Fire officer handbook of tactics chapter 9

• Firefighting involves suppressing the fire and completing necessary tasks inside the structure.
• It requires staying in the burning building long enough to complete suppression and rescue tasks.
• Fire creates dense smoke, elevates temperatures, and extends flames searching for fuel and spreading rapidly.
• Fire consumes oxygen, requiring firefighters to control the oxygen supply to win the battle.
• Firefighters have the advantage of an unlimited external oxygen supply and can carry small amounts inside.
• Ventilation is a crucial firefighting tactic that helps control the fire by managing the oxygen supply.
• Improper ventilation can lead to the fire gaining strength and causing significant casualties.
• Mastering ventilation is essential for saving buildings from destruction.

Changes Affecting the Fire Service

• Reduced staffing levels
• Energy conservation resulting in tight-building syndrome
• Greater focus on property conservation
• Enhanced ventilation fans
• Increased use of plastics that cause toxic smoke
• Plastics also cause quicker flashovers.
• Building techniques using lightweight materials that fail quickly when exposed to fire.
• Building designs with large, open floor plans that allow fire to spread easily
• "Green building" designs that limit ventilation options like roof cutting

Ventilation Defined

• Ventilation involves removing toxic combustion products and replacing them with fresh air.
• Ventilation is an ongoing battle between firefighters and fire for control of the building.
• Fires fill structures with deadly toxins and flammable gases.
• Firefighters must strategically use the correct methods to combat fire.
• Total ventilation is essential for interior fire suppression in structures.
• Failure to ventilate results in firefighters pushed back by heat and smoke.
• Inadequate ventilation results in total loss of the structure.
• Lack of ventilation can cause the structure burning to the ground.
• UL and NIST studies emphasize controlled ventilation, particularly stopping ventilation that cause wind-driven fires.
• Ventilation is still crucial after water is applied to the fire.
• Ventilation helps visibility and allows firefighters to complete critical tasks.
• Those tasks include life and fire search, exposing hidden fires, extinguishing fires, and salvage operations
• Toxic combustion products harm firefighters and civilians if exposed to severe conditions.
• Ventilation decisions depend on timing, location relative to the fire, and flow paths.

Reasons for Ventilation

• Venting allows attack teams to enter and operate within the structure (fire ventilation).
• Venting provides fresh air for trapped occupants and improves visibility for search (life ventilation).
• SCBA use has caused some to think that ventilation is less important and this thinking is flawed.
• SCBA use ignores potential victims in the building.
• SCBA assumes that masks are always protective.
• There have been firefighter fatalities due to mask problems in contaminated areas.
• Ineffective ventilation and SCBA use lead to dangerous heat buildup, potentially resulting in flashover.
• Ventilation allows firefighters to operate in tenable atmospheres and prevent flashover by using hoselines effectively.
• If the fire floor is hot with a hoseline operating, products of combustion, flame, heat, smoke, and steam from the hoselines must come back toward the nozzle team to reach an escape route.
• Venting opposite the nozzle should alleviate that issue as long as windows being vented are not facing into the wind.
• Tighter buildings due to energy conservation efforts increase the challenges of ventilation.
• Buildings are too tight with little natural air exchange unless vented.

Venting for Life vs. Venting for Fire

• Timing distinguishes life and fire ventilation.
• Life ventilation should begin immediately after recognizing a life hazard.
• It may intensify the fire but should draw it away from the hazard or not worsen conditions.
• Breaching a window of a room with trapped victims is a calculated risk.
• Evaluate the possibility of rescuing the victim before the fire reaches them.
• Understanding venting for life vs. venting for fire is important.
• Fire ventilation is delayed until resources are available to attack.
• In some cases, venting is withheld until the fire is knocked down.
• If there are water difficulties, don't break the glass until a charged hoseline is in place.
• Once the attack begins, vent the windows on the fire area opposite the hoseline to speed up the advance.
• If there are high winds, ventilation should be withheld until the area is cooled to avoid a wind-driven fire.
• Interior teams should be aware the fire can cause the window to fail.
• Interior teams must be prepared to control the fire, position with the wind at their back, retreat, or stop the wind.

