BIG FIRE = BIG WATERA DISCUSSION OF LARGE FIRE STRATEGY AND

TACTICS

INTRODUCTION

Large fires present a unique set of challenges for fire departments. They differ from the bread and butter house fires that are often routine. This presentation will address some of these challenges and better prepare firefighters , engineers, and officers for the “Big One”

OBJECTIVES• Participants will demonstrate a knowledge of proper size-up of large fires• Participants will recognize the unique hazards present with fires in large buildings• Participants will become familiar with industry accepted methods of calculating

required flow• Participants will demonstrate proper techniques for long hose stretches• Participants will demonstrate proper techniques for supporting elevated streams• Participants will demonstrate proper techniques for utilizing master stream devices

SIZE-UPThe initial size-up of a large fire is a critical step in developing an incident action plan.

An acronym that can be used to assure the proper information is gathered is:

COAL WAS WEALTH

C – ConstructionO – OccupancyA – ApparatusL – Life Hazard

W – Water SupplyA – Auxiliary Appliances and AidesS- Street Conditions

W – WeatherE – ExposuresA – AreaL – Location and extent of the fireT – TimeH – Height

CONSTRUCTIONConstruction type has a significant effect on fire tactics.

• Fire Spread• Time to collapse• Access• Concealed Spaces and voids

CONSTRUCTION (continued)

Construction Classifications• Type I – Fire Resistive

• Structural elements are constructed of non-combustible material. (concrete encased steel

• Typically large multi-story building

• Type II – Non-combustible• Structural elements have limited

combustibility (usually masonry walls with structural steel and decked roof system)

• While structure itself may not burn, rapid collapse is a possibility due to exposed steel components

• Most modern commercial buildings are Type II

CONSTRUCTION (continued)

• Type III – Ordinary• Load bearing walls are

noncombustible, and the roof assemblies are constructed of wood

• This type of construction is prevalent in most “downtown” or “main street “ areas

• Type IV – Heavy Timber• Exterior is usually masonry with

the floor and roof systems constructed of large solid or laminated wood beams.

• Usually warehouses and manufacturing buildings and some older churches

CONSTRUCTION (continued)

Type V – Wood Frame• Most common type of construction. • Structural components are primarily

made of wood.• Homes, newer small businesses, and

some motels

OCCUPANCY

The occupancy type has a direct affect on incident priorities. Additionally, the configuration and contents are dependent on type of occupancy.

OCCUPANCY(continued)

Occupancy groups: • Group A -Assembly • Group B -Business • Group E -Educational • Group F -Factory Industrial• Group H -Hazardous • Group I -Institutional • Group M -Mercantile • Group R -Residential • Group S –Storage

Identify the type of occupancy and determined the types of hazards associated with it.

• Consider the materials present and how they affect fire load.

Try to determine if the building has been renovated to a different type of occupancy than originally intended.

• Renovations can create voids and confusing floor plans

APPARATUS & STAFFING

Determine if enough resources are available to mitigate the incident.• Large fires are manpower intensive.

• Larger hand lines must be used.• Longer stretches will be required.• Size of the structure can cause the scene to be spread out over long distances.

• Large amounts of water may be required• Elevated streams may be required

LIFE HAZARDLife hazard concerns are significant in commercial buildings. Statistically, the majority of multiple firefighter deaths occur in commercial buildings.

• Disorientation• Large open spaces• Narrow aisles• Maze-like configurations• Highly piled stock

Life Hazard Considerations

• Heavy fire loads• Building size• Stock amount and configuration• Overhead hazards

• Rooftop air conditioners• Roof mounted heavy machinery• Hoppers• Water tanks

• Voids and concealed spaces

LIFE HAZARD(Continued)

Two career firefighters killed following a partial collapse

Charleston Sofa Super Store: 9 Firefighters killed

Worcester Cold Storage Fire: 6 Firefighters killed

Houston Motel Fire: 4 Firefighters Killed

Memphis Family Dollar: 2 firefighters die

WATER SUPPLY

It is necessary to understand the amount of water required to extinguish the fire and the resources available.

• Be familiar with the available water supply in the area• Pre-planning• Familiarization of local water system

• Be familiar with the capabilities of responding apparatus• Place pieces with larger pump capacities at the water source

• Be familiar with methods to calculate the estimated required fire flow

WATER SUPPLY (Continued)

Calculating the estimated required fire flow:

• National Fire Academy formula:Designed to estimated the flow requirements for offensive, interior operations where a direct attack will be used to extinguish the fire.

• x % of involvement

WATER SUPPLY (Continued)

Example: NFA Formula

• If this building is 100’ long by 50’ wide• We assume 50% involvement

• (100 x 50)/ 3 = 1667• 1667 x .50 = 833• Estimated required fire flow would be:

833 gpm

LIMITATIONS:• Designed f or offensive, interior operations involving direct attack• Formula becomes inaccurate if the level of involvement is greater than 50% or if the

required flow is greater that 1000gpm• Formula is based on area and not volume. Ceiling heights greater that 10 feet may

require more flow.• This method is best used for pre-plan calculations

WATER SUPPLY(Continued)

Calculating estimated fire flow• Iowa State University method:This method was created in the 1950s and is based on the volume of the structure. This formula is based on a 30 second application.

