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15 May 2026
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Featured FRI Magazine article: Fires in high-rise buildings – initial attack by Ian Schnetler
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https://www.frimedia.org/uploads/1/2/2/7/122743954/fri_vol_3_no_12.pdf
This week’s featured Fire and Rescue International magazine article is: Fires in high-rise buildings– initial attack written by Ian Schnetler, chief fire officer, City of Cape Town Fire and Rescue Service (at the time of writing the article), (FRI Vol 3 no 12). We will be sharing more technical/research/tactical articles from Fire and Rescue International magazine on a weekly basis with our readers to assist in technology transfer. This will hopefully create an increased awareness, providing you with hands-on advice and guidance. All our magazines are available free of charge in PDF format on our website and online at ISSUU. We also provide all technical articles as a free download in our article archive on our website.
Fires in high-rise buildings– initial attack
By Ian Schnetler, chief fire officer, City of Cape Town Fire and Rescue Service (at the time of writing the article)
In this third part of the five part series of articles focusing on ‘Fires in high-rise buildings’, we detail the initial attack during high-rise fires.
Fires in high-rise occupancies continue to be perilous resulting in loss of life and property, despite the advancement in technology and equipment as high-rise buildings are generally tightly sealed and present a great potential for the occurrence of backdrafts.
Initial attack
During the initial attack in high-rise fires, the forward fire commander leading the attack will be responsible for selecting the method of ascent to the reported fire area ie elevator or stairs, depending on conditions and safety concerns. The annunciator panel must be checked for additional information prior to ascending to fire floors.
The initial attack companies need to go upstairs with full personal protective equipment (PPE), self-contained breathing apparatus (SCBAs), spare cylinders, portable radios, flashlights, hose packs and basic forcible entry tools. If access is via an elevator, an extinguisher should also be taken. Other equipment will be pooled in the lobby until a resource sector is established.
As soon as the fire floor is reached and identified, the officer would need to give the incident commander a progress report of conditions on the fire floor, immediate needs and a confirmation of the actual fire floor(s) number. The incident commander should then establish the fire floor as a sector ie floor 16 equals sector 16.
When a building has multiple standpipes, the forward fire commander must advise the incident commander where water is needed and the incident commander will confirm the availability of pumped water to that particular riser.
Crews preparing to enter the fire floor should be aware of the floor layout, including the locations of elevators, stairs and floor subdivisions or zones.
They should also be aware of the distribution pattern of the supply and return air systems. Smoke and heat under pressure will migrate to the lesser pressure of open shafts and return air ducts, usually located in the core.
Crews may be crawling at floor level in limited vision and the officer must select the most unobstructed approach, with the flow of heat away from the firefighters as much as possible.
Only members trained in the operation, use and methods of escape from elevators will operate the lifts.
Crews will most likely be advancing from a stair located in the ‘core’ of the building. If the core is surrounded by an open, unsubdivided, floor plan, the potential for fire wrapping around the core exists. To protect against this, the officer in charge of the fire floor should create a backup line in the opposing direction to protect the point of entry/egress. Fire can also communicate overhead in the plenum space above the dropped ceiling. An additional line may be required to cool and protect this area.
Crews advancing on a high-rise fire should employ a straight stream or narrow angle fog when possible. This is both to reduce the amount of local steam production and to provide the maximum reach and volume for hose streams. The objective of the attack line is to create the greatest amount of steam conversion at the point of fuel gas generation (the seat of the fire), benefiting from cooling and smothering at that point. Steam created by directing fog streams into other heated areas will serve to reduce the overall heat on the floor but will also penetrate the turnouts and hoods of the firefighters, making their progress toward the seat of the fire slower, if not impossible.
For safety reasons, the initial line should be equipped with a fog nozzle. High-rise buildings are tightly sealed and present a great potential for backdrafts. In addition, the increasingly volatile loads created by synthetic furnishings and materials have accelerated the rate and intensity of burn.
At the same time the structures are becoming more lightweight and decreasing in total mass. The result is an increased potential for rapidly rising temperatures and flashover before arrival. The loss of windows can also suddenly accelerate the fire as driving winds bring new oxygen to the flame.
