1. Chapter 14
Collapse

2. Objectives Explain the role of situational awareness in collapse.
Identify the indicators used to anticipate collapse.
Identify the various types of collapse.
Apply risk analysis to fireground safety.

3. Objectives
Identify the specific basic competencies all fire fighters should have to perform at a structural collapse.
Explain the essential elements of the collapse of the World Trade Center twin towers on September 11, 2001.

4. Collapse: The Greatest Threat on the Fireground
How fire fighters die
Heart attacks (the greatest killer today)
Smoke inhalation
Falls
Building collapse

5. Situational Awareness
The perception of the surroundings in terms of time and space
The understanding and comprehension of these observations
The projected outcome of a change in these conditions

6. Communication Essential for situational awareness
Protocols for collapse warnings

7. Anticipating Collapse
Rely on training and experience.
Use indicators and known precipitators.

8. General Visual Indicators of Collapse
Cracks in walls
Leaning walls
Pitched or sagging floors
© monbibi/ShutterStock, Inc.

9. General Visual Indicators of Collapse
“Racked” doorways
Presence of building stabilization and bracing features
Courtesy of Glenn Corbett.

10. Audible and Physical Indicators of Collapse
Moaning/groaning sounds
Cracking noises
Any type of movement
Movement/shifting of water on floor

11. Audible and Physical Indicators of Collapse
Smoke pushing through cracks in the wall
Vibrations
Lack of water runoff from firefighting operations

12. Environmental Precipitators of Collapse
Heavy snow or rain load on roof
Heavy wind collections
Earthquake
Impact load

13. Occupancy Precipitators of Collapse
Overloading of floors and/or roof
Concentrated loads
Water-logged goods

14. Existing Structural Instability Precipitators of Collapse
Structural compromises of load-bearing members during renovations
Previous fire damage
Rotting or corrosion of structural members from water leaks/damage

15. Existing Structural Instability Precipitators of Collapse
Compromised/broken structural elements
Eccentrically loaded columns
Buildings under renovation/construction and buildings being moved

16. Fire and Explosion Damage Precipitators of Collapse
Sustained moderate to heavy fire conditions
Explosion
Loss of wood structural mass due to fire attack

17. Lightweight Construction Precipitators of Collapse
Unprotected, bare steel members subjected to fire
Wooden I-beams and lightweight wood trusses subjected to fire
Courtesy of Green Maltese,

18. Risk Analysis After fire fatalities Questions are asked
Were fatalities caused by antiquated macho attitude?
Taxpayers are saddled with unnecessary expenses.

19. Risk Analysis Professional fire services
Analyze the relationship between risk incurred and benefits obtained
Are well informed about construction features of buildings that have been available for study for many years

20. Types of Collapse
Global collapse
Partial collapse
© Photos.com.

21. Types of Collapse Progressive collapse Secondary collapse
Courtesy of FEMA.

22. Types of Collapse
Pancake collapse

23. Types of Collapse
Lean-to-floor collapse

24. Types of Collapse
V-shaped floor collapse

25. Types of Collapse Cantilever floor collapse A-frame floor collapse
Inward outward collapse

26. Types of Collapse 90-degree wall collapse Lean over collapse
Curtain wall collapse
Courtesy of Glenn Corbett.

27. Establishing Collapse Zones
Fire fighters and fire apparatus must be kept out of collapse zones.
Untrue: “Staying back one third the height of the wall is safe.”
Fire fighters must remain at least the full height of the wall away.
© Beth Keiser/AP Images.

28. Minimum Collapse Competencies for Fire Fighters
Identified by NFPA 1670: Standard on Operations and Training for Technical Search and Rescue Incidents
Higher competency levels require higher training.

29. World Trade Center: Our Worst Collapse Tragedy
History of the World Trade Center
Two of the tallest and largest buildings ever built
Each tower was 110 stories high and each floor was 40,000 square feet.
Each side of the building measured 210 feet in length.

30. World Trade Center: Major Structural Components
Exterior walls
A series of columns in the center core
Lightweight steel floor trusses forming a composite floor
Hat truss

31. World Trade Center: Mechanism of Collapse
Studied by the National Institute of Standards and Technology (NIST)
Used visual evidence of the exterior damage and computer modeling

32. World Trade Center: North Tower (Tower 1)
Structural damage from the planes
Jet fuel and dislodged fireproofing
Open paths for fire spread
Weakened core columns
Sagging of the “south floors”
Bowed south perimeter columns

33. World Trade Center: South Tower (Tower 2)
Damage to the center core columns
Jet fuel and dislodged fireproofing
Sustained fires had an ample air supply
Weakened core columns
Sagging of the “east floors”
Bowed east perimeter columns

34. World Trade Center: Questions About Incident
How many trusses were destroyed in the initial impact?
How many failed in the subsequent fires?
How much fireproofing was knocked off by the plane impact?
How many center core columns were damaged and destroyed?

35. World Trade Center: Questions for the Future
Should lightweight trusses be used in high-rises?
Should spray-on fireproofing come under more scrutiny?
What role should fire services have in construction and regulation?

36. World Trade Center: In the End
Be proactive in securing your safety and the safety of others.
Get involved in the construction of a new building.
Get involved in the code development and adoption process.

37. Summary
All fire fighters have the responsibility to know the conditions for collapse in different types of buildings.
Fire fighters and fire apparatus should be kept out of collapse zones.