Required fire flow =

WATER SUPPLY(Continued)

Example: Iowa State University method

Using the same dimensions as the previous example, plus an estimated height of 20 feet.

• (100 x 50 x 20)/100 = Estimated fire flow• (100,000)/100 = 1000

Estimated Fire flow Is 1000 gpm

WATER SUPPLY (Continued)

Activity:

Utilizing the formulas provided, determine the estimated required fire flow for the following building.

NFA Formula:Fire flow = x % involvement

Iowa State University Formula:

Fire flow = Length = 75 feet

Width = 40 feet

Involvement = 30%

Height = 20 feet

WATER SUPPLY(Continued)

• NFA formula:• GPM = {(Length x Width)/3} % of involvement• = (75 x 40)/3 = 1000• = 1000 x .30 = 300• Required flow = 300 GPM

• Iowa State University formula:• GPM = (length x width x height)/100• = (75 x 40 x 20)/100 = 600• Required flow = 600 GPM

AUXILIARY APPLIANCES AND AIDS

Fire protection resources on scene are of great value:• Sprinkler systems• Sprinkler systems should be supported early in the incident

• Standpipes• May be utilized to reduce long hose stretches

• Ventilation management equipment.• May be utilized to control flow paths

AUXILIARY APPLIANCES AND AIDES

• Plant managers, Plant engineers, Fire engineers, and Maintenance supervisors are very good sources of information.• Familiar with products on the premises• Familiar with building features that may affect fire behavior or

firefighting operations

STREET CONDITONS

Access to larger fire scenes should always be a concern. • Traffic around the structure• Access to the building• Access to water supply• Apparatus staging• Power lines and other obstacles to ladder trucks• Proximity of operational areas to apparatus

• Don’t let your apparatus become an exposure

WEATHER

Weather conditions can have a profound affect on operations at large fires

• Manpower • Extreme temperatures can

drastically reduce a firefighter’s work capacity

• Life safety• Flooding and severe weather

can cause a heightened risk to firefighters.

• High winds affect fire behavior

EXPOSURES

Exposures become endangered due to heavy fire conditions, huge amounts of radiant heat, and proximity to the fire building.

Considerations:• Life hazard – the most severely threatened

life hazard is the first consideration• Flame frontage – exposures directly

threatened by the actual fire front• Exposure distance – the closer the

exposure, the more danger of involvement• Wind – structures downwind are subject

to higher heat transfer• Exposure construction and features –

buildings with a combustible finish will absorb heat quicker than those with non-combustible exteriors.

AREA

Area is a key size-up concern. The bigger the building, the bigger the problem.• Consider the square footage involved vs. square footage threatened• Utilize pre-fire plans are good sources of information.

• Compartmentalization• Construction features that increase danger of collapse

• Exposed structural component• Trusses span long distances• Parapet walls• Mansards and facades • Contents

• Hazardous materials• Heavy fire load

LOCATION AND EXTENT OF THE FIRE

Determination of what is actually burning is critical. • Contents/ Fire load• Structural components

LOCATION AND EXTENT OF THE FIRE

Determine the possibility of hidden fires and fire extension• Shafts, ducts, and hoppers• Suspended ceilings

TIME

Time of day can affect incident priorities depending on the type of occupancy.• Numbers of workers present can be affected by the time of day.• Access to the structure will be affected by time of day

• Vehicles in lot• Secured access points

• Stock levels (fire load) can be affected by time of day

HEIGHT

Concerns with the height of the building are related to reach and fire spread.

• Will your aerial apparatus have the needed reach.• Most buildings are within reach of the aerial equipment dependent on access to the

perimeter of the building.

• Be aware of buildings that have parapets and mansards. • One story may not actually be one story.

Look for indicators of the buildings actual height.

HEIGHT(Continued)

The height of the building can directly effect fire spread.• Consider each floor above the fire as an exposure

• Based on construction features and materials, fire can spread quickly upward through a building.

ADDITIONAL CONCERNS FOR THE INCIDENT COMMANDER

• Large fires may be hard to size up. Conflicting reports can be common due to large floor spaces and high ceilings. It is often appropriate to view reports from the roof as most reliable. Interior crews may have a limited perspective of fire conditions.

• Communicate mode of attack• All personnel should be informed of the type of operation.

• Accountability must be established early in the incident . Incident Management Tools should be utilized to ensure all personnel know their responsibility and work area.• Quickly establish divisions/sectors

• Develop an exit strategy.• Quickly recognize when fire conditions change and warrant an evacuation of fire

department personnel.• Fires can develop at an alarming speed

• When working above ground level, make sure ground ladders are in place to provide alternate means of egress

• Do not hesitate to force extra doors to provide access points to the fire.• Be aware of ventilation flow paths

ADDITIONAL CONCERNS FOR THE INCIDENT COMMANDER

Develop a risk profile for collapse potential• Construction characteristics

• Wide spans• Exposed trussed roof systems• Heavy loads on the roof• Facades and Mansards

• Establish Collapse Zones• Recognize potential for collapse early

in the incident and place apparatus in safe locations.

Click to play video