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Ladders, Types and Components of Ladders

Ladders:

A ladder is a vertical or inclined set of rungs or steps. There are two types: rigid ladders that can be leaned against a vertical surface such as a wall, and rope ladders that are hung from the top. The vertical members of a rigid led are called stringers or rails rigid ladders are usually portable but some types are permanently fixed to buildings. They are commonly made of metal, wood, or fiberglass, but they have been known t be made of tough plastic.

Primary Functions of a Ladder: –

  • It Provide a vertical path between grades.
  • It Provides an escape path and a means to evacuate people.
  • Ladders can be used as a working platform.

Secondary Functions of a Ladder: –

  • It Provides stable footing and distribute weight on pitched roofs.
  • It Creates a ladder gin to raise or lower people or objects.
  • Ladders provide a platform for equipment.
  • It Creates a ramp for equipment or patients.
  • It Creates a water chute with use of trap/salvage cover.

Purpose:

Ground Ladders provide firefighters a means of safe access and egress, above and below ground for rescue, ventilation and fire fighting purposes.

It may also be used as bridging, ladder drain, catch basin, PPV, ladder sling, portable sump and other applications.

Location:

Engine Companies, Truck Companies.

Components:

Bed Section -Base or lowest section of an extension ladder.

Fly Section – Upper section of an extension ladder.

Butt – Bottom of the ladder:

Spurs – Metal safety plates on butt used for stabilization (aluminium or steel) Beam – Main structural member of ladder that supports the rungs.

Rungs:

  • Dogs/Pawls/Locks – Locks that hold the fly section up.
  • Halyard -Nylon rope used to extend fly section.
  • Pulley-Grooved wheel that halyard is pulled through.
  • Anchor -Connected to the bottom of the bed to hold halyard rope.
  • Guides -Slots or channels that fly section is raised.
  • Stops -Metal pieces that prevent fly from extending to far.
  • Tips -Top of the ladder.
  • Heat Sensors -Indicates exposure to excessive heat.
  • Hooks -used to secure to roofs. Made of cold rolled steel.

Basic Construction:

  • Incorporates 3 1/4″ C-Channel beam with rung plates, riveted for strength.
  • 1 1/4″ corrugated rungs are welded and expanded, spaced 14″ apart.
  • 1/2″ Nylon rope halyard. Open truss type.
  • Two metal rails connected by aluminium truss blocks.
  • Truss blocks support the rungs.

24′ Extension Ladders:

  • 900A, made by Duo Safety in Oshkosh, Wisconsin.
  • Aluminium (6061-T6) solid beam construction.
  • 72 pounds.
  • 24’6″ full extended with a maximum reach of 23’6″.
  • 21 3/4″ bed section width. 19″ fly section width.
  • Rungs made with a two-step process, weld and expanding the rungs (24).
  • Rated at 750 lbs. working load with a 4 to 1 safety margin (3, 000 pounds).
  • Meet/exceed all applicable standards established by NFPA 1931.

14′ Roof Ladder:

  • 775A series, made by Duo Safety in Oshkosh, Wisconsin.
  • Aluminium (6061-T6) solid beam construction.
  • 28 pounds. 14’2″ long.
  • 19′ bed section width. Rungs are made with a two-step process, weld and expanding the rungs (9).
  • Rated at 750 lbs. working load with a 4 to 1 safety margin (3, 000 pounds).
  • 3/4″ Roof hooks, tested to 2, 000 pounds.
  • Meet/exceed all applicable standards established by NFPA 1931.

10′ Attic Ladders:

  • 585A series, made by Duo Safety in Oshkosh, Wisconsin.
  • Aluminium (6061-T6) hinged beam construction.
  • 16 pounds.
  • 101″ long open, 11’1/4″ long closed.
  • 13. 25″ open width.
  • 6 total rungs, have swivel footpads. Rated at 300 lbs. working load.
  • Meet/exceed all applicable standards established by NFPA 1931.

Single Ladder:

  • Primary advantage of the single or straight ladder.
  • Can be quickly placed into service by a single fire fighter.
  • Single section/single bed.
  • Fixed length.
  • Length vary from 6-32 feet.
  • Most common lengths range from 12-24 feet.

Roof ladders:

  • Roof ladders are single ladders that have hooks attached to the tip end.
  • Hooks nested between the beams at the tip of the ladder.
  • Used to anchor the ladder when used on a pitched roof.
  • Lengths vary from 12-24 feet.

Folding ladder (attic ladder):

  • A special type of single ladder that have hinged rungs.
  • Can be folded into a compact assembly with one beam resting against the other.
  • Narrower when open than regular single ladders.
  • Lengths range from 8-16 feet.
  • Most common length is 10 feet.

Extension ladders:

  • A ladder that has two or more sections.
  • Fly sections manually raised and lowered by a halyard, or halyard and cable to permit length adjustment.
  • Preferred to by the fully extended length.
  • Lengths normally range from 12-35 feet.

Pole ladders (Bangor ladder):

  • Extension Ladder Extension ladders that have stay poles added for stability.
  • Manufactured with 2-4 sections.
  • Lengths vary from 40-65 feet.
  • Most do not exceed 50 feet.

Combination ladders:

  • Uses:
  • Step ladder.
  • Single or straight ladder.
  • Extension ladder.
  • Lengths range from 8-14 feet.
  • Most popular is the 10 foot model.

Ladders reach:

  • The designated length of a ladder derived from a measurement of the maximum extend length.
  • This is not the ladders true reach.
  • Reach will be less than the designated length:
  • Reach is the total length of a ladder from ground to tip when set at a 70″ angle.
  • NFPA allows ladders under 35 feet to reach 1 foot less than stated.

Next Post:-

Operations, Commands, Maintenance of ladders.