Understanding Flow Paths and Heat Transfer

• Recognizing and understanding how smoke, heat, flame, and fresh air interact in a structure is key.
• Research developed knowledge after catastrophic fires where firefighters died when conditions changed rapidly.
• Initial research focused on wind-driven fires, and has expanded to include understanding flow paths.
• It’s important to attack with the wind at your back.
• Heavy plastic fuel loads mean smoke is more toxic, flames blow downwind at the attack team, and conditions change fast.
• Knowing where air enters (intake path), how smoke/heat travels, and where it exits (exhaust path) is key.
• Plan attack and rescue efforts from safe, effective locations.
• Firefighters should avoid being in the exhaust path at a serious fire.
• Modern plastic fire loads rapidly transition to flashover, it is more deadly to be in this path.
• Fire creates its pressure, and wind exerts pressure.
• Gases flow from high to low-pressure areas.
• Recognizing low-pressure areas can save lives by avoiding exhaust paths.
• Many firefighters died in the line of duty because of sudden fire growth and being in the exhaust path of developing fires.
• If firefighters are caught in the flow path, they should retreat to another room within the structure.
• The FDNY developed practices to avoid similar circumstances, such as:
• Closing the apartment door behind searching firefighters.
• Ordering exterior firefighters to not vent windows, unless there is permission from an incident commander.
• Deploying a curtain over exterior windows on the upwind side.

Additional Safety Measures

• Firefighters are taught to force doors to other apartments in fire-resistant apartment houses to provide refuge.
• This refuge must be on the same high-pressure side of the fire apartment.
• This tactic has saved firefighters' lives in devastating conditions.
• Firefighters should determine if it is safe to move up the interior stairs before doing so.
• They must weigh the risks and rewards by answering:
• Are there civilians trapped above?
• Are alternate escape routes available?
• Is a hoseline operating effectively?
• If the hoseline is not likely to control the fire, can the door be closed?
• Altering flow paths with ventilation efforts can impact safety.
• A firefighter venting a window in the fire room can worsen conditions by admitting oxygen.
• Ventilation remote from the fire room can trigger a sudden inrush of air through the building.
• If interior doors are closed, and doors/windows are closed on the downwind side, there will be very little air flow.
• Topside ventilation over stairwells can create an exhaust outlet.
• Burning plastics react to any airflow, and accumulated smoke on upper floors can ignite by the draft.
• Hoselines flowing adequate water or keeping the door to the fire area closed is the only sure protection.
• Budget cuts and personnel reductions have caused slower placement of hoselines.

Types of Ventilation: Horizontal and Vertical

• Window venting is called horizontal ventilation.
• Roof, topside, or vertical ventilation (to be covered later).
• Horizontal ventilation can save lives: If adjacent people are in the fire area, venting the windows will allow airflow.
• If you don’t remove the victim immediately, you may worsen their situation.
• Generally, horizontal ventilation for a life hazard must be followed with immediate rescue.
• If possible, close the door between the fire, the victim, and the vented window (temporary measure).

How to Ventilate

• Damage from fire extinguishment and ventilation should align with the fire damage and life hazard.
• A rule of thumb is to let the heat be the guide, not the smoke.
• Open windows if you can manipulate the locking devices.
• Break the glass if you are driven back by heat, or if the smoke is drastically hindering visibility or mandating SCBA use (after the hoseline is charged).
• Open windows for low-intensity fires (smoky mattress or food on the stove).
• Mechanical ventilation is beneficial for cool smoke, posing few dangers during structural fires.
• Window venting is best for most fires in houses and similar-sized structures.
• Interior forces evaluate conditions before venting.

