1. Building Construction (Fire Fighter I)
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CHAPTER 7
Building Construction
(Fire Fighter I) 1

2. Fire Fighter I Objectives
Explain how occupancy classifications affect fire suppression.
Explain how the contents of a structure fire affect suppression operations. 2

3. Fire Fighter I Objectives
List the characteristics of each of the following types of building construction: masonry, concrete, steel, glass, gypsum, wood, engineered wood, and plastic.
List the five types of building construction. 3

4. Fire Fighter I Objectives
Describe the characteristics and effects of fire on Types I, II, III, IV, and V construction.
Describe the characteristics and effects of fire on balloon-frame and platform-frame construction.
Describe the purpose of a foundation in a structure. 4

5. Fire Fighter I Objectives
Explain the warning signs of foundation collapse.
Explain how floor construction affects fire suppression operations.
Describe the characteristics of fire-resistive floors, wood-supported floors, and ceiling assemblies. 5

6. Fire Fighter I Objectives
List and describe the three primary types of roofs.
Describe the characteristics of trusses.
List the types of trusses.
Describe the effects of fires on trusses.
Describe the characteristics of walls. 6

7. Fire Fighter I Objectives
List the common types of walls in construction.
Describe the characteristics of door and window assemblies and fire doors and windows.
Explain the effect that interior finishes have on fire suppression operations. 7

8. Fire Fighter I Objectives
Describe the hazards that buildings under construction or demolition pose to fire fighters.
Describe how building construction factors into preincident planning and incident size-up. 8

9. Introduction Building construction affects how fires grow and spread.
Fire fighters need to understand how each type of building construction reacts when exposed to the effects of heat.
Determines when it is safe to enter a burning building and when it is necessary to evacuate 9

10. Occupancy How a building is used
Classifications indicate who is likely to be inside, how many people, and what they are likely to be doing. 10

11. Contents Must be considered when responding to a building.
Vary widely, usually related to occupancy.
Similar occupancies can pose different levels of risk. 11

12. Types of Construction Materials
The properties of these materials and the details of their construction determine the basic fire characteristics of the building itself.
Key factors that affect combustibility:
Combustibility
Thermal conductivity
Decrease of strength at elevated temperatures
Thermal expansion when heated 12

13. Masonry Inherently fire resistive Poor conductor
Openings can allow fire to spread.
With prolonged exposure to fire, masonry can collapse.
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© Ken Durden/ShutterStock, Inc. 13

14. Concrete Naturally fire resistive Poor conductor of heat
Strong under compression
Weak under tension
Can be damaged through exposure to fire
Spalling 14

15. Steel Strongest material in common use
Strong in both compression and tension
Will rust if exposed to air and moisture
Not fire resistive
Good conductor of heat 15

16. Steel Expands and loses strength when heated
Any sign of bending, sagging, or stretching indicates immediate risk of failure.
Courtesy of Captain David Jackson, Saginaw Township Fire Department 16

17. Other Metals Aluminum Copper Zinc
Siding, window and door frames, and roof panels
Often melts and drips in fires
Copper
Primarily used for piping and wiring
Zinc
Used as a protective coating for metals 17

18. Glass Noncombustible but not fire resistive
Ordinary (nontreated) glass will break when exposed to flame. 18

19. Gypsum Board Very good insulator Limited combustibility
Paper will burn, but gypsum itself will not.
Often used as a firestop
Prolonged exposure to fire will cause failure. 19

20. Wood Most common building material
Engineered wood products also called manufactured board, human-made wood, and composite wood.
May warp, contain toxic products, burn, and fail quickly. 20

21. Wood Most important characteristic is combustibility.
Weaken when consumed by fire
Ignites, burns, decomposes based on:
Ignition, moisture, density, preheating, size, and form
High temperatures decrease strength via pyrolysis. 21

22. Plastics Rarely used for structural support Combustibility varies
Many plastics release dense, toxic smoke when they burn.
Thermoplastic materials melt and drip.
Thermoset materials lose strength but will not melt. 22

23. Types of Construction Type I: Fire resistive Type II: Noncombustible
Type III: Ordinary
Type IV: Heavy timber
Type V: Wood frame 23

24. Type I: Fire-Resistive
All structural components must be noncombustible.
Used for:
Large numbers of people
Tall or large area
Special occupancies
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25. Type I: Fire-Resistive
Building materials should not provide fuel for a fire.
Steel framing must be protected.
Fires can be very hot and hard to ventilate.
In extreme conditions Type I buildings can collapse. 25

26. Type II: Noncombustible
All structural components must be noncombustible.
Fire-resistive requirements are less stringent than Type I. 26

27. Type II: Noncombustible
Structural components contribute little or no fuel.
Fire severity is determined by contents.
Most common in single-story warehouses or factories 27

28. Type III: Ordinary Used in a wide range of buildings
Masonry exterior walls support floors and roof.
Usually limited to no more than four stories
Limited fire resistance requirements
© Brandon Bourdages/ShutterStock, Inc. 28

29. Type III: Ordinary Two separate fire loads:
Contents
Construction materials
Fire resistance depends on building age and local building codes.
Exterior walls, floors, and roof are connected. 29

30. Type IV: Heavy Timber Exterior masonry walls
Interior structural elements, floors, and roof of wood 30

31. Type IV: Heavy Timber No concealed spaces or voids
Used for buildings as tall as eight stories
Open spaces suitable for manufacturing and storage
New Type IV construction is rare. 31

