Lifting and Rigging
Q1. What is lifting equipment ?

Lifting equipment is any work equipment where the principal function is to lift and lower loads. This term also applies to any accessory used to attach or support the equipment doing the lifting. Equipment that lifts only as an incidental aspect of its main function (eg a pallet truck, or a system for conveying parts through an oven) is not considered lifting equipment.

Q2. What is a lifting accessory ?

A lifting accessory is any equipment used to attach a load to the lifting equipment, which is not a permanent part of the load (eg hooks, ropes, chains, shackles and eyebolts) or lifting equipment.

Q3. How often should lifting equipments be subject to thorough examantions?

Thorough examination of lifting equipment must take place every 12 months - or every 6 months if the equipment is used to lift people. Any accessories used in lifting should also be inspected every 6 months. These are the minimum requirements, where there is no formal 'examination scheme' drawn up by a competent person.

The competent person may impose a more rigorous examination scheme, for example when the lifting equipment:

  • is used in extremes of temperature (eg in a foundry or a freezer)
  • is used in a potentially corrosive environment (eg seafront)
  • is subjected to particularly heavy use
  • could lead to potentially catastrophic consequences if it failed (eg resulting in multiple deaths or the release of dangerous material)

In some cases, the period between thorough examinations may be extended under an 'examination scheme', where either deterioration will be very slow (eg when lifting equipment is only very occasionally used and stored in dry, non-corrosive environments); or when it is one of a very large number of identical items - where a sampling and inspection scheme may be more appropriate.

In addition to these scheduled examinations, equipment will require a thorough examination following:

  • any accident or dangerous occurrence
  • any significant change in conditions of use
  • the replacement of any parts that are subject to thorough examination
  • any long periods of inaction

Q4. What is a competent person ?

A competent person is someone who has appropriate practical and theoretical knowledge and experience of the equipment for which they act as 'competent person'. This knowledge and experience can help them detect defects / weaknesses and assess whether they will affect the continued safe use of the equipment.

The competent person must be sufficiently independent and impartial to make objective decisions. However, this should not be the same person who performs routine servicing / maintenance, as they would be responsible for assessing their own work.

A competent person may be employed by a separate company or selected by an employer from their own staff. They should have genuine competence, authority and independence to ensure examinations are properly carried out, so that any recommendations that arise can be made without fear or favour.

Q5. Does new lifting equipment have to be thoroughly examined before use ?

You must have lifting equipment examined in the following circumstances:

Before using it for the first time - unless the equipment has an EC Declaration of Conformity which is less than one year old and the lifting equipment was not assembled on site. If it was assembled on site, it must be examined by a competent person to confirm that the assembly was correct and safe.
After assembly, and before use at each location - for all lifting equipment that requires assembly or installation before use (eg tower crane) - to ensure it has been installed correctly and is safe for use

Q6. Does lifting equipment need to be marked with a safe working load ?

Yes. Machinery and accessories for lifting loads must be clearly marked to indicate their safe working loads (SWL). Where the SWL depends on the configuration of the machinery for lifting loads, the machinery must be marked to indicate its SWL for each configuration, or provided with such information which is kept with the machinery.

On chain and wire slings, the SWL should be marked legibly and indelibly on a durable tag or label attached to the sling; or marked on the ferrule or master link.

Where it may not be possible for the marking to show the SWL, there are other ways of 'indicating' the safe working criteria for the equipment. In some cases, a 'surrogate' marking may be acceptable, such as a capacity indicator on an excavator. However, colour coding alone to denote SWL is not normally acceptable, but can be a useful additional feature (eg of textile slings) and may be a key element in the marking of some equipment, such as access and rescue ropes.

Individual lifting accessories forming part of a specific item of lifting equipment (that is not disassembled after use and so remains part of that equipment), do not need to be marked.

However, the lifting equipment must be marked with a SWL rating that is suitable for all items in its assembly.

Q7. What is the difference between a hoist and a crane ?

