Fire brigade lifts – a special chapter
It only became possible to build high buildings with safe access to all floors with the invention of lifts. Right at the very beginning of this development there were fire disasters in these newly built high-rise buildings. It became clear early on that firefighting would only be possible with the help of lifts - the fire brigade lift was born.
The legal basis for the installation and operation of fire brigade lifts is prescribed in the federal state building codes, model high-rise building guideline, special construction ordinance and the regulations of the local fire brigades. Normally fire brigade lifts are required in high-rise buildings, i.e. those with rooms for people above at least 22 m. Furthermore, in hospitals special requirements must be observed.
"Safe areas” especially important
DIN EN 81-72 specifies the characteristics of fire brigade lifts. The standard pictogram according to DIN EN 81-72 identifies a fire brigade lift. The acceptance documents must include an evacuation concept with a description of the evacuation phase, fire brigade operation and above all information on the rescue of trapped people. "Safe areas” are especially important in this regard.
The actual fire brigade operation of the lift is initiated by the fire alarm. The lift travels to the evacuation level and remains there with open doors. All travel commands are deleted. Further flawless functioning of the lift must be ensured for the same period as the building structure. Fire resistance class F90 according to DIN 4102-2 is required for buildings up to 60 m in height (corresponding to REI90 according to DIN EN 13501), F120 above 60 m. The emergency power supply must be secured in safe, fire-protected areas.
Maximum travel speed is 4.5 m/s
The fire brigade lift must be installed in a separate shaft. Other lifts in the same shaft must have the same fire resistance class. Safe operation applies to all lifts in in a group. The top floor must be reached in at least 60 seconds in the case of conveyance heights up to 200 m.
To avoid suction effects and prevent the emergency power supply becoming excessive, the maximum travel speed of fire brigade lifts is 4.5 m/s. There are also special requirements regarding ladders, emergency doors and emergency flaps and for protection of the electrical installations regarding water protection and water disposal. Sprinkler systems are not allowed in the shaft and machine room.
To keep lift shafts, safety stairways and lobbies free of smoke in the event of fire, pressure ventilation systems activated by the fire alarm system are used. The maximum operating pressure, flow direction, exit flow speed and maximum force for opening doors must be observed in this regard.
Special call tableau for the fire brigade
Particular sizes must be complied with when designing the car: at least 1100 x 1400 mm for 630 kg conveyance capacity, or when used with stretchers 1100 x 2100 mm at 1000 kg conveyance capacity, each with a minimum access width of the lift doors of 800 mm or 900 mm. Regional regulations include additional requirements regarding door designs, e.g. glazed inspection openings, in general a minimum door width of 900 mm or designs according to DIN EN 81-58. The ability to liberate oneself from inside must be guaranteed and the emergency flap in the car roof must be at least 0.5 m x 0.7 m including ladder. Only fire class-A non-combustible materials may be used for the car.
Operational safety and clear detection of the operating state indicated are required for controls and operating and display elements in a fire brigade lift. Among other things, this includes the main power and emergency power supply and a clear fire brigade switch and resulting fire incident control.
A special call tableau for the fire brigade must be installed at the main entrance of the building in addition to the normal ones. Activation of the fire brigade switch puts the lift in effect completely under the control of the fire brigade. Location displays are essential: the car location must at all times and with absolute operational safety be detectable in the car itself, at the main stop, in the control room of the emergency services management and in the machine room.
OIng. Dipl. -Ing. Werner A. Boehm, Weinstadt