Fire and emergency services safety officer chapter 14. Incident Hazards & ISO Responsibilities

Incident Hazards & ISO Responsibilities

• Each incident type presents unique hazards that must be identified during size-up and throughout operations.
• A key ISO responsibility is recognizing and correcting hazards to prevent responder injuries.
• The ISO must check in with the IC, receive a briefing, and conduct an independent 360-degree assessment.
• During assessment, the ISO notes the condition of the emergency, potential personnel hazards, and resource deployment.
• At structural fires, the ISO notes construction type to visualize fuel/fire loading and identify potential weak points.
• The ISO determines fire location, what's burning, the fire's phase/stage, and potential fire spread direction.
• By reading the smoke, the ISO judges the types of fuel involved and the fire's progress.
• Effective hazard assessment requires knowledge and skill in all areas of fire and emergency services operations.
• Necessary knowledge and skill comes from education, training, and experience.

Environmental and Physiological Hazards

• Fire and emergency services operations are inherently hazardous and physically demanding.
• Firefighters work in toxic environments with limited workspace, wearing heavy protective gear.
• Physiological and environmental hazards further intensify the physical demands.
• Weather, extreme temperatures, cardiac strain, noise, and long shifts add stress to the human body.
• Incident Commanders, supervisors, and the ISO must monitor personnel functioning within their physical capabilities.

Weather Conditions

• Weather conditions can adversely affect all operations and impact the health and stamina of fire crews.
• The ISO must monitor changes in weather and notify the IC of potential hazards.
• Adverse weather includes storms, high humidity/temperatures, freezing rain, snow, extreme cold, and high wind.
• Personnel should monitor daily weather forecasts and be alert to inclement weather statements.
• Pair forecasts with real-time conditions to understand how they may affect emergency operations.
• The ISO can request updated weather conditions from dispatch or use cellular/wireless devices.
• Adverse weather can reduce the operational capacity of equipment and apparatus.

Specific Weather-Related Hazards

• Ice makes advancing hoselines, performing ventilation, and forcible entry difficult.
• Ice-covered hoses, ladders, and apparatus create slipping hazards.
• Ice/snow on structures can cause ladders to slip, and accumulation on power lines can cause them to sag/fail.
• Assess parking areas to reduce the chance of apparatus sliding on icy roadways.
• Snow can obscure tripping hazards, obstacles, and unstable structural features like skylights.
• Rain and fog can reduce visibility and make metal surfaces slippery.
• Rain can freeze on equipment and apparatus as the temperature drops.
• High humidity can cause smoke to remain close to the ground and obscure visibility.
• Humidity can cause personnel to tire quickly, raise body core temperature, and become dehydrated.
• High winds can create dangerous fire behavior changes.
• Winds as slow as 10 mph can be deadly if personnel aren't alert to changing conditions.
• The ISO must continuously monitor wind velocity and direction.
• Ensure personnel and hose streams are not placed in a windward position.
• Generally, wind speeds greater than 20 mph reduce aerial ladder load capacity; ensure operations are within manufacturer guidelines.
• Lightning is a significant concern for all personnel operating at emergency events.
• All aerial ladder operations must be curtailed and personnel should take all possible precautions to ensure their safety during storms.
• Storms can cause downed power lines and trees, blocking access.
• Hail can damage apparatus and injure personnel.
• Flash flooding can sweep away vehicles and people, even with minimal depth.
• Visibility-reducing situations (dust storms, fog, blizzards) create driving and scene operation hazards.
• The ISO must ensure personnel operate within a safe zone with proper traffic control.

Heat and Cold Stress

• Both hot and cold environments can fatigue personnel.
• The ISO monitors resource and personnel availability and makes recommendations to the IC.
• In hot climates, personnel may rapidly succumb to heat stress and require rehabilitation earlier and more frequently.
• Dehydration may require additional fluids and medical care.
• Extreme cold temperatures can cause skin and clothing to stick to metal tools/equipment.
• Cold can cause frostbite injuries and reduce stamina.
• Hoselines, pumps, and water supplies can freeze, causing a loss in water supply or pressure.
• Hose, tools, and equipment can be damaged or become inoperable.

