Ceiling Pockets vs. Concealed Spaces

[4everlearning]

Situation = Owner wants to install nominally 10 ft. high fume hoods in a lab with 8 ft. high gyp ceiling.
Engineering = stud-out an alcove approx. 2 ft. all around top of fume hood. Top of fume hood clears bottom of upper slab by inches. Although alcove is framed 2 ft. around fume hood, the gyp at 8 ft. ceiling height will butt right to fume and be caulked at joint. Also, the alcove framing will have one layer of 5/8" Type X gyp over studs.
Construction = At 8 ft. ceiling height an existing automatic sprinkler system provides coverage. Existing heads are not quick response. The front of the fume hood will require an approx. 4" opening in 8 ft. ceiling plane to allow for sash operation. The largest volume of alcove is approx. 16 ft. x 6.5 ft. x 2 ft. high. (< 1000 ft^3)
Is this alcove a "ceiling pocket" or "concealed space" as defined by NFPA sections 8.6.7 and 8.14.1 respectively. Ultimately, does this space require sprinkler protection?

 

[cdafd]

is it combustible constrution in the void space such as wood???

also, there are exceptions in nfpa 13 that negate the sprinkler requirement.

 

[4everlearning]

Thanks cdafd.
Noncombustable construction in the alcove area.
Yes, I see section 8.6.7 does have exceptions "if" the area is designated a "ceiling pocket". If designated a "ceiling pocket", we would be required to install sprinkler head(s) in this area since the existing heads (at 8 ft. ceiling plane)are not quick response.
I'm not sure if this area can be considered "concealed" since there is the opening at the front of the fume hood.

 

[cdafd]

check section 8.14.1.2 nfpa 13 2002 edition what use to be labeled exceptions