I am in doubt weather or not a trapezoid construction as shown in the attached picture should be categorised as obstructed combustible. What would you think? And where would I be able to find a list of definitions for combustible materials?
The reason I ask, is because of the trapezoid steel. In case of a fire, there is a risk that the steel will collapse. I'm in doubt if the trapezoid therefore could be categorised as combustible in the NFPA13 code.
And how would you categorise the construction shown in the picture?
It appears as a parrallelogram to me but it may be the camera angle.
While the term pocket ceiling is not defined in NFPA 13, this appears to be case where I would evaluate the design based on Section 8.6.7.1 of the 2002 edition.
To find the definition of combustible, start in the building code that references NFPA 13. What I see in the photo appears to be IIB, which is noncombustible construction.