Fire Apparatus Pump Theory

1. Fire Apparatus Pump Theory Section 180

2. Introduction • Types of pressure encountered in the fire service • Identify the types of fire pumps & components of pumps • Identify the function, theory, principles of operation of fire pumps 180-1.00

3. Types of pressures encountered in the fire service • Static pressure • Residual pressure • Flow pressure • Normal operating pressure • Negative pressure 180-1.01

4. Static pressure • The pressure exerted in all directions at a point in a fluid at rest Static pressure is stored potential energy that is available to force water through a pipe, fittings, fire hose & adapters 180-1.01a

5. Residual pressure • The pressure remaining in a system while water is flowing The total available pressure not used to overcome friction or gravity while forcing water through pipes, fittings, fire hose & adapter 180-1.01c

6. Flow pressure • The forward velocity pressure at a discharge opening when water is flowing The rate of flow {velocity} of the water coming from the discharge opening produces this force called velocity or flow pressure 180-1.01d

7. Water pressure

8. Normal operating pressure • The pressure found in the water distribution system during normal consumption demands Occurs when some water is flowing in the system 180-1.01b

9. Grid system

10. Negative pressure • Also called vacuum . Pressure that is less than atmospheric pressure Negative pressure in the fire service is the result of drafting operations, which results from removing all the air from the pump & using atmospheric pressure to lift water from a source lower than the pump 180-1.01e

11. Terms related to the basic principles of fire service hydraulics Atmospheric pressure – the atmosphere that surrounds the earth has depth & density & exerts pressure upon everything on earth Capacity – The maximum amount of water a pump will deliver at the indicated pressure

12. Displacement – Movement of a given amount of a fluid w/ each stoke of a pump Flow {GPM} – Gallons per minute, the measurement of the amount of water moved through a fire pump Friction loss – Loss of pressure created by the turbulence of water moving against the interior walls of the hose or pipe.

13. Friction loss ex 1

14. Friction loss ex 2

15. Head Pressure (gain of loss) – Water pressure due to elevation. For every 1’ increase in elevation, 0.434 psi is gained. 1 M in height 10 kPa is gained Hydrant pressure – The force of water when it enters the pump from the distribution system Net engine pressure – The actual amount of pressure being produced by the pump

16. Nozzle reaction – The counterforce directed against the people or device holding a nozzle by the velocity of water being discharged Pound per square inch PSI - Pump discharge pressure – The actual velocity pressure (measured in PSI) if the water as it leaves the pump & enters the hose line.

17. Vacuum – A pressure that is less than normal atmospheric pressure Velocity – The rate of motion of a particle in a given direction, speed Water hammer – When the flow of water is suddenly stopped, the resulting surge is referred to as a water hammer

18. Water hammer

19. Break Break Time!! Thank Goodness

20. The firefighter shall identify & describe the following guages: Compound gauge – A gauge connected to the intake side of the pump that is capable of measuring positive & negative intake pressures Discharge/pressure gauge – A gauge on the discharge side of the pump that registers the pump discharge pressure 180-1.03

22. Suction Pressure

23. Pressure loss

24. Flow chart