Chapter 14 Ventilation

Question 1

Ventilation

Answer 1

is the process of removing smoke, heat, and toxic gases from a burning building and replacing them with cooler, cleaner, more oxygen rich air.

Question 2

Three products of combustion

Answer 2

1. smoke
2. heat
3. toxic gases

Question 3

Chase

Answer 3

smoke heat and toxic gases will spread horizontally, along the ceiling until they find a path such as a stair way elevator shaft.

Question 4

Mushrooming

Answer 4

as smoke accumulates it raises then banks down

Question 5

Seat of fire

Answer 5

the main area of the fire

Question 6

Backdraft is resolved with what type of ventilation?

Answer 6

Vertical Ventilation

Question 7

Mechanical Ventilation

Answer 7

used to direct the flow of combustion gases using negative and positive pressure fans

Question 8

Negative pressure ventilation

Answer 8

fans can be used to draw or pull smoke smoke through openings

Question 9

Positive Pressure ventilation

Answer 9

introduce fresh air to displace smoke and other products of combustion.

Question 10

Hydraulic Ventilation

Answer 10

Sweet spot 2-4 ft. from opening stream should cover 85-90% of opening. 30 degree power cone stream

Question 11

Convection

Answer 11

refers to the transfer of heat through a circulating medium of liquid or gas.

Question 12

Wind and atmospheric forces

Answer 12

Leeward (downwind) do not ventilate

Windward- clears room of smoke and heat

Question 13

Fire Resistive Construction Type 1

Answer 13

Hard to ventilate- Pipe chase fire spread, Leap frogging

Question 14

Leap Frogging

Answer 14

fire can also spread from one floor to another through exterior windows a phenomenon

Question 15

Ordinary Construction Type 3

Answer 15

Cock lofts (vertical vent.) , void spaces in wall plumbing and electrical chases

Question 16

Word-Frame Construction Type 5

Answer 16

newer platform frame techniques prevent spread

ballon framing spread fire lateral quickly

Question 17

Tactical priorities

Answer 17

1. Venting for Life Safety
2. Venting for Fire Containment
3. Venting for Property Conservation

Question 18

Vet. for life safety

Answer 18

helps to clear smoke, heat, and toxic gases from the structure, which gives occupants a better chance to survive and FF enabled to advance hose

Question 19

Vent. for Fire Containment

Answer 19

limits fire spread, less heat more visibility helps fire fighters to advance and extinguish fire

Question 20

Vent. for Property conservation

Answer 20

limits damages associated with smoke, heat, water and overhaul operations can all be reduced.

Question 21

Where should ventilation be located?

Answer 21

Directly over seat of fire/ through open door or window that opens outside.

Question 22

Types of ventilation

Answer 22

Horizontal (usually used on residential fires), Vertical (roofs/floors)

Question 23

Horizontal Ventilation

Answer 23

tactics- natural and mechanical
commonly used on residential fires.
1. generally fast and easy to use
2. can be used from inside or outside
3. most effective when opening is directly to outside
4. may utilize natural and mechanical method.
5. Unburned side to burned side

Question 24

Natural Ventilation

Answer 24

Depends on convection current, wind and other natural air movements to allow a contaminated atmosphere to flow out of a structure.

Question 25

Mechanical Ventilation

Answer 25

horizontal tactic that uses positive- introduces fresh air and negative pressure fans "ejectors"

Question 26

Hydraulic Ventilation

Answer 26

another form of mechanical ventilation that uses a broken fog stream, power cone to move smoke gases out

Question 27

Sounding

Answer 27

is a way to test the stability of a roof with a tool such as an axe or pike pole

Question 28

Basic indicators of roof collapse

Answer 28

1. spongy roofs 2. any visible indication of sagging 3. any indication that the roof assembly is separating from the walls such as the appearance of fire or smoke near the roof edges 4. structural failure of any portion of the building even if it is some distance from the ventilation operation 5. sudden increase in the intensity of the fire from the roof opening

Question 29

Roof covering

Answer 29

constitutes the weather resistant surface of the roof and may have several (shingles, gravel, rubber foam and metal panels

Question 30

Roof decking

Answer 30

rigid layer made of wooden boards plywood sheets or metal panels, water proof membrane and insulation.

Question 31

Gusset plates

Answer 31

2x4 wood pieces can be connected gusset plates they fail quickly in a fire

Question 32

pitched roof laths

Answer 32

thin parallel strips of wood instead of solid sheeting to support the outer covering

Question 33

Arched roofs

Answer 33

generally found in commercial structures because they create large open spans without requiring the use of columns. (bowstring 6-20 ft.) collapse is sudden and quick

Question 34

Triangular cut

Answer 34

works well on metal roof decking because it prevents the decking from rolling away as it is cut.

Question 35

Peak Cuts

Answer 35

limited to peaked roofs sheeted with plywood, 4x8 ft.

Question 36

Trench Cut (defensive ventilation tactic)

Answer 36

ventilation is used to stop fire spread in long narrow buildings such as strip malls and small storage complexes. (strip malls, tench cut creates a large opening ahead of the fire by removing a section of fuel and letting heated smoke and gases flow out of the building.

Question 37

Secondary Cut

Answer 37

used to limit the fire spread

Question 38

Primary Cut

Answer 38

located over the seat of the fire

Question 39

Concrete roof ventilation

Answer 39

difficult to ventilate, use vents skylights and other roof penetrations or horizontal ventilations

Question 40

Ventilating Metal Roof

Answer 40

discoloration and warping of this material may indicate the seat of fire. melting tar causes roof to slip

Question 41

Ventilating Basements

Answer 41

difficult to ventilate, basements generally have just a few small windows.

Question 42

Stack effect

Answer 42

can occur in high rise structures. the stack effect is a response to the differences in temperature inside and outside a building.

Question 43

Cold outside warm inside

Answer 43

smoke heat rises

Question 44

hot outside cold inside

Answer 44

smoke and heat sinks

Question 45

Ventilating Large Buildings

Answer 45

more difficult in large buildings than in smaller ones, sprinkler suppression will cool the smoke cold air fills the area it becomes more difficult to clear, clear areas one at a time.

Question 46

Roof Construction

Answer 46

1. support system truss | 2. Roof covering failure OSB, Tile

Question 47

walk on roof at what degree

Answer 47

30 degree

Question 48

roof ladder or aerial platform

Answer 48

40 degrees or more

Question 49

Smoke/heat follow what path

Answer 49

path of least resistance