chapter 9 copyright © 2007 thomson delmar learning 9.1 water supply
TRANSCRIPT
CHAPTER
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9.1Copyright © 2007 Thomson Delmar Learning
Water Supply
CHAPTER
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9.2Copyright © 2007 Thomson Delmar Learning
Objectives (1 of 3)
• Explain the value of proper water supply to other goals of firefighters.
• Identify sources of water supply for drinking and firefighting.
• Explain the difference between ground water and surface water.
• Explain the purpose of mobile water supply apparatus.
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9.3Copyright © 2007 Thomson Delmar Learning
Objectives (2 of 3)
• Explain the features of water distribution systems.
• Identify types of fire hydrants and their uses.
• Identify valves associated with water distribution systems.
• Explain how to operate a rural water supply.
• Explain a portable water tank operation.
• Explain tender operations.
9.1
CHAPTER
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9.4Copyright © 2007 Thomson Delmar Learning
Objectives (3 of 3)
• Identify the proper pressures associated with water distribution systems.
• Conduct a test of the operability and flow of fire hydrants.
• Determine the static, residual, and flow pressures of water sources.
• Identify the cause of obstructions and damage to fire hydrants and mains.
CHAPTER
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9.5Copyright © 2007 Thomson Delmar Learning
Introduction (1 of 2)
• Water supply is one of the most critical elements of firefighting.
• Water supply is important in areas with a water distribution system.
• Water supply is even more important in areas without a water supply system.
• Firefighters must know how to establish a water supply.
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9.6Copyright © 2007 Thomson Delmar Learning
Introduction (2 of 2)
• Water source, quantity, and how it is delivered are key questions.
• Fire flow capacity is dictated by the water supply.
• Fire flow requirement is the amount of water required for putting out the fire.
• Water availability will dictate the strategy, tactics, appliances, and fire streams used.
CHAPTER
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9.7Copyright © 2007 Thomson Delmar Learning
Sources of Water Supply
• You need to know where water comes from and how it gets from that point to the fire scene.
• Many natural and man-made factors affect water sources.– Weather is the greatest factor.
• Some areas have abundant water supply while others have none.
CHAPTER
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9.8Copyright © 2007 Thomson Delmar Learning
Groundwater (1 of 2)
• Most of the earth’s freshwater supply is groundwater.– Usually results from rain
– May collect in pockets called aquifers, and rise as springs
• Water may reach surface through drilling and pumping.
• Water must have enough pressure for firefighting.
CHAPTER
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9.9Copyright © 2007 Thomson Delmar Learning
Groundwater (2 of 2)
• Well pump with storage tanks
CHAPTER
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9.10Copyright © 2007 Thomson Delmar Learning
Surface Water (1 of 2)
• Surface water is the world’s most common source.
• Natural water sources used for firefighting are rivers, lakes, and ponds.
• Man-made sources include lakes, ponds, reservoirs, swimming pools, and tanks.
• Tidal changes may affect water sources.
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9.11Copyright © 2007 Thomson Delmar Learning
Surface Water (2 of 2)
CHAPTER
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9.12Copyright © 2007 Thomson Delmar Learning
Mobile Water Supply Apparatus
• Most engines today have at least a 500 gallon tank.
• Tenders have tanks from 1,000 to 8,000 gallons.– Some tenders may
have a pump.
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9.13Copyright © 2007 Thomson Delmar Learning
Tanks, Ponds, and Cisterns
• Other developed sources are water tanks, ponds, and cisterns.
• Water tanks may be underground, ground level, or elevated.
• A cistern can hold large quantities of water (30,000 gallons or more).
• Connections for tanks or cisterns include dry hydrants, drafting pits, or other type.
CHAPTER
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9.14Copyright © 2007 Thomson Delmar Learning
Water Distribution Systems (1 of 2)
• Include a method of getting water, treatment processes, storage, supply, and distribution
• Supplied by three means– Gravity fed– Pumped system– Combination pumped-gravity system
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9.15Copyright © 2007 Thomson Delmar Learning
Water Distribution Systems (2 of 2)
• After treatment, water goes into the distribution system.
