Chapter 5 - Principles of Water Flashcards Preview

IFSTA Pumping and Aerial Apparatus Driver/Operator Handbook - 3rd Edition > Chapter 5 - Principles of Water > Flashcards

Flashcards in Chapter 5 - Principles of Water Deck (37)
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1

For fire protection purposes, ordinary fresh water is considered to weigh ______ or _____.

62.4 lb/cu ft
8.3 lb/gal

2

At ____, water converted to steam occupies approximately ____ times its original volume.

212*F
1,700

3

The speed at which fluid travels through a hose or pipe is determined by the _______ upon that fluid as well as the ____ of the orifice through which it is flowing

Pressure
Size

4

First Principle of Water

Fluid pressure is perpendicular to any surface on which it acts

5

Second Principle of Water

Fluid pressure at a point in fluid at rest is the same intensity in all directions

6

Third Principle of Water

Pressure applied to a confined fluid is transmitted equally in all directions.

7

Fourth Principle of Water

The pressure on a liquid in an open vessel is proportional to its depth.

8

Fifth Principle of Water

The pressure of a liquid in an open vessel is proportional to the density of the liquid

9

Sixth Principle of Water

The pressure of a liquid at the bottom of a vessel is independent of the shape of the vessel.

10

Atmospheric pressure at sea level is ___ psi, which is considered standard atmospheric pressure.

14.7 psi

11

Any pressure less than atmospheric pressure is called _____, and absolute zero pressure is called a _____________.

Vacuum
Perfect Vacuum

12

In the fire service, ____ refers to the height of a water supply above the discharge orifice.

Head

13

To convert head in feet to head pressure, you must divide the number of feet by _____ (the number of feet that 1 psi will raise one square in column of water).

2.304

14

The water flow definition or ________ is stored potential energy available to force water through pipes, fittings, hose, and adapters

Static Pressure

15

For every 1-foot increase in elevation, ______ psi is gained.

0.434 psi

16

The difference between static pressure and normal operating pressure is ________.

The friction caused by water flowing though the pipes, valves, and fittings of the system.

17

_________ is the portion of the total available pressure not used to overcome friction loss or gravity while forcing water through pipes, fittings, hoses, or adapter.

Residual Pressure

18

While water is flwoing from a discharge opening, the forward velocity pressure is considered _________.

Flow Pressure.

19

_________ refers to the center line of the bump or the bottom of a static water supply source above or below ground level. _______ is the position of an object in relation to sea level.

Elevation
Altitude

20

The pressure losses or gains due to gravity are called ____________.

Elevation pressure

21

Above sea level, atmospheric pressure decreases approximately ___ psi for every ____ feet.

0.5 psi
1,000 feet

22

The fire service definition of ____________ is that part of the total pressure lost while forcing water through piping, fittings, fire hose, and adapters.

Friction Loss

23

The following causes friction loss in a fire hose:

>Movement of water molecules against each other.
>Linings of fire hose/delaminating hose
>Couplings
>Sharp bends/kinks
>Change in hose size or orifice by adapters
>Improper gasket size

24

First Principle of Friction Loss

If all other conditions are the same, friction loss caries directly with the length of the hose or pipe.

25

Second Principle of Friction Loss

When hoses are the same size, friction loss varies approximately with the square of the increase in the velocity of the flow.

(e.g.)
flow of 200 to 400 gpm (2^2 = 4)
3.2psi @ 200gpm = 12.8psi ub 400gpm. (3.2 x 4 = 12.8)

26

Third Principle of Friction Loss

For the same discharge, friction loss varies inversely as the fifth power of the diameter of the hose.

(e.g.)
(2.5)^5/3^5 = 97.66/243 = 0.4 that of the 2.5 inch. Therefore, the 3-inch hose has 60% less friction loss than the 2.5-inch hose.

27

Fourth Principle of Friction Loss

For a given velocity, friction loss is approximately the same, regardless of the pressure on the water.

28

With water being virtually incompressible, a pressure of _____ psi is required to reduce it volume ___ percent.

30,000 psi
1%

29

There are three methods of moving water in a system.

>Direct Pumping System
>Gravity System
>Combination System

30

A fire hydrant that received water from only one direction is known as a __________.

Dead-End Hydrant