Hot or Humid Conditions

• Hot and/or humid conditions can overheat apparatus during pumping operations.
• The ISO should communicate with pump operators to ensure early detection of operability issues.
• The ISO should ensure the IC has a rapidly deployable backup plan with alternate apparatus, especially during interior fire suppression.
• Personnel operating at a scene with high intensity activity must be provided proper work/rest periods.
• Follow NFPA 1584, Standard on the Rehabilitation Process for Members During Emergency Operations and Training Exercises.
• Personnel must be monitored when operating at traffic scenes where radiated heat increases heat-related illness potential.

Cold Conditions

• Cold weather can freeze fire hoses and couplings.
• Icy conditions can be created in areas where water is being applied during fire suppression activities.
• The ISO must monitor for the development of hazardous conditions and communicate them to the IC.
• The ISO must monitor personnel for signs of hypothermia and/ or frostbite.
• Rehabilitation should provide relief from the elements.

Cardiac Arrest

• Cardiac-related events at emergency incidents are a leading cause of firefighter illness and death.
• Cardiac and cardiac-related issues continue to be leading causes of firefighter fatalities.
• Research shows fatalities can occur at the scene or after personnel have returned to service.
• The physical demands required in many operational settings are extremely high.
• Some firefighters may have hidden, undiagnosed cardiac disease that may precipitate into sudden cardiac arrest
• It is critical that medical surveillance monitoring and proper rehabilitation is established at emergency and planned events.
• All operations personnel should be cleared from the medical evaluation and rehabilitation area prior to being reassigned.
• Early detection of a possible cardiac event is critical to saving lives.

Noise

• Emergency incidents have several sources of noise that can adversely affect personnel
• Apparatus, generators, equipment, and radio communications add to the noise level.
• Repeated exposure to high levels of noise is known to cause permanent hearing loss
• The safety and health program in fire and emergency services departments should address awareness of high noise situations and preventive hearing protection options.
• The ISO should evaluate noise levels and the hearing protection provided for their personnel.
• Recommendations should be made to the IC if unsafe noise conditions exist so modifications and corrections can be made.
• High noise levels can also lead to a condition called tunnel hearing
• Tunnel hearing can cause people to concentrate so closely on one task that they lose their sense of situational awareness.
• The IC, other operational supervisors, and the ISO must maintain acute situational awareness during any incident by listening to other personnel, asking questions about the operation, and monitoring any incident changes.
• The IC and other personnel should be alerted if there is any indication that personnel safety is or will become compromised.

Extended Work Shifts

• Extended work shifts can cause fatigue and stress in responders.
• As the work shift gets longer, the chance of injury becomes greater.
• Personnel can lose track of time and not realize how long they have been actively involved in an operation.
• Longer shifts equate to lessened situational awareness, which increases the risk of injury.
• The ISO must monitor operation activities, weather conditions, and personnel performance to ensure work shift length does not endanger personnel.
• For operations that last more than a day, the Incident Command team must determine the appropriate rotation schedule of personnel.
• See Chapter 13, Risk Management Principles, for ways to manage long work shifts.

Structure Fire Development and Hazards

• Research shows that fires go through four distinct stages: incipient, growth, fully developed, and decay.
• Fires may move through these stages in order (fuel-controlled fires) or rekindle and begin to grow again (ventilation-controlled fires).
• Actual conditions can vary widely within a building made up of multiple compartments.
• ISOs should assume that an entire structure is the compartment that fire is affecting rather than just the compartment of origin.
• Open interior doors, hallways, and stairwells connecting rooms extend the possible growth potential of a fire beyond its compartment of origin.
• At a fire scene, the stages of fire development are a guide for what could occur during the fire but are not a pattern of what will occur every time.
• ISOs should assess the changing hazards and fire conditions at the incident rather than assume that the fire will follow the same pattern identified in laboratory tests.

Factors That Affect Compartmental Fire Development

• Compartment fires can be considered to be room and content fires, but construction features can differ greatly between occupancy types.
• Factors affecting the development of compartment fires:
  • Fuel type
  • Availability and location of additional fuels
  • Compartment volume and ceiling height
  • Ventilation
  • Thermal properties of the compartment
  • Ambient conditions
  • Fuel load
• All personnel operating on a fire scene should evaluate these factors to ensure safe and efficient suppression methods are employed.
• The ISO should forecast fire spread based on fire department suppression efforts and conduct an ongoing assessment of hazards as they relate to the stages of fire growth.
• Hoseline placement and size, ventilation, coordination of effort, and flow rate should be monitored for desired effect.
• Any unusual fire behavior, fire spread beyond the compartment of origin, or the potential for hidden fires should be communicated to the Incident Commander.

