Chapter 07-High-Rise Building Fires

© 2009 Delmar, Cengage Learning

High-Rise Building Fires

Chapter 7


Objectives

• Understand and explain why high-rise buildings present a difficult and different fire problem for firefighters, including the unique fire behavior problems that may be encountered in a high-rise fire

• Recognize the difference in construction methods of high-rise buildings and explain how different construction materials and designs impact fire behavior in these buildings


Objectives (cont’d.)

• Describe the fire fighting strategies and tactics used to locate, confine, and extinguish high-rise fires

• Describe the special problems that may be encountered on high-rise fires such as communications issues, the stack effect, ventilation concerns, evacuation issues, and elevator control


Objectives (cont’d.)

• Describe and explain the purpose of the special fire protection equipment which may be found in high-rise buildings

• Describe when a stairwell support system may be needed


Introduction

• As cost of land increases, building upwards instead of outwards is more popular

• Codes for high-rises vary throughout the country• High-rises present special conditions and

problems for firefighters that will be discussed throughout this chapter


High-Rise Buildings

• From 1996 to 1998: 15,500 high-rise fires in U.S., $252.3 million in annual property loss, 930 civilian injuries including 60 civilian deaths.

• Residential fires usually contained in one room, opposite for manufacturing, industrial fires

• Construction and design divided into three time periods


Figure 7-1 Fire in high-rise buildings

can present firefighters with unique challenges.


Early Fire-Resistive Buildings (1870 to 1920)

• Little or no concern for fire safety• Floors supported by concrete piers

– Created open void space where fire/heated gases could move underneath the structure

• Terra cotta tile to provide fire resistance• Water supply line installations too small• Careful planning and risk assessment required


High-Rise Construction (1920 to 1960)

• Have features not found in earlier or later construction

• Steel framed and tiled with concrete or masonry• Windows can be opened and leak air for

ventilation• Example: Empire State Building


High-Rise Buildings Constructed after 1960

• Modern steel and glass buildings found in most downtown areas

• Characteristics of these high-rises:– Gypsum board: used in interior finishes for walls and

ceilings– Lightweight concrete: blown onto metal to provide a

coat of fire-resistive material– Central core construction: elevators, stairs, and

support systems are located in center of building


High-Rise Buildings Constructed after 1960 (cont’d.)

• HVAC systems may have to be shut down and windows broken during fires– Fire dampers installed to prevent fire and heated

gases from circulating in other parts of buildings– Knowledge of the specific building system needed– Pre-planning with building maintenance should be

sought


High-Rise Buildings Constructed after 1960 (cont’d.)

Figure 7-6 Central core floor plan for high-rise building


Stack Effect

• Natural movement of air within a tall building caused by temperature difference between outside and inside of building– Becomes stronger as the building gets taller and the

temperature difference becomes greater

• Stratification location: when light heated air flows upward and reaches a point where it is same temperature/weight as surrounding air


Figure 7-7 Stratification inside a high-rise building


Ventilation

• Planned and systematic removal of smoke, heat, and gases from a structure

• Traditional ventilation not always available in high-rises

• If no horizontal ventilation:– Enclosed stairwell can be used– Hold open door on fire floor into stairwell– Use positive air pressure fans (with caution)


Elevators

• Elevator use has caused grave injuries or death in the past

• Used when fire is higher than sixth floor• Remotely located elevators may be used• Knowledge of policies and procedures is

necessary


Use of Elevator Systems

• Manual control system– Phase 1

• Brings cars to the lobby or designated place nonstop

– Phase 2• Manually control elevator from inside car

– Phase 3• If lobby smoke alarm is activated, cars will not return

there, but this will show designated floor in that event


Stairwells

• If elevators are unsafe, use of stairwell support procedure is implemented – Teams stationed two floors apart in stairwell– First team carries equipment up two floors to waiting

firefighters– Second team carries it up two more floors– First team descends and rests while waiting to carry

and pass on additional equipment


Pressurized Stairwells

• Designed to provide occupants and firefighters a smoke-free environment while moving within the stairwell– Enclose the stairwell tightly – Add a fan to increase the air pressure


Building Fire Protection Systems

• Building systems available to firefighters are:– Standpipes– Sprinkler and water supply systems– Fire pumps– Fire communications and command systems– Pressurized stairwells


Standpipes

• Most building codes require them• Look at them as fire water mains built into the

building with an outlet• Pressure at each floor will vary and in some

cases can be too high– Pressure reducer will need to be installed


Figure 7-10 Fire department connection and post indicator valve. Notice the target indicating that the valve is open and the attached alarm system to notify when the valve is closed.


Sprinklers and Water Supply Systems

• Most new high-rises are equipped• Can quickly control and extinguish most fires

with water from two or less heads• In taller high-rises, building is divided into zones

with a water supply tank installed in each zone


Fire Pumps

• Required in all high-rise buildings• Designed to increase pressure in the sprinkler

and/or standpipe system• Can be found singly or in pairs• Essential for inlet and discharge gauges to be

checked • Critical that bypass valve is left closed after

pump testing


Fire Communication Systems

• Steel columns and beams enclosed with concrete absorb energy from fire department radio communications systems– Makes communication ineffective

• Newer buildings have communication systems installed– Hard wiring allows intra-building communication using

series of high reliability speakers and telephone devices located throughout building


Search and Rescue

• Establish systematic search method to ensure all areas are checked for remaining occupants

• Set up accountability system for those found and those missing

• Watch for convergence cluster behavior– People gather in groups in one location to feel safe


Relocation of Occupants

• Total evacuation is usually neither practical or feasible

• Dependant upon:– Number of people needing to be moved– How they can be moved– If a safe refuge area is available within the structure


Salvage

• Typically have valuable contents like computers, office equipment, business records, and personal items

• Need for property protection is generally downward as water flows downward

• To help salvage efforts, should channel the flow of water down the stairs or through drains


Overhaul

• Labor intensive and precedent plan is needed– Direct initial overhaul efforts– Direct fire fighting forces to hidden shafts – Direct forces to false ceilings to be pulled down or

opened

• Crews should be assigned to every floor above the fire for smoke and extension and below to confirm extinguishment


Summary

• High-rise fires becoming increasing problem• Issues include communication, height, and

ventilation problems• Need to be able to work systems within a high-

rise effectively• Evacuation, salvage, and overhaul issues need

to be addressed appropriately

Education

Chapter 07-High-Rise Building Fires