Pumping Apparatus Driver/Operator — Lesson 12 Pumping Apparatus Driver/Operator Handbook, 2 nd Edition Chapter 12 — Static Water Supply Sources

Pumping Apparatus Driver/Operator — Lesson 12

Pumping Apparatus Driver/Operator Handbook, 2nd Edition

Chapter 12 — Static Water Supply Sources

Pumping Apparatus Driver/Operator

12–2

Learning Objectives

1.Match to their definitions terms associated with static water sources.

2.Select facts about theoretical, maximum, and dependable lift.

3.State the equation for determining the maximum lift that a pumper can achieve.

(Continued)


12–3

Learning Objectives

4.Calculate maximum lift.

5.State the equations for determining pressure correction and net pump discharge pressure at draft.

6.Calculate net pump discharge pressure at draft.

(Continued)


12–4

Learning Objectives

7.List types of natural static water supply sources.

8.State the equation for determining the adequacy of a natural stream.

9.Calculate natural stream adequacy.

10. Answer questions about the accessibility of natural static water supply sources.

(Continued)


12–5

Learning Objectives

11. Dam a stream with a ladder and salvage cover.

12. List common types of man-made static water supply sources.

13. Select facts about various man-made static water supply sources.

(Continued)


12–6

Learning Objectives

14. State the equations for determining the capacity of various kinds of pools.

15. Calculate swimming pool capacities.


12–7

Static Water Source Terms

• Drafting — Raising water from a static source to supply a pumper

• Lift — Elevation difference between static water source and pump intake

(Continued)


12–8


• Vacuum — The pressure differential between the inside of the pump and intake hose and the atmosphere that allows water to be forced into the hose and pump

• Theoretical lift — Vacuum that would allow water to be raised by atmospheric pressure to a height in accordance with this pressure

(Continued)


12–9


• Maximum lift — The maximum height to which any amount of water may be raised through a hard intake hose to the pump

• Dependable lift — The height a column of water may be lifted in sufficient quantity to provide a reliable fire flow


12–10

Theoretical Lift

• Customary — At sea level a pump can theoretically lift water 33.8 feet. For every 1,000 feet of altitude, atmospheric pressure decreases by about 0.5 psi.

• Metric — At sea level a pump can theoretically lift water 10 m. For every 100 m of altitude, atmospheric pressure decreases by about 1 kPa.

(Continued)


12–11

Theoretical Lift

• Because a total vacuum is not possible in field conditions, fire department pumpers cannot be expected to draft water that is located 33.8 feet (10 m) below the level of the pump.


12–12

Maximum Lift

• Varies depending on the atmospheric pressure and the condition of the fire pump and primer

• Is no more than 25 feet (7.5 m) in most circumstances


12–13

Calculating Maximum Lift

• Customary

L = 1.13 Hg

L = Height of lift in feet

1.13 = A constant

Hg = Inches of mercury

(Continued)


12–14

Calculating Maximum Lift

• Metric

L = (0.013 56)(Hg)

L = Height of lift in meters

0.013 56 = A constant

Hg = mm of mercury


12–15

Dependable Lift

• Every fire pump in good repair should have a dependable lift of at least 14.7 feet (4.5 m).

• This takes into account:– Surrounding atmospheric pressure– Friction loss in the intake hose

(Continued)


12–16

Dependable Lift

• All fire pumps are rated when drafting from a lift of 10 feet (3 m) through 20 feet (6 m) of hard intake hose.

• As the lift or length of intake hose is increased, the capacity of the pump decreases accordingly.


12–17

Determining Pressure Correction

• Customary

Pressure correction =

Lift + Total intake hose friction loss

2.3

• Metric

Pressure correction =

Lift + Total intake hose friction loss

0.1


12–18

Determining Net Pump Discharge Pressure at Draft

NPDPDraft = PDP + Intake pressure correction

NPDPDraft = Net pump discharge pressure at draft

PDP = Pump discharge pressure in psi or kPa


12–19

Natural Static Water Supply Sources

• Lakes

• Ponds

• Rivers

• Oceans


12–20

Adequacy of Natural Static Water Supply Source

• The adequacy of large sources is generally not a major issue. However, fire department personnel must evaluate small streams and ponds with more caution when determining their adequacy for fire protection.


