Water Supplies

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Water Supplies

• Essentials of Fire Fighting
• NFPA 1001
• Water Supplies SFFMA 12

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History of Water Supply Systems

• Primitive communities built around natural
  sources of water.
• Early Roman civilization developed the first
  recorded municipal water system.
• Aqueduct brought water from distances
• Aqueduct water stored in covered masonry cisterns
• Cistern water delivered through lead or bored
  stone pipes

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History of Water Supply Systems (cont)

• Roman water supply system almost vanished with
  decline of Roman Empire.
• Nothing in North America could properly be called
  a comprehensive water system until 1800 when the
  Philadelphia Waterworks began delivering water.
• In the mid 19th century, New York City and Boston
  developed rudimentary systems that flowed from
  reservoirs through hollowed out logs. The logs
  had large wooden plugs that allowed for tapping
  the system for fire fighting. (The plugs in the
  wooden pipes were called fire plugs and the
  term is still used today for fire hydrants.)

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List the four fundamental components of a modern
water system.

• Source of supply
• Means of moving water
• Treatment facilities
• Distribution and storage system

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What sources of surface water and groundwater are
available for water supply?

• Surface water sources
• Rivers
• Lakes
• Groundwater supply
• Water wells
• Water producing streams

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How is the amount of water a community may need
determined?

• An engineering estimate of total needed to
  furnish industrial, business, residential and
  fire fighting use.

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What are the three methods of moving water is a
system?

• Direct pumping
• Gravity
• Combination of gravity and pumping

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Treatment Facilities
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Does all water need to be treated before it is
pumped into a distribution system?

• No, some water such as spring and well water
  needs no further purification.

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What are some methods used by treatment
facilities for removing contaminants from water?

• Coagulation
• Sedimentation
• Filtration
• Chemicals
• Addition of bacteria or other organisms

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What is the fire departments main concern
regarding treatment facilities?

• That maintenance errors loss of power supply or
  natural disaster could knock out the pumping
  station reducing the volume and pressure of water
  available for fire fighting.

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What should fire departments do to combat such
concerns?

• Fire districts should have a plan to deal with
  possible shortfalls.

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Water Distribution System

• Distribution system - part of the system that
  receives the water from the pumping station and
  delivers it throughout the area
• Dead-end hydrant - hydrant that receives water
  from only one direction
• Circulating-feed hydrant hydrant that receives
  water from two or more directions
• Grid system distribution system that provides
  circulating feed from several mains

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What is the function of a valve in a
water-distribution system?

• To control the flow of water

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How often should valves be operated to keep them
in good condition?

• At least once a year

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How does the fire department know where water
system valves are located?

• Through records supplied by the water utility

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Why would the fire department want to know where
water system valves were located?

• The department can check the condition and
  accessibility of the valves during fire hydrant
  inspections and inform the water department if
  any valves need attention

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What are the two broad categories of valves?

• Indicating which visually show whether the gate
  or valve is open, closed, or partially closed
• Non-indicating which do not show the position
  of the gate or valve seat

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Friction Loss Factors

• Different construction materials cast iron,
  ductile iron, asbestos cement, steel, plastic or
  concrete
• The importance of using the proper pipe material
  for soil conditions and pressures
• Conditions that require extra protection
• Internal surface material and resistance to water
  flow

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What are the main causes of decreased pipe size
and increased friction loss in distribution mains?

• Encrustation from mineral deposits and sediment,
  and foreign materials settling out of the water

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What is friction loss?

• That part of the total pressure lost as water
  moves through a piping system or hose

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Fire Hydrants
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What kind of valve may a dry-barrel hydrant have?

• A compression, gate or knuckle-joint valve that
  opens either with pressure or against pressure

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Where is this valve located? Why?

• Underground below the anticipated frost line for
  the geographic area to prevent the water system
  from freezing

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Why must a dry-barrel hydrant be completely open
or completely shut?

• The drain on the dry-barrel hydrant is open when
  the hydrant is not flowing water and is closed
  when the hydrant is operating. If the hydrant is
  not completely open, the drain is left partially
  open and the resulting flow from the hydrant
  contributes to soil erosion around the base of
  the hydrant

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How is a dry-barrel hydrants ability to drain
tested?

• After the hydrant has flowed some water, it is
  closed and all discharge outlets except one are
  capped. When the firefighter performing the test
  places a hand over the discharge, the firefighter
  should feel a slight vacuum pulling the palm
  toward the discharge

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What kind of valves do wet-barrel hydrants have?

• Usually a compression-type valve at each outlet
  but may have only one valve in the bonnet that
  controls the flow of water to all outlets

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Of what are hydrant bonnets, barrels and
footpieces generally made?

• Cast iron

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Of what are hydrant working parts usually made?

• Bronze

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Of what are hydrant valve facings usually made?