The primary differences between a hoist and a crane are the ways each can move, the ability to convert them for other tasks, and the complexity of their design. A hoist and a crane are both are used to move objects. While a hoist can only lift or lower them vertically, a crane can, in addition to that, move objects horizontally as well. Some highly advanced crane designs allow the load to be rotated in three dimensions as well. Generally, the part of a crane that is used to lift and lower a load is a hoist.

A hoist and a crane may both be used to move a load, but a hoist can move it in only one direction along a straight, vertical line. Such a device is said to have one degree of freedom. A good way to visualize this is to think of an elevator. It moves up and down a shaft, also known as a hoist way, suspended by cables from a hoisting mechanism that powers its motion. The elevator is limited to traveling up and down in a straight line within that shaft.
Typical cranes can move their loads up and down in a straight, vertical line, but they can also move them horizontally both forward and backward and side to side. Most cranes can move a load in a straight line in three independent axes and can be said to have three degrees of freedom. There are some jobs for which a hoist and a crane are both suitable. Some tasks, however, require the use of a crane for greater flexibility in how and where to move the load.

A common example of this flexibility of motion is the small crane inside a claw machine game used to retrieve toys as prizes. The operator positions a crane by moving it forward and backward as well as left and right and presses a button to drop a claw. An open claw drops vertically into a pile of toys, closes, and is retracted upward with or without a toy in its grasp. There would be little point to this game without the crane feature. With a hoist only, the operator could only lower and raise the claw in the same place every time, which requires no skill.

Specialized cranes called rotary cranes typically have this same capability, but also incorporate rotational motion for added performance. They may be able to rotate in up to three independent axes as well as to move in a straight line in those three directions. These rotations are known as roll, pitch, and yaw. This allows a rotary crane to operate with up to six degrees of freedom, although some models are designed with fewer degrees of freedom. Rotary cranes may be used in robotic applications, for example, or in industrial transportation applications such as on trucks, locomotives, or ships.

Another difference between a hoist and a crane is that a many cranes can be converted for other operations aside from moving a load. In demolition, for example, a wrecking ball may be added for the purpose of bringing down an unwanted structure. For construction purposes, a scoop may be used to gather up dirt or waste materials that are to be moved. Hoists are not generally designed for conversion for other uses beyond lifting and lowering a load.

Hoists are commonly installed as sub-components of cranes. They are typically the mechanisms used to lift and lower the loads moved by cranes. This is another way a hoist and a crane differ. Cranes are more complex devices than hoists and are not sub-components of hoists.

Q8. What is a chain hoist ?

A chain hoist is a mechanical device used for lifting heavy loads of objects and equipment. It is made with a pulley, which is held together by a closed chain. The closed chain forms a loop, which makes it easy to be pulled by hand.

There are several large and small pulleys located throughout a chain hoist. There is one large and one small pulley are situated on the same axle, as well as a also a mobile pulley that holds the load in place.

For the load to be raised with the chain hoist, the closed chain has to be pulled. When it is pulled, the large pulley draws in more chain than what is released by the smaller side. From here, the lifting process begins.

There are three types of chain hoists: air, manual, and electric. The manual one and the air one are designed with reduction gears, hook pivots, and swivels. Suspended by a top hook, or by a push or geared trolley, these devices move objects slowly and carefully while making height adjustments. The attached load is well secured so it can be left fixed without requiring a great deal of supervision.

The electric chain hoist, on the other hand, is generally used for lifting heavy-duty industrial loads. It allows the user to pull from the side as well as vertically.

Q9. What is a lever hoist ?

The term lever hoist may be applied to any small, portable lifting device which relies on the manual operation to lift or lower heavy loads. Lever hoists fall into two main categories: cable or rope hoists and chain hoists. Both variants rely on a ratchet and pawl system to rotate a gear or pulley a pre-set distance that lifts the load. The ratchet and lever mechanism is equipped with a hook or fastener which is used to suspend the lever hoist from a suitable support. Both lever hoist types may be used in any orientation for lifting, tensioning, or pulling operations although chain type hoists are generally more suited to vertical lifting.

