Fire Hydrants

Overview

1. Hydrant Uses2. Hydrant parts3. Types of hydrants4. Inspection and

installation5. Operation and

maintenance

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Hydrant Uses

1. Fire fighting

2. Flushing mains/sewers

3. Filling tank trucks for offsite delivery

4. Construction use

Hydrant Parts

Upper section-business end of hydrant-connection to firehose or pump truck

Lower section-connects to main-can create negativepressure

Upper Section Components

Operating nut (5-sided)--turn counterclockwise

Upper barrel (cast/duct iron)--carries water to nozzle outlets

Outlet nozzles (threaded bronze)1. Connect hose (use main pressure2. Connect suction hose -- pumper truck

Most hydrants: 2--2.5” nozzles (direct hose connection)1--4.5” nozzle (for suction)

Lower Section Components

Lower barrel (static/centrifugally cast iron): carries water between base and upper barrel

Connection to upper barrel > 2” from ground line

Main valve--operating stem, resilient valve gasket (see next slide)

Base--AKA: shoe, elbow, foot, inlet piece

ground line2”

Common hydrants1. Dry barrel

Wet-topDry-top

2. Wet barrel3. Warm climate4. Flush

Dry barrel hydrant:-main valve, drain at base-filled w/ water only when main valve open-drain opens as main valve closes-ideal for freezing climates

Common hydrants1. Dry barrel

Wet-topDry-top

2. Wet barrel3. Warm climate4. Flush

Wet-top hydrant:

-threaded end of operating rod and operating nut not sealed from water

Common hydrants1. Dry barrel

Wet-topDry-top

2. Wet barrel3. Warm climate4. Flush

Dry-top hydrant:

-threaded end of operating rod and operating nut are sealed from water

Common hydrants1. Dry barrel

Wet-topDry-top

2. Wet barrel3. Warm climate4. Flush

Wet barrel hydrant:-no main valve-always filled with water-if broken, water will flow until repaired

Warm climate hydrant:-lower barrel always full, under pressure-no drain

Common hydrants1. Dry barrel

Wet-topDry-top

2. Wet barrel3. Warm climate4. Flush

Flush hydrant:

-below ground (flush)-operating nut, nozzles in box w/ removable cover-airports, pedestrain malls

Dry hydrant main valves

1. Standard compression2. Slide gate3. Toggle

Standard compression: -sealed by upward water pressure from main on valve seal ring

-turning operating stem pushes lower valve plate down--water comes up!

Dry hydrant main valves

1. Standard compression

2. Slide gate

3. Toggle

Slide gate:

-simple gate valve

-turning operating stem raises gate--allowing water into lower barrel

Dry hydrant main valves

1. Standard compression

2. Slide gate

3. Toggle

Toggle:

-valve opens horizontally

-operating arms sciscor and pull valve open

-lower barrel extends below connection to main

opening fire hydrant valve

Auxillary Valve

-should be installed on

every hydrant

-can turn individual hydrants

off for repair

-flanged connection common

water main

Breakaway hydrants

-”Traffic” design

-easier to repair if hit by vehicle

-two-part barrel with flanged coupling

-designed to break on impact avoiding damage below ground

-no excavation required

Inspection and Installation

-inspect at time of delivery operating nut: size, shape, turn orientationoutlet nozzle: size, config., thread dimensions inlet connection: size, type, main valve size

-after inspection: cycle full open/close

-storage:indoors, no water entry

Installation concerns

1. Location

2. Footing, blocking

3. Drainage

4. Color

Location:

-setback 2’ from curb (or further if no curb)

-pumper outlet faces street

-guard posts

2’ setback

auxillary valve

Valve box

pumper outlet

Installation concerns

1. Location

2. Footing, blocking

3. Drainage

4. Color

Footing, blocking:

-firm footing (concrete slab)

-blocking keeps hydrant stable relative to main (in case of water hammer)

-tie hydrant valve to mainthrust block

3/4” shackle rods(tie to main if blocking

not possible) footing

Installation concerns

1. Location2. Footing, blocking3. Drainage4. Color

Drainage:-1/3 yard drainage stone below hydrant and above drain

-put barrier above stone to prevent clogging with dirt

clean drainage stone

soil barrier

Installation concerns

1. Location2. Footing, blocking3. Drainage4. Color

Color:

-visible colors-reflective paint-color coding capacity

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Installation concerns

1. Location2. Footing, blocking3. Drainage4. Color

Hydrant Maintenance

-inspected annually, twice annually in cold climates

-make sure dry before winter (in freezing climates)

-keep electronic records

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End Chapter 9

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