OCCUPANTS OF MOST BUILDINGS are trained to evacuate as soon as fire alarm system occupant notification occurs. In some special-purpose industrial occupancies, however, immediate evacuation by some personnel might not be feasible. For example, an alarm in a chemical manufacturing facility might necessitate an orderly shutdown of equipment, a step that could help avoid creating conditions that present a greater danger to far more people than the fire that resulted in the building evacuation. In other cases, an orderly equipment shutdown might be needed to avoid damage to costly specialized equipment; personnel whose duties are to effect an orderly shutdown would remain in the control room while others immediately evacuate.
NFPA 101®, Life Safety Code®, provides requirements for the protection of industrial occupancy personnel who need to remain in the building at the time of general evacuation. The provisions help assure that, when those persons are ready to leave the building, a safe route will be available.
In this example, the code classifies the control room as an ancillary facility subject to special requirements. The ancillary facility that houses personnel who will experience delayed evacuation is required to be separated from the predominant industrial space by minimum two-hour fire resistance-rated barriers. The fire-rated separation around the ancillary facility is permitted to employ all the windows needed for viewing the industrial space, as fire-rated glazing materials for use in a 2-hour barrier are readily available. Further, the ancillary facility must be provided with one egress route separated from the predominant industrial space by minimum 2-hour fire resistance-rated barriers so as not to force occupants to travel through the fire area. The protected egress path from the ancillary facility to an outside wall of the main building might be provided by an exit passageway, an egress component that can be equated to a fire-rated exit stair enclosure that is tipped onto its side so as to run horizontally.
Industrial occupancies often have buildings within a building for functional purposes. For example, a quality control laboratory might be positioned on the manufacturing floor. The code classifies the lab as an ancillary facility subject to special requirements. The ancillary facility is enclosed by walls and has a ceiling. Personnel working within the facility can lose awareness of what is happening in the manufacturing area and would not be expected to hear, smell, taste, and—depending on the presence of windows — see evidence of fire in the main industrial space.
The code requires that the ancillary facility be arranged to allow occupants to travel in independent directions immediately upon leaving the facility so as not to have to pass through, or in close proximity to, a fire in the predominant industrial space. For those familiar with the code concept of common path of travel, this requirement is equivalent to allowing no common path in the egress route from the ancillary facility exit access door to the main building exit.
The industrial occupancy ancillary facility provisions demonstrate a feature of NFPA 101 that makes the code so effective at protecting building occupants — its occupancy-based format. The requirements applicable to a school are different from those applied to a hospital, which are different from those for factories. Each occupancy chapter tailors its protection requirements in recognition of occupant characteristics and the functional needs of the occupancy. Life safety is provided without interfering unnecessarily in day-to-day operations, which is just one reason why the code is so widely used.