Fuel Type

• The type of fuel involved in combustion affects the heat release rate (HRR).
• Fires involving Class B and C fuels will eventually spread to the building contents and structure, resulting in a primarily Class A-fueled fire.
• In a compartment fire, surface-to-mass ratio is one of the most fundamental Class A fuel characteristics influencing fire development.
• Combustible materials containing high surface-to-mass ratios, they are much more easily ignited and will burn more quickly than the same substance with less surface area.
• Fires involving Class B flammable/combustible liquids will be influenced by the surface area and type of fuel involved.
• A liquid fuel spill will increase that liquid’s surface-to-volume ratio, generating more flammable vapors than the same liquid in an open container.
• The increase of vapor due to the spill will also allow more of the fuel to ignite, resulting in greater heat over a shorter period of time.
• Structure fires involving single types of fuels are rare.
• Modern homes and businesses are largely filled with contents made from petroleum-based materials (plastics or synthetic fabrics).
• These fuels have a higher heat of combustion and produce higher HRRs than wood alone.
• Burning synthetic fuels produces products of combustion that contain large quantities of solid and liquid particulates and unburned gases.
• A compartment fire that results from a flammable/combustible gas leak may begin with a rapid ignition of the gas and an explosion.
• If the fuel source is not controlled, it will continue to burn at the point of release, extending to adjacent combustibles.

Heat Release Rate (HRR) & Surface-To-Mass Ratio

• Heat Release Rate (HRR): Total amount of heat produced or released to the atmosphere from the convective-lift phase of a fire, per unit mass of fuel consumed per unit time, expressed in kilowatts or British Thermal Units (BtU).
• Surface-To-Mass Ratio: Ratio of the surface area of the fuel to the mass of the fuel.

Availability and Location of Additional Fuel

• Factors influencing the availability and location of additional fuels: building configuration, construction materials, contents, and proximity of the initial fire to these exposed fuel sources.
• Building configuration includes:
  • Number of stories above or below grade
  • Compartmentation
  • Floor plan
  • Openings between floors
  • Continuous voids or concealed spaces
  • Barriers to fire spread
• Each of these elements may contribute to either fire spread or containment.
• Open floor plan spaces may contain furnishings that provide fuel sources on all sides of a point of ignition.
• Compartmentalized configuration may have fire-rated barriers separating fuel sources and limiting fire development to an individual compartment.
• In buildings where the construction materials are flammable, the materials themselves add to the structure’s fuel load.
• The orientation of fuels as well as their surface-to-mass ratio will influence the rate and intensity of fire spread.
• Combustible interior finishes can be a significant factor influencing fire spread.
• Structure contents often influence compartment fire development.
• Synthetic furnishings will begin to pyrolize rapidly under fire conditions, even when located some distance from the origin.
• The chemical makeup of foam and its high surface-to-mass ratio speed the process of fire development.
• Proximity and continuity of contents and structural fuels also influence fire development.
• Fuels located in the upper level of adjacent compartments will pyrolize more quickly from the effect of the hot gas layer.
• Continuous fuels will rapidly spread the fire from compartment to compartment.
• Fire location within the building will influence fire development.
• Fires located low in the building will cause vertical extension through atriums, unprotected stairways, vertical shafts, and concealed spaces due to convected heat currents.
• Fires originating on upper levels generally extend downward much more slowly following the fuel path or as a result of structural collapse.
• The ISO must consider the presence of modern construction and furnishings.
• Residential structures built after 1990 burn hotter, faster, and produce more smoke with flammable properties than traditional construction.
• The greater use of synthetic materials in home furnishings in residential homes, regardless of age, also contributes to this growth rate.
• Ventilation and extinguishment must be well coordinated with little margin for error. Poorly coordinated tactics can harm firefighte

Compartment Volume and Ceiling Height

• A fire in a large compartment will develop more slowly than one in a small compartment.
• Slower fire development is due to the greater volume of air and the increased distance radiated heat must travel from the fire to the contents that must be heated.
• A large volume of air will support the development of a larger fire before the lack of ventilation becomes the limiting factor.
• A high ceiling can also complicate the extent of fire development.
• Large hot smoke and fire gases can accumulate at the ceiling level, while floor level conditions remain relatively unchanged.
• Firefighters may mistake floor level conditions for the actual state of fire development.
• If the large hot gas layer ignites, the situation becomes immediately hazardous.

