Chapter 5 - Principles of Water

Question 1

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

Answer 1

62. 4 lb/cu ft

8. 3 lb/gal

Question 2

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

Answer 2

212*F

1,700

Question 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

Answer 3

Pressure

Size

Question 4

First Principle of Water

Answer 4

Fluid pressure is perpendicular to any surface on which it acts

Question 5

Second Principle of Water

Answer 5

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

Question 6

Third Principle of Water

Answer 6

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

Question 7

Fourth Principle of Water

Answer 7

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

Question 8

Fifth Principle of Water

Answer 8

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

Question 9

Sixth Principle of Water

Answer 9

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

Question 10

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

Answer 10

14.7 psi

Question 11

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

Answer 11

Vacuum

Perfect Vacuum

Question 12

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

Answer 12

Head

Question 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).

Answer 13

2.304

Question 14

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

Answer 14

Static Pressure

Question 15

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

Answer 15

0.434 psi

Question 16

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

Answer 16

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

Question 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.

Answer 17

Residual Pressure

Question 18

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

Answer 18

Flow Pressure.

Question 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.

Answer 19

Elevation

Altitude

Question 20

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

Answer 20

Elevation pressure

Question 21

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

Answer 21

0.5 psi

1,000 feet

Question 22

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

Answer 22

Friction Loss

Question 23

The following causes friction loss in a fire hose:

Answer 23

> 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

Question 24

First Principle of Friction Loss

Answer 24

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

Question 25

Second Principle of Friction Loss

Answer 25

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)

Question 26

Third Principle of Friction Loss

Answer 26

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.

Question 27

Fourth Principle of Friction Loss

Answer 27

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

Question 28

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

Answer 28

30,000 psi

1%

Question 29

There are three methods of moving water in a system.

Answer 29

> Direct Pumping System
Gravity System
Combination System

Question 30

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

Answer 30

Dead-End Hydrant

Question 31

A grid system should consist of the following components:

Answer 31

> Primary Feeders
Secondary Feeders
Distributor

Question 32

Large pipes, with relatively widespread spacing, that convey large quantities of water to various points of the system for local distribution to the smaller mains.

Answer 32

Primary Feeders

Question 33

Network of intermediate-sized pipes that reinforce the grid within the various loops of the primary feeder system and aid the concentration of the required fire flow at any point.

Answer 33

Secondary Feeders

Question 34

Grid arrangement of smaller mains serving individual fire hydrants and blocks of consumers.

Answer 34

Distributors

Question 35

The ___________ is the average amount of water used per day based on the total amount of water used in a water distribution system over the period of one year.

Answer 35

Average Daily Consumption (ADC)

Question 36

The ____________ is the maximum total amount of water that was used during any 24-hour interval within a 3-year period.

Answer 36

Maximum Daily Consumption (MDC)

Question 37

The ____________ is the maximum amount of water used in an 1-hour interval over the course of a day.

Answer 37

Peak Hourly Consumption (PHC)