CHAPTER 9 Copyright © 2007 Thomson Delmar Learning 9.1 Water Supply

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Water Supply

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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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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.

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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.

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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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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.

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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.

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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.

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Groundwater (2 of 2)

• Well pump with storage tanks

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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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Surface Water (2 of 2)

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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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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.

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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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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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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.

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Wet Barrel Hydrant

• Have water in the barrel

• Used in non-freezing temperature areas

• Each outlet controlled by separate valve

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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.

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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

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Specialty Hydrants

• Wall hydrants mounted on side of building for direct connection to water supply system

• Flush-type hydrants

• High-pressure hydrants

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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.

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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)

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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.

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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.

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Portable Water Tanks (2 of 2)

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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.

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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.

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• 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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Tender Operations (4 of 4)

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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.

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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.