Book 29 Smoke Removal

Question 1

There are two basic methods that are utilized to pressurize a contaminated area to enhance or direct the travel of contaminants to the exterior. These are ?

Answer 1

natural and mechanical positive pressure ventilation.

Question 2

Positive pressure is most efficient when the exhaust opening (heat hole, window, door, etc.) is between ____ to ____ the size of the entrance opening.

Answer 2

3/4 to 1 3/4

Question 3

Compared to negative pressure ventilation, positive pressure ventilation is approximately ____ as effective at removing contaminants from a building.

Answer 3

twice

Question 4

If it is not possible to utilize the prevailing wind as an advantage, positive pressure has proven effective AGAINST winds (leeward to windward) of up to ___ mph; efficiency will be reduced accordingly.

Answer 4

25

Question 5

In series

Larger blower in front about ___ feet from entrance

2nd blower placed far enough to seal the door.

Increases the capacity of front blower by ___%

Answer 5

2

10 percent

Question 6

In series

If the area in front of an entrance opening is limited to ____ feet or ____ feet (i.e., raised porch), place the smaller blower in the entrance opening and the larger blower three to four feet back from the door. Use the larger cone of pressurized air to seal the entrance opening.

Answer 6

3 feet or 4 feet

Question 7

Additionally, remember that removing screens on windows prior to using these openings for ventilation purposes will increase the efficiency of these openings by at least ____%.

Answer 7

50

Question 8

Disadvantages of negative ventilation

Personnel exposed to contaminates
Increased maintenance
blowers block doorway
must be placed in windows or doors
Not effective removing top of room contaminates

Answer 8

reference

Question 9

Natural ventilation

Although this method may perform satisfactorily, it is dependent on the following factors:

Proximity of the ventilation opening to the contaminants to be removed.

Ability of the contaminants to travel unobstructed to a ventilation opening.

Number and size of ventilation openings.

Direction of wind.

Humidity.

Temperature differential between the interior and exterior of a building.

Answer 9

reference

Question 10

If a gasoline powered blower is being utilized and an exhaust odor is noticeable inside the building or area to be ventilated, this is an indicator that the exhaust opening is not large enough.

Answer 10

reference

Question 11

Multi-habitational occupancies can be effectively ventilated with positive pressure by:

First, pressurizing appropriate stairways and hallways.

Second, ventilating contaminated rooms

Answer 11

reference

Question 12

Water powered blowers will produce considerably more CFM than the same size gasoline blowers and should be considered for metro rail tunnels, high rise buildings, large underground parking structures, and very large commercial buildings. They also pressurize air without carbon monoxide as a by-product and should be considered in rest homes, hospitals, and other types of structures where respiratory concerns should be considered. Water powered blowers are intrinsically safe and can be utilized at hazardous materials incidents.

Answer 12

reference

Question 13

Depending on the type of fire, concentrations of carbon monoxide within the range of 500 parts-per-million (ppm) to 1200 ppm are easily obtainable during overhaul operations.

NOTE

For comparative purposes, the following guidelines are regarded as acceptable carbon monoxide concentration standards:

to 500 ppm of carbon monoxide can be inhaled for one hour without appreciable effects.

to 700 ppm of carbon monoxide inhaled for one hour will cause some appreciable effects.

to 1200 ppm of carbon monoxide inhaled for one hour is dangerous.

Concentrations of 4000 ppm of carbon monoxide and over are fatal in less than one hour.

Measurements during actual overhaul operations have indicated that positive pressure can easily reduce carbon monoxide concentrations of 1000 ppm to approximately 130 ppm to 220 ppm.

Answer 13

reference

Question 14

A single 18” blower is adequate for an average (2000 square feet) single family dwelling.

Answer 14

reference

Question 15

If any fire does begin to accelerate or spread, it can easily be controlled by:

Extinguishing the fire.

Turning the blower 90 degrees away from opening.

Reducing the RPM of the blower.

Increasing the distance between the overhaul area and the blower.

Shutting the blower off.

Answer 15

reference