Both kinds of lever hoists makes use of the mechanical advantage of a lever to lift loads which would be impossible to move by hand. The rope hoist, or “come-A-long” as it is colloquially known, employs a steel rope wound onto a pulley which incorporates an inbuilt ratchet system and a mounting hook. The other end of the rope is fitted with a small hook block used to attach the load.

Once the rope hoist has been securely attached to a suitable support using the mounting hook, the ratchet is unlocked and the rope pulled down to the load. The load is then attached to the hook block and the pawl re-engaged. The load may then be lifted by cranking the handle up and down. Typically the downward cycle of this cranking motion will turn the pulley and retrieve a length of rope in turn raising the load. The upward stroke usually does not turn the pulley and only serves to bring the handle back to the top of its travel to perform another cycle.

The chain-operated lever hoist works in a similar fashion except there is no pulley system. Instead, it employs a gear over which a free falling length of chain travels. The operating lever of the chain hoist is also fitted with a pawl system and may employ additional gears which increase the speed and power of the hoist. Each time the handle is cycled, it turns the gear which advances or retrieves the chain to raise or lower the load. The chain hoist handle mechanism is fitted with a release feature which means that, as in the case of the rope hoist, the work is achieved on one half of the stroke cycle.

The benefit of using a rope hoist is the fact that there is no free falling length of chain which makes it ideal for horizontal pulling operations. Although the chain hoist may be also used in these applications, the excess chain on the non-load side is impractical, making it better suited to vertical lifting operations. One safety consideration that should be kept in mind at all times when using either lever hoist is never to exceed the rating of the hoist. The lever hoist can be particularly susceptible to overload failures with the rope hoist being especially dangerous due to the possibility of whip injuries should the rope break.

Q10. What are tie down straps?

Tie down straps are straps, often used in commercial trucking or transportation, which are used to keep items on a truck or pallet from falling off while in transport. These straps come in a number of different colors and lengths, though they are often provided with sufficient length to go across a large flatbed truck. They can be made from different materials and are often treated with vinyl or other substances to ensure they are durable and will not break from moderate wear or usage. Tie down straps typically have hooks at each end to secure them to a truck, and they may have a ratcheting mechanism for easier use.

Sometimes called cargo straps, or simply “tie downs,” tie down straps are often used in trucking or for moving products over various distances. They are usually used for open transport, such as on the back of a flatbed truck, though they can be used in an enclosed truck as well to secure objects along the sides. Tie down straps are usually produced in various lengths, though someone may also be able to connect several small straps together. They are often brightly colored so they are easier to see for removal and to spot if they come loose.

Since tie down straps are often used to secure heavy or large objects, they are usually made from durable materials. This includes fabrics, frequently treated with vinyl coatings or other strengtheners, though synthetic materials can also be used. Tie down straps are often made with hooks placed at each end of the straps, which allows them to easily connect to various surfaces on trucks. These hooks can also be used to connect multiple straps together, and once pulled tight they will usually provide a secure connection that will not come apart.

While tie down straps can simply consist of the straps themselves, they often have a ratcheting mechanism included on the straps for easier use. Once the tie down is in place, the ratchet can be used to begin pulling one end of the strap toward the other. This allows the strap to become tighter, and as long as each end is well secured prior to ratcheting, the strap will be pulled quite tight. The use of ratcheting tie down straps often ensures a tighter strapping; this reduces how much objects can move after being strapped down, which prevents damage to objects and reduces wear on the straps caused by shifting objects rubbing against the straps.

Q11. What is wire rope ?

Wire rope is a heavy, tensile, strong, weather-resistant hoisting cable made from many small metal filaments wrapped and braided together. You can get a lot of strength and flexibility out of this type of rope because the separate wires equalize pressure throughout the bunch and work well with pulleys. It can be found on a modern farm, a fishing boat, and an international dock.

