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Course 725 - Forklift Safety

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Types of Powered Industrial Trucks (PITs) - Forklifts

PIT Classifications

A forklift is a type of “powered industrial truck” (PIT) covered by OSHA standards. Like other powered industrial trucks, its purpose is to move, carry, push, pull, and lift a material load then stack it or place it in a storage rack (tier). Forklifts come in many sizes and capacities. They can be powered by batteries, propane, gasoline, or diesel fuel. Some are designed to be used in a hazardous location or atmosphere where an ordinary forklift might cause a fire or explosion.

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Class I Electric Motor Rider Trucks
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Powered industrial trucks are classified into seven types based on their characteristics. Each type of powered industrial truck has its own unique characteristics and some inherent hazards. Powered industrial trucks may operate on almost any surface, from smooth level floors to rocky uneven ground. Different trucks are designed and manufactured to operate in different work environments.

Class I Electric Motor Rider Trucks

These forklifts are equipped with either cushion or pneumatic tires. The cushion tired lift trucks are intended for use indoors on smooth floors. The pneumatic tired models are suitable for dry outdoor areas.

These vehicles are powered by industrial batteries and are generally found from the loading dock to the storage facility. They should also be used in areas where air quality factors need to be considered.

Class II Electric Motor Narrow Aisle Trucks

These forklifts are suitable for companies that have narrow aisles in their facilities to maximize the use of storage space. Class II vehicles have unique features that are designed to minimize the space occupied by the truck while improving speed and efficiency.

Class III Electric Motor Hand Trucks or Hand/Rider Trucks

These trucks are hand controlled by the operator who is in front of the truck. The operator controls the lift truck using a steering tiller. All of the controls are mounted on the top of the tiller which is moved side to side to steer the truck. Class III vehicles are battery powered with the smaller capacity units using industrial batteries.

class II
Class II Electric Motor Narrow Aisle Trucks
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class III
Class III Electric Motor Hand Trucks or Hand/Rider Trucks
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class IV
Class IV Internal Combustion Engine Trucks (Solid/Cushion Tires)
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class V
Class V Internal Combustion Engine Trucks (Pneumatic Tires)
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class IV
Class VI Electric and Internal Combustion Engine Tractors
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class VII
Class VII Rough Terrain Forklift Trucks
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Class IV Internal Combustion Engine Trucks (Solid/Cushion Tires)

These forklifts are used primarily inside on smooth dry floors. They typically load, transfer, and unload palletized loads in manufacturing plant/warehouse loading docks and storage areas. The cushion tired forklifts are lower to the ground than pneumatic tired forklift trucks, which is more useful in low clearance areas.

Class V Internal Combustion Engine Trucks (Pneumatic Tires)

Class V trucks are the most common type of forklifts for inside or outside use in warehouses and other areas. They are powered by internal combustion engines and are available for use with LPG, Gasoline, Diesel, and Compressed Natural Gas fuel systems.

Class VI Electric and Internal Combustion Engine Tractors

These forklifts are versatile and can be used in various areas. They are equipped with either internal combustion engines for outdoor areas of use or battery powered electric motors for indoor use.

Class VII Rough Terrain Forklift Trucks

These forklifts have large flotation type tires for outdoor use on uneven and rough surfaces. They are most often used at construction sites to transport and lift materials to various locations and levels on the worksite. You will also see these forklifts in lumber yards and auto recycler facilities.

Workers driving rough terrain forklifts must perform work on slopped and possibly unstable surfaces. Dips, holes, excavations and overhead powerlines can also make operating rough terrain forklifts hazardsous. Workers must be extra cautious due to the type of work being performed so that they do not experience rollovers, tipovers and collisions.

For more information on the various types of forklifts see OSHA's Safety and Health Topics page on Powered Industrial Trucks - Forklifts.

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power source 2

Power Sources

The two main power sources for powered industrial trucks are:

  1. internal combustion, which uses a traditional engine that runs on liquid petroleum gas (LPG), compressed natural gas (CNG), gasoline, diesel, or other fuel; and
  2. electric, which uses an on-board battery.

Other power sources that may become more widespread in the future include fuel cells and hybrid systems. Hydrogen fuel cells will have zero emissions and quiet operation plus the ability to be refueled as quickly as gasoline engines. Hybrid systems will use a combination of fuel cells and batteries.

Attachments

Sometimes special attachments are installed onto the forks to extend the reach, clamp a barrel, act as a hoist, lift odd-shaped items (e.g., a roll of carpet), or even lift people.

Whenever an attachment is used that could affect the capacity or safe operation of a forklift, its use must be approved by the forklift manufacturer.

attachments
Forklift Attachment Examples
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The employer must mark the forklift to show the new weight with attachment. The maximum capacity at the highest elevation must also be shown.

Designations

The hazards commonly associated with powered industrial trucks vary for different vehicle types, makes and models. All forklifts have a hazard designation assigned to them that tells whether they are suitable for use in certain kinds of hazardous atmospheres. You can find the designation on the forklift’s load capacity plate. The table below explains the designations.