Ventilation

• Ventilation in a compartment significantly influences how fire develops and spreads within the space.
• Pre-existing ventilation is the actual and potential ventilation of a structure based on structural openings, construction type, and building ventilation systems.
• All buildings have the potential to exchange air inside the structure with the air outside the structure.
• Air exchange is due to constructed openings, leakage through cracks, or the HVAC system.
• Room/compartment fires take two forms: fuel-controlled and ventilation-controlled.
• When sufficient oxygen is available, the characteristics and configuration of the fuel control fire development (fuel-controlled).
• When the available air supply begins to limit fire development, the fire is ventilation-controlled.
• Fuel and fuel load in today’s typical fires will cause fires to quickly become ventilation-controlled.
• When a fire becomes ventilation-controlled, the available air supply will determine the speed and extent of fire development and the direction of fire travel.
• Fire will grow in the direction of ventilation openings because of the introduction of fresh air.
• Potential openings can alter the ventilation profile under fire conditions.
• Windows can fail or doors can be left open, increasing ventilation into the compartment.
• Bi-direction flow paths can be deadly to firefighters and civilians inside the structure.
• Wind conditions at structure fires can influence the direction of airflow.
• Changes in ventilation can create rapid fire development and place firefighters in extreme danger.
• When the fire becomes ventilation-controlled, the fire’s HRR will decrease.
• Control the air, control the fire.
• The ISO should watch operations to ensure ventilation activities are coordinated.
• Sudden fresh air creates a rapid increase in HRR when windows/doors fail, or firefighters ventilate.

Fuel-Controlled vs Ventilation-Controlled

• Fuel-Controlled: A fire with adequate oxygen in which the heat release rate and growth rate are determined by the characteristics of the fuel, such as quantity and geometry.
• Ventilation-Controlled: Fire with limited ventilation in which the heat release rate or growth is limited by the amount of oxygen available to the fire

Ambient Conditions

• Ambient conditions, such as high humidity and cold temperatures, can slow the natural movement of smoke.
• Strong winds place additional pressure on one side of a structure and force both smoke and fire out the opposite side.
• If a window fails or a door is opened on the windward side of a structure, fire intensity and spread can increase significantly, creating a “blowtorch” effect.
• During fire suppression activities, wind direction and velocity can prevent or assist in ventilation activities.
• The ISO’s responsibility is to forecast the failure of building components on the windward side of the structure and keep the IC appraised.
• Cold temperatures can cause smoke to appear white and give a false impression of the interior conditions based upon the color of smoke.
• Atmospheric air pressure can also cause smoke to remain close to the ground, obscuring visibility during size-up.
• NOTE: Ambient temperature and humidity outside the structure can have an effect on the ignitability of many types of fuels, these factors are less significant inside a compartment.

Fuel Load

• The total quantity of combustible contents of a building, space, or fire area is referred to as the fuel load.
• The fuel load includes all furnishings, merchandise, interior finish, and structural components of the structure.
• Estimate the fuel load based upon your knowledge and experience.
• Knowledge of building construction and occupancy types will be essential to determining fuel loads.
• Building fuel loads impact firefighter safety when offensive tactics are insufficient for large fuel loads.
• ISOs should inform the IC of excessive fuel loads if the IC is unaware.

