Chapter 8 Timber Truss Roof Collapse

Question 1

What did the tragic timber truss trilogy illustrate about fires in buildings with timber truss construction

Answer 1

truss collapse can push out masonry wall on FFers
ffers can fall through the collapsed truss roof
ffers can be crushed by collapsing truss roof

Question 2

what is a timber

Answer 2

wooden construction larger than 2 x 4 but not large enough to be classified heavy timber

Question 3

what is the most common design of a timber truss?

Answer 3

bowstring truss

Question 4

what is the most dangerous roof system a firefighter will encounter

Answer 4

truss construction.. known to collapse during early stages of fire and will often cause subsequent collapse of front or rear masonry wall

Question 5

a building with bowstring truss construction has how many bearing walls

Answer 5

4

Question 6

a firefighter who discovers any type of truss in the building should immediately do what

Answer 6

informed command

Question 7

in a timber trust building where will the main fire be located?

Answer 7

in the roof structure, not the content below

Question 8

what are the three size up indicators of the trusts roof in the building?

Answer 8

1. open space without columns
2. mounted roof shape
3. certain occupancies frequently use truss construction, such as supermarkets, bowling alleys, garages, theaters, places of worship, dealerships, piers and armories

Question 9

when a fire extends to a timber truss attic space how should firefighters prepare?

Answer 9

prepare for defensive outside attack and protect exposures

Question 10

what is the fire strategy of the first arriving engine company at a timber truss roofed building without a ceiling

Answer 10

attack the fire directly with a large diameter hose line with plenty of reach (50 feet). fire should show immediate signs of extinguishment or outside attack should be ordered

Question 11

when attacking a fire in a timber Truss building when should a backup line be added

Answer 11

if the first hose line controls the fire, large backup line should be stretched to sweep the underside of the roof

Question 12

when roof stability is assured and venting is needed how should firefighters ventilate

Answer 12

firefighters can sometimes open the skylights or scuttle covers quickly and leave the roof immediately… and vent openings may be made in the front and rear sloping portions of the roof

Question 13

what is the key to safety when operating a fire in a trust constructed building

Answer 13

communications… when the truss is identified, notify command

Question 14

what are the most unstable structures in the community

Answer 14

places of worship

Question 15

at a church fire once the fire is knocked down what should be done

Answer 15

the walls and attic should be checked for concealed fire spread

Question 16

what is a strategy when attacking a church fire

Answer 16

1. first in officer sizes up fire to see if it can be extinguished by hose line
2. large attack hoseline and backup should be stretched
3. check walls and attic after fire knocked down
4. withdrawal, defensive operations if first two lines unsuccessful

Question 17

when should defensive operation set up begin at a church fire

Answer 17

while offensive attack is being initiated, if it fails defensive lines are ready

Question 18

for defensive operations at a church, where should the first aerial be position to operate?

Answer 18

in a corner safe area (A/B or A/D)with the aerial raise to the rose window

Question 19

At a church fire, if ventilation is needed to stretch the attack hose line.. how should this be accomplished

Answer 19

venting the stained-glass windows nearest the fire on both sides of the building

Question 20

when the steeple is located at the front of the structure, what should be your concern

Answer 20

the A exposure wall must be considered a collapse hazard danger

Question 21

in a church what do the wall support?

Answer 21

the roof

Question 22

because of the church steeple in the interconnected roof inside bearing walls which exposures of a church are the most dangerous during a fire?

Answer 22

A, B, D are the most dangerous

Question 23

if fire extends to the attic of a place of worship, what are your concerns?

Answer 23

the fire cannot be extinguished with handheld hose lines, severely limited access to attic space means no possibility to vent…. defensive operations