Chapter 5

Question 1

Water may be used on combustible liquids that whose specific gravity is?

Answer 1

Higher than 1, to smother fires in combustible liquids

Question 2

What does the first principle of pressure state?

Answer 2

Pressure exerted by the weight of water is perpendicular to the walls of the container

Question 3

What does the second principle of pressure state?

Answer 3

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

Question 4

What does the third principle of pressure state?

Answer 4

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

Question 5

What does the fourth principle of pressure state?

Answer 5

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

Question 6

What does the fifth principle of pressure state?

Answer 6

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

Question 7

What does the sixth principle of pressure state?

Answer 7

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

Question 8

When is atmospheric pressure greatest?

Answer 8

Atmospheric pressure is greatest at low altitudes and least at very high altitudes. Sea level is 14.7 psi which is considered standard atmospheric pressure.

Question 9

Any pressure less than atmospheric pressure is called? What is absolute zero called?

Answer 9

Vacuum
Perfect vacuum

Question 10

In the fire service the term head refers to?

Answer 10

The height of a water supply above the discharge orifice

Question 11

What is elevation?

Answer 11

The center line of the pump or the bottom of a static water supply source above or below ground level.

Question 12

What is altitude?

Answer 12

The position of an object in relation to sea level

Question 13

Does height above or below sea level make the pumper have to work harder to produce the pressures required for effective fire streams?

Answer 13

Above sea level makes the pressure drop which makes the pumper have to work harder

Question 14

The friction loss in older hose may be as much as how much percent greater than new hose?

Answer 14

As much as 50% greater

Question 15

What does the first principle of friction loss state?

Answer 15

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

Question 16

What does the second principle of friction loss state?

Answer 16

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

Question 17

What does the third principle of friction loss state?

Answer 17

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

Question 18

What does the fourth principle of friction loss state?

Answer 18

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

Question 19

There is much less pressure loss in a water distribution system when fire hydrants are ?

Answer 19

Supplied in two or more directions

Question 20

At least how often should water main valves be operated to keep them in good condition?

Answer 20

Once a year

Question 21

What are the two common types of indicator valves?

Answer 21

post indicator valve (PIV) and the Outside stem and yoke valve (OS&Y)

Question 22

What are the most common type of valves used on most public water distribution systems?

Answer 22

Nonindicating valves

Question 23

Where are nonindicating valves normally located? And how can you operate them?

Answer 23

Usually are in manholes or valve boxes, below grade valves if properly installed can be operated above ground with a special socket wrench on the end of a reach rod

Question 24

If valves are installed according to established standards it will be necessary to close off how many hydrants from service while a single break is repaired?

Answer 24

Only one perhaps two fire hydrants

Question 25

Water pipes that are used underground are generally made of?

Answer 25

Cast iron, ductile iron, asbestos cement, steel, plastic, or concrete

Question 26

The fire department should do what before flushing hydrants in no emergency situations?

Answer 26

Fd should coordinate with the local water authority before flushing hydrants in no. Emergency situations. This may cause customers to receive rusty or foul smelling water for a period of time.