thank you very much. The 2007 NFPA is the same in our point of view.
1) Please help us to understand the meaning of "having no access".
Does access mean also openings for maintenance?
2) In A.220.127.116.11.1 (NFPA 2007) is written:
"Minor quantities of combustible materials such as but not limited to: cabeling, nonmetallic plumbing piping, nonstructural wood, etc. can be present in concealed spaces constructed of limited or noncombustible materials but should not typically be viewed as requiring sprinklers. For example, it is not intent of this section to require sprinklers, which would not otherwise be required, in the interstitial space of a typical office building solely due to the presence of the usual amount of cabeling within the space. The threshold value at which sprinklers become necessary in the concealed space is not defined".
We have in our project an typically office building with offices and a corridor in the center. The building is made out of steel and concret.
In the suspended ceiling above the offices we have cabeling covered by metal pipes. But there is also opening for maintenace. In addition there will be sprinkler pipes for the sprinkler under the suspended ceiling, and pipes for the heating and cooling system (cooling with armaflex insulation).
Above the corridor there will be installed ducts for the ventilation system and cable trays for the internal and external network plus telephone. The cabeling will be done starlike, so that many cables will be installed. The trays will be covered with metall.
So far we think, that it is not necessary to put sprinklers inside the suspended ceiling, because the quantities of combustible materials is present but low. What do you think?
Thank you very much in advance!