Key Takeaways
- Always select the appropriate rigging equipment and ensure it is in good condition.
- Accurately calculating the load weight and understanding the center of gravity are essential for safe lifting operations.
- Regular training and certification from reputable organizations help maintain compliance and improve safety practices.
- Clear communication among the rigging team and thorough planning of the lift are critical components of safe rigging operations.
- Recognize and avoid common rigging mistakes such as overloading equipment, improper sling usage, and incorrect attachment methods.
Rigging and Lifting Operations
While rigging and lifting are closely related, they are distinct processes within the overall operation. Rigging involves preparing the load for lifting. Proper rigging ensures that the load is balanced and secure, minimizing the risk of accidents during the lift. On the other hand, lifting involves the actual movement of the load. Lifting requires skilled operators who can control the lifting equipment and maneuver the load without causing damage or injury.
The rigging and lifting procedure follows these steps:
- Planning and Preparation: Involves assessing the load that needs to be moved, developing a lifting plan, and ensuring that the lift area is clear of obstructions.
- Selection of Rigging Equipment: Choosing the right rigging gear and inspecting equipment for wear, damage, and proper certification
- Rigging Setup: Attaching the gear to the load and double-checking all rigging points are secured.
- Lifting: Includes conducting a pre-lift meeting to brief all personnel involved in the operation and the actual lifting process.
- Moving the Load: Carefully maneuvering the load to its intended location.
- Lowering and Securing the Load: Lowering the load gradually, removing the rigging gear, and storing the equipment properly for future use.
What is Rigging Equipment?
The use of rigging equipment is crucial for several reasons:
- Safety: Proper rigging equipment ensures that loads are securely fastened and balanced, reducing the risk of accidents and injuries. Using the right equipment minimizes the chances of load slippage, tipping, or falling during lifting operations.
- Efficiency: Rigging equipment helps streamline lifting operations by providing the necessary support and control for handling heavy loads. This efficiency reduces downtime and increases productivity on worksites.
- Load Protection: By using appropriate rigging gear, the integrity of the load is maintained. Rigging equipment, such as soft slings or padded hooks, can prevent damage to sensitive or delicate items during lifting and transport.
- Compliance: Adhering to industry standards and regulations requires the use of certified rigging equipment.
Types of Rigging Equipment and Hardware
- Wire Rope Slings: Made of steel wire strands, these slings are known for their strength and durability. They are suitable for heavy loads and harsh environments.
- Chain Slings: Constructed from alloy steel chains, these slings offer high strength and flexibility. They are ideal for lifting heavy and abrasive loads.
- Synthetic Slings: Made from materials like nylon or polyester, these slings are lightweight and flexible. They are gentle on delicate loads and resistant to moisture and chemicals.
- Grab Hooks: Designed to grab onto a link of a chain, providing a secure attachment point. They are commonly used in conjunction with chain slings.
- Slip Hooks: Feature a latch that prevents the hook from slipping off the load. These hooks are often used with web slings and wire ropes.
- Swivel Hooks: Equipped with a swivel mechanism, these hooks can rotate 360 degrees, allowing for better maneuverability and alignment of the load.
- Anchor Shackles (Bow Shackles): Have a larger, rounded bow that allows for multiple slings to be attached. They are versatile and commonly used in rigging applications.
- Chain Shackles (D Shackles): Feature a D-shaped design that provides a secure connection for lifting equipment. They are suitable for straight-line pulls.
- Shoulder Eye Bolts: Designed with a shoulder that allows them to be used at various angles. They are suitable for both vertical and angular lifts.
- Non-Shoulder Eye Bolts: These bolts are intended for vertical lifting only. They are not suitable for angular pulls.
- Turnbuckles: Used to adjust the tension and length of ropes, cables, and other rigging systems.
- Pulleys: Simple devices with a wheel and a groove for a rope or cable. They are used to change the direction of the load or reduce the amount of force needed to lift it.
