Chapter 15 Pressurized Ventilation

Question 1

What are the two basic types of pressurized ventilation?

Answer 1

Positive and Negative pressure

Question 2

Name four factors that are essential to effective PPV

Answer 2

The proper use of an entrance opening
The size and location of an exhaust opening
controlling the flow of pressurized air
and appropriate training and communication

Question 3

What determines the proper distance between a blower and an entrance?

Answer 3

The distance necessary to seal the opening with a pressurized cone of air

Question 4

When using two blowers of unequal size in the inline position to seal an entrance with pressurized air, where should the larger blower be positioned?

Answer 4

Approximately two feet back from the entrance opening

Question 5

With respect to PPV, what is the definition of sequential ventiliation?

Answer 5

Ventilating specific areas in a strategic sequence that will maximize the flow of pressurized air through a contaminated area and minimize the time required for ventilation.

Question 6

How can Carbon Monoxide from gasoline-powered blowers be eliminated?

Answer 6

By using exhaust tube extensions on the exhaust muffler

Question 7

Normally, where should pressurized ventiliation begin in multiple story buildings?

Answer 7

Start at the lowest contaminated levels and ventilate toward the upper contaminated levels

Question 8

Why can stratification be detrimental to natural ventilation operations?

Answer 8

The stratification of smoke and fire gases can cause the porducts of combustion to bank downward, contaminating additional areas of the building.

Question 9

Name some advanteds of using PPV during overhaul

Answer 9

A flow of fresh, cool air will reduce heat, humidity, and the accumulation of toxic gases

Question 10

When implementing PPV, is the exhaust opening created before of after the entrance?

Answer 10

Always before the entrance opening

Question 11

What is the primary goal of ventilation?

Answer 11

to reduce contaminants in confined areas

Question 12

How large should the exhaust opening be to maximize the efficiency of the PPV?

Answer 12

.75-2.0 times the size of the entrance opening

Question 13

What is the key to effective PPV?

Answer 13

controlling the entrance and exhaust portals as well as the path of the airflow

Question 14

PPV has proved effective against winds of up to how fast?

Answer 14

about 25 mph

Question 15

Removing screens on windows can improve PPV effectiveness by what percent?

Answer 15

50 percent

Question 16

How far can PPV be effective in a confined area?

Answer 16

up to 1000 ft.

Question 17

Fire can generate pressures how many times greater than atmospheric pressure?

Answer 17

3 times greater

Question 18

Cross-ventilation operations can be effective on buildings up to how many floors?

Answer 18

up to 25 floors

Question 19

PPV can reduce CO concentrations from 1000 PPM to what?

Answer 19

130 ppm-220ppm

Question 20

How much CO (ppm) can a single gasoline-powered blower introduce into a structure?

Answer 20

140ppm-160ppm

Question 21

How much CO can a typical person inhale over an 8 hr period?

Answer 21

50ppm

Question 22

How much CO, when consumed over an hour, can be dangerous?

Answer 22

1000 ppm-1200ppm

Question 23

What levels of CO are fatal if inhaled in less than an hour?

Answer 23

4000 ppm

Question 24

How much CFM should a blower be to be most effective?

Answer 24

7,000-10,000 cfm

Question 25

When using PPV fans on a dumpster fire, how far away should you place the fan?

Answer 25

8-10 ft. away

Question 26

PPV can reduce the core temp of personnel by how much during supression operations?

Answer 26

as much as 5 degrees

Question 27

What is indicated when exhaust of gasonline powered blowers are detected?

Answer 27

exhaust openings are too small