C0llapse of a Burning Building Flashcards
1
Q
Collapse zones have increased to…
A
1.5-2 times height of a wall.
2
Q
Who determines collapse zones?
A
officer in command
3
Q
The largest number of FF’s killed in single building collapse was…
A
Chicago, IL / 21 FFs died in collapse of stockyard building
4
Q
What are the four factors that will increase burning building collapse?
A
age
abandonment
lightweight materials
faulty renovations
5
Q
What cracks masonry walls of abandoned buildings?
A
freeze thaw cycle
6
Q
NFPA says that unprotected lightweight steel bar joists will fail after how many minutes of fire exposure?
A
5-10
7
Q
Fire resistance and collapse resistance are directly related to what?
A
mass of a building
8
Q
Why is there a lack of research into why burning buildings collapse?
A
offers small benefit to anyone other than FFs
hard to analyze objectively
9
Q
The term structural collapse is defined in this book as…
A
any portion of the STRUCTURE that fails as a result of fire
10
Q
The definition of a falling object is…
A
any object OTHER than the structure that falls, is thrown, or knocked from the building (there are more injuries by these than by structural collapse)
11
Q
What is the most common falling object at a structure fire?
A
broken glass from vented windows
12
Q
How thick is glass from a residential building?
A
1/16-1/8 inch
13
Q
How thick is glass from commercial building?
A
1/4-1/2 inch and weighs 2.5-5 lbs/sqft
14
Q
Who is responsible for falling glass and when?
A
during firefighting-FF outside
during overhaul-FF inside
15
Q
When anything must be thrown from a window, permission from who is required?
A
officer in command
16
Q
The final and most important reason for the absence of collapse information is what?
A
lack of FD documentation and records of collapse
17
Q
Which collapse kills the most FFs?
A
floor
18
Q
What is the second most dangerous collapse?
A
roof
19
Q
What is the third most dangerous collapse?
A
wall
20
Q
What is the fourth and final dangerous collapse?
A
ceiling
21
Q
Fuel load consists of what?
A
content + structure
22
Q
What is active fire protection?
A
automatic sprinklers and hose streams
23
Q
The removal of any part of an arch will cause what?
A
the entire arch to fail
24
Q
If a non-bearing wall collapses during a fire, how will it fall?
A
straight out in one piece at a 90 degree angle
25
If a bearing wall fails, it can cause what?
second collapse of the floor it supports
26
What forces are a beam subject to?
compression
tension
shear
27
How can beams be supported (least to most stable)?
cantilever
simple supported
continuous
28
What is the most dangerous of the three basic methods of construction?
braced frame (aka Post & Girt)
29
Braced-frame construction collapses in what manner?
inward-outward
30
How does an inward-outward collapse work?
top=in
| bottom=out
31
What is a perpendicular truss used in steel bar truss floor systems to provide lateral stability?
bridge truss (aka purlin)
32
What is a wall reinforcement built on the outside of a structure that is sometimes called a wall column?
buttress
33
What is a buttress constructed on the inside of a wall called?
pilaster
34
What can cause a curtain wall collapse of a veneer wall?
impact of aerial master stream
35
What type of wood frame building collapse is indicated by the structure slowly starting to lean over?
lean over collapse
36
A lean to floor collapse can be classified in what two ways?
supported or unsupported
37
In a 90 degree wall collapse, the top of the failing wall will strike the ground where?
at a distance equal to the height of the failing section
38
What type of collapse happens when floor beams pull loose or collapse at both ends?
pancake collapse
39
A column is a vertical structure subject to what type of force?
compressive
40
Columns and bearing walls make up what kind of framework?
vertical framework
41
Girders and beams make up what kind of framework?
horizontal framework
42
Bearing walls, columns, and girders can be classified as what type of structural members?
primary
43
Ridgepoles, hip rafters, headers, and trimmer floor beams can be classified as what type of structural members?
primary
44
Which type of collapse is more destructive...column or beam?
column
45
What type of stair is an opening in a floor slab for between floors (sometimes called access stair)?
convenience stair
46
What is the top masonry tile or stone in a parapet wall that is designed to carry off rain water (sometimes called capstone)?
coping stone (can weigh 5-50 lbs)
47
What is a bracket or extension of masonry that projects from a masonry wall?
corbel
48
What are the four flanking zones called around a burning building?
