The OP was about draftstopping. Read the charging language.mtlogcabin said:
R302.12 Draftstopping. In combustible construction where
there is usable space both above and belowthe concealed space
of a floor/ceiling assembly, draftstops shall be installed so that
the area of the concealed space does not exceed 1,000 square
feet (92.9 m2). Draftstopping shall divide the concealed space
into approximately equal areas. Where the assembly is
enclosed by a floor membrane above and a ceiling membrane
below, draftstopping shall be provided in floor/ceiling assemblies
under the following circumstances:
1. Ceiling is suspended under the floor framing.
2. Floor framing is constructed of truss-type open-web or
perforated members.
If the required thermal barrier is applied to the studs, what's the problem?
On the other hand, fireblocking is a different animal.
R302.11 Fireblocking. In combustible construction,
fireblocking shall be provided to cut off all concealed draft
openings (both vertical and horizontal) and to form an effective
fire barrier between stories, and between a top story and the
roof space.
Fireblocking shall be provided in wood-frame construction
in the following locations:
1. In concealed spaces of stud walls and partitions, including
furred spaces and parallel rows of studs or staggered
studs, as follows:
1.1. Vertically at the ceiling and floor levels.
1.2. Horizontally at intervals not exceeding 10 feet.
...
4. At openings around vents, pipes, ducts, cables and wires
at ceiling and floor level, with an approved material to
resist the free passage of flame and products of combustion.
The material filling this annular space shall not be
required to meet the ASTM E 136 requirements.
R302.11.1 Fireblocking materials. Except as provided in
Section R302.11, Item 4, fireblocking shall consist of the
following materials.
...
7. Batts or blankets of mineral wool or glass fiber or
other approved materials installed in such a manner as
to be securely retained in place.
R302.11.1.2 Unfaced fiberglass. Unfaced fiberglass
batt insulation used as fireblocking shall fill the entire
cross section of the wall cavity to a minimum height of
16 inches (406 mm) measured vertically. When piping,
conduit or similar obstructions are encountered, the insulation
shall be packed tightly around the obstruction.
Fiberglass melts at >1300°F; Spray foam at 250°F
Conclusion:
The insulation contractor could install 16" of fiberglass insulation at the floor and ceiling (and at 10' intervals), and around any wire/pipe penetrations and spray foam the balance of the cavity.