12–21

Calculating Natural Stream Adequacy

• Customary

Q = A x V x 7.5

Q = Flow in gpm

A = Area in ft2 (width x depth)V = Velocity in ft/min

7.5 = A constant (the number of gallons per ft3)

(Continued)


12–22


• Metric

Q = A x V x 1 000

Q = Flow in L/min

A = Area in m2 (width x depth)V = Velocity in m/min

1 000= A constant (the number of liters per m3)

(Continued)


12–23


• The rule of thumb for evaluating pond and small lake capacity is that every 1 foot (0.3 m) of depth of an area of 1 acre (0.4 ha) (approximately the size of a football field) provides 1,000 gpm (4 000 L/min) for 5 hours.


12–24

Accessibility of Natural Static Water Supply Sources

• Common problems include:– Inability to reach the water with a pumper– Wet or soft ground approaches– Inadequate depth for drafting– Silt and debris– Freezing weather


12–25

Inability to Reach the Water with a Pumper

• Bridges too high above the water’s surface

• Bridges that will not support the weight of the fire apparatus

• Extremely high banks

• Terrain that will not allow the apparatus close enough to reach the water with intake hoses

(Continued)


12–26

Inability to Reach the Water with a Pumper

• Problems can be avoided by:– Using public boat launching facilities– Constructing gravel drives– Installing dry hydrants– Clearing brush to drafting points with a

high potential for use– Noting appropriate drafting sites in pre-

incident plans


12–27

Wet or Soft Ground Approaches

• Soggy approaches may not support the weight of fire department apparatus.

• Grass and vegetation can obscure holes and soft spots.

• Settling may occur after a vehicle stops for a period of time.

(Continued)


12–28

Wet or Soft Ground Approaches

• Frozen ground that allows the apparatus to be safely driven across at first may later thaw out and cause the apparatus to sink in place.

• Very marshy land or land with a high sand content may be too soft to support the weight of the apparatus.


12–29

Inadequate Depth for Drafting

• A depth of 2 feet (0.6 m) of water is suggested above and below a barrel-type strainer.

• Floating strainers may be used if water is not deep enough for barrel-type strainers. These strainers allow safe drafting from water as shallow as 1 foot (0.3 m) deep.

(Continued)


12–30

Inadequate Depth for Drafting

• Low-level strainers can draft from portable water tanks and can draw water down to a 1- to 2-inch (25 mm to 50 mm) depth.

• In small, fast streams with inadequate draft depth, a ladder and salvage cover can be used to dam the stream and raise the water level to permit drafting.


12–31

Silt and Debris

• May clog the strainer, resulting in reduced water intake

• May cause seizing-up or damage to fire pumps

• May clog fog stream nozzles

(Continued)


12–32

Silt and Debris

• All hard intake lines should have strainers attached when drafting from a natural source.

• The intake hose should be located and supported so that the strainer does not rest on or near the bottom to avoid getting dirt and debris into the strainer.

(Continued)


12–33

Silt and Debris

• Either a single ladder or a roof ladder can be used to keep the strainer off the bottom.

(Continued)


12–34

Silt and Debris

• Can be avoided by the installation of a dry hydrant– Allows access to natural sources without

the set-up time required for a regular drafting operation

– Avoids the wet ground approach problem and can circumvent the problem of silt and debris when installed properly


12–35

Aiding Access to Frozen Ponds and Lakes

• Barrels filled with antifreeze solution are floated on the water’s surface before the water freezes. If the need to draft arises, the top and the bottom of the barrel may be knocked out to provide an access hole for the intake hose and strainer.

(Continued)


12–36


• Wooden plugs or plastic garbage cans are stabilized at a location so that they may be driven through the ice if the need to draft arises.

• It may be necessary to cut a hole through the ice using an axe, chain saw, or power auger.

(Continued)


12–37


CAUTION! Extreme caution should be taken when operating on the ice. Provisions for making an ice rescue should be on scene before firefighters begin working on the ice. All firefighters working in close proximity to bodies of water must wear personal flotation devices (PFDs).


12–38

Swift Water

• The current may make it difficult to keep the strainer submerged below the surface of the water.