The plenum space above the dropped ceiling may represent the largest unobstructed space on the floor, as much as 25 percent of total floor volume. If fire conditions permit, crews should check the space for fire extension by pushing up one of the panels but not in an area where impinging heat will impede the progress of the attack line. If high heat prevents standing and visually inspecting this space, hose streams can be used to rip down the panels, however, crews must assess whether this will aide or impede their attack.
Firefighters advancing on a fire may find their progress blocked by partial walls or other subdivisions of the floor. Space dividing panels sometimes can be knocked down and permanent walls of gypsum on steel studs may be breached to provide nozzle access to the fire.
Where possible, crews should attempt to flank the fire and convecting gases. Core area fires are the most difficult because the fire often involves both stair areas.
Fires near the exterior walls are easier to flank and confine but are more prone to rapid extension to the next level through broken glass.
It is important to verify auto stair door unlocking.
Verify air handler status. Shut down if not known to be beneficial. Rescue on the fire floor is most difficult when the core area is involved. The core fire may have prevented occupants from reaching the stairs. Firefighters removing occupants may have to remove them through the flame back to the stairs.
Firefighters should search any involved floor with a charged line and use it as a reference point when searching. If the smoke is dense, return to the line after sweeping each room or area to orient yourself.
Providing ventilation on the fire floor is extremely difficult. Every effort must be made not to break the glass with hose streams until knockdown is achieved or wind conditions are known, as the sudden addition of wind driven oxygen may accelerate the fire beyond the limits of the attack line. Building exhaust systems, if present, may be employed to some advantage and the windows may be broken from above or below in a coordinated manner after wind direction and intensity are verified or after fire control.
Crews on the upper or lower floors are not moving in smoke or heat and can determine the location of the lee side of any winds by removing a panel.
Ventilating on the lee side reduces the potential for gusts pushing flame into the attack crews but winds acting upon a high-rise are unpredictable and frequently change direction and speed. Be cognisant of conditions in the building and achieve ventilation as soon as possible when crews are in hot, vulnerable tactical positions or pull the crews out. Crews must use extreme caution to protect against falling if windows have been removed. Some glass panels extend to the floor level.
The severity of the heat in a serious fire may limit the time a firefighter can be on the fire floor to ten minutes or less. First units arriving should provide for rotation of crew from the less exposed positions on the floor above and in the stairs, to taking a turn on the attack line. Command must provide for the immediate and continuous relief of these initial crews until fire control is achieved. Crews rotating off the floor and through rehab can be assigned to the less demanding sectors and tasks remaining to be accomplished, such as beginning a property conservation effort on the floors below.
Floor above
The objectives of the crews operating on the floor above are to evacuate the floor, to assess and control vertical extension of the fire and when possible, to provide ventilation for the floor below. In a protracted fire, the floor above will be subjected to intense heat and any occupants must be removed as soon as possible to safe refuge.
Vertical extension must be checked in:
• Elevator shafts
• Supply air ducts/return air ducts make up air ducts
• Utility shafts (pipes, electrical chases)
• Dumbwaiter/trash chutes/mail chutes
• Auto-ignition through failed window glass or mullions
• Around floor slabs at spandrels
• Auto-ignition through floors or raceways and expansion joints or cracks caused by floor failure
• Floor materials directly above fire area
All rooms and closets on the floor above must be opened for inspection. Dropped ceiling panels should be removed to locate the supply/return ducts and observe conditions in the plenum. Hollow columns and pipe chases may be checked by making small holes with a Halligan tool.
A hose stream must be introduced at each point of extension including flooding the floor if the fire is communicating to the carpet and padding. Caution must be observed in putting water into electrical distribution areas, including raceways in the floor. Hoselines on the floor above can be introduced from the evacuation stairs if the floor is clear of smoke. If not, bring them down from upper landings in the attack stairway. The numerous points of possible extension require multiple lines. If present, hoselines can be utilised for areas requiring a reduced volume, such as duct shafts.
Care must be exercised not to breach shaft openings, breach spandrel panels or break glass until necessary and hoselines are in place. If fire extends through the lower windows and melts the mullions or breaks out a window on the floor above, direct a fog stream into the opening but avoid hitting the remaining glass if possible. The sudden cooling would cause the loss of additional panes and expose the entire floor to flame impingement.
