02 The Equation

Question 1

The Equation

Answer 1

EP = NP + FL + APP + ELEV

Question 2

If more than one size of hose is used, ________________ for each size will need to be figured.

Answer 2

Friction Loss

Question 3

A proper fire stream:

Answer 3

Flow enough water to quickly and efficiently extinguish the fire without causing unnecessary water damage.

Question 4

To be called a fire stream, the hose line must have a ______________ attached.

Answer 4

Nozzle

Question 5

Nozzles give a fire stream its:

Answer 5

Shape, reach, and velocity.

Question 6

Fire streams are affected by…

Answer 6

1. Discharge pressure
2. Nozzle design
3. Nozzle setting
4. Gravity
5. Wind

Question 7

Standard Nozzle PSI

Answer 7

Smoothbore - 50 psi
Fog Nozzle - 100 psi
Smoothbore Master - 80 psi

Question 8

A good solid stream is

Answer 8

1. A stream that has not lost its continuity by breaking into showers or spray
2. A stream that shoots 9/10 of whole volume inside a 15in. diameter circle and 3/4 its volume into a 10in. diameter circle at it’s breakover point
3. A stream stiff enough to attain, under fair conditions, the named height or distance, even through a breeze
4. A stream that, with no wind blowing, will enter a room through a window and strike the ceiling with enough force to splatter well

Question 9

As a general rule, the max nozzle diameter should not exceed ________ of the hose to which it is attached.

Answer 9

1/2

Question 10

Momentary Nozzle Reaction

Answer 10

When the nozzle is first opened and their is a greater nozzle reaction.

Question 11

Momentary Nozzle Reaction is about ______ higher than the nozzle reaction from the flowing stream.

Answer 11

20%

Question 12

Steam Expansion Ratios

Answer 12

Temp / Coefficient Factor
212 / 1,700:1
500 / 2,400:1
1200 / 4,200:1

Question 13

Laminar Flow

Answer 13

Relatively low velocities

Question 14

Friction Loss (FL) in a fire hose is governed by

Answer 14

1. FL varies with the quality of the hose.
2. FL varies directly with the length of the hose (measured in 100ft lengths)
3. FL varies with the square of the velocity (if velocity is doubled, FL is quadrupled)
4. For a given flow, the FL varies inversely as teh fifth power of the diameter of the hose (most important factor when limiting the effects of FL)
5. For a given velocity, FL is independent of the pressure

Question 15

FL varies with quality of hose

Answer 15

1. Thickness of inner lining
2. Age of hose
3. Weave of the jacket

Question 16

Coefficient Formula

Answer 16

FL = CQ2L

Question 17

Coefficients of Hose Sizes

Answer 17

1 3/4in = 15.5
2 1/2in = 2
3in = 0.80
4in = 0.20
5in = 0.08

Question 18

The only accurate way to figure the FL in any length of hose is to:

Answer 18

place pressure gauges on each end of the line and subtract the difference.

Question 19

How to test FL in hose

Answer 19

1. Place pressure gauges at both ends of 100ft of hose
2. Flow desired GPM
3. Subtract pressure from nozzle end from the starting end
4. Bingo. FL for the 100ft section.

Question 20

Combination Hoseline

Answer 20

Multiple hoselines that join into one or one that divides into two or more. (most common is multiple into one)

Question 21

Using multiple supply lines drops the FL.

Answer 21

Mistake people make is not dividing the GPM by the number of supply lines.

Question 22

Appliance

Answer 22

Devices designed to work in conjunction with hoses to deliver water. (Placed in middle or at the end)

Question 23

Averaged FL for various Appliances

Answer 23

Siamese - 5psi
Wye - 5 psi
Deck Gun - 10 psi
Ladderpipe - 15 psi
Standpipe System - 25 psi

Question 24

Elevation

Answer 24

Pressure created by gravity

Question 25

Back Pressure

Answer 25

Gravity working against hose line (up a hill)

Question 26

Forward Pressure

Answer 26

Gravity working with a hose line (down a hill)

Question 27

Master Stream Use

Answer 27

Volume needed is above 350pgm

Question 28

Master Stream Types

Answer 28

Monitors
Deck Guns
Elevated Platforms
Ladderpipes