corner safe areas
49
What is a bend, twist, or curve of a structural element under a load called?
deflection
50
Deflections should be reported to who?
officer in command
51
What is the front or face of a building called?
facade
52
What are the four collapse dangers of a facade?
marquee
cornice
canopy
parapet wall
53
What is a gravity support beam end that is designed to release itself during a fire?
fire cut beam
54
How is the fire cut beam good and bad?
advantage for those operating outside
| disadvantage for those operating inside
55
What is the measure of max heat release when all combustible material in a given fire area is burned?
fire load
56
Structural collapse during a fire is directly proportional to what?
fire load
57
What is a RELATIVE fire rating in hours that indicates performance during a fire?
fire resistance rating
58
What type of construction was the World Trade Center?
frame tube (4" thick near bottom and 1/4" thick at top)
59
What is a structural element that supports a floor or roof beam?
girder
60
What is a total collapse called?
global collapse
61
What two loads make up the gravity load?
dead load
| live load
62
What type of support is used to reinforce an opening in the floor?
header beam
63
What is the hierarchy of building elements from least to most serious?
```
deck
beam
floor
roof
girder
column
bearing wall
```
64
Header and trimmer beams are what type of supports?
primary structural supports
65
What is the center section of an I-beam called?
web section
66
Wood i-beams have top and bottom sections that are what size?
2x2
67
The terms joist, beam, and rafter are used how?
interchangeably
68
What do you called the concealed space in between floors and is used to contain mechanical or electrical equipment?
interstitial space (aka plenum space)
69
One kip equals how many pounds?
1000 lbs
70
What is a horizontal piece of timber, stone, or steel placed over the opening in a wall?
lintel
71
An axial load passes through what point of a structure?
center
72
What is the most efficient manner that a load can be transmitted?
axial
73
Due to heat, axial loads can become what?
eccentric or torsional
74
What is a load applied at one point?
concentrated load
75
What type of load remains constant or is applied slowly?
static load
76
A FF who slowly and softly applies his weight is demonstrating the principle of?
static loading
77
Most structural elements are designed with a safety factor of what?
2 or more
78
What makes something a timber?
wood larger that 2x4
79
What do you call a partition wall that extends from floor slab to floor slab above?
demising wall
80
What type of wall is the most unstable and likely to collapse during a fire?
freestanding wall
81
What is a bearing wall that supports floors and roofs of two buildings?
party wall
82
What is the difference between the vertical collapse zone and the FD collapse zone?
vertical collapse = height of wall
| FD collapse zone = 1.5-2x height of wall
83
What is the major fire problem in a fire-resistive building?
central AC system
84
How many fire deaths in the US are caused by smoke, not fire?
3/4
85
How do you fully protect a fire-resistive high rise?
automatic sprinklers
fire walls
fire partitions
86
FF hoselines cannot extinguish fires in floor areas over what sqft?
5000 sqft
87
What is the fire problem associated with noncombustible/limited combustible building?
flat, combustible roof deck
88
What is the major fire problem in ordinary constructed building?
fire & smoke spread in concealed spaces
89
A wooden column in Heavy Timber construction must be what size?
not less than 8"
90
A wooden girder in Heavy Timber construction must be what size?
not less than 6"
91
What is the only type of construction that has combustible exterior walls?
wood-frame
92
The officer must consider the possibility of extension on how many sides of fire area?
six
93
What is the "seventh side" of wood frame buildings that has to be considered?
combustible exterior walls
94
After newly recruited FFs learn about the dangers of fire, the next most important subject is what?
building construction
95
Wood buildings often experience which two collapses simultaneously?
wall and floor
96
In ordinary construction, what collapse first...floor or walls?
floors and wall will collapse sometime later
97
What is the collapse danger in fire-resistive buildings?
concrete
98
What is becoming the most widely used construction type?
noncombustible/limited combustible
99
What is the collapse danger to a FF in a noncombustible/limited combustible building?
roof cave in
100
What is the main advantage of lightweight steel roof support?
non combustibility (doesn't add fuel to fire)...but will fail after only 5-10 minutes of heat
101
What is the structural hazard of an ordinary constructed building?
parapet wall
102
What are the structural hazards of heavy timber buildings?
falling masonry walls that crash to the ground (doesn't collapse during early stages of fire)
103
What are the structural hazards of a wood-frame building?
combustible bearing wall
104
What are the three ways that a masonry wall will collapse?
