Essentials of Fire Fighting, 5th Edition

Chapter 12 — Water Supply

Firefighter I

Firefighter I12–2

Chapter 12 Lesson Goal

• After completing this lesson, the student shall be able to make hydrant connections and draft from a static water source according to the authority having jurisdiction (AHJ).

Firefighter I12–3

Specific Objectives

1.Describe dry-barrel and wet-barrel hydrants. 2.Discuss fire hydrant marking and location. 3.Summarize potential problems to look for when inspecting fire hydrants.

(Continued)

Firefighter I12–4

Specific Objectives

4.Explain the process of fire hydrant testing. 5.Discuss alternative water supplies. 6.Discuss rural water supply operations.7.Operate a hydrant. (Skill Sheet 12-I-1) (Continued)

Firefighter I12–5

Specific Objectives

8.Make soft-sleeve and hard-suction hydrant connections. (Skill Sheet 12-I-2)9.Connect and place a hard-suction hose for drafting from a static water source. (Skill Sheet 12-I-3)10. Deploy a portable water tank. (Skill Sheet 12-I-4)

Firefighter I12–6

Hydrants

• Usually made of cast iron with bronze working parts

• Must be opened and closed slowly to prevent damage

Firefighter I12–7

Dry-Barrel Hydrants

• Installed in areas where prolonged periods of subfreezing weather are common

• Have main valve located below frost line that prevents water from entering hydrant barrel (Continued)

Firefighter I12–8

Dry-Barrel Hydrants

• Operation• Must be completely

open or closed to prevent leaking

• When shutting down, verify that water left in hydrant barrel is draining out (Continued)

Firefighter I12–9

Dry-Barrel Hydrants

• In some areas, hydrants must be pumped out after each use to prevent water contamination

• If water is bubbling out of ground, broken component in barrel is allowing water to get past drain opening

Firefighter I12–10

Wet-Barrel Hydrants

• Installed in warmer climates where prolonged periods of subfreezing weather uncommon

• Horizontal compression-type valve at each outlet

• Always filled with water

Firefighter I12–11

Fire Hydrant Marking

• Rate of flow from individual hydrants varies for several reasons

• NFPA® has developed system of marking hydrants

• Local color-coding may differ from NFPA®

Firefighter I12–12

DISCUSSION QUESTION

What types of fire hydrant marking systems are used in your area?

Firefighter I12–13

Fire Hydrant Locations

• Decisions usually made by water department personnel based on recommendations from fire department

• Should not be spaced more than 300 feet (100 m) apart in high-value districts

(Continued)

Firefighter I12–14

Fire Hydrant Locations

• Locate hydrant at every other intersection

• Intermediate hydrants may be required where distances between intersections exceed 350 to 400 feet (105 to 120 m)

• Other factors affect location/spacing

Firefighter I12–15

Hydrant Testing and Inspections

• Responsibility of fire department personnel

• Firefighters should look for wide array of items

Firefighter I12–16

Fire Hydrant Testing Process

• Many departments no longer responsible for testing

• Most basic test normally conducted is flow test

Firefighter I12–17

Flow Test Steps

• Select hydrant• Remove all outlet caps• Inspect outlet threads• Lubricate all outlet threads• Replace all caps except one 2½-

inch (65 mm) cap

(Continued)

Firefighter I12–18

Flow Test Steps

• Connect cap-type pressure gauge to outlet on second hydrant nearby

• Turn second hydrant on, record static pressure

• Turn test hydrant on fully, allow water to flow briefly

(Continued)

Firefighter I12–19

Flow Test Steps

• Use pitot tube, gauge to measure flow rate

• Record pitot gauge reading

(Continued)

Firefighter I12–20

Flow Test Steps

• Take/record residual pressure reading from gauge connected to second hydrant before shutting test hydrant off

• Turn off second hydrant, remove gauge, replace cap

• Turn off test hydrant(Continued)

Firefighter I12–21

Flow Test Steps

• Test for vacuum created by operating drain valve (dry barrel)

• Replace cap on outlet• Repeat procedure with each

hydrant

Firefighter I12–22

DISCUSSION QUESTION

What types of situations or areas would require an alternative source of water?

Firefighter I12–23

Alternative Water Supply Sources

• Lakes• Ponds• Rivers• Ocean• Swimming pools• Farm stock tanks• Underground cisterns

Firefighter I12–24

DISCUSSION QUESTION

Can you think of any other types of alternative water supplies?

Firefighter I12–25

Drafting From Alternative Water Supplies

• Process of drawing water from static source to pumper

• Can use almost any static source of water if sufficient in quantity, not contaminated

(Continued)

Firefighter I12–26

Drafting From Alternative Water Supplies

• Depth of water from which to draft

Firefighter I12–27

Dry Hydrants

• Installed at static water sources to increase water supply available

• Usually constructed of steel or PVC pipe with strainers at water source, steamer ports to connect to pumper

• Designed to supply at least 1,000 gpm (4 000 L/min) (Continued)

Firefighter I12–28

Water Shuttles

• Involve hauling water from supply source to portable tanks from which water may be drawn to fight fire

• Recommended for distances greater than ½ mile (0.8 km) or greater than the fire department’s capability of laying supply hoselines

(Continued)

Firefighter I12–29

Water Shuttles

• Critical elements– Fast-fill, fast-dump capabilities– Water supply officers at fill/dump

sites– Traffic control– Hydrant operations– Hookups– Tank venting

Firefighter I12–30

Water Shuttles

• Key components• Dump site• Portable tanks

(Continued)

Firefighter I12–31

Water Shuttles

• Ways in which water tenders unload– Gravity dumping– Jet dumps that increase

flow rate– Apparatus-mounted

pumps– Combination of these

methods(Continued)

Firefighter I12–32

Water Shuttles

• According to NFPA® 1901, water tenders on level ground should be capable of dumping/filling at rates of at least 1,000 gpm (4 000 L/min)

(Continued)

Firefighter I12–33

Water Shuttles

• To fill water tenders quickly, use best fill site, large hoselines, multiple hoselines

• Multiple portable pumps may be necessary

Firefighter I12–34

DISCUSSION QUESTION

What are the advantages and disadvantages of a water shuttle operation?

Firefighter I12–35

Relay Pumping

• Can be used in situations where water source is close enough to fire scene to render water shuttles unnecessary

• Factors to consider– Water supply must be capable of

maintaining desired volume of water– Relay must be established quickly (Continued)

Firefighter I12–36

Relay Pumping

• Determining number of pumpers needed and distance between them– Several factors to take into account– Apparatus with greatest pumping

capacity should be at water source

(Continued)

Firefighter I12–37

Relay Pumping

• Determining number of pumpers needed and distance between them – Large-diameter hose or multiple

hoselines increase distance, volume a relay can supply

– Water supply officer should consider all factors and determine correct distance

Firefighter I12–38

Summary

• Because water is still the primary fire extinguishing agent used by firefighters in North America, and because fires often occur considerable distances from major water sources, fire departments must develop ways to transport available water from its source to where it is needed.

(Continued)

Firefighter I12–39

Summary

• Firefighters must know what water supply systems have been developed and what their responsibilities are when these systems are used.

Firefighter I12–40

Review Questions

1.What is the difference between dry-barrel and wet-barrel hydrants?2.How are fire hydrants marked?3.What factors affect hydrant location and spacing?

(Continued)

Firefighter I12–41

Review Questions

4. List alternative water supplies. 5.What are three key components of a water shuttle operation?