Usually, wire rope is comprised of steel strands arranged in an array around a central core. This design allows the entire wire to hold a lot of weight and still stay ductile. The individual filaments are wrapped into a bunch called a strand. Several of these strands, perhaps six or nine, are then arranged into an even larger bunch called a wire surrounding a central core, the sheath.

Wire rope can be made from steel or iron. Most types for outdoor use are galvanized so they won't rust through corrosion. Wire that hasn't been galvanized is called "bright." Other types are available with alloys that add various advantages. Wire rope usually can be maintained with cleaning and lubricating to make sure it remains compatible and safe with rigging hardware.

Some characteristics of wire rope are diameter, breaking strength, resistance to corrosion, difficulty of flattening or crushing, ability to be bent, and average lifespan. For each application of pulleys, chains, and weights, an industrial engineer needs to determine the correct type rope. Only that size, weight, and braid of rope can be used to ensure that it won't fray or snap.

People use wire rope to protect forests, unload imported goods, or provide raw food. Farmers use it to lift entire grain silos. Firefighters that take water out of lakes for dropping onto flames must tie the scoop to the helicopter. In major ports, both the docking ships and the vehicles on the ground need it in rigging to move giant pallets.

The most important aspect of wire rope is how it will function under the stress of each application. In many uses, it supports giant, heavy objects, and if it fails, lives could be in danger. Always know the breaking strength of your rope and, unless you are a professional, don't use it in a way that could potentially injure someone.

Q12. What is a synthetic sling?

A sling connects the crane hook to the load and is an import rigging tool. Slings can be made of steel wire rope, chains or synthetic man made fibers like polyester, nylon. A synthetic sling is a sling made up of synthetic yarn like nylon, polyester.

Q13. How are synthetic slings better than conventional wire ropes and chains?

Synthetic slings made of man made high tenacity fibers have many advantages and conventional wire ropes and chains. Some of these are :
Very light and therefore easy to rig and handle.
Do not damage sensitive or delicate surfaces, therefore lower industrial wastage.
Are colour coded for ease of identification, therefore less chances of misuse.
Improve productivity and employee morale, therefore better labour relationships.
Do not rust or corrode and therefore do not weaken with age.
Easy visual inspection, saving frequent inspection and proof load costs.
Save storage costs as they are flexible and light and therefore easy to store.
Grips load tightly along the contours of the load.
Eliminates need for consumables like grease and hand gloves, therefore lower recurring costs.
Lower injuries to employees and riggers, therefore lower compensation claims.
Reduces machine downtime, in industries where dies or work rolls will have to be changed using slings.

Q14. What are the disadvantages of using synthetic slings?

The disadvantages if used improperly are :
Can be easily cut or damaged if used unprotected over sharp edges.
Can not be used in temperatures exceeding 80 degree Celsius.
Higher initial cost compared to conventional slings but pay back period is very quick.

Q15. What is the difference between a webbing sling and round sling?

A webbing sling has two eyes at two ends and has a flat construction. It is a very popular design, but has one major disadvantage. The fibers which provide the strength to lift the load are also the ones which come in contact with the load.
Therefore, in case of damage to the yarns, the sling has to be taken out of service. A round sling is an endless hank of yarn wound without any break and is a far better designed sling. The inner core yarn, which provides the strength to lift the load, is protected by the outer casing, which comes into contact with the load. Also the load bearing points (the points which go on the crane hook) keep changing, whilst on a webbing sling the points are fixed. (at the "eyes" of sling) and open to wear and tear. If these points are not inspected regularly, they could lead to potential "weak spots" in the sling.

Q16. What is an anchor shackle ?

A shackle is a U- or O-shaped piece of metal secured with a bolt, pin or spring that connects items together. An anchor shackle is a specific kind of shackle that is used to secure a moving object to a fixed object. The shape of the anchor shackle allows the moving object to push and pull from several directions without creating a shearing force on the device. These shackles have many industrial uses, but are especially common on boats. There they do everything from holding rigging lines to securing the boat's actual anchor.

