Pump Ops Chpt 7 Flashcards
Friction loss and elevation pressure loss are combined with the loss associated with appliances added to the layout to create ______.
Total pressure loss TPL
May be determined using calculations or for more precise information, by performing tests using the actual equipment and conditions likely to be encountered in the field.
Friction loss
The only truly accurate method for determining _______ in a particular hose lay involves pressure at both ends of the hose line and subtracting the difference.
Pressure loss
Friction loss formula
FL= CQ2L
FL friction loss
C friction loss coefficient
Q flow rate in hundreds of gallons per minute
L hose length in hundreds of feet
Generally, a loss of ____ or greater is assumed when flowing the rated capacity. For this text, it is assumed that there is a _____ loss for flows less than 350 gpm and a ____ loss for each appliance in a hose assembly when flowing 350 gpm or greater. For this manual, a friction loss of ______ for all master streams appliances, regardless of flow, will be used.
25 psi
0 psi
10 psi
25 psi
Elevation Pressure loss
EP= 0.5H
EP elevation pressure in pounds per square inch
0.5 a constant
H height in feet
Pump discharge pressure
PDP = NP + TPL
PDP pump discharge pressure in pounds per square inch
NP nozzle pressure in pounds per square inch
TPL total pressure loss
Solid steam nozzle handline
50 psi
Solid stream nozzle (master stream)
80 psi
Fog nozzle
100 psi
Low pressure fog nozzle
50 or 75 psi
When required to discharge a specified pressure, fire apparatus pumps take advantage of the water pressure coming into the pump water supply and add the required pressure to achieve________.
Net pump discharge pressure NPDP
NDNP = PDP - intake reading
NDNP net pump discharge pressure from a positive source
PDP pump discharge pressure
____ operate using a ____ that moves back and forth in a cylinder.
Piston pumps
piston
As a minimum, all fire apparatus with a rated pump capacity of 750 gpm of greater must be equipped with at least ____ 2 1/2 inch discharges. Pumps rated less than 750 rpm are required to have only ____ 2 1/2 inch discharge.
two
one
A friction loss of ___ for all master stream appliances, regardless of flow, will be used
25 psi
Involves friction loss, loss to gain due to elevation, as well as appliance friction loss when flows exceed 350 gpm
Total pressure loss
The _______ whether used as a supply or attack line, presents the simplest friction loss calculation
Single hose lay
When using more than one hoseline of equal length and equal diameter, friction loss calculations need only be made for
One line
When two hoselines of equal length are Siamesed to supply a fire stream, friction loss is approximately _______ less than that of a single hoseline at the same nozzle pressure
25 percent less
In order to determine the required pressure for a standpipe system, the _____ must be calculated
Total pressure loss
Occasionally, and incident may require the use of multiple hoselines of the same or different diameter that are of unequal length. When presented with this scenario, the driver must calculate the friction loss for each hoseline supplied by separate discharges to individual nozzle. The hose with the highest friction loss represents the __
Total pressure loss at the pump, assuming that there is minimal change in elevation
Multiple hoseline unequal length
When hoselines are unequal in and or diameter is different, the total pressure loss is based on the
Highest pressure loss in any of the lines
When calculating pressure loss with a master stream device, the driver operator must add _____ to the pressure loss calculation
25 psi
