Water Supply

Question 1

Why is water our primary extinguishing agent?

Answer 1

Because of its availability, affordability, effectiveness. It’s easily stored and can be conveyed long distances.

Question 2

What are the 3 methods of moving water within a system?

Answer 2

• Direct pumping system
• Gravity System
• Combination system

Question 3

What are the 3 pressure measurements for hydrants?

Answer 3

• Static pressure
• Flow pressure
• Residual pressure

Question 4

What is static pressure?

Answer 4

When there is little or no water flow.

Question 5

What is flow pressure?

Answer 5

The forward velocity pressure at a discharge opening while water is flowing.

Question 6

What is residual pressure?

Answer 6

The pressure left at a hydrant while water is flowing at a nearby hydrant.

Question 7

Describe dry-barrel hydrants.

Answer 7

Used in areas with prolonged freezing periods. The main valve is located below the frost line.

Question 8

Describe a wet-barrel hydrant.

Answer 8

Used in warmer areas, always filled with water.

Question 9

What are the 4 hydrant colors and their coordinating flow?

Answer 9

Red- less than 500 GPM
Orange- 501-999 GPM
Green- 1,000 - 1499 GPM
Blue - 1,500 or more GPM

Question 10

Discuss hydrant location.

Answer 10

Generally, hydrants should not be spaced more than 300 feet apart in high volume districts. Other factors include, types of construction, types of occupancies, building densities, size of water mains and required fire flows for occupancies in a given area.

Question 11

Name a few potential problems to look for when inspecting a fire hydrant.

Answer 11

• Obstructions, posts, poles, bushes, weeds, fences
• Outlets facing the wrong way
• Not enough clearance between outlets and the ground
• Damage to hydrant
• Rust or corrosion
• Caps missing
• Frozen or freely turning stem nut
• Obstructions inside the hydrant
• Painted proper color

Question 12

Explain the process of testing a hydrant.

Answer 12

• Remove all caps, grease, check threads
• Replace all caps except one 2 1/2”
• Connect a cap type gauge to a second hydrant nearby.
• Turn the second hydrant on and record static pressure
• Turn on the test hydrant to flush out debris
• Measure flow rate/GPM and record
• record the residual pressure from second hydrant before shutting off the test hydrant
• Turn off both hydrants
• Test for vacuum with hand (dry barrel hydrant)
• Replace cap

Question 13

Discuss alternative water supplies.

Answer 13

Alternative water supplies are lakes, rivers, ponds, pools and cisterns that collect rainwater. The process of drawing water from a static source to a pumper is called drafting. Depth should be considered, use strainers (not resting on bottom).

Question 14

Discuss rural water supply operations.

Answer 14

The use of a tanker truck or engine to bring water to the scene of an incident. Portable tanks are used and drafted from.

Question 15

What are the 4 basic methods by which a tanker/tender unloads?

Answer 15

Gravity dumping
Jet dumps
Apparatus mounted pumps
Combination of these methods

Question 16

What is relay pumping?

Answer 16

The use of two or more pumper to move water over a long distance by operating them in series.

Question 17

What are the 3 key components of a water shuttle operation?

Answer 17

• Attack apparatus at the fire (dump site)
• Fill apparatus at the fill site(unless self filling vacuum tankers are used)
• Eater tenders(mobile water supply apparatus) to haul water from the fill to the dump site.

Question 18

What is a pitot tube?

Answer 18

An instrument that is inserted into a flow of liquid to measure the velocity pressure of the stream.