From a load standpoint, a shackle is a solid loop of metal. In order to be a true shackle, there cannot be any openings in the loop that makes up the fastener. Since the shackle would be of little use if it were simply a solid loop of material, it has an opening called a gate that is able to be closed. There are several methods used for closing the gate in the shackle in order to effectively create a single piece.

There are two common fastening methods for most shackle bolts or pins. For these shackles, the bolt or pin makes up a portion of the loop itself. When they are open, the bolt or pin that holds them shut is typically removed from the shackle entirely. When in use, a bolted shackle has a set of threaded loops on each side of the opening that allows the bolt to hold the shackle shut. A pin shackle is very similar, but the pin simply slides through the opening and is secured on both sides.

Anchor shackles connect to a fixed object and a moving one. The gate on the shackle is generally set to face the fixed object, and the bulk of the shackle faces the moving one. An anchor shackle is usually round; the rounder the shackle, the better it is at balancing the forces on it. The round shape allows the moving load to pull from any direction but still have the same relative force applied to the anchor shackle. A round shackle is generally lighter-duty than a U-shaped shackle of the same weight, but it can withstand changes in directional force that would damage the U-shaped version.

Q17. What is a lifting hook ?

A lifting hook is a device used as part of a hoist, pulley system, or other lifting system to secure loads for movement. The hook itself can vary in size, shape, and function, and most are made of a heavy metal such as steel. The lifting hook is likely to feature some sort of latch that snaps into place to close off the mouth of the hook; this prevents the rope or cable being secured by the hook from slipping off the lip and becoming unstable or completely falling.

Smaller hoist and lift systems will generally feature a smaller hook. The lifting hook can be secured directly to a cable or rope, though in some cases, the hook features some sort of chassis or frame that allows it to move freely and independently from the cable itself. This independent movement will prevent the cable from winding and potentially binding or breaking as the load being lifted moves. The hook will swivel instead, allowing the load to rotate without turning the cable itself. A swivel lifting hook is usually mounted on larger systems, though very small, light-duty hoists can feature such a swiveling device as well.

The shape of the hook generally looks like a J, and the lip will usually protrude slightly outward to protect the tip from getting caught on a rope or other materials being lifted. A gate will close the open end of the J, much like the gate of a carabiner used for rock climbing. The gate is usually spring loaded to prevent accidental opening during use, but is not itself a load-bearing device. It is meant simply to prevent the rope or cable from sliding off the hook during use.

Sometimes a lifting hook is designed for use with a chain. If this is the case, the hook is often secured to the chain using a cotter pin assembly. This system features a threadless bolt that slides through an opening on the hook; the chain can be fed around this bolt, and then the bolt is slid through yet another opening on the hook. Once in place, a cotter pin is slid through an opening in the bolt to ensure it does not slide back through the hook hole. These assemblies are easy to use and generally fairly reliable, though the cotter and pin will often need to be large depending on the size of the hook itself and the weight capacity for which it is rated.

Q18. What is material handling equipment ?

Material handling equipment includes all machinery and devices uses to move goods throughout a factory or warehouse. This term may also include equipment needed to transport these goods from the warehouse to the final consumer. Material handling equipment selection can be critical to the success of a manufacturer or industry. Depending on the application, this equipment can impact everything from productivity to profit margins. Generally, different types of material handling equipment are broken down into categories based on the role they play in the manufacturing process.

Transportation-related material handling equipment includes both internal and external machinery. Inside the factory, this equipment may refer to a crane, conveyor belt, hoist, or forklift truck used to move materials. This category of equipment may travel between production areas, or from an assembly line to a storage or packing room. Outside the factory, transportation-related equipment generally refers to commercial trucks or shipping containers used to move goods to stores and other retail outlets.

Positioning equipment refers to devices used to reposition materials and products. These may include automated robots or feeders that precisely orient parts to fit into assembly line equipment. It also refers to tilt or transfer tables that lift or lower pallets and assembled goods. Finally, positioning equipment may include lifts or hoists used to store materials on shelves in a warehouse.

