Floors that are physically open to one another <br />should be arranged as a single evacuation zone. <br />This avoids the confusion possible when occupants <br />in portions of the space hear an evacuation signal, <br />but cannot clearly decipher it. A common example <br />of this situation is a series of parking garage levels <br />connected by open ramps. The group of intercon- <br />nected levels should be designed as a single evacu- <br />ation zone on the "floor, floor above, and floor <br />below" automatic evacuation scenario. <br />Atriums and other large open spaces spanning <br />multiple floors also deserve special attention in <br />buildings with selective evacuation. The arrange- <br />ment depends upon the egress arrangement and <br />the building's evacuation plan. The entire atrium <br />should comprise one evacuation zone. It may be <br />desirable to activate only the atrium zone upon <br />receipt of an alarm signal from within the atrium, <br />and not from alarm signals in other areas. - <br />Designers should consider the legibility of signals <br />in areas adjacent to the atrium, so as not to cause <br />occupant confusion. <br />Considerations -Voice Alarm Systems <br />• Arrange evacuation zone boundaries along <br />fire or smoke separations. <br />■ Coordinate the evacuation zones with the <br />building evacuation plan. <br />■ Place areas or floors open to one another in <br />a single zone. <br />■ Arrange each bank of elevators into a manu- <br />al-select zone. <br />■ Arrange each stairway into a separate zone <br />(manual-select type if no initiating devices <br />within stairway). <br />■ Arrange each atrium on a separate zone, <br />and consider message legibility when <br />arranging activation of adjacent areas. <br />FIRE DEPARTMENT <br />COMMUNICATIONS SYSTEMS <br />Fire department communications systems are two- <br />way telephone systems typically required in high- <br />rise buildings. The command center contains the <br />control unit with the main handset for use by the <br />fire department commanders (Figure 6.8a). Either <br />handsets or jacks for handsets are then placed in <br />areas of the building for firefighters to communi- <br />cate with the command center (Figure 6.8b). If the <br />system uses jacks, a number of portable handsets <br />with plugs are provided in the command center for <br />distribution to firefighters. <br />(Fig. 6.8a) Fire officer <br />(Fig. 6.8b) A firefighter <br />speaking into the handset <br />using a handset in a re- <br />at the control panel for a <br />mote jack located inside <br />fire department communi- <br />a stairway. <br />cation system. This panel <br />also houses the handsets <br />used by firefighters at <br />remote jacks. <br />Designers should plan for handsets or jacks in <br />locations where firefighters are likely to be operat- <br />ing. NFPA 72 requires only one handset or jack per <br />floor, one per exit stairway, and one in each fire <br />pump room. NFPA 101 requires them on every <br />level in each enclosed stairway, each elevator car, <br />and each elevator lobby. The IBC currently requires <br />handsets or jacks in the same locations as NFPA <br />101 and also in standby power rooms, fire pump <br />rooms, and areas of refuge. These additional jacks <br />or handsets can provide more rapid communica- <br />tions from these critical areas. <br />I <br />I <br />I <br />FIRE SE,RV:IC.E 'FtATUR&S OF BU:ILD:INGS AND FIRE PR.OTE'C'TION SY,S'TEWS 57 <br />173 <br />