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From the `12 IBC, Section 1207.2:
"Walls, partitions and floor/ceiling assemblies separating dwelling units from
each other or from public or service areas shall have a sound transmission
class (STC) of not less than 50 (45 if field tested) for air-borne noise when
tested in accordance with ASTM E 90.................Penetrations or openings in
construction assemblies for piping; electrical devices; recessed cabinets;
bathtubs; soffits; or heating, ventilating or exhaust ducts shall be sealed,
lined, insulated or otherwise treated to maintain the required ratings.
This requirement shall not apply to dwelling unit entrance doors; however,
such doors shall be tight fitting to the frame and sill."
Mark,
The way that I read that Section, ...it is the walls, partitions and
floor \ ceiling assemblies that are being separated from the
public spaces, and not a dwelling unit.........It is my belief that the
restroom must have some type of "required" Sound Barrier
installed [ not less than the STC of 50 ].........To accomplish this,
some type of ceiling [ aka - lid, or floor \ ceiling above ] must be
installed with some approved type of acoustical insulation.
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