90 degree
curtain fall
inward-outward
105
What is the most COMMON type of masonry wall failure?
90 degree
106
Is a canopy more or less dangerous than a marquee?
more, because of lightweight construction
107
What is the main difference between a cornice and parapet, marquee, and canopy?
cornice will burn and spread fire
108
The area beneath a marquee, canopy, or cornice is considered to be what?
inside the building
109
Parapet walls often collapse during what stage of a fire?
overhaul
110
Who is responsible for reporting signs of structural failure?
all FFs
111
Failure of what is the leading cause of FF death by collapse?
floor
112
Fire resistance of a floor is directly related to its what?
mass
113
What are the three ways all floors fail?
floor deck
floor beam
multilevel floor (most dangerous)
114
A building with frontage greater than what will normally have columns and girders rather than just two bearing walls?
>25'
115
What is the tactic to protect FFs from floor deck collapse?
sound the floor
| keep one leg outstretched to reduce weight
116
What is the tactic to protect FFs from floor beam collapse?
use the reach of hose streams
117
What is the tactic to protect FFs from multilevel floor collapse?
withdraw
118
Floors may have fire resistance ratings of 1,2,3, or 4 hours. However FFs must realize what?
fire resistance rating has NOTHING to do with collapse (there is no test for collapse resistance)
119
What are three other reasons to ignore fire resistance rating?
large sections act different than small test sections
installation requirements are not always followed
real fire may be hotter than test fire
120
After a fire rages for hours, who should be called?
structural engineers
121
If FFs are withdrawn from high rise, you should continue to what?
supply sprinklers
| use master streams
122
What are the three reoccurring factors that contribute to floor collapse?
vacant buildings
renovated buildings
overloaded buildings
123
The most dangerous time for floor collapse is when?
decay stage (end of the fire)
124
The history of multilevel floor collapse says the risk is highest when doing what?
salvage/overhaul
125
What is the alternative to interior salvage/overhaul?
hydraulic or defensive overhauling
126
What are the three most common type of sloped roofs?
gable
hip
gambrel
127
How many primary members with a flat roof?
2 (bearing walls)
128
How many primary members with gable roof?
3 (2 bearing walls and 1 ridge rafter)
129
How many primary members with hip roof?
9 (4 bearing walls, one ridge rafter, and 4 hip rafters)
130
The stability of a roof deck depends on what two things?
number of purlins running perpendicular
| spacing of trusses
131
Which roof has largest area of unsupported decking?
truss roof
132
What is the safest roof to walk on?
rafters (closest together)
133
Roof rotting is often found where?
at roof edges
134
Roof coverings can be divided into what two categories?
```
built up (ex. tar/gravel)
prepared (slate, tile, asphalt, etc.)
```
135
Can a high-pitched roof, like and A-frame or English Tudor be worked on safely even with a roof ladder?
NO
136
A roof ladder cannot protect a FF from what type of collapse?
roof rafter collapse (only working from aerial protects FF)
137
What is the most common connector for timber trusses?
split ring (purpose to relieve shear force on bolt)
138
What is the most common shape of timber truss?
bowstring
139
The strength and stability of a truss depends on what?
smallest web member
140
What is the most dangerous roof system a FF will encounter?
truss construction (known to collapse in early stages of fire)
141
How many bearing walls does a bowstring truss roof have?
4
142
During a fire, what is key to safe operation with timber truss roofs?
early identification (can lead to defensive strategy)
143
Bowstring truss roof fires should tell chiefs to listen to reports from who?
those above fire...NOT below
144
In a timber truss roof, the main fire will be where?
roof structure...NOT contents
145
The fire strategy of the first arriving engine at a timber truss roof should be to what?
attack fire directly with LDH that can reach 50' (if it doesn't work in first few seconds, FFs should be withdrawn)
146
The only truss identification that can be made by shape is which?
bowstring
147
How do you quickly determine if fire has spread to bowstring truss?
triangular cut in front or rear slope from aerial
148
What is the key to operating at a fire in a truss constructed building?
communication
149
The large open space required in a place of worship usually means what type of roof?
timber truss
150
What is the most unstable part of places of worship?
tower and steeple
151
How many chances do you get to extinguish church fire?
one
152
At a church fire, what should the second LDH do?
immediately back up first line
153
As soon as flames in a church are knocked down, what should be checked?
walls and attic
154
Where should the first aerial ladder be positioned at a place of worship?
rose window
155
What are the most dangerous sides to a burning place of worship?