When to Ventilate Windows

• If you can stand up long enough to manipulate the locks, then raise the windows.
• If you can’t stand up that high or that long due to the heat, then it’s time to take out the glass.
• Have an idea of the progress of fire control and search efforts.
• If the fire seems to be under control and the primary search is complete, you may want to raise the windows.
• Be aware that conditions will probably worsen before they get better, and smoke is high in carbon monoxide.
• Venting provides fresh air and improves conditions; breaking glass provides twice as much window-opening area.
• Firefighters must time their ventilation efforts properly by:
• Acting too soon and allowing the fire to extend.
• Waiting too long and subjecting firefighters to unnecessary heat.
• Venting for fire should take place right after the hoseline begins its attack and they should be coordinated via radio.
• With tightly sealed areas with energy-efficient windows, ventilating as the attack crew enters can have catastrophic results.
• The attack crew needs to control if and when to vent windows.
• Ventilating as the attack team moves in is likely to result in rapid fire growth.
• Delaying ventilation until water has been applied but it is also an option but that means the team will take more heat for a longer time.
• It is better to apply heat and steam, rather than flame, on the team.

Energy Conservation

• Energy conservation practices dry out combustibles.
• A fire becomes an open-burning stage within minutes, risking flashover in the areas around it.
• Once fire starts to invade your room, you had retreat time, because the fire’s energy still had to heat combustibles.
• As such, firefighters should be aware of operating in energy-efficient buildings and be prepared for rapid changes.
• There is a small opening in a window done by the ladder company officer, after knockdown, to test the effect venting will have on operations.
• Difficulty is venting windows with a hose stream, and clearing the entire sash area for entry or escape.
• Vinyl sashes require more effort to remove than wooden sashes, and aluminum-framed windows defy even repeated blows from an axe.

Outside Teams

• Have one or more members ready to vent fire-area windows from the outside.
• The outside ventilation team is responsible for an immediate exterior survey
• Locate victims and the fire, and create firefighter escape routes.
• Coordinate ventilation efforts with the interior teams.
• Don't vent until water application and fire knockdown, unless necessary for a life-saving entry.
• Hurricane damage creates impact-resistant window glazing, making normal ventilation impossible.
• Firefighters operating in such areas must realize windows may not be an escape route.
• Glazing (glass-Lexan-glass) requires extra precautions because it throws very fine chips and dust.
• Use a circular saw with a standard carbide-tipped (wood-cutting) blade for the breach.
• Use short chopping strokes, and do not strike the glazing at a 90° angle if a saw is not available.

Additional Precautions

• Impact-resistant wall materials may also exist.
• Assign an outside ventilation team early in each incident to locate and clear such obstructions by using:
• A circular saw with carbide-tipped blade
• A carbide-tipped circular saw or chainsaw is beneficial for wood-frame buildings.
• Other factors that influence vertical/horizontal ventilation:
• Fire size and location
• Building construction
• Available staffing
• Weather, particularly wind
• Horizontal ventilation is preferred at minor to moderate fires, and at fires that produce large quantities of smoke.
• Horizontal ventilation is often faster, easier, and less costly to repair than vertical ventilation.
• Peaked roofs can easily be vented by smashing gable ends or dormers instead of cutting the roof itself.
• Flat roofs made of poured concrete construction require effort.

Vertical Ventilation

• Vertical ventilation is a determining factor in expanding fire.
• Burning materials produce hot gas that takes up huge volumes of space.
• Heated gas rises creating increasing pressure in the building.
• Creating a path for upward travel of gas takes the heat with it, rather than it remaining inside.
• An opening of proper size and placement in the roof under these circumstances should be done.
• Horizontal fire extension is slowed, and visibility and heat conditions improve as fresh air is drawn in at lower levels.
• Use this tactic for fires in attics, cocklofts, and floors directly below the roof.
• By heating up products of combustion, fire has made by-products mobile, so you can open doors, windows, or skylights.
• Smoke will easily pour out. If this natural process isn’t enough, mechanical ventilation can be used.
• For a smoldering mattress or low-heat basement fire, smoke may be too cool for normal ventilation and smoke will stay low.
• Fully developed fires knocked down but not extinguished are prime candidates for mechanical ventilation to remove gas.