- Blocks: Similar to pulleys but often include multiple wheels. They are used in conjunction with ropes or cables to create mechanical advantage and facilitate the lifting of heavy loads.
- Spreader Bars: Horizontal bars used to distribute the load evenly across multiple points. They prevent the load from bending or buckling and are commonly used for lifting large, unwieldy objects.
- Lifting Clamps: Devices that attach to the load and provide a secure grip for lifting. They come in various types, including plate clamps, beam clamps, and pipe clamps, each designed for specific applications.
- Wire Ropes: Made of multiple strands of steel wire twisted together, these ropes are extremely strong and durable.
- Synthetic Ropes: Made from materials like nylon, polyester, or polypropylene, these ropes are lightweight, flexible, and resistant to environmental factors.
- Load Binders: Devices used to tighten and secure loads on trailers and other transport vehicles. They come in two main types: ratchet binders and lever binders.
How to Choose The Right Equipment for the Job
Environmental conditions also influence the choice of rigging equipment. Operations in extreme temperatures, corrosive environments, or areas with chemical exposure demand equipment made from materials that can withstand these conditions. Load stability and center of gravity are also key considerations as understanding how the load will behave when lifted helps in selecting the right rigging configuration to maintain balance and control. Lastly, the type of lift being performed—whether it’s a vertical lift, a horizontal move, or a combination of both—dictates the choice of equipment.
Common Rigging Terms
- Load Angle Factor: The effect of the angle at which the sling is used on its load-bearing capacity. Lower angles can significantly reduce the safe working load.
- Tag Line: A rope used to control the load's movement during lifting and positioning.
- Hoist: This refers to the action of lifting a load vertically. For example, "Hoist the load" means to raise the load using a lifting device such as a crane or hoist.
- Snub: To snub means to stop or slow the movement of a load. This is done by tightening the rigging or applying brakes on the lifting device.
- Slew: This action involves rotating the crane's boom horizontally. "Slew left" or "slew right" directs the operator to move the boom in the respective direction.
- Safety Factor: The ratio of the equipment's breaking strength to the maximum load it should carry. "Check the safety factor" ensures that the rigging setup has a sufficient margin of safety.
Rigging Methods and Techniques
Choker Hitch
The choker hitch involves wrapping a sling around the load and passing one end of the sling through the other end, creating a tightening loop or noose. This method secures the load tightly as tension is applied. This hitch is ideal for lifting cylindrical objects, such as pipes, logs, and bundles. It provides a strong grip, preventing the load from slipping. However, it should not be used for lifting fragile or delicate items, as the tight grip can cause damage.
Basket Hitch
In a basket hitch, the sling is placed under the load, and both ends are attached to the lifting device, forming a basket shape. This method cradles the load, providing excellent stability and balance. The basket hitch is best suited for lifting balanced and stable loads, such as pallets, crates, and machinery. It distributes the load weight evenly across the sling, reducing stress on the lifting points and ensuring a secure lift.
Bridle Sling
A bridle sling involves using multiple slings connected to a single hook or lifting point. Each sling leg attaches to different points on the load, distributing the weight evenly and providing balanced support. Bridle slings are commonly used for lifting large, irregularly shaped, or heavy loads, such as construction beams, large equipment, and vehicles. They provide multiple attachment points, ensuring stability and balance during the lift.
Double Wrap Choke
The double wrap choke method is similar to a choker hitch but involves wrapping the sling around the load twice before securing it. This technique creates a tighter grip on the load, enhancing stability. The double wrap choke is useful for lifting materials that are prone to slipping or sliding, such as pipes, cables, or lumber. The double wrap guarantees a more secure grip, preventing movement during the lift.
Vertical Hitch
A vertical hitch involves attaching a single sling to the load, lifting it directly upward. This method is straightforward but requires the load to be well-balanced and stable. The vertical hitch is suitable for lifting loads that are evenly balanced and have a single attachment point, such as drums, barrels, and crates. It is a simple and effective method for vertical lifts.
