Types and classes of lift trucks

Lift trucks come in many shapes because warehouses, factories, lumber yards and construction sites ask very different things of them. Each design has its own stability characteristics, controls, blind spots and failure modes, which is why an operator needs separate training for each type. This lesson sets out the seven-class system used across North America, explains the main truck designs within each class, and covers power sources and the special ratings needed for hazardous locations.

The seven classes

Manufacturers, trainers and CSA B335 group lift trucks into seven classes based mainly on power source, tire type and how the operator rides. The same seven-class system, developed by the Industrial Truck Association, is used in the United States, so equipment and training materials from both countries line up.

Counterbalanced trucks

The counterbalanced truck, found in Classes 1, 4 and 5, is the most common design. The load rides on forks in front of the front wheels, and a heavy counterweight at the rear balances it. Sit-down models are the norm for longer travel; stand-up models, where the operator stands sideways at the rear, are common on docks where the operator gets on and off often. Three-wheel electric models turn very tightly but are less stable laterally than four-wheel models, a point Lesson 4 returns to.

Counterbalanced trucks need wide aisles because the whole truck must turn to face the rack. They carry the load ahead of the front axle, so the load moment matters greatly: the further the load sits from the front wheels, the less the truck can safely lift. They are usually fitted with an overhead guard to protect the operator from falling objects and an operator restraint such as a seatbelt.

Narrow aisle trucks

Class 2 trucks are built to work in narrow aisles and high racking. The main types are:

• Reach trucks, where the mast or forks extend forward on a pantograph or moving mast to pick a pallet, then retract so the load sits within the wheelbase during travel. Outrigger legs at the front carry the load. The operator usually stands sideways and drives with a tiller or joystick.
• Order pickers, where the operator rides up with the forks on a platform to pick individual items from high shelves. The operator must wear a fall protection harness attached to the designated anchor, because the platform may rise far above the floor.
• Turret and swing-mast trucks, which rotate the forks to pick from either side of a very narrow aisle without turning the truck. They are often guided by rails or wires in the floor.

Narrow aisle trucks bring their own hazards: the operator can be crushed between the truck and racking, falls from order picker platforms, loads falling from height, and pedestrians trapped in an aisle with nowhere to step aside. Many sites ban pedestrians from narrow aisles while a truck is working and use aisle-entry sensors to warn of conflicts.

Hand and hand-rider trucks

Class 3 trucks are the powered pallet trucks and stackers found in grocery stores, retail backrooms and on docks. Walkie models are controlled by an operator walking beside or behind the tiller; rider models have a small platform. They look simple, which leads employers to skip training, but they cause many foot injuries, crush injuries against walls and docks, and falls from dock edges. A walkie truck pulling an operator backward into a wall or rack is a common pattern, which is why the tiller handle has a belly button or reversing switch that stops or reverses the truck if it presses against the operator.

Powered pallet trucks are lift trucks for the purposes of training. An employee who uses one needs training and evaluation on that type of truck just as a counterbalanced operator does. Manual (non-powered) pallet trucks are not powered lift trucks, but they still cause strains and crush injuries and belong in the site's material handling procedures, with a pointer to the manual handling principles in HSE-107.

Internal combustion trucks

Class 4 trucks use internal combustion engines on cushion tires, which are solid rubber bands pressed onto the wheel. They suit smooth, dry floors such as docks and warehouses. Class 5 trucks use pneumatic or solid pneumatic tires and handle rougher surfaces, gravel yards and outdoor work. Engines run on propane (LPG), gasoline, diesel or compressed natural gas. Propane is common indoors because it burns relatively cleanly and cylinders are easy to change, but every engine produces carbon monoxide. Lesson 8 covers fuels and exhaust.

Tractors and tuggers

Class 6 tow tractors pull trains of carts or trailers. They are common in manufacturing plants that deliver parts to assembly lines and at airports. Their hazards are different from those of a forklift: a long train swings wide on corners and can cut across a pedestrian path, carts can derail or uncouple, and coupling and uncoupling carts puts workers between moving units. Lesson 10 covers tuggers in more detail.

Rough terrain trucks and telehandlers

Class 7 covers rough terrain trucks built for unpaved sites. Straight-mast rough terrain forklifts look like large counterbalanced trucks with big pneumatic tires. Variable-reach rough terrain trucks, usually called telehandlers, carry the forks on a telescoping boom. Telehandlers can place loads on upper floors or far from the machine, but their capacity changes dramatically with boom angle and extension, so the operator must use the load chart for every lift. Some can be fitted with work platforms, buckets or winches, each of which changes the rating. Lesson 10 covers telehandler load charts.

Power sources compared

Electric trucks have taken a growing share of new truck sales in North America. Lithium-ion batteries in particular change maintenance and charging practices; Lesson 8 compares them and points to HSE-322 for battery room hazards.

Hazardous locations

Where flammable gases, vapours, dusts or fibres may be present, a standard truck can be an ignition source. Trucks for these areas must be designed and listed for the hazard: for example, with protected electrical systems, spark-arresting exhaust and limited surface temperatures. CSA B335 and the Canadian Electrical Code classify hazardous locations, and the truck's type designation and markings must match the area. Never take an ordinary truck into a spray booth, a solvent store, a grain elevator gallery or another classified area without confirming the truck is rated for it.

Attachments

Attachments let a truck handle loads that forks cannot: side shifters, fork positioners, clamps for cartons, paper rolls or bales, rotators, push-pulls for slip sheets, booms, carpet poles and drum handlers. Every attachment adds weight and usually moves the load centre forward, which reduces the truck's capacity. The truck must carry a capacity plate that reflects the attachment, and the operator must be trained on it. Some attachments, such as clamps, also add a hazard of crushing or dropping the load if hydraulic pressure is lost.