2120 Ch 9 PowerPoint

1. Building Construction Related to
the Fire Service
Fourth Edition
Chapter 9 — Steel Construction

2. ‣ Describe the material properties of
steel.
Learning Objective 1

3. Steel is an alloy of iron and carbon.
Courtesy
of
Ed
Prendergast

4. Steel is an alloy of iron and carbon.

5. One inherent disadvantage of steel is tendency
to rust when exposed to air and moisture.

6. During alloying process, elements are combined
to produce steel that can be used for a specific
purpose.

7. The lower carbon content of steel
results in a ductile material.
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of
McKinney
(TX)
Fire
Department

8. One common structural steel is ASTM A 36
which includes manganese, carbon, and silicon.

9. Steel expands when it is heated.

10. An important factor of steel use is the
support system used with a beam.

11. Deterioration of steel strength at elevated
temperatures is significant for the fire service.

12. Deterioration of steel strength at elevated
temperatures is significant for the fire service.
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of
Colorado
Springs
(CO)
Fire
Department

13. Steel is a good conductor of heat
because it is a heavy material.

14. Unprotected steel structural members with less
mass require less heat to reach the failure
temperature.

15. Structure fires typically do not generate
temperatures hot enough to melt steel.

16. Structure fires typically do not generate
temperatures hot enough to melt steel.

17. ‣ Describe methods used to protect steel
construction elements during a fire.
Learning Objective 2

18. Steel is not inherently fire-resistive.

19. Spray-applied fire-resistive materials
(SFRM) are efficient and inexpensive.

20. For an SFRM to be effective, proper
installation procedures must be followed.

21. Most fire-insulating materials can be applied in
specific thicknesses to achieve different fire-
resistance ratings.

22. Low-density mineral fiber materials are soft,
easily dislodged from the steel and are not
suitable for exterior use.

23. NOTE
‣ Asbestos has not been used in SRFMs
since the 1970s.

24. Cementitious materials may be used
as an insulating material for steel.

25. NOTE
‣ Some manufacturers of cementitious
cement add magnesium oxychloride,
or oxysulfate calcium aluminate,
phosphate, or ammonium sulfate.

26. Gypsum can be used as an insulating material
either in the form of flat boards or a plaster.

27. Gypsum board is available as regular
or type X.

28. The value of gypsum as an insulating material
arises in part from water that is chemically
combined within the material.

29. Gypsum board can be used to protect
columns and beams.

30. NOTE
‣ For more information about
construction systems and materials
and their ratings, consult the UL Fire
Resistance Directory.

31. Intumescent and mastic materials undergo a
chemical reaction when exposed to the heat of a
fire.

32. Intumescent and mastic materials undergo a
chemical reaction when exposed to the heat of a
fire.

33. A membrane ceiling is commonly used to
protect a steel floor or roof assembly.

34. The ceiling material acts as a thermal barrier to
protect the steel that supports the floor or ceiling
above.

35. Ceiling materials are never rated
independently.

36. Membrane ceilings are popular because
building utilities can be concealed.

37. ‣ Explain how steel is used in the
construction of structural framework.
Learning Objective 3

38. Steel is used in the construction of a structural
framework that supports the floors, roof, and
exterior walls.
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of
McKinney
(TX)
Fire
Department

39. Steel is used in the construction of a structural
framework that supports the floors, roof, and
exterior walls.

40. It is not efficient to use steel in the form of solid
slabs or panels because it is a dense material.

41. The design of the connections in
steel-frame buildings is important.

42. The design of the connections in
steel-frame buildings is important.

43. A rigid frame system is designed to resist
bending forces resulting from the supported
loads and lateral forces.

44. The joints in a simple frame are designed
primarily to support a vertical force.

45. The connections in a semi-rigid frame possess
enough rigidity to provide some diagonal support
to the structure.
Courtesy
of
Colorado
springs
(CO)
Fire
Department

46. Steel trusses can carry loads across greater
spans more economically than beams can.

47. Two applications of the basic steel truss
are the joist girder and the open web joist.

48. Open web joists are available with depths up to
6 feet (2 m) and spans up to 144 feet (45 m).

49. Open web joists are available with depths up to
6 feet (2 m) and spans up to 144 feet (45 m).

50. When round bars are used for the diagonal
members, the open web truss is known as a bar
joist.
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of
Ed
Prendergast

51. Steel rigid-frame buildings with inclined
(or gabled) roofs are widely used.
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of
Ed
Prendergast

52. Steel rigid-frame buildings with inclined
(or gabled) roofs are widely used.

53. Steel rigid-frame buildings with inclined
(or gabled) roofs are widely used.

54. Steel arches are used to support roofs on
buildings where large unobstructed floors are
needed.

55. Steel can be used in slender
components such as rods and cables.

56. Steel rods and cables are sometimes
used in suspension systems to support
roofs.
Courtesy
of
Ed
Prendergast

57. Types of steel columns can range from simple
single-piece cylindrical pipes to complex tower
assemblies.

58. Steel columns can be disproportionately thin
compared to their length due to the high
compressive strength of steel.

59. The possibility of buckling in a column is a
function of length, cross-section, and the method
of support.

60. In general, columns used for structural support
in buildings should not have a slenderness ratio
greater than 120.

61. Investigation of a structural collapse must
include an evaluation of any columns and their
means of support.

62. Steel structural components can be used
to support floors in multistory buildings.

63. Open-web joists can also be used to support
precast concrete panels or wood decking.

64. Where floor loads or spans dictate, steel beams
are used to support flooring instead of open-web
joists.

65. Building codes specify the degree of fire
resistance for various structural members.

66. ‣ Identify common reasons for collapse of
steel structures.
Learning Objective 4

67. Steel structures can collapse under
fire conditions.

68. Steel structures can collapse under
fire conditions.

69. Connection types and strength will influence the
overall strength of steel structures under fire
conditions.

70. Rigid connections used in the beam and girder
type of frame have a greater mass of steel at the
point of connection.

71. Steel connections frequently use a
steel web known as a gusset plate.
Courtesy
of
McKinney
(TX)
Fire
Department

72. The knee joint between the roof and the wall will
be the strongest part of the frame in gabled rigid-
frame structures.