Type Built-in Safeguards Against Fire Hazards
D (Diesel forklift) Minimum acceptable safeguards
DS D + additional safeguards for fuel, exhaust and electrical systems
DY DS + all electrical equipment enclosed plus temperature-limiting features
E (Electrical forklift) Minimum acceptable safeguards
ES E + safeguards to prevent sparks and limit surface temperatures
EE ES + all electric motors and equipment are completely enclosed
EX E,ES, or EE + can be used in flammable vapor or dust atmospheres
G (Gasoline forklift) Minimum acceptable safeguards
GS G + additional safeguards for fuel, exhaust and electrical systems
LP (Liquid Petroleum) G + minimum safeguards for liquid petroleum gas
LPS LP + additional safeguards for fuel, exhaust and electrical systems

Selecting the Right Forklift for the Environment

hazardous atmosphere

The hazards commonly associated with powered industrial trucks vary for different vehicle types, makes and models. All forklifts have a hazard designation assigned to them that tells whether they are suitable for use in certain kinds of hazardous atmospheres. You can find the designation on the forklift’s load capacity plate. The table below explains the designations.

Operating a forklift in an environment where chemicals or other substances are present can be hazardous. Use only forklifts that are designed for operations under those conditions.

To select the appropriate forklift, you must know the type of location (Class) in which the forklift will be operated, the name of the chemical or substance and how likely it is that the hazardous condition would be present (Division).

Below are the various classes of locations in which a forklift may be used:

  • A Class I location contains flammable gases or vapors.
  • A Class II location contains combustible dust.
  • A Class III location contains easily ignited fibers.
  • An Unclassified location is a general storage, commercial or industrial location without the hazard conditions described above.

Below are the two divisions used to define how likely a hazard is present:

  • A Division I location has a high potential for the hazard to be present.
  • A Division II location has a lower potential for the hazard to develop.

Selecting the Right Forklift for the Environment (Continued)

To select the right forklift for each class and division, use the table below.

Look in the first column of the table for the hazard class of the material.

Find the row that has the chemical or substance handled.

Choose the second or third column based on the division that represents the exposure condition.

Hazard Classification Acceptable Forklift Designations
Class 1: Flammable gases or vapors are or may be present in quantities sufficient for explosion or ignition. Division 1: Condition exists continuously, intermittently, or periodically under normal operating conditions. Division II: Condition may occur accidentally (e.g., puncture of a storage drum)
  • Acetylene
  • Acetaldehyde
  • Butadiene
  • Cyclopropane
  • Diethyl ether
  • Ethylene
  • Ethylene oxide
  • Isoprene
  • Propylene oxide
  • Hydrogen (or gases or vapors equivalent in hazard to hydrogen, such as manufactured gas)
  • Unsymmetrical dimenthyl hydrazine (UDMH)
Forklift use prohibited DY, EE, EX (also DS, ES, GS, LPS) if the only exposure is sealed containers or liquefied or compressed gases in containers
  • Acetone
  • Acrylonitrile
  • Alcohol
  • Ammonia
  • Benzine
  • Bensol
  • Butane
  • Ethylene dichloride
  • Gasoline
  • Hexane
  • Lacquer Solvent
  • Natural gas
  • Naphtha
  • Propane
  • Propylene
  • Styrene
  • Xylenes
  • Vinyl acetate
  • Vinyl chloride
EX DY, EE, EX (also DS, ES, GS, LPS) if the only exposure is sealed containers or liquefied or compressed gases in containers
Class II: Combustible dust is present Division I: Explosive or conductive mixture may be present under normal conditions or where equipment failure can lead to both this condition and arching or sparking. Division II: Explosive mixture not normally present but where deposits of dust may cause heat rise in electrical equipment.
  • Aluminum, magnesium, and their commercial alloys
  • Other metals of similarly hazardous characteristics
Forklift use prohibited Forklift with electrical enclosures manufacturer approved where magnesium, aluminum or aluminum bronze may be present
  • Carbon black
  • Coal or coke dust
EX Forklift manufacturer approved for this location.
Other combustible dusts EX DY, EE, EX
Class III: Easily ignitable fibers or flyings are present but not likely to be in suspension in quantities sufficient to ignite. Division I: Locations in which these materials are handled, manufactured or used Division II: Locations in which these materials are stored or handled (other than manufacture)
  • Baled waste
  • Cocoa fiber
  • Cotton
  • Excelsior
  • Hemp
  • Istle
  • Jute
  • Kapok
  • Oakum
  • Sisal
  • Spanish moss
  • Synthetic fibers
  • Tow
DY, EE, EX DS, DY, ES, EE, GS, LPS (Type E may continue to be used if used previously at this location.)
Unclassified Locations: Piers and wharves inside and outside general storage, general industrial or commercial properties D, E, G, LP (more protective designations may also be used)

Instructions

Before beginning this quiz, we highly recommend you review the module material. This quiz is designed to allow you to self-check your comprehension of the module content, but only focuses on key concepts and ideas.

Read each question carefully. Select the best answer, even if more than one answer seems possible. When done, click on the "Get Quiz Answers" button. If you do not answer all the questions, you will receive an error message.

Good luck!

1. Powered industrial trucks are classified into seven types based on _____.

2. Which of the following forklift classes are hand controlled by the operator who is in front of the truck?

3. The two main power sources for powered industrial trucks are ____ and _____.

4. Which of the following forklift designations indicates that a diesel forklift has all electrical equipment enclosed?

5. A Class I, Division I area in which a forklift operates will have _____ for the presence of flammable gases or vapors.


Have a great day!

Important! You will receive an "error" message unless all questions are answered.