1. Chapter 10 Noncombustible Construction

2. Objectives
Understand the difference between noncombustible and fire-resistive construction.
Identify the different types of steel building components and their characteristics.
Describe the use of masonry, including concrete, in noncombustible buildings.

3. Objectives Describe different types of steel structural systems.
Describe the hazards of a metal deck roof fire.
Understand the hazards of high fire loads in unprotected steel structures and ways to improve the situation.

4. Introduction
Difference between noncombustible and fire-resistive construction
The level of fire resistance (fire rating) assigned to the structural frame, walls, floors, and roof
Noncombustible construction has little fire resistance.
Fire-resistive construction has moderate to heavy fire resistance.

5. Noncombustible Construction
Allowable area and height is much less than fire-resistive construction.
Maximum height is 12 stories.
Fire-resistive construction can have unlimited height.
Fire-resistive construction can use steel for its framing system.

6. Steel
Modulus of elasticity about 29 million pounds per square inch (psi)
High tensile strength and shear strength
Strong but lightweight members have little inherent fire resistance.

7. Fire Characteristics of Steel
Substantial elongation
Above 1300˚F, steel members may fail.
Cold-drawn steel will fail at about 800˚F.
Steel transmits heat readily.

8. Unwarranted Assumptions
False belief in steel’s “fireproofness”

9. Water on Hot Steel Water is the fire department’s heat removal medium.
Myth: Water should not be thrown on heated steel.
Cooling effect of water draws steel back to its original dimensions.

10. Definitions: Steel Construction Members
Angles
Bars
Box columns
Box girders
© Melinda Fawver/ShutterStock, Inc.

11. Definitions: Steel Construction Members
Castellated beams
Channels
I-beams
Plates
Created by Glenn Corbett.

12. Definitions: Steel Construction Members
Purlins
Rolled or built-up members
Spandrel girders
Tees
Courtesy of Jack Boucher/Library of Congress.

13. Definitions: Steel Construction Members
Tubes
Wide-flange shapes
Zees
Courtesy of Jason Roe, All Metals Incorporated

14. Steel as a Construction Material
Makes it possible to erect tall buildings
Variety of shapes:
C: channels
CB: castellated beams
L: angles
S: America Standard (I-beam)
W: wide flange beams and columns
WT: structural tees

15. Steel as a Construction Material
Numbers designate the specific size: depth in inches × weight per foot of length
Has consistency in structural characteristics
Can be connected to other structural elements
Used for fire escapes

16. Steel as a Construction Material
Provides the tensile strength that concrete lacks
Used in concrete flooring systems
Used to repair failures in concrete buildings

17. Steel Buildings Used in peaked roofs
Bar joists span the main trusses to support a flat roof
Courtesy of Glenn Corbett.

18. Steel Buildings Steel is almost universally unprotected.
Buildings often can only be classified as noncombustible

19. Protected Noncombustible Sprinklered Construction
Found occasionally
Major structural elements have fire resistance.
Building itself is not fire resistive.

20. Rigid Frames
Column is narrow at the base and tapers to its widest point at the top.
Rafter is also tapered.
Wide haunch resists the outward thrust of the roof.
Clear spans of about 100 feet.
© Glen Jones/ShutterStock, Inc.

21. Steel-Framed Buildings
Many are prefabricated.
Butler Company is a prominent manufacturer.
Courtesy of Butler Manufacturing.™

22. Huge Spans Span collapses can be sudden and tragic.
Adjacent bents are tied together.
Tying the steel units together creates dependencies between torsional or eccentric loads.
The higher the resistance to wind load, the more likely a progressive collapse.

23. Developing Wide-Span Trusses
Designs may push the limits of steel.
Hasty field changes or errors in construction can have catastrophic consequences.

24. Deep Parallel-Chord Trusses
Floor beams in hospitals
Interstitial space
Such voids should not be used for storage or maintenance.
Automatic sprinklers should be required.

25. Heavy Parallel-Chord Trusses
Have been used as transfer beams
Often hidden in partition walls

26. Trussed Arches Arch of a steel arch bridge is often a truss.
Is a compression structure

27. Exterior Walls of Steel-Framed Buildings
Wall composition varies.
Metals, cement-asbestos board, masonry, concrete, and reinforced plastics found
Wall insulation and coatings also factors

28. Cement-Asbestos Board
Noncombustible and is often used for friable construction
Friable construction is used where an explosion is a possibility.
Will break away readily and relieve pressure

29. Glass-Fiber Reinforced Plastics
Noncombustible
Resinous binder most often used with it is flammable.

30. Aluminum Noncombustible, but has a low melting point
Has little mass per unit of area, so it disintegrates rapidly in a fire

31. Precast Prestressed Concrete Panels
Usually erected in large sections
Collapse is hazardous to fire fighters.

32. Masonry Walls Most common walls for unprotected steel-framed buildings
Made of concrete block or a composite
Usually only curtain walls
Important to analyze the effect of the expansion of the steel frame on the wall

33. Galvanized Steel Walls
Used when heat conservation is not important
Asphalt asbestos protected metal (AAPM)
Robertson Protected Metal (RPM) is one proprietary name.