A,B,D
156
Where is primary venting done at a place of worship?
rose window
157
What is a semi-circle or U shaped wall?
apse
158
What is masonry built against a wall for added support?
buttress
159
What is a space reserved for clergy?
chancel
160
What is the main seating area
nave
161
What is the space at the right angle to the nave and chancel?
TRANSEPT (125)
162
When a fire building has a steel bar joist roof system, what type of ventilation is preferred?
horizontal ventilation ahead of hoselines
163
A FF who becomes disoriented by smoke while on a roof should do what?
get on hands and knees and crawl
164
Steel starts to distort at what temperature?
1000-1100 degrees
165
What temperature is required to melt steel?
2400 degrees
166
Fire is a typical structure can reach what temp?
1700 degrees
167
What are the three ways to protect steel?
encase in concrete
membrane ceiling
SFRM
168
From a FFs point of view, what is the best method for protecting steel?
concrete encasement
169
What is the least effective way of protecting steel?
SFRM
170
Open web steel bar joists can be spaced how far?
up to 8' (wide spacing allows FFs to fall through vent holes)
171
What is the principle danger to a FF in a noncombustible/limited combustible structure?
potential for early collapse
172
At 1100 degrees, steel loses how much of its load carrying capacity?
40%
173
A roof designed only to support a snow load may have a load capacity of what?
20 lbs/sqft
174
Type 2 buildings are designed for what type of occupancies?
low hazard (low fire load) ie. schools, offices, retail shops
175
In order to make steel fire resistive, you must what?
protect it
176
What is the strategy for firefighting in a lightweight wood truss roof building where there is content involvement OR structure involvement?
contents - stretch interior hoseline and extinguish fire
| structure - withdraw and use exterior attack
177
Does a directly affixed ceiling collapse in small pieces or large chunks?
small pieces...usually caused by water absorption
178
What is the most dangerous type of ceiling?
suspended
179
What three occupancies are most likely to have suspended ceilings?
stores
top floor of multiple dwelling
renovated buildings
180
What part of a suspended ceiling traps or pins FFs in a burning building?
grid system
181
How do you reduce the danger of suspended ceiling collapse?
prevent extension into concealed space above it
182
What is the most important first step for the rescue of a FF trapped beneath a suspended ceiling that has collapsed?
sweep the area with a hoseline
183
What is the safest area in a wooden interior of a building?
stairway (also best avenue for initial attack)
184
What is a straight run stair most often constructed of?
wood or concrete
185
What is an L shaped stair constructed of and where is it most often found?
wood / private homes
186
What type of stair is preferred in modern building construction?
U return stair
187
What is the safest type of fire escape?
exterior screened stairway
188
How wide is the exterior screened stairway?
wide enough for 2 people to descend side by side
189
If a FF sees a young child or elderly person standing on a fire escape, they should consider it what?
life hazard (bring them through window under fire and taken down interior stairway)
190
What is the most frequent cause of injury to FFs on standard fire escapes?
falls and step collapse
191
Does the inward/outward collapse give any warning signs?
generally no...sometimes the only clue is a fire burning for a long time on the lower floor
192
Which type of collapse is most dangerous?
inward/outward because it happens suddenly
193
Of the three major types of construction in the US, which present the greatest firefighting danger?
braced frame wood buildings
194
The first large wood frame buildings on the east coast were what type of constructions?
braced frame (aka post-and-girt)
195
What is the danger in lightweight wood truss constructions?
early floor and roof collapse
196
Where does a braced frame constructed building fail?
mortise & tenon connection (weakest point)
197
Older buildings are renovated under what type of building codes?
"performance" codes NOT spec codes
198
How does NFPA classify buildings under construction?
"special occupancy structures"
199
If a fire is threatening a crane, how large should the collapse zone be?
height of crane
200
How far must worker "shanties" be from a building under construction?
30 feet (should be considered a target hazard)
201
What is the recommended strategy for fires in formwork that supports floors?
outside aerial master streams
202
In most states, laws require a vertical standpipe be installed in any building under construction that rises above how many feet or floors?
