Integral to the telecommunications infrastructure in buildings are the secure communications rooms, consisting of the MDF and generally one or more IDF's. These rooms must be secure, environmentally conditioned and clean before Telecommunications can work in them, especially as fiber must be terminated in these rooms, requiring a very clean environment. Expensive and delicate networking devices, requiring environmental conditioning, also are housed in these rooms. In this regard, the MDF and IDF's shall be completed, including environmental conditioning, and completed early in the project timetable. In particular, all penetrations shall be completed and sealed before telecommunications work can proceed in these environments.
The MDF also serves as the distribution point for voice, video and data, and shall be secure to protect the integrity of these systems. Grounding and bonding shall be provided in the MDF in strict accordance with industry standard, and extended to all IDF's.
The building backbone cabling consists of fiber cable for data and video, and copper cable for voice. These cables shall be run between the MDF and all IDF's. The infrastructure for the building backbone cabling shall consist of conduit between the MDF and IDF's where the run is vertical and horizontal. Ladder racks or cable trays can be used for some horizontal runs.
Industry standard will be strictly observed for the building backbone pathways. Conduits shall be sized to be no more than 40% full by volume when serving the entire number of cables entering the IDF, even though some of these jacks many not be activated initially, to allow for growth and for situations where every jack may be activated. Two 45-degree sweeps shall be used instead of 90-degree fittings. No more than 180 degrees of bends shall exist in conduits without inclusion of an easily accessible pull box, the location of which shall be clearly marked on drawings. In situations where cable tray, conduit, or sleeves extend outside the construction area into occupied portions of the building, they shall be fire-stopped in accordance with industry code.