34. Metal Panels Prefabricated metal panels in a sandwich construction
Courtesy of Glenn Corbett.

35. Metal Panels Plastics are often used with metal panels.
Insulation, vapor seal, or adhesive in the panels may be combustible.

36. Polyurethane Insulating Panels
Protected by gypsum board and stainless-steel sheathing
If a cutting torch is later used, a smoky, destructive fire may result.

37. Aluminum Sandwich Panels
Can be made with foamed polyurethane
Some are listed by Underwriters Laboratories for low flame spread ratings.
Smoke-developed ratings may be quite high.

38. Failure of the Closure of the Wall Panel to the Floor Slab
Design of panel walls
Method of installation
Degradation of insulation
Expansion of metal under fire conditions

39. Prefabricated Metal Panels
Use neoprene gaskets between the panel and wall separating motel rooms.

40. Light Gauge Steel-Framed Walls
Surge in use
U-shaped tracks
Brick veneer, EIFS, or stucco finish
Load bearing
Courtesy of Glenn Corbett.

41. High-Rise Framing
Steel once stood unchallenged as a method for high-rise buildings.
Concrete now is finding more use.

42. Builders’ Hesitation
Brick, stone, and terra cotta were added to framed buildings.
Goal was to reduce the apparent or perceived height of the building.
Now, glass and metal exterior panels are common and firestopping is less reliable.

43. Tilt-Slab Hazards Special hazard
Walls braced with tormentors or braces until the roof secured
Courtesy of Glenn Corbett.

44. Tilt-Slab Hazards
If the roof is being lost in the fire, beware of wall collapse.
If heavy smoke is present, the sprinklers are not controlling the fire.

45. Steel-Framed Buildings Under Construction
Wind forces must be resisted, because the building is not fully connected.
Braces may not be properly installed.

46. Plastic Design in Steel Construction
Connections are built to transfer loads beyond the column.
Beams are lighter and columns are smaller than they would be otherwise.
The lighter the steel, the less fire resistance.

47. More on the Fire Characteristics of Steel
Conducts heat
Tin ceilings
Elongates as temperature increases
Loses strength at high temperatures
Courtesy of the estate of Francis L. Brannigan.

48. Steel Conducts Heat Steel transmits heat.
Tin ceilings can transmit fire.
The conductivity of steel can be a factor in spreading fires.

49. Ships Practice of using ships as buildings is growing.
Ships have steel walls known as bulkheads.
Welding operations are performed without concern for heat transmission.

50. Self-Storage Facilities
Have many of the characteristics of ships
Fire can spread from unit to unit by conduction and radiation.
© John Spink/AP Images.

51. Steel Elongates Expands from 0.06% to 0.07% for each 100°F rise
At 1000˚F, a steel member will expand 9½ inches over 100 feet of length.
Above 1000˚F, steel starts to soften and fail.

52. Elongating Steel
Exerts a lateral force against the structure that restrains it
Expansion of steel may cause the displacement of masonry.

53. Effects of Hot, Fast Fires on Steel Buildings
Failure temperatures are reached rapidly.
Lateral thrust against the wall is minimized.
Overturning can be anticipated.

54. Steel Fails Steel above 1000˚F starts to lose strength rapidly.
© Harald Koch/AP Images

55. Steel Fails
National Fire Protection Association (NFPA) 251 (American Society of Testing and Materials E119) test reaches 1000˚F in 5 minutes.
National Institute of Standards and Technology (NIST) test reaches 1500˚F in 5 minutes.

56. Standard Tests of the Fireproofing of Steel Columns
Test ends when a temperature of 1200˚F is exceeded at one point or 1000˚F is exceeded on the average in the column.
A principal variable is the weight or mass of the steel unit.
Ventilation is also a factor.

57. Overcoming the Effects of a Fire on Steel
Ignore the problem.
Rely on an inadequate code enforcement.
Take a calculated risk.
Fireproof (insulate) the steel.

58. Overcoming the Effects of a Fire on Steel
Protect the steel with sprinklers.
Fireproof the steel with a water cooling system.
Locate the steel out of range of the fire.

