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Types of Ladders

ladder parts
Portable Ladder Categories and Capacities.
(Click to enlarge)

Ladders are often the first tool we choose when working at elevation. This may explain why more workers are injured in falls from ladders than from any other elevated surface - roofs, scaffolds, balconies, even stairs. Why do workers fall from ladders?

Most falls happen because workers select the wrong type of ladder for their job or they set up the ladder improperly and the ladder shifts or slips unexpectedly. Workers also fall when they're not working safely on the ladder - their foot slips, they lose their balance, they overreach, or something knocks the ladder over.

Ladder Selection

Be sure the ladder being used has the proper duty rating to carry the combined weight of the user and the material being installed. A ladder's duty rating tells you its maximum weight capacity. There are five type classifications with associated duty ratings:

  • Type IAA - These are special duty ladders. Type IAA ladders are for extra-heavy-duty professional use only.
  • Type IA - These ladders have a duty rating of 300 pounds. Type IA ladders are recommended for extra-heavy-duty industrial use.
  • Type I - These ladders have a duty rating of 250 pounds. Type I ladders are manufactured for heavy-duty use.
  • Type II - These ladders have a duty rating of 225 pounds. Type II ladders are approved for medium-duty use.
  • Type III - These ladders have a duty rating of 200 pounds. Type III ladders are rated for light-duty use.

Check out this short audio clip by Dan Clark of the Here Dan reviews the two types of ladders, freestanding and self-supporting, and how employees can be safe using each.

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1. Why do most falls from ladders occur?

a. Too many workers on a ladder
b. Selecting the wrong ladder for the job
c. Rungs on the ladder break
d. Unstable ground

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Scissor Lift
Scissor lift.

Necessary Questions

Ask these questions before deciding on a ladder:

  • Will heavy items be held while on the ladder?
  • Does the elevated area require a long ladder that can be unstable?
  • Will work be performed at this height over an extended period of time?
  • Will working on a ladder require standing sideways or reaching?
  • Are there any obstructions preventing safe ladder use?

If the answer to any of these questions is "Yes," then you may need to consider using something other than a ladder. If possible, bring in other equipment such as a scissor lift or scaffolding.

2. Each of the following situations is a reason to reconsider using a ladder EXCEPT _____.

a. if you must work more than 15 feet in elevation
b. if you must work on the ladder sideways
c. if you must use heavy items while on the ladder
d. if the ground is uneven or unstable and can't be corrected

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Portable Ladders

ladder parts
Parts of a Ladder
(Click to enlarge)

Portable ladders help you access a work area or provide support while you work. Portable ladders make getting to a work area easy, but they can increase the potential for falls if not used properly. Portable ladders are versatile, economical, and easy to use. However, workers sometimes use them without thinking safety. The Bureau of Labor and Statistics reports that 20 percent of fatal falls at work occur from heights less than 15 feet (4.5 m), and 50 percent of fatal falls are from a height less than 35 feet (10.6 m).

Here are some OSHA requirements for using portable ladders:

  • The minimum clear distance between side rails for all portable ladders must be 11.5 inches (29 cm).
  • The rungs and steps of portable metal ladders must be corrugated, knurled, dimpled, coated with skid-resistant material or treated to minimize slipping.
  • Non-self-supporting and self-supporting portable ladders must support at least four times the maximum intended load; extra heavy-duty type 1A metal or plastic ladders must sustain 3.3 times the maximum intended load.
  • When portable ladders are used for access to an upper landing surface, the side rails must extend at least 3 feet (.9 m) above the upper landing surface. When such an extension is not possible, the ladder must be secured and a grasping device such as a grab rail must be provided to assist workers in mounting and dismounting the ladder.
  • A ladder extension must not deflect under a load that would cause the ladder to slip off its supports.

3. When portable ladders are used for access to an upper landing surface, the side rails must extend _____ above the upper landing surface.

a. four rungs
b. a minimum of 4 feet (1.3 m)
c. at least 3 feet (.9 m)
d. two rungs

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Extension Ladders

ladder parts
Extension ladder extended 3 feet above landing.

We use ladders to do all sorts of tasks, so it's not surprising that many types of ladders are available. Let's look at the most common types. Characteristics of extension ladders include:

  • They offer the most length in a general-purpose ladder.
  • They have two or more adjustable sections.
  • The sliding upper section must be on top of the lower section.
  • They are made of wood, metal, or fiberglass.
  • The maximum length of extension depends on material
  • They support only one worker.

4. Which type of ladder offers the most length for general purpose jobs?

a. Straight ladder
b. Extension ladder
c. Articulating ladder
d. Folding ladder

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ladder parts
This image shows a standard folding ladders

Folding and Platform Ladders

Standard folding ladders have flat steps, a hinged backs and are not adjustable.

  • Use them only on firm, level surfaces.
  • They are available in metal, wood, or reinforced fiberglass.
  • they must have a metal spreader or locking arm and cannot exceed 20 feet.
  • They only support one worker.

Platform Ladders: The platform ladder is a self-supporting portable ladder that is non-adjustable in length, with a platform provided at the highest intended standing level.

  • It has a hinged design for ease of storage and is intended for use by one person.
  • The top platform is surrounded on three sides by a railing that is at least 20 inches higher than the platform surface.
  • A folding Bucket (Pail) Shelf may also be provided.

5. How many persons may work on a folding or platform ladder?

a. 4
b. 3
c. 2
d. 1

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Straight or Single Ladders

ladder parts
This image shows a straight or single ladder.