Load-formation material-handling equipment includes packaging machinery used to prepare goods for shipping. This includes pallets and skids used to stack products, as well as boxes and crates. It may also refer to shrink-wrapping machines or other packing materials. This category of material-handling equipment also encompasses bulk handling containers, which hold products like grain, liquid, or oil.

Storage and retrieval equipment refers to all racks or shelving used to house goods after production. This includes warehouse shelving or racking systems, as well as bins and cabinets used for smaller goods. It may also refer to silos or drums used to store liquids and other bulk items prior to shipping. Products that are stored directly on pallets or on the floor do not include any type of storage equipment in most cases.

Some definitions of material-handling equipment also include systems used to track these goods as they move through the manufacturing and distribution process. Inventory-control software programs fall into this category, as do tags or bar codes used to identify packaging. Finally, portable bar code or magnetic stripe readers also belong to this category of equipment.

Q19. What is safe working load ?

Safe working load (SWL) is the load that a lifting device such as a crane, a cherry picker, or a lifting arrangement can safely lift, suspend or lower. Other synonyms include working load limit (WLL), which is the maximum working load designed by the manufacturer. The load represents a mass or force that is much less than that required to make the lifting equipment fail or yield. The SWL is calculated using a given safety factor (SF) which for lifting slings could be given for example 5:1. The failing load is also known as minimum breaking load (MBL). 

Q20. What is safety factor ?

Factor of safety (FoS), also known as safety factor (SF), is a term describing the structural capacity of a system beyond the expected loads or actual loads. Essentially, how much stronger the system is than it usually needs to be for an intended load. Safety factors are often calculated using detailed analysis because comprehensive testing is impractical on many projects, such as bridges and buildings, but the structure's ability to carry load must be determined to a reasonable accuracy.Many systems are purposefully built much stronger than needed for normal usage to allow for emergency situations, unexpected loads, misuse, or degradation.

Q21. What is ultimate load ?

Ultimate load, strength requirements are specified in terms of limit loads (the maximum loads to be expected in service) and ultimate loads (limit loads multiplied by prescribed factors of safety). With respect to aircraft structure and design, ultimate load is the amount of load applied to a component beyond which the component will fail.

Q22. What is a trolley hoist ?

A trolley hoist is a hoist suspended from a trolley. A hoist can be connected to a trolley by hook or clevis, or a hoist can be integral with the trolley. Trolley Hoists are available with varying spans and capacities. Trolley Hoists feature adjustable I-beams and heights for optimal use. Trolley Hoists are weather and moisture proof. Trolley Hoists need only one operator and are capable of heavy-duty lifting.A trolley is a wheeled carriage, cage or basket that is suspended from and travels on an overhead track.

Q23. What is a single girder crane ?

A single girder crane is an overhead travelling crane that utilizes a single bridge beam attached to the two runway/end trucks. This bridge beam or single girder supports a lifting mechanism or hoist that "runs" on the bottom flange of the bridge beam.

Q24. What is a double girder crane ?

A double girder crane is an overhead traveling bridge crane that utilizes two bridge beams set atop the runway (end) trucks. Generally this type of crane utilizes a top running trolley hoist, which moves along the top of the two bridge beams on its own set of trucks/trolley wheels. The hook from the hoist "falls" between the two bridge beams. Headroom under the crane is increased by utilizing this hoist/crane configuration.

Q25. What is an overhead crane ?

An overhead crane is a crane with a single or multiple girder (bridge girder) bridge carrying a movable or fixed hoisting mechanism and traveling on an overhead fixed runway structure.
An overhead crane, also known as a bridge crane, is a type of crane where the hook-and-line mechanism runs along a horizontal beam that itself runs along two widely separated rails. Often it is in a long factory building and runs along rails along the building's two long walls. It is similar to a gantry crane. Overhead cranes typically consist of a hoist to lift the items, the bridge, which spans the area covered by the crane, and a trolley to move along the bridge.