59. Ignoring the Problem
Potential for fire damage to steel buildings is not clearly understood.
Unwarranted confidence in the fact that the steel is noncombustible

60. Steel Highway Structures and Bridges
Unprotected steel that is vulnerable to an occasional gasoline truck fire
New York City Fire Department developed preplans in place for the East River bridges 70 years ago.

61. Hazards of Concentrated Fire Loads
Unprotected steel buildings may have highly concentrated fire loads.
“One-high story” buildings with internal structures
Mezzanines, sometimes built of wood
Other combustible spaces

62. Hazards of Concentrated Fire Loads
Metal trailers are hazardous, especially when grouped.
Prefabricated buildings, especially with certain types of insulation in walls

63. Excavation Bracing Building excavations are being made much deeper.
Walers and rakers
An excavation is loaded with combustibles.
Tiebacks 

64. Buildings Under Construction
Steel may be unprotected for extended periods.
World Trade Center used ordinary plywood to save $1 million.

65. Relying on Inadequate Codes
Building codes
Unprotected noncombustible or protected noncombustible
“Protection” refers to physical protection of the steel with gypsum board, spray-on fireproofing, or the like.

66. Study the Type of Construction
Column, girder, and beam construction is common.
If a masonry bearing wall is substituted for some of the exterior columns, the building is wall-bearing.

67. Assumption About Fires
They burn only upwards.
A fire involving a wooden balcony or a metal deck roof could well cause steel framing to move and thus cause brick- veneered walls to fall.

68. Steel High Above the Floor
Building codes vary.
Typically, steel used to support roofs at a certain distance (20 to 30 feet) above the floor does not require protection.

69. The McCormick Place Fire
Loss of $154 million
The main exhibit area provided a clear area of 320,000 square feet.
© Paul Cannon/AP Images.

70. The McCormick Place Fire
The columns were trusses themselves.
The columns were fire protected up to a height of 20 feet.
The roof trusses were unprotected.

71. What Could Have Been Done Better?
Modern building codes would have required automatic sprinkler system.
Sprinklers could have limited the spread of this fire.
Codes were inadequate.

72. The New McCormick Place
Structural steel is protected with directly applied fireproofing delivering 1-hour fire resistance.
The entire building is sprinklered.
Provisions have been made for smoke venting.

73. Important Test Experiences
Underwriters Laboratories tested in the aftermath of the fire.
Tests were done in building 30 feet high with typical fuels.
The first test fires had 1500˚F after 5 minutes and 45 seconds.
A bar joist reached 1540˚F and an I- beam 1355˚F in just over 5 minutes.

74. Taking Calculated Risks
Financial calculation
Engineering calculation
“Forgetting it” calculation
Steel industry

75. Insulated Metal Deck Roof Fire Problems
General Motors plant at Livonia, Michigan
Metal deck roof was principal contributing factor to plant destruction.
© AE/AP Images.

76. Insulation Is useless when it absorbs moisture
Must be protected from capillary attraction
A bituminous coating serves as the adhesive and sometimes as a moisture- stopping vapor barrier.
Built-up roof

77. Rubber Roof Type II construction
Single ply of EPDM over fiberboard and plastic insulation
Metal fasteners, seam tapes, and flammable adhesives
Wind-aided fire in Brooklyn

78. Modified Bitumen Roof
Traditional built-up roof modified with synthetic polymers for reinforcement
Hot or cold application

79. An Approved Roof
Is one that meets Underwriters Laboratories (UL) standards
Can be UL listed but still be a combustible metal deck roof

80. When a Fire Occurs The metal deck heats up.
Heat is conducted through the deck to the bituminous adhesive.
Adhesive liquefies and then vaporizes.
When the gas mixes with the air below, it ignites from the fire below.

81. Prevention of Metal Deck Roof Fires
Use Factory Mutual Class I roofing or a UL Classified Roof.
Provide adequate automatic sprinkler protection for the roof, even though the contents may be non-combustible.

82. Fires of Interest Tinker Air Force Base A fire was started by roofers.
The sprinklers were below a wire lath and plaster ceiling.
The water did not hit the underside of the roof deck, and the fire burned unimpeded.

83. Fires of Interest Wabush Mines
A fire in a large building damaged a metal deck roof 90 feet above the floor.
Even if the roof had been Class I, damage would have been severe.

84. Class I
Some think it means “completely satisfactory under all circumstances.”
A Class I roof with any combustibles should not be used over a high-value installation.

85. Atomic Energy Commission (AEC)
Studied fire protection for thousands of acres of metal deck roofs
Decided to add sprinklers to government plants
Over $20 million was spent on sprinklers and water supplies.

