Yes, finally, the devices are not spaced far enough apart and, in fact, are installed almost back-to-back. The reason this installation violates the rules is that their close proximity to each other would allow a fire in one unit to more easily pass through to the next, spoiling the wall's fire rating. The NEC has a rule regarding this in Section 21 of Chapter 3, "Wiring Methods and Materials."
300.21 Spread of Fire or Products of Combustion states: "Electrical installations in hollow spaces, vertical shafts, and ventilation or air-handling ducts shall be made so that the possible spread of fire or products of combustion will not be substantially increased. Openings around electrical penetrations through fire-resistant-rated walls, partitions, floors, or ceilings shall be fire-stopped using approved methods to maintain the fire resistance rating.
"FPN: Directories of electrical construction materials published by qualified testing laboratories contain many listing installation restrictions necessary to maintain the fire-resistive rating of assemblies where penetrations or openings are made. Building codes also contain restrictions on membrane penetrations on opposite sides of a fire-resistance rated wall assembly. An example is the 600mm (24 in.) minimum horizontal separation that usually applies between boxes installed on opposite sides of the wall. Assistance in complying with 300.21 can be found in building codes, fire resistance directories, and product listings."
The Fine Print Notes (FPN) in this NEC section mentions compliance with the building codes. A check of the 2003 edition of The International Building Code gives you the requirements for protecting the rating of one-hour rated fire walls in 712.3.2. If you are using the 2000 edition of the IBC, it is in found in 711.3.2. The entries are identical and state, in part, "Outlet boxes on opposite sides of the wall shall be separated as follows: (1.1) By a horizontal distance of not less than 24 inches (610mm)."
This problem would have been a lot easier to notice if it had been new construction and the relationship of both boxes were able to be seen because the walls were not yet covered with drywall board. As it was, it took a sharp inspector only a couple of rooms to notice that the appliances were installed back-to-back and not a couple of feet apart as the approved plans indicated.
This installation no-no might also have come to light after the hotel reopened and the manager began to notice that these rooms seemed to have developed a new trend for complaints of noisy neighbors and too-loud TVs from the occupants of these adjacent guest rooms, since sound can also pass more easily through these openings, as well as heat and smoke.
Greg Kessinger, SET, CFPS, president of an alarm installing company since 1981, teaches NICET training classes to fire alarm system designers and installers and continuing education seminars for Ohio's fire alarm inspectors. You can reach Greg Kessinger at 888-910-2272; e-mail: email@example.com; or visit his website at www.FireAlarm.org.