Friction Loss And Water Flashcards
Large diameter hose friction loss variance.
2.5 - 3in comparison
3in = three to the 5th
2.5 to the fifth.
Velocity of waters effect on friction loss.
Difference is squared
Twice the velocity 2x2 - tripled 3x3
Pressure variance from source to discharge.
Pressure at source will always be greater
Critical velocity
Point that friction on small diameter hose our nozzle causes too much agitation in stream
Water hammer forces
Force in reverse end of line can be serval time that’s of waters velocity.
Concern of water treatment facilities as source
Power outage and mechanical failure
Circulation feed or looped line
Hydrant that receives water from more than one source.
Less friction loss
Grid system parts
Primary- large main source of lines
Secondary - network of intermittent sized pipes that reinforce grid
Distributors - small connecting lines
Residential line size
6in
Industrial line size
8 in
Minimum line size every ___ feet
8 in line every 600 ft
How often should valves be exercised.
Once a year at minimum
Hollow metal post attached to valve housing.
PIV
Open shut window
Valve with threaded stem that controls gate open and close
OS+Y
Threads out indicate open
Most common valve type
Non indicating valve
Hidden in manholes
Water capacity ADC
Average daily consumption
Over one year
Water capacity MDC
Max daily consumption.
Over three year period
water consumption
PHC
Peak hour consumption
One hour interval daily
Weight of water
Gallon and cubic foot
- 5 lbs per cubic foot
8. 33 lbs gallon
DEF. Specific Heat
heat absorbing capabilities of a substance
Measure against btu of water.
BTU
Amount of heat required to increase on lbs of water one degree.
Latent heat of vaporization
Quantity of heat absorbed when liquid changes to a vapor
Concept of exposure surface area
More surface area the more heat absorbed
Fog vs straight stream
Water to steam expansion.
1:1700
Pressure DEF:
Force per unit in an area
PSI or PSF
Force DEF:
Measurement of weight correlated to gravity
Principles of fluid pressure
3 main things
Fluid -is a perpendicular force
- pressure equal in all directions
- virtually incompressible
Head pressure formula
Height to PsI by x 2.304
Elevation Vs. Altitude
Elevation - center line of pump or static water supply source
Altitude - object distance above or below sea level
Altitude considerations
2,000 ft starts to truly effect pressures.
Every 1,000 decreases atmospheric pressure by .5
3 private water source uses
Fire
Fire sanitary
Fire and manufacturing
Auto pressure control activation time and Max
3-10 engaged
30 psi over
