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WARNING!WARNING!FIREFIGHTERS ARE FREQUENTLY FIREFIGHTERS ARE FREQUENTLY

INJURIED OR KILLED WHEN INJURIED OR KILLED WHEN

BURNING STRUCTURES BURNING STRUCTURES

COLLAPSE WITH OUT WARNINGCOLLAPSE WITH OUT WARNING

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Firefighter Hazards Firefighter Hazards Related to Building Related to Building

ConstructionConstruction

The primary objective of understanding The primary objective of understanding building construction and materials is to building construction and materials is to apply this information to the fireground.apply this information to the fireground.

Firefighters should use this knowledge to Firefighters should use this knowledge to monitor signs of structural instability.monitor signs of structural instability.

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Dangerous Building ConditionsDangerous Building Conditions

There are two primary types of There are two primary types of dangerous conditions that may be dangerous conditions that may be posed by a building.posed by a building.

1. Conditions that contribute to the 1. Conditions that contribute to the spread & intensity of the fire.spread & intensity of the fire.

2. Conditions that make the building 2. Conditions that make the building susceptible to collapse.susceptible to collapse.

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TermsTerms CONCENTRATED LOADCONCENTRATED LOAD - Load applied to a small Load applied to a small

area, example; a/c unit placed on a roof structurearea, example; a/c unit placed on a roof structure

DEAD LOADDEAD LOAD – The weight of the building materials – The weight of the building materials and any part of the building permanently attached to and any part of the building permanently attached to it.it.

DESIGN LOADDESIGN LOAD – A load the designer planned for in – A load the designer planned for in the building design.the building design.

UNDESIGNED LOADUNDESIGNED LOAD – A load not planned for. – A load not planned for.

DISTRIBUTED LOADDISTRIBUTED LOAD – A load applied equally over – A load applied equally over an area.an area.

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FIRE LOADFIRE LOAD – All the parts or contents of a – All the parts or contents of a building that will burn. The amount of building that will burn. The amount of heat released from a fuel in lbs\sq ft.heat released from a fuel in lbs\sq ft.

LIVE LOADLIVE LOAD – The weight of all materials – The weight of all materials and people associated with but not part of and people associated with but not part of the structure.the structure.

IMPACT LOADIMPACT LOAD – a load that is in motion – a load that is in motion when it is applied. This could be a hose when it is applied. This could be a hose stream striking the side of the building.stream striking the side of the building.

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AXIAL LOADAXIAL LOAD – A load padding through the – A load padding through the center of the mass of the supporting center of the mass of the supporting element, perpendicular to its cross section.element, perpendicular to its cross section.

ECCENTRIC LOADECCENTRIC LOAD - a load perpendicular - a load perpendicular to the cross section of the supporting to the cross section of the supporting element that does not pass through the element that does not pass through the center of mass.center of mass.

TORSION LOADTORSION LOAD – A load parallel to the – A load parallel to the cross section of the supporting member cross section of the supporting member that does not pass through mass.that does not pass through mass.

Application of LoadsApplication of Loads

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Application of Loads PicturesApplication of Loads Pictures

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Loads applied to structural Loads applied to structural elements as forceselements as forces

COMPRESSIONCOMPRESSION – – A force that tends to push A force that tends to push materials together.materials together.

TENSIONTENSION – – A force that pulls materials apart.A force that pulls materials apart.

SHEARSHEAR – – A force that tends to break material A force that tends to break material by causing its molecules to slide past each by causing its molecules to slide past each other.other.

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Types of Loads pictureTypes of Loads picture

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COMMERCIALCOMMERCIALBUILDINGS BUILDINGS

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Building CollapseBuilding Collapse

Knowledge of the type of construction Knowledge of the type of construction is vital during fire operations because is vital during fire operations because of the possibility of collapse.of the possibility of collapse.

Some buildings because Some buildings because

of their age & construction of their age & construction

are more inclined to are more inclined to

collapse than others. collapse than others.

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Collapse ZoneCollapse Zone

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Indictors of Possible Building Indictors of Possible Building CollapseCollapse

Cracks or separations in walls, floors Cracks or separations in walls, floors ceiling and roof structuresceiling and roof structures

Evidence of existing structural Evidence of existing structural instability such as the presence of tie instability such as the presence of tie rods & stars that hold walls together.rods & stars that hold walls together.

Loose bricks, blocks or stones falling Loose bricks, blocks or stones falling from buildingsfrom buildings

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Cracks or separations in walls, floors, ceilings &

roof structure

Deterioration of mortarbetween masonry

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Signs of collapseSigns of collapse Deterioration of mortar between the Deterioration of mortar between the

masonrymasonry

Walls that appear to be leaningWalls that appear to be leaning

Structural members that appear to be Structural members that appear to be distorteddistorted

Fire beneath floors that support Fire beneath floors that support heavy machinery or other extreme heavy machinery or other extreme weight loads.weight loads.

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Signs of collapseSigns of collapse

Prolonged fire exposure to the Prolonged fire exposure to the structural membersstructural members

Unusual creaks and cracking noisesUnusual creaks and cracking noises

Structural members pulling away Structural members pulling away from walls from walls

Excessive weight of building contentsExcessive weight of building contents

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Parapet Wall CollapseParapet Wall Collapse

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RESIDENTIALRESIDENTIALCOLLAPSECOLLAPSE

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Parallel Chord TrussParallel Chord Truss

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Wood TrussesWood Trusses

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Truss Construction Void SpacesTruss Construction Void Spaces

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Types of ConstructionTypes of Construction Truss constructionTruss construction Bowstring trussesBowstring trusses Wood trussesWood trusses Open web steel joistOpen web steel joist Void spacesVoid spaces Engineering wood structural membersEngineering wood structural members

Roof structuresRoof structures Parapet wallsParapet walls Synthetic materialsSynthetic materials Fire-resistive and noncombustible Fire-resistive and noncombustible

constructionconstruction

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WRAP-UPWRAP-UP

Firefighters must know and understand Firefighters must know and understand building construction.building construction.

There are five common types of There are five common types of construction.construction.

Truss construction is dangerous because Truss construction is dangerous because trusses collapse under fire conditions.trusses collapse under fire conditions.

Firefighters need to be aware of the Firefighters need to be aware of the hazards associated with structure fires.hazards associated with structure fires.