• Rubber
• Leather
• Composition materials

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Who is responsible for the location, spacing and
distribution of fire hydrants?

• Fire chief or fire marshal

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Generally how far apart should fire hydrants be
spaced in high-valve districts?

• Not more than 300 feet

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What are the general rule of thumb for hydrant
spacing?

• One hydrant near each street intersection, and
  intermediate hydrants where distances between
  intersections exceed 350 to 400 feet

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Hydrant Safety

• Tighten caps on outlets not used
• Do not stand in front of closed caps
• Do not lean over top of operating hydrant
• Close hydrant slowly
• Check downstream drainage
• Do not flow without adequate drainage
• Do not flow across a busy street
• Do not flow onto street in freezing weather
• Control pedestrian and vehicle traffic

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Rural Water Supply

• Firefighters tend to take municipal water
  systems with their intricate network of
  treatment facilities, storage tanks, pipes,
  pumps, valves and hydrants for granted until
  they have to suppress a rural fire, find a water
  source, or create a means of getting water to the
  fire

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What are some alternative water sources?

• Private industrial systems
• Oceans
• Swimming pools
• Farm stock tanks and ponds
• Any static body of water

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What are some alternative supply methods?

• Tanker/Tender shuttle
• Relay pumping
• Combination shuttle and relay

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Note

• Fire department personnel should make every
  attempt to identify, mark, and record alternative
  water supply sources in pre-incident planning.
  Considerations should be given to the effect that
  weather has on the amount of water available and
  the accesses to water sources

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Drafting
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What is the term for raising water from a static
water source to supply a pumper?

• Drafting

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How can silt and debris render a static source of
water useless?

• By clogging strainers, seizing or damaging pumps,
  and by allowing sand and small stones to enter
  attack lines and clog nozzles

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What basic precautions should the firefighter
take when drafting to avoid rendering the water
source or the equipment useless?

• Place a strainer on all hard-suction lines
• Locate and support the strainer so that it does
  not rest on the bottom
• Use special floating strainers in shallow sources

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What rule of thumb may be used for placing a
strainer at the effective depth?

• Ensure 24 inches of water above and below the
  strainer

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What is the shallowest level of water from which
strainers can draw?

• 1 to 2 inches

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Shuttling
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What is a water shuttle?

• The hauling of water from a supply source to
  portable tanks from which water may be drawn to
  fight fire

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When is water shuttling recommended?

• For distances greater than ½ mile or greater than
  the fire departments capability of laying supply
  hoselines

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

• Attack apparatus at the fire (dump site)
• Fill apparatus at fill site
• Mobile water apparatus to haul water between fill
  and dump sites

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How is the attack apparatus supplied with water?

• Attack apparatus may draft directly from the
  portable tanks, or other apparatus may draft from
  the tanks and supply the attack apparatus

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What capacity range is available in portable
tanks?

• 1,000 gallons and upward

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What device maintains the water level when
multiple portable tanks are used?

• Jet siphon

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How does a jet siphon work?

• It uses a 1 ½ inch discharge line to pull water
  from one tank into another

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How are portable reservoirs constructed?

• The most common is a collapsible or folding style
  that uses a square metal frame and a synthetic or
  canvas duck liner another style is a round
  synthetic tank with a floating collar that rises
  as the tank is filled, making it self-supporting

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What are the four basic methods by which
tankers/tenders unload water?

• Gravity dumping through large 10 or 12 inch dump
  valves
• Jet dumps
• Apparatus-mounted pump
• A combination of these methods

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What dumping or filling rates does NFPA 1901
require of apparatus on ground level?

• At least 1,000 gpm

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Who pumps the water from the tanker/tender?

• A trained apparatus driver/operator

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Who activates gravity dumps?

• A firefighter, which saves time as the
  driver/operator does not need to exit the cab

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Relaying
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What is a water relay?

• Relaying water from the water source through a
  series of pumpers spaces between the water source
  and the fire

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When is a water relay used?

• When the water source is close enough to the fire
  scene that relay pumping apparatus can be used

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What two factors must be considered when
contemplating the establishment of a relay
operation?

• The water supply must be capable of maintaining
  the desired volume of water required for the
  duration of the incident
• The relay must be established quickly enough to
  be worthwhile

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What factors determine the number of pumpers
needed for a water relay?

• Volume of water needed
• Distance between water source and fire scene
• Hose size available
• Amount of hose available
• Pumper capacities

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Which apparatus should be located at the water
source?

• The one with the largest pumping capacity

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What is the function of the water supply officer?

• Determining the distance between pumpers and
  coordinating water supply duration

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How does the water supply officer determine the
distance between pumpers?

• Consults a prepared chart listing friction loss
  at particular flows for the hose size being used

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What is the best way to prepare for relaying
operations?

• Advance planning
• Practice during training exercises

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The END