Hitches with Multiple Slings
Using multiple slings in a hitch involves combining two or more slings in various configurations to lift a load. These configurations can include double basket hitches, double choker hitches, and more. This technique is ideal for lifting loads with multiple attachment points or complex shapes, such as large machinery or structural components. They provide enhanced stability and load distribution.
Spreader Bars and Lifting Beams
Spreader bars and lifting beams are horizontal bars used to distribute the load evenly across multiple points. They prevent the load from bending or buckling and provide stability during lifting. This is commonly used for lifting large, flat, or wide loads, such as panels, sheets, and beams.
OSHA Rigging Requirements
- Inspection: Rigging equipment must be inspected before use on each shift and as necessary during its use to ensure that it is safe. Any defective rigging equipment must be removed from service immediately.
- Safe Working Load: Rigging equipment must not be loaded beyond its rated capacity, and the working load limits should be clearly marked on all slings.
- Material and Construction: Slings must be made of materials that are suitable for the load and the environment in which they are used. For example, synthetic slings should not be used in environments with high heat or exposure to chemicals that can degrade the material.
- Storage: Rigging equipment should be stored in a manner that prevents damage or deterioration when not in use.
- Qualified Riggers: Only qualified riggers should perform rigging work. Qualified riggers are individuals who have been trained and have demonstrated the ability to safely perform rigging operations.
- Structural Stability: The standard requires that the structural stability of the steel framework be maintained during rigging and hoisting operations.
- Fall Protection: Rigging workers must use appropriate fall protection measures when working at heights. This includes the use of personal fall arrest systems, guardrails, and safety nets.
- Communication: Effective communication must be maintained between the crane operator and the rigging crew to ensure that the load is moved safely and accurately.
Common Rigging Safety Hazards and Risks
- Overloading: Exceeding the safe working load of rigging equipment can lead to equipment failure, resulting in dropped loads and potential injuries.
- Improper Sling Angles: Using slings at incorrect angles can reduce their load capacity and increase the risk of failure.
- Equipment Failure: Defective or damaged rigging equipment can fail during use, leading to accidents.
- Falling Loads: Inadequate rigging practices can cause loads to shift, slip, or fall. This can result in serious injuries or fatalities to workers in the vicinity.
- Swinging Loads: Loads that swing uncontrollably during lifting can strike workers or other objects, causing injuries and damage.
- Pinch Points and Crush Hazards: Rigging operations often involve handling heavy equipment and loads, creating pinch points and crush hazards. Workers must be aware of these dangers and use proper personal protective equipment (PPE).
- Environmental Factors: Weather conditions, such as high winds, rain, or extreme temperatures, can affect the safety of rigging operations.
- Electrical Hazards: Can be caused by the use of hoisting and hauling equipment near energized lines, tools and equipment not properly grounded, defective electrical tools, and worn or frayed electric cables.
Safe Rigging Practices
Choosing Hitch Types
Selecting the correct hitch type is essential for securing the load properly. Each hitch type has specific applications and advantages. For instance, a choker hitch provides a tight grip and is ideal for cylindrical objects, while a basket hitch offers excellent load stability for balanced items. Understanding the characteristics of each hitch type guarantees the load is rigged securely and safely.
Understanding Sling Angles and Tension
The angle at which a sling is used can significantly impact its load-bearing capacity. Lower sling angles increase the tension on the sling, reducing its effective load capacity and increasing the risk of failure. It is crucial to maintain proper sling angles ideally between 45 and 60 degrees.
Inspecting Rigging Equipment and Hardware
Before each use, check all rigging components for signs of wear, damage, or defects. Look for frayed slings, bent hooks, worn shackles, and other issues that could compromise the equipment’s integrity. Any damaged or defective equipment should be removed from service immediately. Additionally, periodic inspections by qualified personnel help ensure long-term safety and compliance with regulatory standards.
