Chp 8

Question 1

Fireground methods for determining PDP

Answer 1

Flowmeters
Hydraulic calculators
Pump charts
Condensed Q method
GPM flowing

Question 2

PDP

Answer 2

Actual pressure of the water as it leaves the pump and enters the hoseline
Pump intake plus net pump discharge pressure

Question 3

Flowmeter

Answer 3

Device installed in a discharge line that senses the amount of water flowing in GPM
Can correct inadequate flow hidden by automatic nozzles

Question 4

Types of flowmeters

Answer 4

Paddlewheel: Mounted at the top of a straight section of the discharge pipe
Spring probe: Stainless steel probe detects movement in discharge piping
Both accurate +-3%
Must have digital readout within 6” of the control valve

Question 5

Flowmeter appliations

Answer 5

Diagnosing waterflow problems (kink or partially closed valve, burst line)
Relay pumping (throttle up till flowmeter no longer increases)
Standpipe operations (add up flows of all lines and pump to that flow, but have to lower pressure if line is closed or use pressure governor)

Question 6

Hydraulic calculators

Answer 6

Manual or electronic

Calculate PDP without mental calcs

Question 7

Pump chart

Answer 7

Specific to each dept

Round to 5 psi

Question 8

Condensed Q

Answer 8

3”: FL=Q^2 (remember Q is gpm flowing/100)
Result is 20% higher than Cq^2L
4”: FL=Q^2/5
5”: FL=Q^2/15

Question 9

GPM Flowing

Answer 9

2.5”=Drop 10
Not applicable if flowing <160 gpm
Note: gpm increases 1 psi per 100 ft for every 10 gpm increase
1.5”=FL for 2.5” flowing 4x water for 50-75 gpm
80-100 gpm each 5 psi incr is 3 psi of FL
105-125 gpm each 5 psi incr is 4 psi of FL