Dunn - Chapter 15, 16 & 17

Question 1

What are the three ways that a wood frame building can collapse during a fire?

Answer 1

a) 90 degree angle
b) Lean over
c) Inward-outward collapse

Question 2

How is a 90 degree angle wall collapse signaled?

Answer 2

By the corners of the falling wall splitting apart from the remaining walls.

Question 3

How is a lean-over collapse indicated?

Answer 3

By the burning structure SLOWLY starting to tilt or lean to one side.

Question 4

Which collapse is the most dangerous?

Answer 4

The inward-outward collapse is the MOST DANGEROUS because it is sudden, it gives no visible warning signs prior to failure and unlike most other building failures, it may involve the collapse of two, three or four walls SIMULTANEOUSLY.

Question 5

What are the corner safe areas?

Answer 5

They are the four flanking zones around a burning wood frame building.

Question 6

Which type of wood constructed building presents the GREATEST firefighting danger?

Answer 6

Braced-frame wood constructed buildings.

Question 7

If a fire weakened the bearing wall studs of all three floors AT THE SAME TIME, what would occur?

Answer 7

The GROUND floor wall studs would fail first.

Question 8

What are the four most widely used methods of wood-frame construction over the past 200 years?

Answer 8

a) Braced frame
b) Balloon frame
c) Platform frame
d) Lightweight wood frame construction

Question 9

Braced frame construction

Answer 9

Sometimes called “post & girt” construction.
Vertical timbers called “posts”
Horizontal timbers called “girts” (found at each floor level)
Connected together by MORTISE & TENON joints.

Question 10

What is an indication of “balloon frame” construction?

Answer 10

The unobstructed opening b/t each stud in the exterior wall, extending from the foundation sill to the attic cap, is an indicator of balloon construction.

Question 11

Platform construction

Answer 11

The MOST widely used method of wood-frame construction.
Platform construction is SUPERIOR to balloon or braced frame construction because there are no concealed wall voids that extend for more than one floor.

Question 12

L/W wood truss construction

Answer 12

It is INFERIOR construction

It suffers floor and roof collapse.

Question 13

What is the danger of L/W wood truss construction?

Answer 13

The danger is early floor and roof collapse of the truss floors and roofs.

Question 14

What are the three contributing causes of wood-frame building collapse?

Answer 14

1) Fire destruction of bearing walls,
2) The mortise & tenon joint of a braced-frame wooden building
3) The overload of an exterior wooden wall.

Question 15

During a fire in a building under construction that is exposing the crane, what should the size of the collapse zone be?

Answer 15

A collapse zone EQUAL TO the height of the crane must be set up.

Question 16

What is “Spalling” collapse?

Answer 16

The failure of the outer layers of concrete, caused by the rapid heating of moisture inside the concrete.

Question 17

In some “fast track” construction projects, one concrete floor is poured every?

Answer 17

48 hours.

Question 18

How many days does it take for concrete to reach its MAXIMUM STRENGTH?

Answer 18

27 days.

Question 19

When do most serious fires in a building UNDER CONSTRUCTION and the MOST SERIOUS floor collapses occur?

Answer 19

They occur during a fire in the formwork.

Question 20

Worker shanties in buildings under construction are required to comply with what regulations?

Answer 20

a) Non-combustible construction
b) At least 30’ from the building under construction
c) Cannot be grouped together.

Question 21

What is the recommended strategy to extinguish fires in formwork supporting floors?

Answer 21

The use of outside aerial master streams.

All F/F’s should be removed from the building during this operation.

Question 22

What is the major cause of fire extension of a framework fire in a cast-in-place building under construction?

Answer 22

Burning timbers.

They will also be blown around and dropped down onto exposures and smaller building causing incipient fires.

Question 23

Where is the destructive pressure of a large caliber stream the greatest?

Answer 23

In the area where the water leaves the nozzle.

Question 24

What is the most serious collapse danger of a LCS?

Answer 24

The large volume of water it discharges into a burning building.

Question 25

When a LCS strikes a BRICK WALL in smoke……

Answer 25

It makes a “SPLATTERING” sound made by the stream striking the wall.

Question 26

When a LCS strikes the sidewall of a WOODEN building….

Answer 26

A “DRUM” sound is made by the stream striking the wall.

Question 27

When a LCS stream enters a window……

Answer 27

The sound of the LCS is REDUCED and only a distant rumble is heard.

Question 28

A collapse zone is the distance away from the wall……..

Answer 28

a) Equal to one
b) One and a half
c) Two times the height of the unstable wall.