Chapter # 11 Operating Fire Pumps Flashcards
On some newer apparatus the pump will not throttle up if what is not set?
The parking brake.
Test have indicated that a apparatus may override the parking brake system at engine speeds as low as what?
1300 rpms. This is why the wheels should be chocked.
Some newer apparatus do not provide a speedometer check to ensure the pump is engaged, why?
Because the speed reading is taken from the rear of the transfer case.
What should be done in a pumping operation after the wheels are chocked?
Pull the tank to pump valve.
A pump should be set in volume (parallel) if it appears that what percent of the pumps capacity will be needed?
50% (some manufacturers recommend 70%)
When an external water supply becomes available, open the intake valve while closing what?
The tank to pump valve.
These do not have sufficient flow to prevent encrustation and sedimentation from decreasing the flow capacity.
Single mains that supply small amounts of water.
Subjecting dead ends mains to high flow requirements may make what happen.
Sediment to flow into the fire pump intake screen, reducing water flow.
Recommended Practice for Fire Flow Testing and Marking Hydrants.
NFPA 291
Class AA / light blue
1500 gpm or greater
Class A / Green
1,000 - 1,499 gpm.
Class B / Orange
500-999 gpm
Class C / Red
Less then 500 gpm.
Many departments that prefer a forward lay also carry what to aid in the process?
A four way hydrant valve.
What is another name for a dry barrel hydrant?
Frost Proof Hydrant
What is the max recommended length of hose when using 2 /12” or 3” hose to connect a hydrant to a pumper?
300’ max
What is the most direct way to supplement hydrant pressure and perform drafting operations?
A reverse lay.
This method is used in cases when a size up must be made before laying a supply line.
A reverse lay.
When reverse laying a supply hose, it is not necessary to use what?
A four way hydrant
After a hydrant connection is made the tank-to-pump valve must be closed if the intake is not equipped with what?
A shutoff valve.
A dry barrel hydrant should;d be opened fully, but it is also recommended that after fully opening the hydrant that it be closed how much, to relive the strain on the valve stem and internal components.
One quarter turn.
Name four methods for preventing pump overheating while hoselines are not flowing.
Pull booster line. Open a discharge drain valve. Partially open the tank fill or pump tank line. Use a bypass or circulator valve.
T or F When a pumper is connected to a hydrant and is not discharging water, the pressure shown on the intake gauge is the STATIC PRESSURE. When the pumper is discharging water, the intake gauge reading is the RESIDUAL PRESSURE. The difference between the two is used to determine how much more water the hydrant can supply.
True
Name the three methods for determining additional water available from a hydrant.
Percentage Method. First- Digit Method. Squaring the lines method.
What is the percentage method equation?
Percent drop = ( Static - Residual )(100) / Static
Percentage method table.
0-10 % = 3 times the amount of water being delivered.
11-15% = 2 times the amount of water being delivered.
16-25% = Same amount as being available.
25% + = more water might be available, but not as much as is being delivered.
Faster and easier method then the percentage method, but can not be used when using metrics.
First-digit Method
Find the difference in psi between the static and residual. Multiply the first digit in the static by either 1, 2, or 3. Determine which of these number the first digit must be mutiplyed by to become equal to or less then the first digit in the static pressure. Then that tells you if you can add 3,2,or 1 additional line with equal flow.
First-digit method
The additional amount of water can be determined by squaring the number of lines currently flowing and multiplying this by the original pressure drop.
Squaring the lines method
When using the squaring the lines method the pressure drop is quadrupled each time the flow is what?
doubled.
Should a pressure control device be shut off when shutting down the pump?
Yes