Chapter 6- Water Flashcards
(36 cards)
What is the order from largest to smallest of water supply pipes?
- Feeders
- Secondary Feeders
- Distributors
Is there less FL in a water distribution system when fire hydrants are supplied by one direction or two (or more) directions?
There is much less FL when a hydrant is supplied from two or more directions.
A fire hydrant that receives water from only one direction is called….
A dead-end hydrant.
When a fire hydrant receives water from two or more directions it is called…
Circulating feed or looped line.
To ensure sufficient water, how many primary feeders should run from the source of supply to the high risk industrial districts?
Two or more.
In residential areas, what is the recommended size for fire hydrant supply lines?
6 inches with 8-inch cross-connecting mains at intervals of not more than 600 feet.
What is the recommended size water mains in industrial areas?
8-inch mains with 8-inch cross-connecting mains every 600 feet.
How often should water control valves be operated to keep them in good working condition?
At least once a year
Valves for water systems are broadly divided into what two types?
Indicating and non indicating
Valves in private protection systems are generally indicating or non indicating?
Indicating
Name the two types of indicating valves.
PIV-post indicator valve: Open/Shut
OS&Y-outside stem/screw and yoke: The threaded portion of the stem is out when the valve is open
The OS&Y valve is most commonly used in what application?
Sprinkler systems
What two types of valves are used in water distribution systems?
Gate valves
Butterfly valves
Name the types of materials that can be used for underground water pipe.
Cast iron
Ductile iron
Asbestos cement
Steel
Plastic
Concrete
Which materials should be used for added strength in underground water pipes in unstable or corrosive soils?
Steel pipe
Reinforced concrete pipe
What two factors govern the heat absorbability of water?
Specific Heat
Latent Heat of Vaporization
Water has the ability to extinguish fire in several ways. Name them and explain.
The primary way is cooling, or absorbing, heat from a fire.
Another way is by smothering (excluding oxygen).
When using water to smother a fire in combustible liquids, the specific gravity must be higher or lower than 1?
The specific gravity must be higher than 1. Floating liquids will not be smothered by water.
How does the exposed surface area affect water’s ability to act as an extinguishing agent?
The greater the surface area of the water exposed to heat, the greater the heat absorbed.
What is the definition of Specific Heat?
The measure of the heat-absorbing capacity of a substance.
What are the two units of measurement used to measure heat transfer? Which do we use?
British Thermal Units (BTU’s)
Joules 1 BTU = 1.055 kJ
We generally use BTU’s.
Define BTU.
The amount of heat required to raise the temperature of 1 pound of water 1 degree (F). [starting at 60 degrees]
Define Specific Heat.
The specific heat of any substance is the ratio between the amount of heat needed to raise the temperature of a specified quantity of a material and the amount of heat needed to raise the temperature of an identical quantity of water by the same number of degrees.
Define latent heat of vaporization.
The quantity of heat absorbed by a substance when it changes from a liquid to a vapor.
