone know about sound transmission through cmu vs. insulation or any other product?
if there's tables for dead loads, are there tables for sound transmission through different media?
i was just recently involved in a movie theatre project.  sound transmission between theatres needed to be controlled.  the construction detail between theatres was a double metal stud wall with an air space between them.  there was also some detailing that had to be done at the roof.  the roof deck had to be broken between theatres.
the classic "wood-frame house construction" by the us dept. of agriculture (handbook no. 73) has a 6 page chapter on "sound insulation". it states that "the resistance of a building element, such as a wall, to the passage of airborne sound is rated by its sound transmission class (stc)". this book is very affordable on ebay.
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