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31 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What is the first principle of pressure in relation to pump operation in firefighting? |
1. Pressure is perpendicular to any surface on which it acts |
Perpendicular |
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What is the second principle of pressure in relation to pump operation in firefighting? |
2. Pressure of a fluid at rest is the same intensity in all directions |
Intensity |
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What is the third principle of pressure in relation to pump operation in firefighting? |
3. Pressure applied from outside a fluid contained in a vessel is transmitted equally in all directions |
External pressure |
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What is the fourth principle of pressure in relation to pump operation in firefighting? |
4. Downward pressure of a fluid in an open vessel is proportional to it’s depth |
Depth |
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What is the fifth principle of pressure in relation to pump operation in firefighting? |
5. Downward pressure of fluid in an open vessel is proportional to the density of fluid |
Density |
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What is the sixth principle of pressure in relation to pump operation in firefighting? |
6. Downward pressure of a fluid at the bottom of a vessel is independent of the shape of that vessel |
Shape |
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Define head, in relation to pump operations: |
The depth of water |
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What is pressure, in relation to pump operations? |
Pressure is the force acting on a given surface area |
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Which basic formula can be used to calculate increase/decrease in pressure due to the branch height above the pump? |
P = 10 x H Where: P = Pressure in kPa, & H = head in metres |
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How many kPa should be added or subtracted per metre of height loss or gain? |
10 kPa |
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To calculate head (in metres), which formula should be used? |
H = P/10 |
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Friction loss is dependent on what? |
-diameter of hose -length of hose -roughness of hose interior |
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What is the first law of friction loss? |
1. Friction loss increases directly with the length of the hose |
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What is the second law of friction loss? |
2. Friction loss increases directly with the decrease of hose diameter |
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What is the second law of friction loss? |
2. Friction loss increases directly with the decrease of hose diameter |
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What is the third law of friction loss? |
Friction loss increases directly as the square of the flow |
The faster the flow rate, the greater the resistance. |
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What is the fourth law of friction loss? |
4. Friction loss increases with the roughness of the hose interior |
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DRISL |
-Diameter of hose -Roughness of hose -Independent of pressure -Square of the flow rate -Length of hose |
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Friction loss for 38mm x 30m hose? |
150kPa |
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Friction loss for 50mm x 30m hose? |
75kPa |
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Friction loss for 65mm x 30m hose? |
25kPa |
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Friction loss for 90mm x 30m hose? |
5kPa |
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Friction loss is calculated per length of hose. True or false? |
True |
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Atmospheric pressure = ? |
100kPa (or 1 bar) |
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Atmospheric pressure, in theory, can provide how much ‘lift’ in metres? |
10m (in theory) 7.5m (maximum attempted) |
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How is capacity (in litres) calculated for a rectangular water supply? |
Capacity (litres) = length x breadth x depth x 1000 |
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How is volume calculated (in litres) for a cylindrical water source? |
Volume = 3 x radius squared x height x 1000 |
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How is the capacity/rate of flow (in litres per minute) calculated in a flowing source? (ie. a river or creek) |
Capacity/rate of flow (litres per minute) = depth x width x flow rate x 1000 |
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As the height of water in a vessel increases, what relationship does this have on head? |
Pressure exerted at it’s base increases (by 10kPa per metre) |
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In what direction is pressure exerted? |
Perpendicular to any surface on which it acts |
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What is the function of the branch? |
Converts energy of water pressure into velocity or kinetic energy |
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