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37 Cards in this Set
- Front
- Back
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water system that uses a pump?
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direct pumping system
disadvantage is their total dependence on pumps, |
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gravity system
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primary water source located at a higher elevation than the distribution system so gravity supplies the pressure
-adequate when source is located 100 ft higher than highest point in distinction system |
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combination system
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uses pumps and gravity
-majority of communites in north america have a combination system |
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what are hydrants made of?
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cast iron
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distibution system and treatment
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once treated it delivers water throughout whole system including the hydrants.
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water hammer
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rapid deceleration of water by closing a hydrant to fast
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dead end hydrant
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only receives water from one end
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grid system
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circulating feed from multiple directions
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dry barrell hydrant
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used in colder clmiates subject to freezing
-main valve located below frost line, opening 1 stem nut gives water to all discharges at once |
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residential supply line
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according to american water works association recc for supply mains in residentail areas is 6 inches with closely grided 8 inche mains cross connecting
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wet barrel
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"california hydrant"
hydrant barrel always filled with water, stem only can open 1 opening at a time |
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valves that control water flow
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indicating (piv and osy)
nonindicating (gate and buttefly) usually in utility manhole |
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water supply valves should be operated how often?
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atleast once a year
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indicator valves
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post indicator-hollow metal post that houses valve stem, a plate inside attached to stem reads open or shut
os&y- a yoke on the outside with a threaded stem that opens or closes the gate inside the valve |
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most valves in fire protection systems are?
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indicator type
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residual pressure
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pressure of water left over when the water is flowing
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flow pressure
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forward velocity pressure at a discharge opening while water is flowing
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main valve of dry barrel is located where?
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below frost line
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wet barrel has what at each discharge
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horizontal compression type valve at each outlet
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green colored hydrant flows
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1000, to 1499 gpm
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orange colored hydrant flows?
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500-999 gpm
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red hydrant flows
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less than 500gpm
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light blue hydrant flows
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1500 gpm or greater
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fire hydrant spacing in a high value district
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300 ft
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who is responsible for spacing, location, and distibution of fire hydrants?
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water dept with recommendations from fire dept
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how do we measure water flow?
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gpm
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water shuttle
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hauling water from a supply source to portable tanks
-distances greater than 1/2 mile -fast fill and fast dump. traffic control, hydrant operations, hookups, and tank venting are critical to efficient water shuttle |
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primary feeders
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larg mains with relatively widespread spacing that convey larg quantities of water to various points for distribution to secondary feeders and smaller mains
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secondary feeders
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network of intermediate mains that subdivide grid within the various loops of prim feeders and supply distributors
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distributors
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grid arrangement of smaller mains serving individual fire hydrant sand blocks of customers
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butterfly valve
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nonindicating valve
tight closing, usually have rubber or rubber composition seat that is bonded to the valve body, valve disk rotates 90 degrees |
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hydrant testing
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most basic annual test is flow test
many fd no longer responsible for the testing of hydrants within their jurisdictions |
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pitot tube do what
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flow test
-hold the tube away HALF the diameter of the orifice |
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min gallons on portable tank
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1000
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relay operations
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source is close enough to fire scene that relay can be used instead of water shuttle. 2 or more pumper to move water over long distance
-apparatus with greatest pumping capabilities at the water source |
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alternative water supplies
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lakes, ponds, river, ocean, swimming pools, farm stock tanks, in some cities underground cisterns collect rainwater
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drafting
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process of drawing water from static source to supply a pumper
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