Chapter 17 Collapse Caused By Master Stream Operations

Question 1

A fire department large caliber stream (master stream) is a ground-based or aerial device with a fog or solid stream capable of delivering more than __

Answer 1

300 GPM, typically master strings deliver 500 to 1000 GPM

Question 2

what are three changes in design and use of large caliber streams, that have increase their effectiveness

Answer 2

1. hose diameter supplying water has increased
2. radio communications /mutual aid agreements
3. most importantly, large caliber streams are no longer restricted to the ground they can be elevated 50-100 feet above street level

Question 3

where is the nozzle pressure of a large caliber stream the greatest

Answer 3

closest to the nozzle, therefore operations that place the master stream nozzle close to buildings can be hazardous

Question 4

what is the most serious collapse hazard of a large caliber stream

Answer 4

the large volume of water it discharges into a building 500 GPM equals 2 tons of water per minute
absorbed water collapses buildings

Question 5

firefighter should understand the principles of control and direction for large caliber streams

Answer 5

1. weight of water- two tons per minute
2. dangers of upper portions of buildings- ( chimney tops, parapet wall) may be unsound to start, before deck gun sweeps them
3. to tons of water equals 4000 pounds, discharged and 100 ft./s at 100 psi

Question 6

a roof surrounded by parapet walls on all four sides is prone to what

Answer 6

water buildup

Question 7

what is the sound of a large master stream striking a brick wall, of wooden building, an open window

Answer 7

splattering
drum
distinct rumble

Question 8

what is the collapse zone for an aerial master stream

Answer 8

the tip of the aerial platform basket should be kept away from the weekend wall at a distance greater than the height of the wall above the bucket floor

Question 9

when an aerial master stream is to be used for quick knockdown where’s the master stream most effective

Answer 9

when placed close to the window of the building for deep penetration in the widest range inside of the floor area

Question 10

what is the hazard associated with placing the master stream nozzle close to the window of the building

Answer 10

when there is a danger of structural collapse, no part of the aerial string bucket and or nozzle should be position where it could be struck by falling wall

Question 11

what is the concern with a master strain into the window of a renovated building

Answer 11

if not enough distance between the front and back wall of the master stream may have sufficient force to collapse the room wall, if the stream travels through unimpeded

Question 12

when there is a danger of wall collapse with explosive force beyond the normal collapse zone…. where should firefighters operate streams

Answer 12

from flanking zones

Question 13

how are large caliber strains useful for fighting the spread of fire through concealed space above a suspended ceiling

Answer 13

large caliber streams directed from below can break into the ceiling exposing flame above

Question 14

what are the two strategies for master stream use

Answer 14

1. use the master stream for temporary knocked down a large body of flame
2. exterior master stream attack use for final extinguishment