Ventilation

Question 1

According to book 29, when performing positive pressure ventilation, removing window screens will increase efficiency by how much?

Answer 1

50% more effective

Question 2

According to book 29, concentrates of carbon monoxide can easily reach how many ppm during overhaul?

Answer 2

500-1200 ppm

Question 3

What are the 4 objectives of ventilation?

Answer 3

• save lives
• assist in firefighter access
• control horizontal spread of the fire
• reduce possibility of flashover or backdraft

Question 4

What is a kerf cut?

Answer 4

Single cut the diameter of the blade through the decking

Question 5

How many inches inside of purlins should cuts be made to avoid metal hangers?

Answer 5

4-6”

Question 6

According to book 29, plans for ventilation operations should begin by doing what?

Answer 6

Identifying the direction contaminants must travel to exit the area

Question 7

Where is the blower placed when performing NEGATIVE pressure ventilation?

Answer 7

INSIDE the structure

Question 8

Positive pressure ventilation is how much more effective than negative pressure?

Answer 8

2 times

Question 9

Positive pressure ventilation is most effective when the exhaust opening is what size of the entrance opening?

Answer 9

3/4 to 1 3/4

Question 10

During positive pressure ventilation, what is an indicator that the exhaust opening is not large enough?

Answer 10

Exhaust odor in the area that needs to be ventilated

Question 11

Positive pressure ventilation is effective against winds of what speed?

Answer 11

25 mph

Question 12

When using blowers in series, what blower shall be placed in front and how far from the entrance? How much more effective does the front blower become?

Answer 12

Large blower in front

2 feet from opening

10% more effective

Question 13

What concentration of CO can be fatal in less than 1 hour?

Answer 13

4000 ppm

Question 14

Positive pressure should never be used in place of what?

Answer 14

SCBA in hazardous atmospheres

Question 15

According to book 29, what is the key to safe and effective vertical ventilation?

Answer 15

Knowledge of rafter type and direction

Question 16

When is a center rafter cut used?

Answer 16

When cutting plywood. Used to create largest hole with fewest cuts.

Can also be used to cut a strip on roofs using 1”x6” sheating

Question 17

What are H clips and what type of roof are they common on?

Answer 17

H clips are using to join the butted ends of plywood together

Common on steep pitch roofs

Question 18

What method is used to remove decking once it has been cut?

Answer 18

“J” hook

Question 19

What should constantly be evaluated during roof cutting operations?

Answer 19

Risk vs gain

Question 20

What cut is used to determine sheating type and thickness of roof composition?

Answer 20

Plug cut

Question 21

What is the difference between a score cut and a skim cut?

Answer 21

Skim cut cuts through decking

Score cuts through composition but not decking

Question 22

According to book 29, smoke indicator holes should be placed where and how often?

Answer 22

Along the path of egress every few yards

Question 23

Turbine ventilators are how much more effective when the are spinning?

Answer 23

30%

Question 24

When cutting a 45 degree inspection cut, how far should you extend the cut after rolling the rafter?

Answer 24

6-10”

Question 25

When dicing, after what cut can the pullers start pulling?

Answer 25

3rd cut

Question 26

How many bays should be left between the cutter and the puller before the puller starts pulling?

Answer 26

1

Question 27

What is the 3rd cut of a center rafter louver?

Answer 27

Bottom cut

Question 28

When extending center rafter louvers, how far inside the rafters should your parallel cuts be? How long should it be?

Answer 28

2-3”

3’6” long

Question 29

The small 18” blower is adequate for a single family dwelling how many square feet?

Answer 29

2,000