Fire Stages

• Incipient Stage: Starts with ignition, fire is small and confined to the material first ignited.
  • Development is largely dependent on fuel characteristics and configuration (fuel-controlled fire).
  • Air in the compartment provides adequate oxygen to continue fire development
  • Radiant heat warms adjacent fuel and continues the process of pyrolysis.
  • A plume of hot gases and flame rises from the fire and mixes with the cooler air in the room.
  • The plume reaches the ceiling, hot gases spread horizontally across the ceiling in what firefighters have historically called mushrooming but is now referred to as a ceiling jet.
• Hot gases transfer heat to other materials.
• Temperature is only slightly above ambient and the concentration of products of combustion is low.
• Occupants can safely escape from the compartment.
• The fire could be safely extinguished with a portable extinguisher or small hoseline.
• Transition to growth stage can occur quickly, depending on fuel type/configuration.
• Growth Stage: Fire begins to influence the environment, the compartment configuration and amount of ventilation matter.
  • The amount of air that is entrained into the plume.
  • The location of the fuel package in relation to the compartment walls affects the amount of air that is entrained and therefore, the amount of cooling that takes place
  • Fuel packages in the middle of the room can entrain air from all sides. Fires in fuel packages near walls can only entrain air from three sides. Fires in fuel packages in corners can only entrain air from two sides.
  • When the fuel package is not in the middle of the room, the combustion zone (the area where sufficient air is available to feed the fire) expands vertically.
  • The expanded combustion zone increases both the temperatures in the developing hot gas layer at ceiling level and the speed of the ceiling jet.
  • Heated surfaces around the fire radiate heat back toward the burning fuel.
  • Maintain or raise the level of the hot gas layer above the floor to provide a more tenable environment.
  • Use effective fire control and ventilation tactics to raise the position of the hot gas layer.
• Ceiling Jet: Horizontal movement of a layer of hot gases and combustion by-products from the center point of the plume, when the vertical development of the rising plume is redirected by a horizontal surface such as a ceiling.
• Thermal Layering: Sometimes referred to as heat stratification and thermal balance. Gases tend to form into layers according to temperature, with the hottest gases found at the ceiling and the coolest gases at floor level.
• Neutral Plane: Level at a compartment opening where the difference in pressure exerted by expansion and buoyancy of hot smoke flowing out of the opening and the inward pressure of cooler, ambient temperature air flowing in through the opening is equal
• Pyrolysis: Thermal or chemical decomposition of a solid material by heating, generally resulting in the lowered ignition temperature of the material
• Isolated Flames: Isolated flames may be observed moving through the hot gas layer when the fire becomes ventilation-controlled indicating that portions of the hot gas layer are within their flammable range
• Rapid Transition: Rapid transition from the growth stage to the fully developed stage is known as flashover.

Fully Developed Stage

• This period occurs when all combustible materials in the compartment are burning.
• Burning fuels release the maximum possible heat for the available fuel and oxygen, producing large gas volumes.
• The fire is ventilation-controlled because heat release depends on compartment openings.
• These openings provide oxygen and release combustion products. More air means higher heat release.
• Flammable products of combustion may flow into adjacent compartments or building exteriors.
• Flames will extend out of the compartment openings because there is insufficient oxygen for complete combustion in the compartment.
• NOTE: No openings means the fire is unlikely to reach the fully developed stage due to limited ventilation

Decay Stage

• Decay occurs as fuel is consumed or oxygen concentration falls, diminishing flaming combustion.
• Decay due to reduced oxygen can differ if ventilation changes before combustion ceases.
• The fire becomes fuel-controlled in the instance of an adequate ventilation, and consumes the available fuel in the compartment, the heat release rate begins to decline.
• A large volume of flammable products of combustion can accumulate within the compartment under limited ventilation conditions.
• Fires involving new construction/modern furnishings are likely to be ventilation-controlled.
• The available oxygen quickly disappears in the insulated buildings creating a false sense that the fire has self-extinguished or entered decay.
• Firefighters in a part of the structure that they thought was uninvolved may find themselves suddenly engulfed if ventilation tactics are not properly coordinated.

Isolated Flames

• Flames in the hot gas layer that indicate the gas layer is within its flammable range and has begun to ignite; often observed immediately before a flashover

Rapid Fire Development

• Flashover: Occurs when combustible materials and fuel gases ignite simultaneously, resulting in full-room involvement.
  • It represents a transition from the growth stage to the fully developed stage.
  • The environment of the room or structure is changing from a two- layer condition to a single well-mixed hot gas condition from floor to ceiling
• Rollover: Unburned fire gases accumulate, ignite, and propagate flames across the ceiling.
  • It's a significant indicator of flashover.
• Backdraft: Explosive combustion of flammable gases when oxygen is introduced into an oxygen-depleted confined space.
  • It occurs in the decay stage, in a space containing a high concentration of heated flammable gases
• Smoke Explosion: Ignition of accumulated flammable products of combustion and air
  • Occurs before or after the decay stage.

