Ch 12 Operations In Lightweight Buildings Flashcards
What is a truss? Pg 335
Allows large areas to be spanned with pieces of material that are much smaller than, and may be spaced father apart than, a standard beam.
What are lightweight steel trusses know as? Pg 335
Bar Joist
What is considered the deadliest style or roof construction per incident? Pg 337
Bowstring Trusses
What is the usual spacing between trusses, how many feet? Pg 337
20 feet
What is the collapse zone for a bowstring truss roof? Pg 338
2 1/2 times the height of the wall
What makes the flat timber truss different from the bowstring truss roof? p. 339
Exterior appearance
What size hole would open up with the failure of one truss in a bowstring truss building? p. 337
40-foot
Where does the problem lie with a metal deck roof? p. 343
Steel’s behavior
What will be a warning sign to roof firefighters if the metal deck roof is going to collapse? p. 344
The roof will sag/drop
Under which conditions do the dangers of trusses exist? p. 335
Fire
Approximately what is the maximum length that can be spanned using a standard wood beam? p. 335
25 feet
What part of the wall is pushed out when the hip rafters
fail? p. 338
Top
What is an indicator that a bowstring truss roof is present on a building?
p. 337
Hump shaped roof
What is the tool of choice when opening a building’s sidewalls to direct a stream into the truss loft?
p. 347-348
Elevating platform
Which is a primary difference between standard and lightweight construction? p. 335
Member mass
In what arrangement are the elements of the truss constructed?
p. 336
Triangles
What type of hose stream should interior crews working under the metal deck roof use to cool the steel?
p. 344
Straight
What should be the minimum collapse zone be at the end walls that have rafters resting on a truss and bearing on a wall? p. 338
2 1/2-times the height of the wall
What shape is the steel bar bent into to form a steel bar joist? p. 343
Z
What is the biggest drawback of lightweight truss designs? p. 340
Lack of mass
What is the primary hazard to the roof firefighters when operating on a metal deck roof? p. 343
Falling into the ventilation hole
Which dangerous member is marketed as a non-squeaking
floor board? p. 342
Plywood I-beam
What should be the next step taken after the fire is knocked down in a building with lightweight roof and
floors? p. 348
Assess the structure
What can be used as a guide to determine if the risk to
firefighters outweighs possibly saving the lives of occupants? p. 347
Has fire entered the voids?
Until which time was the most common construction Class 3
or Class 5? p. 335
1960’s
How far into the wood does the gusset plate penetrate into
the wood members of a truss?
p. 340
1/4 inch
What type of load does the top chord in a truss bear? p. 336
Compressive
