CH 13 Set:01 Fire Hydrant Types, Operations, and Maintenance

What may provide the initial water supply at a fire?

The pumper's tank may provide initial water.

What nearby source is generally more dependable for water supply?

Nearby hydrants generally provide a more dependable, consistent volume under pressure.

When must an alternative water supply be selected?

When hydrants cannot provide sufficient volume or pressure.

What hydrant or piping damage can reduce water supply?

Damaged hydrant valves or connections, broken water mains, and frozen pipes or hydrants.

What distribution-system conditions can reduce hydrant supply?

Demand exceeding capacity, dead-end mains, closed isolation valves, and restricted mains.

What must firefighters know about local hydrants?

Their types, markings, use, inspection, and maintenance.

Who may test fire hydrants?

Firefighters, inspectors, water-department personnel, or private contractors.

What materials commonly make up a hydrant?

Cast-iron bonnet, barrel, and foot piece; bronze internal working parts; and rubber, leather, or composite valve facings.

What are the two primary North American hydrant types?

Dry-barrel and wet-barrel.

What outlets does a standard hydrant have?

At least one 4- or 4½-inch pumper outlet and two outlets for 2½-inch hose couplings.

What valve opening and water-main connection does a standard three-way hydrant have?

A 5-inch valve opening and a 6-inch connection to the water main.

What must hydrant discharge threads match?

The female hose couplings used by the local fire department.

Where are dry-barrel hydrants used?

In freezing climates.

Where is the main valve of a dry-barrel hydrant located?

At the base below the frost line.

What additional supply valve does a dry-barrel hydrant have?

An isolation valve on its distribution line.

Where is a dry-barrel hydrant's operating stem nut?

On top of the hydrant.

When does water enter a dry-barrel hydrant?

When its operating stem opens the main valve.

Which direction opens a dry-barrel hydrant?

Counterclockwise.

How does a dry-barrel hydrant drain after shutdown?

The main valve rises and stops incoming water while the drain plate rises to uncover the drain hole.

Why must a dry-barrel hydrant be fully open or fully closed?

A partly open drain can release water into the soil, erode support around the base, cause leaks, and require reinstallation.

Where are wet-barrel hydrants generally installed?

In climates without prolonged subfreezing weather.

How is flow controlled on wet-barrel hydrants?

Usually by a horizontal compression valve at each outlet.

What actions are required when a hydrant is out of service?

Tag or mark it, notify response-district fire personnel, and notify repair personnel.

What can water bubbling from the ground around a fully open dry-barrel hydrant indicate?

A damaged component allowing water past the drain opening.

What circumstances can put a hydrant out of service?

Damage to the hydrant, piping, or supporting pump; system repairs or upgrades; internal obstructions; or freezing.

What tools are commonly used for hydrant connections?

Spanner wrenches, hydrant wrenches, rubber mallets, gate valves, and hydrant valves.

What are the main uses and features of a hydrant wrench?

It removes outlet caps and operates valves.

How can a rubber mallet help with hose couplings?

Striking coupling lugs helps tighten or loosen connections.

How does a gate valve control hydrant flow?

Turning its screw-type handle lowers or raises a baffle in the waterway.

What four functions can a hydrant supply valve provide?

Allow additional lines, connect a supply pumper, boost pressure, and charge that line before another pumper arrives.

When is a hydrant supply valve especially useful?

During a forward lay from a low-pressure hydrant to the incident.

What hose-clamp handling precaution does the outline emphasize?

Never stand over the handle when applying or releasing the clamp.

How often should hydrants be operated and inspected?

At least annually.

What operations require familiarity with hydrant use?

Supplying suppression water, flushing sediment, inspecting valves and caps, and assisting with flow tests.

Why must hydrants be opened slowly?

Rapid opening can make the hose flail and injure personnel.

Why must hydrants be closed slowly?

Rapid closure causes water hammer that can damage piping and equipment.

What must be verified after closing a dry-barrel hydrant?

That water is draining from its barrel.

How does the outline describe checking dry-barrel hydrant drainage?

Close until resistance is felt, turn back a quarter-turn, cap all but one outlet, and feel for a slight inward vacuum.

What should be done if a dry-barrel hydrant shows no drainage vacuum?

Repeat the check; if it still fails, report a probably plugged drain.

How can a hydrant with only two 2½-inch outlets supply a pump?

Use two 2½- or 3-inch lines connected to a siamese at the pump.

What larger-hose connection does the outline describe for a hydrant with only 2½-inch outlets?

Connect a 4½-inch or larger intake hose using the appropriate reducer coupling.

Why do hard-intake hydrant connections require coordination and teamwork?

Rigid intake hose generally takes more people and is harder to connect than soft intake hose.

What determines apparatus positioning for a hard-intake hydrant connection?

Hydrant distance from the road, outlet direction, and the location of the apparatus intake.

What initial apparatus position does the outline suggest for an intake connection?

Stop with the selected pump intake just ahead of the hydrant outlet.

Which end of hard intake is connected first during hydrant operations?

The apparatus or hydrant end, according to local protocol.

Where may hard intake marked FOR VACUUM USE ONLY be used?

Only for drafting from a static source.