Ch 10 Lightweight Steel Roof and Floor Collapse Flashcards

1
Q

Steel starts to distort and lose strength during a typical structure Fire where flames reach how many degrees? Pg 143

A

1000 to 1100 degrees

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2
Q

It requires more than how many degrees to melt steel? Pg 143

A

2400 degrees

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3
Q

Three common methods to protect steel from the heat of fire are? Pg 145

A

•best method to protect steel is Encasement of the steel with concrete.
•The installation of a fire retarding ceiling between the occupancy and the steel above.
•the most popular, but least effective, method, applying a spray on fire regarding (SFRM) material over the entire surface of the steel.

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4
Q

Four factors determine the speed with which unprotected steel will fail during a fire? Pg 151

A

•temperature of the fire
•the load stress
•the steel thickness
•fire size

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5
Q

There are two common types of roof deck used a above the fluted steel deck of a bar joist roof or C beam support system? Pg 153

A

lightweight insulation or a precast concrete plank.

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6
Q

What strategy should be considered in an unprotected Type II steel building?
p. 149

A

Horizontal ventilation and defensive exterior attack

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7
Q

Which of the following is NOT cited as a reason the spray-on fire retarding material fails to protect steel from the heat of a fire? p. 147

A

Cleaning strips the steel of its adhesive properties

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8
Q

Where should the firefighter place his feet when cutting vent holes in a flat roof? p. 142

A

Roof side of the cuts

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9
Q

Up to what distance apart can open-web steel bar joists be spaced? p. 151

A

8 feet

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10
Q

What is the roof designed to support?
p. 152

A

Rain load

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11
Q

What is done to increase the strength of steel? p. 143

A

Bend it into shape

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12
Q

How much of its load carrying capacity will steel lose at 1,100 degrees Fahrenheit (593 degrees Celsius)?
p. 152

A

40 percent

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13
Q

Which is the best method to protect steel, from the firefighter’s point of view? p. 145

A

Encase it in steel

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14
Q

What size floor or roof beam is created with the C-beam? p. 143

A

20 foot

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15
Q

What causes spalling in concrete?
p. 145

A

Expansion of moisture in the concrete into steam

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16
Q

What may fall on firefighters operating under a membrane
ceiling if the suspension system is not properly constructed? p. 146

A

Ceiling

17
Q

Which is often the cause of failure of the C-beams in the early stages of a fire? p. 150

A

Size-up misjudgment

18
Q

What is being replaced in modern lightweight construction by the bar joist truss and C-beam? p. 143

A

Solid I-shaped beam

19
Q

What temperature must be reached for steel to melt? p. 143

A

2400 degrees Fahrenheit (1 315 degrees Celsius)

20
Q

Which property of the spray-on fire retarding material has become more important that previously thought?
p. 148

A

Adhesion

21
Q

Up to what distance on center were wood joists spaced in the past? p. 151

A

24 inches

22
Q

Which is the most popular but least effective method to protect steel from the heat of fire? p. 145

A

Applying a spray-on fire retarding material

23
Q

Which material is NOT included in the
spray-on-fire-retarding material?
p. 146

A

Asbestos based liquid

24
Q

What characteristic of large-size steel allows it to transfer the heat of a fire to a cooler interior region of
the steel? p. 153

A

Heat sink

25
Q

Which of the following is NOT a factor that will determine how fast unprotected steel will fail during a fire? p. 151

A

Building size

26
Q

Which of the following does steel NOT do during a fire? p. 143

A

Melt

27
Q

What temperature can a typical structure fire reach? p. 145

A

1700 degrees

28
Q

Which shape does the spray-on fire retarding material have problems adhering to? p. 148

A

Round