chapter9 hydrant bradburn
DESCRIPTION
TRANSCRIPT
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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