Before ventilating from the floor above, the firefighters must first determine the direction of any winds. Winds at altitude can be many times stronger than at ground level and the introduction of wind gusts and new air on the fire floor could overwhelm the attack crews. The direction of wind at surface level may or may not be the same at higher elevations due to the effects of stratification or disruptions in flow caused by other buildings.
If no wind is detected at ground level and the location of the fire on the floor below is known, then firefighters should begin the ventilation operation directly over the fire.
Crews on the floor above should place pressure tape, if available, on the window to be broken (if not tempered), advise command that glass will be falling, break the panel by tapping and pull the majority of the glass onto the floor.
After verifying that no significant wind is present and checking with the officer on the attack line and command, they may then break out the lower panels with specialised tools, if available. Tempered and even double-pane, insulated glass is very difficult to break with lightweight tools such as a pike. Recessed windows and decorative screens will make this task even more difficult.
If strong winds are encountered at the upper level, crews must first locate the lee side of the wind by breaking out additional panels. If the lee side proves to be at the unburned end of the floor, it is inadvisable to vent until fire control is achieved, as smoke and heat will flow to the reduced pressure at the opening; quite possibly right over or through the attack team(s).
Again, if ventilation is not possible and there is excessive heat on the fire floor withdraw the firefighters.
Stairwells
A first priority for command/lobby is the identification of the attack and evacuation stairwells and a size-up of smoke conditions in each. If the stairs exit into the lobby, the size-up can be made by lobby sector. If the stairs exit to the exterior, command/lobby must send runners with keys to assess each stair condition and can determine the location of the lee side of any winds by removing a panel.
At the time of arrival to a significant fire, the occupants may be descending both stairs, as most high-rises require both stairs for effective evacuation. Any smoke in the stairwells at this point is probably the result of smoke pressure on the fire floor escaping into the stairs as the occupants exited the fire floor.
If the building is equipped with automatic stair pressurisation, it may be effective at this point if most of the other doors in the stairwell are kept shut. In practice, a mass evacuation will cause most of the doors to be open a substantial amount of the time, with the result in a loss of pressurisation and significant smoke accumulating in the stairs. It is doubtful that with the fire loading now encountered in a high-rise, that the pressure created by building stair pressurisation will be sufficient to contain the smoke pressure generated by a fully involved floor fire.
The purpose of built-in stair pressurisation is to maintain a positive pressure in the stairwell and impound the smoke on the fire floor. Experience has shown that a small fire will be accelerated by the incoming air if the door is left open but that most of the smoke will be held on the fire floor.
A primary objective of the first arriving units is to maintain a smoke-free exit way, both for occupants leaving the building and for firefighters staging and preparing to extend hose.
A large volume fan should be placed at the opening to all stairs to pressurise the stairwell and to provide an upward current of air. This will help to hold the smoke out of the stairs and will allow the occupants to descend into a cleaner environment with every step. In buildings where the stairs continue to the basement level(s), the fans should be placed at that location to keep the noise out of the lobby.
Evacuation of the smoke trapped in the upper stairwell requires a roof opening. If the building is not equipped with stair pressurisation but the stairwell is either open to air or has a dampened opening at the top, the smoke can be fan exhausted by fire department crews using positive pressure ventilation (PPV) with large volume (22 000 CFM) fans. Do not leave the fans unsupervised.
A crew with radio, keys and spare BA cylinders should be sent to the roof door as soon as possible as roof sector. Their task is to open the stair door or hatch at the roof and provide an outlet for smoke.
When firefighters open the stairwell door to advance hoselines on the fire floor, significant smoke will enter the stairwell. Occupants descending from upper floors must be allowed to pass before opening the door and exposing them to hot gases and flame. Persons entering the stairwell after the door is opened and fire attack is initiated, should be directed across the building to the evacuation stairs when possible.
In the next edition of Fire and Rescue International, we will focus on water supply, extending hose lines for initial attack, accountability and safety when dealing with high-rise incidents.
