17 Collapse Caused by Master Stream Operations

Question 1

A typical master stream delivers ______ gpm?

Answer 1

500 to 1,000

Question 2

Fog streams with a delivery rate of more than ________ and a solid-stream nozzle of __________ or more in diameter are considered large-caliber stream nozzles.

Answer 2

300 gpm / 1 1/2 inch

Question 3

The average (master) stream delivers 500 gpm into a burning building, which equals __________ a minute.

Answer 3

4,000 pounds

Question 4

The most serious collapse danger of a large-caliber stream is caused by the _______________ it discharges into a burning building.

Answer 4

large volume of water

Question 5

Firefighters need to understand the following principles of control and direction of large caliber streams:

Answer 5

1. Weight of water - pouring 2 to 4 tons of water a minute into a building
2. Dangers of the upper portion of building - Upper portions of old structures, such as chimney tops, parapet walls and cornices, may be structurally unsound and present a collapse danger even before a fire occurs

Question 6

At a fire where smoke reduces visibility to zero in the street, FFs must rely on the __________ of the large-caliber stream striking objects to determine its effectiveness.

Answer 6

Sound

Question 7

There are two strategies for master streams.

Answer 7

1. Using master stream for a temporary knockdown of a large body of flame.
2. Exterior master stream attack used for final extinguishment.

Question 8

After master streams have been used to extinguish a fire, _________________ becomes a dangerous strategy because of the collapse danger.

Answer 8

Overhauling

Question 9

Before any FF is ordered to re-enter the burned-out, smoldering, water-soaked structure to overhaul, the following safety actions should be taken.

Answer 9

1. Allow building to drain
2. Safety Officer should conduct a safety survey.

Question 10

The Safety Officer should look for these warning signs:

Answer 10

1. Broken stair treads and cracks in the marble intermediate landings
2. Floor and ceiling sagging due to the weight of water
3. Fire damage to steel columns and girders that are twisted, warped, bent, or elongated.
4. The presence of trusses and/or lightweight steel bar joist or wood I-beam construction
5. Water accumulations and heavy machinery
6. Water-absorbing content (paper bales, baled rags, plumbing supplies

Question 11

The safe transition from interior to exterior attack requires 4 elements:

Answer 11

1. Effective communication
2. An interior sector who has effective command and control over the FF
3. A pump operator who waits for the order to start water from the IC and does not prematurely start water to the master stream
4. An IC who understands the priorities of fireground safety - protections of life first, fire containment second, and property conservation last.