Mechanical Ventilation

• Use hoselines, portable fans, or building ventilation systems.
• Venting involve sucking contaminated air out or blowing fresh air in to remove contaminated air and replace it with fresh air.
• Venting using a fog or spray stream is one of the earliest and simplest means of mechanical ventilation.
• There must be:
• Volume of water flowing.
• Velocity of the stream from of the pattern of the stream and the nozzle flowing pressure.
• Geometry of the opening and the stream, to stand back 6–8 ft from a window or door.
• Dangers of fanning into life a smoldering fire is a problem with all types of mechanical ventilation.
• Using a hose stream has the advantage of personnel being in the best place to detect the fire and to use the hoseline to darken it down.
• It depends on:
• Minor fires where water damage is a concern.
• Areas of poor water supply, to use some water to move smoke may mean running short of water for fire control.
• Areas of below-freezing temperatures if the spray will land where the resulting ice will create fall hazards.
• Potential problems with power supply, personnel requirements, storage space, and explosive gas when using smoke ejectors, blowers, exhaust fans.

Negative vs Positive Pressure

• Channel the products of combustion where you want them to go.
• Remove devices as exhaust devices, sucking smoke through the mechanism.
• That method has proved to be ineffective.
• Fans never fit an opening correctly.
• A churning effect limits the efficiency of the device.
• Debris, curtains, and other objects are drawn against the intake screen, blocking the flow.
• Negative-pressure fans hang in or near doorways that must be used by personnel (potential hazards).
• Combustible gases are drawn across the motor.
• Blow fresh air into the structure to eliminate many of these difficulties and improve airflow efficiency.
• That can reduce stack effect, drawing heat and smoke toward staircases and attack points in high-rise fires.
• By putting positive pressure in a stairwell, the flow of heated gas can be reversed, so attack crews can begin attack on the fire.

Advantages of Positive Pressure Ventilation

• It works best with minor to moderate fires.
• This is where smoke, rather than fire, is of the greatest difficulty.
• PPV fans are set back from doorways.
• It can safely remove flammable vapors and can help get them moving out without dangerous, non-explosion-proof fans.
• Setting up the fan occurs outside the structure, 8–12 ft away from the desired door opening, and its airstream fully covers the opening.
• Larger doors in commercial structures may require several fans, which pushes smoke contaminated air ahead of the fan, as when advancing a fog stream.
• Provide an outlet for this gas opposite the entranceway to speed the process.
• The fan blowing in moves almost twice the smoke as compared to the negative mode.

Disadvantages of Positive Pressure Ventilation

• Fanning a smoldering fire into a serious conflagration
• The best way to prevent this is to have a charged hoseline in place and ready to operate.
• There can potentially be separate fires in remote areas (arson incidents).
• Blowing fresh air can cause the fire to intensify.
• The fan must not blow the fire toward any victims or firefighters on the opposite side.
• VEIS (vent, enter, isolate, and search) tactic requires coordination so fresh air blows directly into a victim.
• Personnel should follow the proper sequence of opening and closing windows

