Pump Manual - Pump Discharge Pressure + Special Pumping Scenarios

Question 1

Wyed lines with equal length, diameter and GPM

Answer 1

1. Add GPM for all nozzles and use as Q for calc’ing FL in supply line
   * 2. If total GPM >350, add 10 psi FL for wye appliance*
2. Calc FL in supply line
3. Calc FL for one discharge
4. Calc PDP by adding FL for supply and one discharge

Question 2

Wyed lines with unequal length, diameter, GPM flow

Answer 2

Same as equal length/diameter, flow, except:

Figure PDP by adding FL for supply + highest pressure handline….gate down lower pressure handline at the wye

Question 3

PDP for spinklers

Answer 3

GPM = 0.5 x P + 15 
P = sprinkler head pressure (typically 7-10 PSI)

Each open sprinkler head requires 20 GPM

Starting pressure should be 150 psi

Question 4

How many sprinklers can a 1750 gpm pumper supply @ 150 GPM?

Answer 4

88 heads

Question 5

Three types of standpipes

Answer 5

Class 1: 2 1/2” outlets for firefighting

Class 2: 1 1/2” hose outlets for occupant use

Class 3: Combination standpipe, integrates class 1 and class 2

Question 6

Appliance friction loss in master stream appliances

Answer 6

25 psi

…if over 350 gpm, which master streams are by definition

Question 7

Starting pressure at base of L31

Answer 7

200 psi

Question 8

Appliance friction loss when pumping an aerial lader

Answer 8

25 psi for waterway piping

+

25 psi for master stream appliance

Question 9

Constant pressure (“open”) relay

Answer 9

All pumpers in relay set the same discharge pressure, attack engine leaves an unused discharge port or waste line “open” to handle access water

Question 10

Maximum Distance Relay

Answer 10

determines how far a pre-determined amount of water can be pumped through a particular hose size

Max distance means maximizing the distance between pumpers in the relay

Question 11

Minimum intake residual pressure

Answer 11

20 psi

Question 12

Maximum net PDP

Answer 12

180 PSI

= 250 PSI pump rating - 50 PSI safety - 20 PSI intake residual = 180 PSI

Question 13

Estimating needed fire flow (NFF) in a relay

Answer 13

NFF = ( L x W x % involvement ) / 3

Question 14

Calculating max distance between pumpers in a relay

Answer 14

Max distance = (165 / FL ) x 100

FL is for 100 ft section
165 and 100 are constants

Question 15

Calculate # of pumpers needed in a relay

Answer 15

= ( Total distance of relay / Max distance ) + 1

Question 16

How much 5” LDH does an engine carry?

Answer 16

900’

Question 17

NFPA standard for max dependable flow for a relay pumper

Answer 17

75% of its rated capacity at draft

Question 18

Types of positive displacement pumps

Answer 18

Rotary vane
Rotary gear

They pump water and air out of the centrifugal pump which creates the partial vacuum necessary to draft water

Question 19

For every 1,000 ft increase in elevation, what happens when drafting?

Answer 19

For every 1000 ft increase in elevation,

• 0.5 psi decrease in atmospheric pressure
• loss of 1 ft in suction or lift in a fire pump

Question 20

Formula for determining lift in a draft: If inches of mercury are known…

Answer 20

Height of lift = 1.13 x (inches of mg)

Question 21

Formula for determining lift in a draft: If height of lift is known…

Answer 21

Inches mg = .885 x height of lift

Question 22

Types of foam systems on our apparatuses

Answer 22

CAFS
Foam Pro
Husky
Perce Quantum system

Generally we carry 40 gallons of Class A or Novacool; some engines carry three 5 gal buckets of AFFF for class B

Question 23

Class A Foam mechanism of action

Answer 23

It attracts carbon
It decreases surface tension of water
Raises moisture content of wood up to 50%
Absorbs 3x the BTUs compared to water alone

Question 24

Class B Foam Mechanism of action

Answer 24

Repels carbon
Forms a film that hovers over a spill
Prevents vapor production and ignition

Question 25

Eductor rates for Class A foam

Answer 25

Initial attack: 0.5%
Overhaul: 0.2%
Exposure protection: 1.0%
Wildland pre-treating: 0.1-0.2%

Question 26

Application rate for class b foam - hydrocarbons

Answer 26

0.1 GPM (foam solution) per sqft of fire (Critical Application Rate, CAR)

Min application run time of 15 min

Eductor rate = 3%

Question 27

Application rate for class b fires - polar solvents

Answer 27

0.2 GPM (foam solution) per sqft of fire (Critical Application Rate, CAR)

Min application run time of 15 mins

Eductor rate = 6%

Question 28

Formula for estimating foam concentrate needed on class B fires

Answer 28

concentrate needed = Area x CAR x Eductor rate x 15 mins

Question 29

Sqft of fire foam supply will cover with aeration nozzle attachment (hydrocarbons)

Answer 29

= (Gal of fam x Nozzle Expansion Ratio) / .045

Nozzle expansion ratio is usually 15

0.45 is a constant

Question 30

Sqft of fire foam supply will cover with aeration nozzle attachment (polar solvents)

Answer 30

= (Gal of fam x Nozzle Expansion Ratio) / .18

Nozzle expansion ratio is usually 15

.18 is a constant

Question 31

3-2-1 rule for foam

Answer 31

When flowing 1 3/4” handline using a portable eductor

• No more than 300’ of hose past the eductor
• 200 PSI to the eductor inlet
• Utilizing 100 PSI nozzle

Question 32

Application rates for novacool

Answer 32

Fire attack: 0.4%

Overhaul and brush fires: 0.1%