Implementing Sling Protection
Sling protection is necessary to prevent damage to slings and the load being lifted. Sharp edges, rough surfaces, and abrasive materials can cut or wear down slings, reducing their strength and safety. Using protective sleeves, edge guards, or padding can help shield slings from damage.
Ensuring Load Center of Gravity
The center of gravity is the point where the load’s weight is evenly distributed. Rigging should be arranged so that the load is balanced around this point, preventing tilting, swinging, or toppling. Uneven weight distribution can lead to accidents, so always ensure the rigging setup aligns with the load’s center of gravity.
Performing Load Tests
Before conducting a full lift, performing a load test is a good practice to verify the rigging setup. A load test involves lifting the load slightly off the ground to check the balance, stability, and integrity of the rigging system. This preliminary lift helps identify any potential issues with the rigging configuration, allowing adjustments to be made before proceeding with the actual lift.
Using Tag Lines
Tag lines are ropes attached to the load to control its movement during lifting. They help prevent the load from spinning, swinging, or shifting, providing better control and safety. Tag lines should be used by trained personnel positioned at a safe distance from the load.
Clearing Potential Area Hazards and Obstructions
Before starting any lifting operation, it is essential to clear the area of any potential hazards and obstructions. This includes removing debris, securing loose objects, and ensuring that the lift path is free of obstacles. Identifying and mitigating environmental hazards, such as uneven ground, high winds, or poor visibility, also contributes to a safer lifting environment.
Mistakes to Avoid During Lifting and Rigging Operations
- Tying Two or More Slings Together: Creates weak points and uneven load distribution and increases risk of sling failure.
- Attaching Sling Directly to a Lifting Lug: Causes excessive wear and damage to the sling and often leads to improper load distribution and potential sling failure.
- Using Defective Wire Rope: Broken strands, kinks, or corrosion can lead to rope snapping.
- Running Sling Directly Through the Lifting Lugs/Eyebolts: Causes abrasion and damage to the sling, creating sharp bends that reduces load capacity.
- Saddling a Dead Horse: Refers to the incorrect placement of wire rope clips can cause slippage.
- Allowing Sling to Bunch on the Shackle: Creates uneven load distribution.
- Using Wrong Shackle Size: Too small or too large shackles compromise rigging setup.
- Shackle to Shackle Connection: Creates unnecessary points of failure and improper load alignment.
Rigging Safety Training
- Understanding Rigging Equipment: Training should cover the various types of rigging equipment, their uses, and limitations. This includes slings, shackles, hooks, and other hardware.
- Load Weight Calculation: Participants should learn how to accurately calculate the weight of loads and understand the importance of not exceeding equipment limits.
- Inspection Procedures: Training must emphasize the importance of regular inspection of rigging equipment for wear, damage, and defects. This ensures that only safe equipment is used in operations.
- Proper Rigging Techniques: Instruction on the correct methods for rigging loads, including the selection of appropriate hitch types and the importance of maintaining proper sling angles and tension.
- Safety Regulations and Standards: Familiarization with OSHA regulations, ANSI standards, and other relevant safety guidelines that govern rigging operations.
- Load Stability and Center of Gravity: Training on how to determine and maintain the load's center of gravity to ensure stability during lifting.
- Use of Tag Lines and Communication: Teaching the use of tag lines for controlling loads and the importance of clear communication among the rigging team.
- Emergency Procedures: Training on how to respond to emergencies, including load failure, equipment malfunction, and other hazards.
Rigging certification can be obtained through several reputable organizations offering comprehensive training and certification programs. A notable source is the National Commission for the Certification of Crane Operators (NCCCO), which provides Rigger Level I and II certification.
The Industrial Training International (ITI) offers programs for various experience levels, while the National Safety Council (NSC) focuses on best practices and safety standards. The Construction Safety Council (CSC) provides industry-specific training, and many community colleges and technical schools offer rigging programs that include certification as part of their vocational training.