Photo1: A dynamic metropolitan local government environment constantly pursues the best models for service delivery
Photo2: As fire can also spread overhead in the plenum space above the dropped ceiling, an additional line may be required to cool and protect
Photo3: Ventilating on the lee side reduces the potential for gusts pushing flame into the attack crews
Photo4: The increasingly volatile loads created by synthetic furnishings and materials have accelerated the rate and intensity of burn
This week’s featured Fire and Rescue International magazine article is: Fires in high-rise buildings– initial attack written by Ian Schnetler, chief fire officer, City of Cape Town Fire and Rescue Service (at the time of writing the article), (FRI Vol 3 no 12). We will be sharing more technical/research/tactical articles from Fire and Rescue International magazine on a weekly basis with our readers to assist in technology transfer. This will hopefully create an increased awareness, providing you with hands-on advice and guidance. All our magazines are available free of charge in PDF format on our website and online at ISSUU. We also provide all technical articles as a free download in our article archive on our website.
Fires in high-rise buildings– initial attack
By Ian Schnetler, chief fire officer, City of Cape Town Fire and Rescue Service (at the time of writing the article)
In this third part of the five part series of articles focusing on ‘Fires in high-rise buildings’, we detail the initial attack during high-rise fires.
Fires in high-rise occupancies continue to be perilous resulting in loss of life and property, despite the advancement in technology and equipment as high-rise buildings are generally tightly sealed and present a great potential for the occurrence of backdrafts.
Initial attack
During the initial attack in high-rise fires, the forward fire commander leading the attack will be responsible for selecting the method of ascent to the reported fire area ie elevator or stairs, depending on conditions and safety concerns. The annunciator panel must be checked for additional information prior to ascending to fire floors.
The initial attack companies need to go upstairs with full personal protective equipment (PPE), self-contained breathing apparatus (SCBAs), spare cylinders, portable radios, flashlights, hose packs and basic forcible entry tools. If access is via an elevator, an extinguisher should also be taken. Other equipment will be pooled in the lobby until a resource sector is established.
As soon as the fire floor is reached and identified, the officer would need to give the incident commander a progress report of conditions on the fire floor, immediate needs and a confirmation of the actual fire floor(s) number. The incident commander should then establish the fire floor as a sector ie floor 16 equals sector 16.
When a building has multiple standpipes, the forward fire commander must advise the incident commander where water is needed and the incident commander will confirm the availability of pumped water to that particular riser.
Crews preparing to enter the fire floor should be aware of the floor layout, including the locations of elevators, stairs and floor subdivisions or zones.
They should also be aware of the distribution pattern of the supply and return air systems. Smoke and heat under pressure will migrate to the lesser pressure of open shafts and return air ducts, usually located in the core.
Crews may be crawling at floor level in limited vision and the officer must select the most unobstructed approach, with the flow of heat away from the firefighters as much as possible.
Only members trained in the operation, use and methods of escape from elevators will operate the lifts.
Crews will most likely be advancing from a stair located in the ‘core’ of the building. If the core is surrounded by an open, unsubdivided, floor plan, the potential for fire wrapping around the core exists. To protect against this, the officer in charge of the fire floor should create a backup line in the opposing direction to protect the point of entry/egress. Fire can also communicate overhead in the plenum space above the dropped ceiling. An additional line may be required to cool and protect this area.
Crews advancing on a high-rise fire should employ a straight stream or narrow angle fog when possible. This is both to reduce the amount of local steam production and to provide the maximum reach and volume for hose streams. The objective of the attack line is to create the greatest amount of steam conversion at the point of fuel gas generation (the seat of the fire), benefiting from cooling and smothering at that point. Steam created by directing fog streams into other heated areas will serve to reduce the overall heat on the floor but will also penetrate the turnouts and hoods of the firefighters, making their progress toward the seat of the fire slower, if not impossible.
For safety reasons, the initial line should be equipped with a fog nozzle. High-rise buildings are tightly sealed and present a great potential for backdrafts. In addition, the increasingly volatile loads created by synthetic furnishings and materials have accelerated the rate and intensity of burn.
At the same time the structures are becoming more lightweight and decreasing in total mass. The result is an increased potential for rapidly rising temperatures and flashover before arrival. The loss of windows can also suddenly accelerate the fire as driving winds bring new oxygen to the flame.
The plenum space above the dropped ceiling may represent the largest unobstructed space on the floor, as much as 25 percent of total floor volume. If fire conditions permit, crews should check the space for fire extension by pushing up one of the panels but not in an area where impinging heat will impede the progress of the attack line. If high heat prevents standing and visually inspecting this space, hose streams can be used to rip down the panels, however, crews must assess whether this will aide or impede their attack.