Fire Behavior and Fire Fighting Operations

• Fire is controlled and extinguished by limiting or interrupting one or more of the essential elements in the combustion process (fuel, oxygen, heat, or chemical reaction).
• Firefighters influence fire behavior:
  • Temperature reduction
  • Fuel removal
  • Oxygen exclusion
  • Chemical flame inhibition
  • Ventilation
• Door Control: Fire fighting tactic intended to reduce available oxygen to a fire and create a controlled flow path in a structure for tactical ventilation, firefighter survivability, and occupant survivability
• Unplanned Ventilation: Any ventilation that occurs outside of planned tactics such as ventilation from failed structural components, wind conditions, or firefighters acting outside of assigned tactics

Wind-Driven Fire Conditions

• Wind-driven conditions can occur in any type of structure with wind speeds as low as 10 mph. Always be observant of wind.
• Unplanned wind from structures and fire fighter freelancing can result in many issues.
• In contrast, tactical ventilation is the planned/coordinated introduction of air and removal of gases needing coordination with fire suppression to prevent unwanted consequences with coordinated tactics.

Fire Behavior Indicators

• Fire officers are not limited to size-up and risk assessment, everyone on the fireground needs to develop and maintain situational awareness.
• Recognize key fire behavior indicators that include not only recognizing what the fire is doing at the moment, but anticipating how fire control actions and tactical ventilation will influence the fire’s behavior.

Smoke

• Volume: Smoke volume is the quantity of smoke visible. Small buildings will fill up with smoke sooner than larger buildings, displaying a large quantity of smoke from the front door on arrival. Volume-pushed smoke will usually flow neither smooth nor turbulent. It floats out of openings, rising slowly.
• Direction: ISOs must carefully observe the level of the neutral plane through windows and doorways in order to communicate changing conditions to other personnel:
  • High neutral plane (the fire is in its early stage, fire at the top): May indicate that the fire is in the early stages of development. Watch the danger of high ceilings; they can hide the dangers of a fire that is in later stages.
  • Mid-level neutral plane (flashover is approaching): Could indicate that the compartment has not ventilated yet and that flashover is approaching.
  • Very low-level neutral plane (backdraft, fire is below): May indicate that the fire is reaching backdraft conditions. This occurrence could also mean a fire is below you. Types of direction describe how smoke moves indicated by speed:
    • Floating or hanging (the same temp as the building or had sprinklers running); early fire, moisture from pyrolysis
    • Volume-pushed = exiting smoke (fast-indicating a large fire); the area that smoke comes from will indicate passage for smoke, which means passage for fire.
    • Heat pushed (indicated by speed) - turbulence fast ( lots of particles/under ventilated) and Laminar smoke slow and the fire is exited from nearby fire.
• Color: Visible products of combustion. The heat within smoke dictates the speed. Color from tar, soot, and carbon and heated gasses.
  • Light white: Pyrolysis (chemical change by heat) is occurring in areas adjacent to the main body of fire. On cold days, smoke turns white and turbulent immediately on leaving the structure. White smoke explosion is possible.
  • Caramel colored smoke usually indicates clean wood burning.
  • Gray - Indicates mid-stage heating or changes in smoke production as if fire increases.
  • Black smoke contains high quantities of carbon particles and is an indicator of the amount of ventilation available at the seat of fire; smoke explosions are possible.
  • Unusual color smoke should give the IC an indication that different extinguishing agents may be needed.
• Smoke Density: The denser the smoke, the lower the visibility, as heat buildup indicates a pending flashover; Black smoke can create fast-moving fires with rapid fire spread (black fire)
• Flow Path: The movement of fresh air toward the base of a fire and the movement of smoke and heated gases out of a structure.

Fire Behavior Indicators cont.