• All firefighters working near the water’s edge must wear a PFD.


12–39

Man-Made Water Supply Sources

• Cisterns

• Private water storage tanks

• Ground reservoirs

• Swimming pools

• Agricultural irrigation systems


12–40

Cisterns

• Underground water storage receptacles found in areas not serviced by a hydrant system

• Receive water from wells or rainwater runoff

(Continued)


12–41

Cisterns

• Are usually for domestic or agricultural use

• Some are placed for fire department use as a backup if the water supply system fails

• Sizes from 10,000 to 100,000 gallons (40 000 L to 400 000 L) are common

(Continued)


12–42

Cisterns

• May be accessed by:– A manhole-type cover that is removed to

provide access for intake hose and strainer– Attached dry hydrant arrangement that

allows for quick connection by a fire department pumper

• May be susceptible to freezing if not below the frost line


12–43

Private Water Storage Tanks

• Are commonly found on large residential, industrial, and agricultural properties

• Range in size from several hundred to many thousands of gallons (liters)

• May be at ground level or elevated

(Continued)


12–44

Private Water Storage Tanks

• May not be reliable, depending on:– Size,– Amount of water inside

at time of fire, and – Appropriate

connections for fire apparatus


12–45

Ground Reservoirs

• Man-made impoundments that have same characteristics as a pond or small lake

• Are commonly found on commercial or industrial properties and at municipal water treatment facilities

(Continued)


12–46

Ground Reservoirs

• Typically contain many millions of gallons (liters) of water

• Are typically more accessible than regular ponds or lakes

• May include dry hydrants to speed their use


12–47

Swimming Pools

• May be difficult to access due to security measures (fences)

• The pump should be flushed with clear water after drafting from a swimming pool to remove any access chlorine from the pump and piping.


12–48

Calculating Swimming Pool Capacities (Square/Rectangular)

• Customary

Capacity in gallons = L x W x D x 7.5

L = Length in feet

W = Width in feet

D = Average depth in feet

7.5 = Number of gallons per cubic foot

(Continued)


12–49

Calculating Swimming Pool Capacities (Square/Rectangular)

• Metric

Capacity in liters = L x W x D x 1 000

L = Length in meters

W = Width in meters

D = Average depth in meters

1 000 = Number of liters per cubic meter


12–50

Calculating Swimming Pool Capacities (Round)

• Customary

Capacity in gallons = x r2 x D x 7.5

(Pi) = 3.14

r = Radius or ½ the diameter in feet

D = Average depth in feet

7.5 = Number of gallons per cubic foot

(Continued)


12–51

Calculating Swimming Pool Capacities (Round)

• Metric

Capacity in liters = x r2 x D x 1 000

(Pi) = 3.14

r = Radius or ½ the diameter in meters

D = Average depth in meters

7.5 = Number of liters per cubic meter


12–52

Agricultural Irrigation Systems

• May flow in excess of 1,000 gpm (4 000 L/min)

• Usually transport water one of two ways:– Open canals– Portable pipes


12–53

Summary

• Although many cities and towns have pressurized water systems that supply fire hydrants throughout the jurisdiction, other entities do not have these vital fire fighting facilities. In these cases, fire departments must rely on water tenders or static water sources in fixed locations.

(Continued)


12–54

Summary

• Regardless of what static sources may be available, departments who depend on these sources for fire fighting water must know where the sources are located, the approximate capacity of these sources, and what impediments may exist that could prevent the department from using the water contained in them.


12–55

Discussion Questions

1.What is the equation for determining maximum lift?

2.What is the equation for determining pressure correction?

3.What is the equation for determining net pump discharge pressure?

4.Name types of natural static water supply sources.

(Continued)


12–56

Discussion Questions

5.What is the equation for determining the adequacy of a natural stream?

6.Name some common types of man-made static water supply sources.

7.What is the equation for determining the capacity of a square/rectangular swimming pool?

8.What is the equation for determining the capacity of a round swimming pool?

Documents

Pumping Apparatus Driver/Operator — Lesson 12 Pumping Apparatus Driver/Operator Handbook, 2 nd Edition Chapter 12 — Static Water Supply Sources