Firefighters advancing on a fire may find their progress blocked by partial walls or other subdivisions of the floor. Space dividing panels sometimes can be knocked down and permanent walls of gypsum on steel studs may be breached to provide nozzle access to the fire.
Where possible, crews should attempt to flank the fire and convecting gases. Core area fires are the most difficult because the fire often involves both stair areas.
Fires near the exterior walls are easier to flank and confine but are more prone to rapid extension to the next level through broken glass.
It is important to verify auto stair door unlocking.
Verify air handler status. Shut down if not known to be beneficial. Rescue on the fire floor is most difficult when the core area is involved. The core fire may have prevented occupants from reaching the stairs. Firefighters removing occupants may have to remove them through the flame back to the stairs.
Firefighters should search any involved floor with a charged line and use it as a reference point when searching. If the smoke is dense, return to the line after sweeping each room or area to orient yourself.
Providing ventilation on the fire floor is extremely difficult. Every effort must be made not to break the glass with hose streams until knockdown is achieved or wind conditions are known, as the sudden addition of wind driven oxygen may accelerate the fire beyond the limits of the attack line. Building exhaust systems, if present, may be employed to some advantage and the windows may be broken from above or below in a coordinated manner after wind direction and intensity are verified or after fire control.
Crews on the upper or lower floors are not moving in smoke or heat and can determine the location of the lee side of any winds by removing a panel.
Ventilating on the lee side reduces the potential for gusts pushing flame into the attack crews but winds acting upon a high-rise are unpredictable and frequently change direction and speed. Be cognisant of conditions in the building and achieve ventilation as soon as possible when crews are in hot, vulnerable tactical positions or pull the crews out. Crews must use extreme caution to protect against falling if windows have been removed. Some glass panels extend to the floor level.
The severity of the heat in a serious fire may limit the time a firefighter can be on the fire floor to ten minutes or less. First units arriving should provide for rotation of crew from the less exposed positions on the floor above and in the stairs, to taking a turn on the attack line. Command must provide for the immediate and continuous relief of these initial crews until fire control is achieved. Crews rotating off the floor and through rehab can be assigned to the less demanding sectors and tasks remaining to be accomplished, such as beginning a property conservation effort on the floors below.
Floor above
The objectives of the crews operating on the floor above are to evacuate the floor, to assess and control vertical extension of the fire and when possible, to provide ventilation for the floor below. In a protracted fire, the floor above will be subjected to intense heat and any occupants must be removed as soon as possible to safe refuge.
Vertical extension must be checked in:
• Elevator shafts
• Supply air ducts/return air ducts make up air ducts
• Utility shafts (pipes, electrical chases)
• Dumbwaiter/trash chutes/mail chutes
• Auto-ignition through failed window glass or mullions
• Around floor slabs at spandrels
• Auto-ignition through floors or raceways and expansion joints or cracks caused by floor failure
• Floor materials directly above fire area
All rooms and closets on the floor above must be opened for inspection. Dropped ceiling panels should be removed to locate the supply/return ducts and observe conditions in the plenum. Hollow columns and pipe chases may be checked by making small holes with a Halligan tool.
A hose stream must be introduced at each point of extension including flooding the floor if the fire is communicating to the carpet and padding. Caution must be observed in putting water into electrical distribution areas, including raceways in the floor. Hoselines on the floor above can be introduced from the evacuation stairs if the floor is clear of smoke. If not, bring them down from upper landings in the attack stairway. The numerous points of possible extension require multiple lines. If present, hoselines can be utilised for areas requiring a reduced volume, such as duct shafts.
Care must be exercised not to breach shaft openings, breach spandrel panels or break glass until necessary and hoselines are in place. If fire extends through the lower windows and melts the mullions or breaks out a window on the floor above, direct a fog stream into the opening but avoid hitting the remaining glass if possible. The sudden cooling would cause the loss of additional panes and expose the entire floor to flame impingement.