• Fire control requires knowing velocity and direction in slow/early stages to suddenly rushing; Pulsations cause conditions to be rich in fuel from closed structures (accomplish ventilation operations above) and noises that indicate whistles from drawing air indicates backdraft.

• Indications of increased heat levels:

  • Blackened or cracked windows, with extreme temperature and location.
  • Sudden heat buildup near an operator, act by applying water or leaving.

• -Flame-

• Flame growth indicates oxygen as fire suppression with ventilation prevents unwanted flame spread.

Building Construction Hazards

• The ISO must be familiar with hazards associated with construction classifications.
• They must also take into account the materials used in construction and the age of construction when monitoring the scene and identifying hazards.

Hazards Associated with Construction Classifications

• Both the International Building Code (IBC) and the National Fire Protection Association (NFPA) classify buildings in five types of construction (Type I through Type V).

Building Elements

• Structural frame -Floor construction -Roof construction
• Unclassified; Manufactured buildings are assembled in a factory, comprising of manufactured buildings that are completely assembled in a factory- Type I Construction Hazards

Type I Construction Hazards Fire Resistive

• Fire Resistive: Noncombustible or limited combustible materials, 3-4 hour ratings for walls columns floors roofing, and considered collapse resistant.
  • Concrete (reinforced or precast) along with protected steel frame
  • They may degrade form effects, contents/furnishing, and coverings.
  • Retain heat and allow fire extensions
• Fire-Resistance Rating: It identifies the amount of time a material or assembly will resist a typical fire
• Common risks; fire resistive, compartments retain heat contributing to rapid fire development, unauthorized penetrations of fire barriers can permit the extension of fire, roofs and windows being difficult to open.
• Type II Construction Hazards
• Noncombustible & non rated steel; Metal cladding or concrete-block. Fire resistance rating is generally 1-2 hours.
• Unprotected metal twists and expands so must remember that the term noncombustible does not always reflect the true nature of the structure.

Type III Construction Hazards Ordinary

• Construction walls noncombustible but interiors are wood found in churches, schools, mercantiles, residential structures. Check local codes.
  • Voids spread fire through the roof and truss systems between wall studs. Renovations contribute to hidden voids and use replacement materials.

Type IV Construction / Heavy Timber

• Characterized by the use of large-dimensioned lumber that is >8 inches. Dimensions must adhere to minimum dimension sizing and all construction needs at least 1 hour ratings.
  • Lack of voids helps prevent fire travel; the concentration can increase fire once started. May include small dimensioned lumber. Beams may melt the glue in laminate and cause failure.

Type V Construction Wood Frame

• Wood Frame/Stick Frame; exterior bearing are wood with veneers with 2 x 4 or 2 x6 inch studs. siding may be composite like Aluminum, Shake shingles, wood clapboards, sheet metal,

Engineered components

• Structures comprised primarily of composite materials and secured with adhesives
• Balloon-Frame Construction
• A type of structural framing where studs are continuous from the foundation to the roof.
• Balloon-Frame Construction often cause fire spreads

Factory-Built Homes Unclassified construction types include factory-built homes

• Factory-built homes do not conform to the model building codes and often use Manufactured Homes: steel chassis and permanent steel undercarriage

Hybrid Modular structure

• Consisting of elements of both modular design and panelized construction.

Building Materials’ Effect on Fire Behavior

• New construction materials and methods have increased the risk to fire operations.

Recent FEMA Sponsored Fire Behavior Studies

• Structural stability of engineered lumber involved in fire
• Legacy and contemporary residential construction
• Engineered floor systems and basement fires
• UL/NIST/Fire Departments pay double dividends with IC risk/benefit assessments as UL recommends code changes.

Age of Construction

• Construction materials will vary based upon geography, climate, and local codes.
  • Pre-20th Century Mortise and tenon/Brace Frame
  • 1900s-1950 mostly been balloon framed
  • Older homes new being torn down contain >engineered materials (integrated or composites)
• Two homes in UL:
• One-story 1,200 square feet, 3 bedrooms, 1 bathroom
• Two-story 3,200 square feet, 4 bedrooms, 2.5 bathrooms Results from experiments and tactical considerations: -Normal stages change with environments and entry acts as ventilation. Closing operations increases safety with coordination. Fire fighters should close off doors between fire to contain in a tenable/safe area.