86. An Unrecognized Problem
Metal deck roof a factor in many losses
Beverly Hills Supper Club in Kentucky
© RF/AP Images.

87. An Unrecognized Problem
Common characteristics
Thick, black, choking smoke
Roof does not need a big opening

88. An Unrecognized Problem
Common characteristics (con’t)
Takes only 800˚F for 5 minutes for heat impinging on the surface of steel decking to start a self-sustaining roof fire .
In most jurisdictions, an ordinary combustible metal deck roof is permitted on a noncombustible building.

89. Fighting the Metal Deck Roof Fire
Marine Corps Supply Depot in Norfolk, Virginia
Marine plywood office

90. Metal Decks on Nonmetal Buildings
Metal decks found on steel-framed buildings as well as masonry buildings
Kensington, MD, fire
A fire broke out in a janitor supply business; roof was hidden by thick smoke.
Identified by chief as probable metal roof fire by dripping tar.

91. Types of Protection for Steel Structures
Unprotected
Dynamic protection
Passive protection
Passive/dynamic combination

92. Unprotected Steel Has potential for early collapse
Wichita, Kansas, automobile showroom fire
Repair bays built of lightweight steel truss construction

93. Need to Cool All Heated Steel
The quantity of water is not excessive.
Cool all the steel that is within reach of hose streams and give special attention to columns.
Solid stream tip might be better than a fog tip.

94. Water Damage
Some argue against the use of water because of the damage it can cause.
If owners had sprinklered the building, water would be discharged anyway.

95. Dynamic Fire Protection
Accomplished with various types of automatic sprinkler systems
Hydraulically calculated sprinkler design is no guarantee of success.
Heavy structural steel sometimes is protected by special lines of sprinklers.
Deluge and fog/foam systems are used for flammable liquids.

96. Passive Fire Protection
Is the legally required level of fire resistance adequate for the fire load as it exists in the building?
Has the protection of steel been provided, and is it maintained?
Is there any legal relief?

97. Passive Fire Protection
Is it up to the fire department simply to do the best it can in the event of a fire?
If the fire department estimate of the situation indicates potential or inevitable disaster, who, if anyone, is notified?

98. What All Personnel Should Know
The requirements for fire resistance as applied to specific buildings
The manner in which fire protection can be degraded

99. Degradable Methods Sprayed-on protection Membrane fireproofing
Fire-rated tile
Considerations
Permitted under local code?
Could tampering have occurred?

100. Passive/Dynamic Protection
Protected combustible construction combines partial static protection of the steel with automatic sprinklers.

101. Code Problems Develop competence
One person or group should become familiar with current and past local building codes.
Building officials may be less than enthusiastic about fire fighter involvement.
Some fire prevention managers are equally unenthusiastic about fire fighter involvement.

102. Code Variances
Code exceptions might be made by building and fire prevention officials.
Codes do not permit waivers to specific requirements.
All modifications to requirements of the code should be fully documented.

103. Preplanning Your “McCormick Place”
Make your own case study.
Consider a possible preplan of a fire in an unprotected steel building being used as an exhibit hall.
Assume there is a balcony running down both sides that is used for sports events but not for exhibits.

104. First Moves
“Bruising battle” for sprinkler protection or denial of the facility to high fire-load exhibits
After you lose, get in writing an agreement that the fire department can take whatever steps necessary to protect life and property during exhibits.

105. Consider a Worst-Case Scenario
An exhibition with a potential for a high rate of heat release in a fire
A hot, fast fire indicates a more severe test of the structure than a slower fire.

106. Consider a Worst-Case Scenario
Do you need an alternative automatic system?
Study the potential water supply and needs.

107. Be Proactive Watch for new ideas.
Step-by-step logic leads to the practical solution.
Be eternally curious.

108. Summary
Steel is the most important metal used in building construction.
Steel has several important characteristics to consider regarding its behavior in fire.
Substantial elongation can take place in a steel member at ordinary fire temperatures (about 1000˚F [538˚C]).
At higher temperatures (above 1300˚F [704˚C]), steel members may fail, bringing about a collapse of the structure.
Cold-drawn steel such as steel tendons used for tensioned concrete and for excavation tiebacks and elevator cables will fail at about 800˚F (427˚C).

109. Summary Steel is a good thermal conductor.
The strength of steel, the consistency of its structural characteristics, and its ability to be connected to other structural elements.
To achieve a peaked roof in a steel-framed building, the framing may consist of columns and beams with triangular trusses.
A number of options are open to the designer to deal with the characteristics of steel as they relate to fire risk.

110. Summary Steel structures can be divided into the following types:
Unprotected
Dynamically protected
Passively protected
Passive/dynamic combination protection