Command

• Before starting the fan, the IC should know:
• Where is the life hazard, including searching firefighters
• What is the location and extent of the fire and is it in any void spaces?
• What is the status of all hoselines, and are they operating or ready to operate?
• What degree of confinement is present - If fire is already large PPV is generally unhelpful
• What exhaust openings are available or can be created?
• What PPV equipment is available?
• Will the power supply create any issues
• What environmental factors exist in the vicinity of the fan?
• Such as dust, powder, weeds, or other materials might be drawn into the fan, damaging it or impeding operations
• You can stop PPV by turning the fan away from the building.
• Wind and heat are used by fire to build up its pressure with the structure.
• Once heat is restrained from rising, it spreads and starts to bank down. This is called the mushroom effect.
• One can:
• Build a fire-resistive partition to contain it
• Position a countering hose stream
• Let the gas continue on its upward journey.
• In multistory structures make an opening directly over any vertical arteries that the fire is exploring.
• Ensure you are creating an exhaust opening, and it should be coordinated with other fire-attack efforts.
• Building geometry and wind direction affects both horizontal ventilation, and depends on the building’s geometry.
• Firefighting teams should radio people at the apartment door to await orders to vent
• They will also be prepared to close the door if the interior team reports any bad reaction.

Bulkhead Ventilation

• Check bulkhead doors for escapees.
• Secure the door to the bulkhead from closing.
• In multistory buildings with a skylight over the staircase, removing or breaking them can quickly provide needed ventilation.
• Protect other personnel from falling gas.
• Break 1 small pane first and give people notification.
• The pipe chase is the second most common vertical avenue.
• Check the route for extension above the fire.

Venting Flat Roofs

• It Includes stores, factories, schools, and apartment buildings.
• These roofs were much stronger than peaked roofs, and designed to support greater live loads.
• The styles are:
• The standard flat roof: main roof joists are right at the roof level. The roof boards are nailed directly to the joists.
• The inverted roof: roof boards are nailed to a framework of 2×4s raised several feet above the main roof joists.
• Metal Deck Roof - fire spreads easily
• Older flat roofs are limited in length to about a 20-ft span between supports, most often a masonry bearing wall or a steel I-beam.
• Covered in tarpaper and hot tar - These tar coverings can build up in very old buildings
• Cut over a fire, that acts on the floor in conjunction with the downward pressure exerted on it to make the floor sag.
• A working fire on the top floor of any large-area, flat-roof building requires an immediate team with tools.
• That toolset is power saws, hooks, a Halligan tool, an axe, and a portable radio.
• Upon reaching the roof, members should vent:
• Vertical shafts
• Bulkhead doors
• Skylights
• Be sure the wind won’t be blowing inward.

Ventilation Methods for a Roof

• Proper tool: Halligan tool clipped to a short rope or hook.
• Size opening for a fire is 8x8 feet
• Site of the fire is often indicated by fire coming out of the windows, rather than smoke.
• Use 3 types of Holes in conjunction with each other. These 3 holes look:
• Triangular like the opening
• Kerf cut: simplest, narrow width
• A triangular-shaped opening with three cuts overlapping
• When making a hole, consider:
• Wind direction
• Means of escape. I- f the fire vents out, it won’t endanger nearby exposures.
• Make the cut not be in-between members and their means of escape.
• Position so that a member never has to step on compromised portions of a roof. Locate joists by sounding them, and placing the cut close to the selected joists.

Removing Roofing

• Knockout holes allow members to insert tools below the roofline for lifting and prying.
• The work proceeds quickly with two saws.
• If given wind shifts, complete all of it cuts before pulling the hole.
• Waterproofing materials on roof decks are combustible, like:
• Tar paper
• Newer rubber roofing

Roof Instability

• Hot coals make fire in a contained area and can be reignited easily.
• A working water source is required, to prevent the rapid spread of fire.
• In this event it is recommended that no water source be close enough to the roof, for the flames to use them as a catalyst.
• Consider roofs that have weakened from:
• Previous fires
• Rot
• Rain roofs are dangerous due to:
• Extra weight was never designed into the original roof supports.
• Two layers could delay or prevent venting the floor under the roof
• Multiple void spaces that hide fire spread.
• There is a potential danger in the form of rain, that is similar to the inverted roof construction.
• A rain roof can be defined as, supported by a raised wooden framework of 2×4s that rests directly on the deck of the roof below.
• It is supported by wooden forms.