Before ventilating from the floor above, the firefighters must first determine the direction of any winds. Winds at altitude can be many times stronger than at ground level and the introduction of wind gusts and new air on the fire floor could overwhelm the attack crews. The direction of wind at surface level may or may not be the same at higher elevations due to the effects of stratification or disruptions in flow caused by other buildings.
If no wind is detected at ground level and the location of the fire on the floor below is known, then firefighters should begin the ventilation operation directly over the fire.
Crews on the floor above should place pressure tape, if available, on the window to be broken (if not tempered), advise command that glass will be falling, break the panel by tapping and pull the majority of the glass onto the floor.
After verifying that no significant wind is present and checking with the officer on the attack line and command, they may then break out the lower panels with specialised tools, if available. Tempered and even double-pane, insulated glass is very difficult to break with lightweight tools such as a pike. Recessed windows and decorative screens will make this task even more difficult.
If strong winds are encountered at the upper level, crews must first locate the lee side of the wind by breaking out additional panels. If the lee side proves to be at the unburned end of the floor, it is inadvisable to vent until fire control is achieved, as smoke and heat will flow to the reduced pressure at the opening; quite possibly right over or through the attack team(s).
Again, if ventilation is not possible and there is excessive heat on the fire floor withdraw the firefighters.
Stairwells
A first priority for command/lobby is the identification of the attack and evacuation stairwells and a size-up of smoke conditions in each. If the stairs exit into the lobby, the size-up can be made by lobby sector. If the stairs exit to the exterior, command/lobby must send runners with keys to assess each stair condition and can determine the location of the lee side of any winds by removing a panel.
At the time of arrival to a significant fire, the occupants may be descending both stairs, as most high-rises require both stairs for effective evacuation. Any smoke in the stairwells at this point is probably the result of smoke pressure on the fire floor escaping into the stairs as the occupants exited the fire floor.
If the building is equipped with automatic stair pressurisation, it may be effective at this point if most of the other doors in the stairwell are kept shut. In practice, a mass evacuation will cause most of the doors to be open a substantial amount of the time, with the result in a loss of pressurisation and significant smoke accumulating in the stairs. It is doubtful that with the fire loading now encountered in a high-rise, that the pressure created by building stair pressurisation will be sufficient to contain the smoke pressure generated by a fully involved floor fire.
The purpose of built-in stair pressurisation is to maintain a positive pressure in the stairwell and impound the smoke on the fire floor. Experience has shown that a small fire will be accelerated by the incoming air if the door is left open but that most of the smoke will be held on the fire floor.
A primary objective of the first arriving units is to maintain a smoke-free exit way, both for occupants leaving the building and for firefighters staging and preparing to extend hose.
A large volume fan should be placed at the opening to all stairs to pressurise the stairwell and to provide an upward current of air. This will help to hold the smoke out of the stairs and will allow the occupants to descend into a cleaner environment with every step. In buildings where the stairs continue to the basement level(s), the fans should be placed at that location to keep the noise out of the lobby.
Evacuation of the smoke trapped in the upper stairwell requires a roof opening. If the building is not equipped with stair pressurisation but the stairwell is either open to air or has a dampened opening at the top, the smoke can be fan exhausted by fire department crews using positive pressure ventilation (PPV) with large volume (22 000 CFM) fans. Do not leave the fans unsupervised.
A crew with radio, keys and spare BA cylinders should be sent to the roof door as soon as possible as roof sector. Their task is to open the stair door or hatch at the roof and provide an outlet for smoke.
When firefighters open the stairwell door to advance hoselines on the fire floor, significant smoke will enter the stairwell. Occupants descending from upper floors must be allowed to pass before opening the door and exposing them to hot gases and flame. Persons entering the stairwell after the door is opened and fire attack is initiated, should be directed across the building to the evacuation stairs when possible.
In the next edition of Fire and Rescue International, we will focus on water supply, extending hose lines for initial attack, accountability and safety when dealing with high-rise incidents.
Photo1: A dynamic metropolitan local government environment constantly pursues the best models for service delivery
Photo2: As fire can also spread overhead in the plenum space above the dropped ceiling, an additional line may be required to cool and protect
Photo3: Ventilating on the lee side reduces the potential for gusts pushing flame into the attack crews
Photo4: The increasingly volatile loads created by synthetic furnishings and materials have accelerated the rate and intensity of burn