Chapter 5 Water Float Analysis

Question 1

what are the reasons it’s necessary to conduct water flow analysis

Answer 1

1. to determine whether a water supply system is operating as designed
2. to determine whether a properly functioning water supply system can provide an adequate flow of water for the target hazards in the area of the test

Question 2

when should flow test be conducted

Answer 2

at least once every five years or

after any extensive water main improvements/ extensions

Question 3

reasons that mathematical calculations of the water flow in the distribution system may not be accurate

Answer 3

1. sedimentation or mineral deposits
2. piping corrosion and deterioration
3. unforeseen valve closure or debris and system

Question 4

_____ are the only reliable way for fire service personnel to determine the quantity of water available for fire protection in a water supply system

Answer 4

water flow test

Question 5

what should the clearance between the bottom of the hydrant butt and a grade be

Answer 5

15”

Question 6

the water supply test involves two hydrants

Answer 6

test hydrant- hydrant for which the test is being conducted, no water is flowed from this hydrant
flow hydrant- hydrant that is open and flowed to create the pressure drop at the test hydrant, more than one flow hydrate may be required

Question 7

where should the test hydrogen be located in relation to the water source

Answer 7

the test hydrant must be located between the flow hydrant and a water source

Question 8

why should 2 1/2 inch outlets be used to conduct flow test

Answer 8

large steamer outlet contains voids/ is not solid stream of water

Question 9

you should open enough hydrants to drop the static pressure at the test hydrogen by at least

Answer 9

10%

Question 10

Steps for conducting an available water test

Answer 10

1. have personal at both test hydrant and flow hydrant
2. test hydrant, remove hydrant And attach static pressure gauge with petcock open… open hydrant bleed air close petcock… fully open hydrant
3. record static pressure
4. flow hydrant, removed 2.5” cap, record project coefficient and inside diameter of orifice
5. fully open flow hydrant taken record pitot up reading, residual pressure on test hydrant should not drop below 20psi
6. close flow hydrant
7. check test hydrant for return to normal pressure, close hydrant and open petcock, remove gauge, replace cap

Question 11

what is the easiest way to determine how much water is flowing from the hydrant outlets

Answer 11

using prepared table for nozzle/ outlet discharge

Question 12

the most commonly used manual calculation method to determine available water flow

Answer 12

graphical method

Question 13

what’s the procedure for graphical analysis of available water flow

Answer 13

1. determine the GPM scale that we used
2. plot the static pressure on the vertical scale at zero GPM
3. locate total water flow, measured during the test
4. located residual pressure recorded during test
5. draw straight line from the static pressure point through the residual pressure point on the water scale
6. mark 20 psi GPM, record the figure