The most common type of portable ladder is a straight or single ladder. It is a non-self-supporting portable ladder that is non-adjustable in length, consisting of one section. Unlike a stepladder that requires level support for all four of its side rails, the Single Ladder requires only two level ground support points in addition to a top support. Ladder levelers may be used to achieve equal rail support on uneven surfaces. (American Ladder Institute)

  • It is intended for use by one person.
  • The length cannot exceed 30 feet.
  • It is available in wood, metal and reinforced fiberglass.
  • It supports only one worker.
  • The top support allows tie off the top of the ladder to increase stability.

6. Which of the following is a non-self-supporting ladder?

a. Platform ladder
b. Folding ladder
c. Straight ladder
d. Articulating ladder

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Articulated Ladders

ladder parts
This image shows an articulated ladder with locking hinges.

An Articulated Ladder is a portable ladder with one or more pairs of locking hinges which allow the ladder to be set up in several configurations such as a single or extension ladder, with or without a stand-off, a stepladder, a trestle ladder, scaffold or work table. (American Ladder Institute)

  • Each pair of articulated joints in the ladder can be locked in one or more positions to accommodate the various configurations.
  • The locking positions of the hinges allow set-up at the proper angles to accommodate each configuration that the manufacturer has designated.
  • When set up in the stepladder configuration, Articulated Ladders range in size from 3 to 15 feet maximum.
  • When set up as a Single or Extension Ladder, Articulated Ladders may have a length of no more than 30 feet.
  • Heavy duty, extra heavy duty, and special duty types (I, IA, and IAA) multipurpose ladders are designed for one or two persons. (Werner Ladders)

7. Which type of articulated (multipurpose) ladder is designed for one or two persons?

a. Types I, IA, and II
b. Types IA, III, and IV
c. Types I, IA, and IAA
d. Types I, II, and III

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ladder parts
This image shows a standard job-made double-cleated ladder.

Double-Cleated Ladders

Double-Cleated ladders are built with a center rail and two cleats that allow travel up and down the ladder at the same time.

  • This ladder is useful when ladders are the only way to enter or exit a working area that has more than 25 employees.
  • More than one person is allowed on the ladder at any time.

8. What is an advantage when using double-cleated ladders?

a. Allows workers to exit and enter a work area at the same time
b. Allows two persons to work on the ladder
c. It is designed for left- and right-handed workers
d. It is easy to make with scrap lumber

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Tripod Ladders

ladder parts
Tripod ladder in an orchard.

Tripod (Orchard) Ladder have a flared base and a single back leg that provides support on soft, uneven ground. Those who use tripod ladders include tree surgeons, topiary specialists, institutional and estate gardeners, orchard owners, hedging contractors, permaculturists and landscapers.

  • The length cannot exceed 16 feet.
  • Metal and reinforced fiberglass versions are available.
  • It supports only one worker.

9. How high may a tripod ladder extend?

a. 12 feet
b. 16 feet
c. 20 feet
d. 25 feet

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Extension Trestle Ladders

123 rf photo
Extension Trestle ladder.

The Extension Trestle Ladder is a self-supporting portable ladder that is adjustable in length, consisting of a Trestle Ladder base and a vertically adjustable Extension section with a means for locking the ladders together. These ladders are often used in pairs to support a scaffold plank. They are intended for use by one person.

  • They have two sections that are hinged at the top and form equal angles with the base.
  • They are used in pairs to support planks or staging.
  • The rungs are not used as steps.
  • The length cannot exceed 20 feet.

For more information on extension trestle ladders, see the American Ladder Institute's webpage.

10. Which type of ladder is often used in pairs to support a scaffold plank?

a. Straight ladder
b. Standard folding ladder
c. Scaffold ladder
d. Extension trestle ladder

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Job-Made Ladders

ladder parts
Single-cleat job-made ladder specifications.

A job-made wooden ladder is a ladder constructed at the construction site. It is not commercially manufactured. A job-made wooden ladder provides access to and from a work area. It is not intended to serve as a work platform. These ladders are temporary, and are used only until a particular phase of work is completed or until permanent stairways or fixed ladders are installed.

Side Rails:
  • Side rails of single-cleat ladders up to 24 ft. long should be made with at least 2x6 in. lumber.
  • Single-rung ladder width should be at least 16 in., but not more than 20 in. btw. rails measured inside to inside.
  • Rails should extend above the top landing between 36 in. (91.5 cm) and 42 in. to provide a handhold for mounting and dismounting, and cleats must be eliminated above the landing level.
  • Must be equally spaced 12 inches on center from the top of one cleat to the top of the next cleat.
  • Cleats should be fastened to each rail with three 12d common nails, nailed directly to the side rails.
  • Cleats should be at least 1x4 in. for ladders 16 to 24 ft. long.
Filler Blocks:
  • Minimum 2x2 in. wood strips inserted btw. cleats
  • The ladder is complete when filler is nailed at the top of each rail.

For more information on job-built ladders, see OSHA Fact Sheet 3661, Reducing Falls in Construction: Safe Use of Job-made Wooden Ladders.

11. Each of the following statements regarding job-made ladders is true EXCEPT _____.

a. they are not to be used as work platforms
b. they are meant as temporary ladders
c. they are commercially manufactured
d. they are used only until a phase of work is completed

Check your Work

Read the material in each section to find the correct answer to each quiz question. After answering all the questions, click on the "Check Quiz Answers" button to grade your quiz and see your score. You will receive a message if you forgot to answer one of the questions. After clicking the button, the questions you missed will be listed below. You can correct any missed questions and check your answers again.

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