• Water mains are divided into feeders.– Primary feeders divide into secondary
feeders and distribution lines.
• Good systems are interconnected into loops and grids.
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9.16Copyright © 2007 Thomson Delmar Learning
Fire Hydrants
• There are two major types of hydrants.– Wet barrel– Dry barrel
• A dry hydrant is a piping system for drafting from a static water source.
CHAPTER
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9.17Copyright © 2007 Thomson Delmar Learning
Wet Barrel Hydrant
• Have water in the barrel
• Used in non-freezing temperature areas
• Each outlet controlled by separate valve
CHAPTER
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9.18Copyright © 2007 Thomson Delmar Learning
Dry Barrel Hydrant
• They are used in areas that have freezing temperatures.
• Valve at base of hydrant controls water flow to all outlets.– Valve should be all
the way open or all the way closed.
CHAPTER
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9.19Copyright © 2007 Thomson Delmar Learning
Dry Hydrant
• Serves as connection point for drafting
• A pipe system with a pumper suction at one end and a strainer at the other end
• Used primarily in rural areas
CHAPTER
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9.20Copyright © 2007 Thomson Delmar Learning
Specialty Hydrants
• Wall hydrants mounted on side of building for direct connection to water supply system
• Flush-type hydrants
• High-pressure hydrants
CHAPTER
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9.21Copyright © 2007 Thomson Delmar Learning
Valves Associated with Water Distribution
Systems (1 of 2)
• Usually these are non-indicating type gate valves and check valves found in public water system.
• Gate valves are butterfly valves.• Check valves control water flow in one
direction.• Backflow preventers are check valves or a
pair of check valves.
CHAPTER
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9.22Copyright © 2007 Thomson Delmar Learning
Valves Associated with Water Distribution
Systems (2 of 2)
• Private water valves are of the indicating type.– Post indicator valve (PIV)– Wall indicator valve (WIV)– Outside stem and yoke (OS&Y)
CHAPTER
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9.23Copyright © 2007 Thomson Delmar Learning
Rural Water Supply
• Operation can occur anywhere.
• Should be understood by all.
• Operations require careful coordination and control.
• Water supply officer should be part of ICS.
CHAPTER
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9.24Copyright © 2007 Thomson Delmar Learning
Portable Water Tanks (1 of 2)
• Tenders are designed to transport water.– Must be able to quickly drop off water and
return to the fill site.
• Each tender should have a portable water tank.
• Tank is usually set up next to attack or supply engine.
CHAPTER
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9.25Copyright © 2007 Thomson Delmar Learning
Portable Water Tanks (2 of 2)
CHAPTER
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9.26Copyright © 2007 Thomson Delmar Learning
Tender Operations (1 of 4)
• A tender operation is a shuttle operation.
• Dump site is where water is delivered.– Site should be able to unload multiple
tenders.– Site should have a turnaround area,
operational area, and access to fireground.– Site should allow for safety of personnel.
CHAPTER
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9.27Copyright © 2007 Thomson Delmar Learning
Tender Operations (2 of 4)
• Fill site should be properly staffed.
• Shuttle operations control fire flow capacity.
• Increased efficiency, more tenders, or larger tanks can help increase flow rate.
• Increasing vehicle speed will not speed up tender operations.
CHAPTER
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9.28Copyright © 2007 Thomson Delmar Learning
• Fire Flow Rate =
Time to fill tender +
Time to drop water +
Travel time to and from dump site
Quantity of Water Carried
Tender Operations (3 of 4)
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9.29Copyright © 2007 Thomson Delmar Learning
Tender Operations (4 of 4)
CHAPTER
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9.30Copyright © 2007 Thomson Delmar Learning
Summary (1 of 2)
• Water is the most common extinguishing agent.
• Understand the relationship between water supplied and amount needed.
• Supplying water requires an understanding of the components of a water distribution system.
• Distribution systems have valves and hydrants to be operated.
CHAPTER
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9.31Copyright © 2007 Thomson Delmar Learning
Summary (2 of 2)
• Firefighters must be able to use mobile supply apparatus, portable water tanks, and conduct shuttle operations.
• Firefighters need to be familiar with testing operability and the flow of hydrants.