Chapter 6 Wood Floor Collapse

Question 1

The leading cause of firefighter death by collapse

Answer 1

floor collapse

Question 2

structural hierarchy of floor system

Answer 2

bearing wall/column
girder
floor beam
floor deck

Question 3

lightweight truss floors

Answer 3

wood truss, wood laminated I-beam, lightweight cold formed steel C floor beams, open web bar joist

Question 4

three ways floors can fail during a fire

Answer 4

1. deck may burn through, leaving supporting joist
2. floor beams collapse, joist fail causing localized
3. multilevel floor collapse, progressive collapse

Question 5

A building with a frontage of ___ feet or more usually have columns and girders

Answer 5

25ft

Question 6

multiply floor collapsed most often happens in buildings that have ____

Answer 6

columns and girders

Question 7

what are the three strategies and tactics that can protect firefighters from floor collapse

Answer 7

1. sound the floor… deck collapse
2. use the reach of the hose stream… floor beam collapse
3. withdrawal firefighters… multi-level floor collapse

Question 8

what is one way and incident commander can use a fire resistive rating?

Answer 8

use the hourly designation as a time limit for interior operations…. and as a guideline for occupant evacuation

Question 9

there are three re-occurring factors that contribute to floor collapse in a burning building

Answer 9

1. vacant buildings
2. renovated buildings
3. buildings overloaded with heavy machinery or dense content

Question 10

what is the most dangerous time for floor collapsed during a fire

Answer 10

at the end of the fire the decay stage, after it’s been extinguished