32. Type V: Wood Frame Most common type of construction in use
All major components are wood or other combustible materials. 32

33. Type V: Wood Frame Used in buildings of up to four stories
Wooden I-beams and trusses
Just strong enough to carry required load
No built-in safety margin
Collapse early and suddenly
Cause veneer to collapse and peel away
Fire fighters should be aware of construction. 33

34. Type V: Wood Frame Balloon-frame construction
Exterior walls assembled with continuous wood studs
Platform-frame construction
Exterior wall studs not continuous 34

35. Building Components
Understanding how various components of a building function will improve a fire fighter’s safety. 35

36. Foundations
Transfer the weight of the building and its components to the ground
Ensures building is firmly planted
Weak or shifting foundations can cause collapse.
© Dorn1530/ShutterStock, Inc. 36

37. Floors and Ceilings Fire-resistive floors
Floor-ceiling system designed to prevent vertical fire spread
If space above ceiling is not partitioned or protected, fire can quickly extend horizontally.
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38. Floors and Ceilings Wood-supported floors
Heavy-timber floors can often contain a fire for an hour or more.
Conventional wood flooring burns readily and can fail in as little as 20 minutes.
Modern, lightweight wood I-beams and trusses 38

39. Roofs Not designed to be as strong as floors Three primary designs:
Pitched roofs
Curved roofs
Flat roofs 39

40. Pitched Roofs Sloped or inclined
Can be gable, hip, mansard, gambrel, or lean-to
Usually supported by rafters or trusses
Require some sort of roof covering
© AbleStock 40

41. Curved Roofs
Used for large buildings that require large, open interiors
Usually supported by bowstring trusses or arches 41

42. Flat Roofs Have a slight slope for drainage
Wood support structures use solid wood beams and joists.
Courtesy of Captain David Jackson, Saginaw Township Fire Department 42

43. Flat Roofs Open-web steel trusses (bar joists) often used for support
Most coverings highly combustible
Ventilation may involve cutting through many layers of roofing. 43

44. Trusses Triangular geometry creates a strong, rigid structure.
Usually prefabricated wood or steel
Three types:
Parallel chord
Pitched chord
Bowstring 44

45. Trusses
Courtesy of Captain David Jackson, Saginaw Township Fire Department 45

46. Trusses Under fire, provide little margin of safety
Failure at one point produces failure for the entire truss.
Steel trusses are prone to failure during fire.
A 100-ft-long beam/truss can elongate as much as 9” (23 cm) when heated to 1000ºF. 46

47. Walls Most visible part of a building
Constructed of a variety of materials
Walls are:
Load-bearing
Nonbearing
Specialized 47

48. Load-Bearing Walls Provide structural support
Either interior or exterior
Support both “dead load” and “live load”
Damaged wall can result in collapse. 48

49. Nonbearing Walls Support only their own weight
Can be breached or removed without compromising structural integrity
Either interior or exterior 49

50. Specialized Walls Party walls Fire walls Common to two properties
Almost always load-bearing
Often a fire wall
Fire walls
Designed to limit horizontal fire spread
Extend from foundation through roof
Constructed of fire-resistant materials 50

51. Specialized Walls Fire partitions Fire enclosures Curtain walls
Interior walls that extend from a floor to underside of floor above
Fire enclosures
Fire-rated assemblies for vertical openings
Curtain walls
Nonbearing exterior walls attached to the outside of a building 51

52. Doors Can be used for entry, exit, light, and ventilation
Mostly constructed of wood or metal
Hollow-core wood doors offer little fire resistance.
Solid-core doors provide some fire resistance.
Metal doors more durable and fire resistant 52

53. Window Assemblies Used for light, ventilation, entry, and exit
Window type depends on a variety of factors. 53

54. Fire Doors and Fire Windows
Constructed to prevent the spread of flames, heat, and smoke
Must meet NFPA 80
Labeled according to approved use 54

55. Fire Doors and Fire Windows
Fire windows are used when a window is needed in a required fire-resistant wall.
Courtesy of Securalldoors.com 55

56. Interior Finishes and Floor Coverings
Finishes and coverings are exposed interior surfaces of a building.
Fire fighters should know the hazards posed by different interior finishes.
Most are plastic derived from petroleum products. 56

57. Manufactured Housing Mobile and modular homes
Lightweight building components
Most components are combustible
Death rate in mobile home fires is three times that of other types of single-family homes. 57

58. Buildings Under Construction or Demolition
Construction or demolition sites pose special problems for fire fighters.
Built-in fire protection features are often missing.
Fire-resistive enclosures can be missing.
Often unoccupied for long periods 58

59. Preincident Planning and Incident Size-Up
Preincident planning allows fire departments the ability to:
Determine the type of construction 59

60. Preincident Planning and Incident Size-Up
It is not possible to preplan every property
Incident size-up
Learn the general characteristics of building types in area
Keep up with changes in building construction
© Steven Townsend/Code 3 Images 60

61. Summary
Fire fighters must understand the basic types of building construction.
Using a structure’s occupancy classification, fire fighters can predict who is in the building.
Building contents are related to the occupancy of the structure. 61

62. Summary
Many materials are used in building construction, and each material reacts differently to heat and fire.
The five types of building construction each have their own strengths and weaknesses and differing levels of resistance to fire. 62

63. Summary
Buildings contain a variety of parts or components. These components are made from several materials, and each react differently to fire. 63