75 feet or seventh floor
203
If the fire companies report all control valves in a standpipe are closed and there is still no water, what should be checked?
cellar outlet valve
204
The successful firefighting operation in a building under construction depends greatly upon what?
pre-plan inspection
205
When is the best time to do a pre-plan inspection of a building under construction?
weekend
206
A FD large caliber master stream is one that can deliver how much water?
>300gpm
207
The average master stream delivers 500gpm which weighs how much?
4000 lbs/minute
208
What sound does a master stream make on a brick wall?
splattering
209
What sounds does a master stream make on a wood building?
drumming
210
What does the sound of a distant rumble mean while operating a master stream?
stream is going through a window
211
Where should a master stream be placed for a quick knockdown?
close to the window (allows for greater reach and side to side movement)
212
What are the first two priorities to consider when positioning apparatus?
1st - life safety
| 2nd - fire containment
213
Where can FFs be during a temporary knockdown strategy with a master stream?
leave structure
| go to floor below fire floor
214
One of the first actions an IC must take at a collapse site is what?
restrict access (secure the scene)
215
After surface victims have been removed from a collapse, what percentage of survivors have been found?
75%
216
When a collapse occurs during a fire, what is the first duty of the officer in command?
determine who is trapped or missing
217
What is the difference between tunneling and trenching?
trenching is slower, but safer (therefore carried out most often)
218
Who is in charge of the scene during the last step of the collapse plan called general debris removal?
fire service
219
What is more effective at monitoring a structure where a secondary collapse is possible, transit or FF?
transit
220
What is the most dangerous type of parapet wall?
ornamental cast stone wall
221
Attached two family houses that share a fire wall must be considered how many structures?
1
222
What is the most frequent last warning sign that causes the IC to withdraw FFs from a building?
large body of fire on several floors in an old building
223
When an evacuation signal is given what should a FF do?
leave all tools that would slow you down INCLUDING SCBA if there is a smoke free path to exit
224
Where should the evacuation assembly point not be located?
front of building or ICP
225
What is a Phase 3 elevator?
protects from toxic fumes, smoke, fire, and water
226
Building 7 collapse solely from what?
```
fire destruction (10 floors of fire burning 7 hours)
collapsed in 13 seconds
```
227
What is noteworthy about Building 7 and the structural hierarchy of collapse?
it was backward...went from beam to girder, to column
228
One expert at NIST states that it takes how much burn time per floor?
1.5 hours
229
There are many benefits in conducting a post fire analysis. Who is the greatest benefit to?
IC or chief doing the analysis
230
After any major fire or ordinary fire with a significant event, when should the post fire analysis begin?
immediately after extinguishment
231
What are the three parts to a post fire analysis?
fact sheet
diagram
photo documentation
232
What are two important facts of the fire analysis fact sheet?
point of origin
| cause of fire
233
When recording a burning building collapse, the FD investigator should state what?
first structure to fail
234
In addition to determining the first structure to fail, the investigator should also determine the cause of failure. If the evidence was destroyed by fire, what should the investigator state?
his subjective opinion...DON"T put unknown
235
At what stages of the fire, do MOST buildings collapse?
stage 2 - fully developed
| stage 3 - decay
236
What came first, strategies or tactics?
STRATEGIES (312-313)
237
When diagramming, the area of fire origin is pinpointed by a what?
greek cross
238
When diagramming, the area of fire damage is marked by what?
diagonal lines
239
When diagramming, the exact location of a fatality is indicated by a what?
cross
"s" is placed for supine
"p" is placed for prone
240
When diagramming, hose steams are shown as what?
line with an arrow for the nozzle
241
When diagramming, how are pumpers indicated?
rectangle (inside rectangle is company number and sequence of when placed in service at fire)
242
What is the most important part of a post fire analysis?
photographic documentation
243
What is the purpose of part 3 (photographs) of a post fire analysis?
prepare a training session
244
How many photos should be included in the slide show?
25 (one will be of the diagram from step 2)
245
How many views of each picture should be included?
2, one up close and one at a distance
246
The most important strategy and tactical consideration at a fire is what?
water supply (pressure and amount should appear on the fact sheet)
247
What is the problem with reporting of cellar fires?
often delayed alarms
248
What is a middle story of a church (side balconies)?
TRIFORIUM (125)
