Chap 8 Timber Truss Roof

Question 0

Timber is

Answer 0

Wood construction larger than 2x4 but not large enough to be classified heavy timber or mill construction

Question 1

3 ways FFs can die when operating at fires involving timber truss

Answer 1

1. Ff can be killed operating outside a burning timber truss roof when the trusses collapse and push out masonry wall , the falling roof causes a 2nd collapse of wall
2. Ff operating on the roof above burning timber truss roof
3. Ffs operating inside a burning building can be crushed and burned when collapsing truss roof falls on them

Question 2

Truss is a

Answer 2

Composition of large wooden members joined together in a group of triangles and arranged in a single plane so that loads applies at intersecting members will only cause direct stress( compression and tension)

Question 3

The timbers in truss are joined together by bolts which pass through the center of metal connectors . The most common connector is ?

Answer 3

Split ring metal connector which is. Embedded in a prepared depression on the face of the timber

Question 4

What is the purpose of the split ring metal connector in timber truss

Answer 4

To relieve the bolts that connect the trusses of shearing stress

Question 5

How many bearing walls does a timber truss roof have ?

Answer 5

4 bearing walls
End of truss sections attach to side walls
Front and rear walls support the sloping hip rafters or roof joists extend directly from from front and rear truss sections

Question 6

Why don’t rear walls in timber truss construction collapse as much as the front walls do?

Answer 6

Rear walls are more stable because of they have less openings than the front walls

Openings in a wall reduce load bearing capabilities and permit fire spread

Question 7

What is the key to safe op at a timber truss fire

Answer 7

Early identification of a truss

Question 8

3 size up indicators for truss roof in building

Answer 8

1. Large open space without columns indicates a long span roof support such as a truss
2. For bowstring trusses only - the mounded roof
   3: certain occupancies frequently use truss construction in the roof ie. supermarkets bowling alleys , places of worship

Question 9

Apse is

Answer 9

Part of the church that is semi- circle or u-shaped wall

Question 10

Chancel

Answer 10

A space reserved for clergy includes the altar and front choir

Question 11

Nave

Answer 11

Main seating area of the church

Question 12

Rose window

Answer 12

Large round window at the front of a gothic church

Question 13

Triforium

Answer 13

Middle story of the church (side balconies )

Question 14

Dome

Answer 14

Hemispherical roof on a circle tower or base

Question 15

Gothic

Answer 15

12 th century architecture , features pointed arch

Question 16

Shapes of timber truss roof

Answer 16

Inclined plane truss (gable shape roof )
Parallel cord ( flat roof )
Bowstring truss (arch roof ) most common

Question 17

What part of places of worship are the most unstable ?

Answer 17

The tower and the steeple

Chimneys next
Then free standing parapet walls

Question 18

Church fires

Answer 18

The first arriving officer should locate and size up fire
He should determine if blaze can be extinguished by a hoseline
If can extinguish, first line is taken through front or side door to attack the seat of the fire to extinguish
Stretch largest hose
2nd large diameter hose should be stretched immediately to back up first line
As soon as flames are knocked down the walls and attic should be checked of concealed fire spread
If 2 hose lines do not extinguish fire withdraw ff and fight fire from outside

Question 19

Which exposures are the most dangerous at places of worship ?

Answer 19

1- because of steeple

2 and 4 because of bearing walls

Question 20

According to Dunn the priorities of FF in places of worship are

Answer 20

1 life hazard
2 incident stabilization
3. Property protection

Question 21

Order of unstable parts of a place of worship

Answer 21

Tower with steeple,
Tower with dome
Chimneys 
Free standing walls 
Bearing walls

Question 22

Primary venting of a place of worship should be where

Answer 22

At the rose window at front of church or temple