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14 Cards in this Set
- Front
- Back
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What are the 2 main reasons for s reduction in pressure |
Frictional loss in the hose line Effects of gravity when working above the water source or pump |
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What are the factors the affect that pressure loss |
Internal diameter of hose Output flow of water Height above or below water source Length of hose line |
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How does the diameter affect the pressure |
The smaller the diameter the greater the frictional loss |
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How does the output flow of water affect pressure |
Higher required output the higher the frictional loss |
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How does thw height in metres above or below water source affect pressure |
Working above will result in pressure loss Working below will result in pressure gain |
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How does length of hose affect pressure |
The longer the line the greater the frictional loss |
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Frictional loss Law 1 |
Pressure loss is directly proportional to the length of the hose through which the water flows |
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Frictional loss Law 2 |
Pressure loss is directly proportional to the square of the flow rate (If flow rate is doubled then frictional loss is quadrupled) |
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Frictional loss Law 3 |
Pressure loss is inversely proportional to the hose diameter Most important single factor (45mm has 5x more frictional loss than 70mm and 32x more than 90mm for the same flow-rate) |
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Frictional loss table |
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Effects of gravity |
Loss 1 bar for every 10m above pump (Roughly 3m per floor = .3bar loss) |
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What must be considered wben estimating pressure loss |
Working pressure of branch Frictional loss rate for hose Effects of gravity |
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What is the water on command order |
Water on Delivery number ? Branch working on ? Floor ? Bar pressure |
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When the water source is twinned and using our largest diameter hose what does that do to our frictional loss |
It gets quartered |
