IFSTA 5 principles of water Flashcards
Water is a compound of how many hydrogen and oxygen atoms
page 167 3rd
Two hydrogen
one oxygen
In what temperature range does water exist in a liquid state
Page 167 3rd
32-212
For fire protection purposes freshwater is generally considered to weigh how much
3rd page 167
- 33 lbs per gallon
62. 4 lbs per cubic foot
in what ways does Water have the ability to extinguish fire
3rd page 168
Cooling/absorbing heat
smother
Water depends on what 4 factors as an extinguishing agent
Page 136 second edition
Specific heat
latent heat of vaporization
exposed surface area
specific gravity
Define specific heat
Page 136 second edition
A measure of heat absorbing capacity of a substance
What unit is used to measure amount of heat transfer
Page 136 second edition
British thermal unit
What is a btu?
Page 136 second edition
The heat required to raise the temperature of 1 pound of water by 1°
Define latent heat of vaporization
Page 137 second edition
The quantity of heat absorbed by substance when it changes from a liquid to a vapor
Each pound of water requires approximately ——- BTUs of additional heat to completely convert into steam
Page 137 second edition
970
The speed with which water absorbs heat transfer is proportional to what
Page 137 second edition
The water surface exposed to the heat
At 212°F water expands approximately ——- its original volume
Page 138 second edition
1700
Define specific gravity
Page 168 3rd
The density of liquids in relation to water
water = 1
less than 1 = floats
greater than 1 = sinks
Define force
3rd page 171
simple measure of weight, expressed in pounds/kgs
Influence causing changes in speed direction shape of a substance
When a nozzle is above the pump there will be
Page 146 second edition
Pressure loss
Define critical velocity
Page 181 3rd
friction becomes so great that resistance agitates the entire system
Where is the primary water supply obtained
Page 152 second edition
Surface water or ground water
Define primary feeders
Page 184 3rd
Large pipes relatively widespread providing large quantities of water to various points of the system for Local distribution to smaller mains
Define secondary feeders
Page 185 3rd
Network of intermediate size pipes within various loops of the primary feeder system aiding the concentration of require Fire
Define distributors
Page 185 3rd
Grid arrangement of smaller mains serving individual fire hydrants and blocks of consumers
Which type of valve is most commonly used in public water distribution systems
Page 186 3rd
Non-indicating valves
Define average daily consumption
Page 188 3rd
Total amount of water used in a water distribution system over the period of one year
True or false private water distribution systems are most often found in residential developments
188 3rd
false
define altitude
Page 176 3rd
Geographic position of object in relation to sea level
define friction loss
Page 177 3rd
Loss of pressure created by the turbulence of water moving against the interior walls of the hose or pipe
what is the first principle of pressure
pg 172 3rd edition
fluid pressure is perpendicular to any surface on which it acts
90 degrees , water pushes on ocean floor
what is the second principle of pressure
pg172 3rd edition
Fluid pressure at a point in fluid at rest is the same intensity in all directions
test tube of water getting confined
what is the third principle of pressure
pg 172 3rd edition
Pressure applied to a confined fluid is transmitted equal in all directions
what is the fourth principle of pressure
pg173 3rd edition
Pressure of a liquid in an open vessel is proportional to its depth
what is the fifth principle of pressure
pg173 3rd edition
Pressure of a liquid is proportional to the density of that liquid
what is the sixth principle of pressure
pg174 3rd edition
Pressure of a liquid at the bottom of a vessel is independent of the shape of the vessel
 what term is used to define a pressure less than atmospheric pressure
pg 175 3rd edition
vacuum
what term is used to define height of a water supply above the discharge orifice
pg175 3rd edition
head pressure
what term defines stored potential energy available to force water through pipes, fittings hose BEFORE it flows from a hydrant?
pg175 3rd edition
static pressure
What term defines portion of the total available pressure not being used to overcome friction loss or gravity while forcing water through pipes fittings hoses
Page 176 3rdedition
Residual pressure
what term defines forward velocity pressure resulting from water being discharge through an opening
page 176 3rd edition
flow pressure
what is the first principle of friction loss
page 178 3rd edition
If all other conditions of the same friction loss varies directly with the length of the hose or pipe
what is the second principle of friction loss
page 178 3rd ed
Friction loss varies approximately with the square of the increase in the velocity of the flow
————————-
200 gpm to 400 gpm, 4x the psi
what is the third principle of friction loss
page 179 3rd ed
friction loss varies inversely as the fifth power of the diameter of the hose
what is the fourth principle of friction loss
page 179 3rd ed
Friction loss is approximately the same regardless of the pressure on the water
what elements do engineers use to estimate amount of water a community needs
page 183 3rd ed
Domestic industrial and fire fighting use
define a distribution system
page 184 3rd ed
Part of an overall water supply system that receives the water from a pumping station and delivers it throughout the area
define a grid system
page 184 3rd edition
Water supply system that utilizes lateral feeders for improved distribution
how many pounds is one cubic foot of water weigh
3rd page 167
62.4 lbs per cubic foot
How much psi does a column of water 2.304 feet in height exert at its base
3rd page 171
1psi
A pressure of how much psi is required to reduce water volume by 1%
3rd page 179
30,000 psi
how often should valves be operated in the water system
3rd page 186
at least once a year
define pressure
3rd page 170
Force per unit area exerted by a liquid or gas measuring pounds per square inch
