Ventilation

Question 1

Ventilation accomplish 4 main objectives

Answer 1

Save lives, assist in firefighter access, control the horizontal spread of fire, reduce the possibility of flashover and backdraft

Question 2

Flashover

Answer 2

condition where all of the contents of a room a heated to their ignition temperature. once reached, the entire room will quickly be involved in flames

Question 3

Backdraft

Answer 3

In a confined area, if the structures contents reach their ignition temperature and there is not sufficient oxygen to support combustion. all that is needed is oxygen to explosively change the superheated area into a inferno

Question 4

Horizontal ventilation

Answer 4

systematic removal of heat, smoke and fire gases through openings such as doors and windows

Question 5

Vertical ventilation

Answer 5

is the opening of the roof or existing roof openings (skylights, hatch cover etc)

Question 6

Heat hole

Answer 6

a hole placed directly over the dire or as close to the fire as safety will allow

Question 7

Strip ventilation

Answer 7

should be placed well ahead of the fire, extending the entire width of the building creating a firebreak, done in conjunction with a heat hole.

Question 8

Decking

Answer 8

material attached to the roof rafters

Question 9

Diaphragm nailing

Answer 9

plywood sheathing is installed so that the 8’ dimension of the plywood crosses the rafter or joists and the 4’ dimension parallels the rafters or joist

Question 10

H clips

Answer 10

metals used to hold the butted ends of plywood together. common on pitched roofs

Question 11

Kerf cut

Answer 11

single cut made through the roof decking. the same width as the chain saw blade

Question 12

Plug cut

Answer 12

Is a small triangular piece composition which is removed from the roof to expose the roof sheathing

Question 13

Plug cut determines

Answer 13

sheathing type and roof composition thickness

Question 14

Score cut

Answer 14

light cut of the roof covering, usually composition only. Used to remove multiple layers of composition

Question 15

Skim cut

Answer 15

a light cut made with the chain saw. no deep enough to cut rafters

Question 16

Smoke indicator hole

Answer 16

small triangular hole cut through the roof decking

Question 17

Ventilators

Answer 17

30% more effective when spinning. Do not remove

Question 18

45 degree inspection cut

Answer 18

will tell you rafter type, direction, sheathing, thinking of composition.

Question 19

45 degree inspection cut

Answer 19

cut at 45 degree angel toward or away from any exterior wall. when contact with a rafter. roll and continue for 6 to 10 inches