NR-12 annex xII: Lifting Equipment for Personnel Lifting and Work at Height

NR-12 Annex XII: Lifting Equipment for Personnel Transport and Work at Height
This document addresses the main points of NR12, the Brazilian Machinery Directive, Annex XII, focusing on the guidelines and safety requirements for lifting equipment used in personnel transport and work at height. It encompasses aerial work platforms, attached baskets, and suspended baskets, detailing their technical specifications, safety measures, and operational procedures. The aim is to ensure the safety of workers and the efficiency of operations in various sectors, such as construction, industrial maintenance, and electrical network services.
Annex XII of NR12 specifically addresses the safety of aerial work platforms, defining them as vehicles designed to elevate people, equipped with a mobile arm (articulated, telescopic or combined) and a platform (with or without electrical isolation). Aerial work platforms consist of several main components, including the chassis, the slewing mechanism, the column, the arms, the booms, and the stabilization system. The platform's nominal capacity is defined by the manufacturer, taking into account the weight and number of permitted occupants.
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by Klaus Duske
 
Aerial Work Platform Definitions and Components
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Aerial Work Platform
A vehicle specifically designed to lift workers and their tools to various heights. These platforms are equipped with a movable arm, which can be articulated, telescopic, or a combination of both. The platform itself can be equipped with electrical isolation for work near energized networks.
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Main Components
The main components of an aerial work platform include the chassis, turning mechanism, column, arms (booms), and stabilizer system. The chassis provides the base for the platform and houses the engine, drive system, and other essential components. The turning mechanism allows the platform to rotate on its base, providing flexibility in positioning the platform. The column supports the arms and platform, while the arms extend to reach different heights. The stabilizer system provides stability and prevents the platform from tipping over.
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Capacities
Each aerial work platform has a nominal capacity defined by the manufacturer. This capacity considers the maximum weight the platform can safely lift, including the weight of the occupants and any tools or materials they are carrying. The manufacturer also specifies the maximum number of occupants allowed on the platform. It is crucial to adhere to these capacity limits to ensure the safety of all personnel involved. For instance, a platform designed for 2 workers and a load of 200 kg should not be overloaded with 3 workers and 300 kg of equipment.
Safety Systems in Aerial Work Platforms
Safety Controls
These controls are designed to prevent accidents and ensure operator safety. For instance, an emergency stop button can be activated immediately to halt all platform operations in case of an emergency. Check valves in the hydraulic system prevent uncontrolled descent if there is a loss of pressure. Additionally, the counterbalance system ensures stability, particularly during platform extension and retraction. The automatic leveling system maintains a stable platform even on uneven terrain, enhancing operator comfort and reducing the risk of tipping.
Stabilization
Stabilization systems are crucial for safe operation, particularly when working at height. The inclination indicator provides a visual warning to the operator when the platform reaches a critical angle, preventing over-tilting and potential accidents. The control system is protected against accidental operation, meaning that the platform can only be moved intentionally by the operator, preventing unintended movements that could lead to instability.
Electrical Protection
Electrical protection is essential for safe operation near energized networks. The platform offers adequate electrical isolation to protect operators from potential hazards. This is achieved through a specific classification according to the voltage, ensuring the appropriate safety measures are implemented based on the working environment. For example, platforms for use near high voltage lines may feature additional insulation and protective measures.
Identification and Signage Requirements
Identification Plate
The identification plate should contain essential information such as the manufacturer’s name and address, serial number, model number, rated capacity, maximum working height, and date of manufacture.
Safety Signage
Safety signage on the aerial work platform should include information about the operating controls and their functions, emergency stop procedures, maximum load capacity, and any special hazards associated with the platform’s operation.
Control Identification
All controls should be clearly labeled with appropriate symbols and/or text descriptions, ensuring easy identification by the operator. This should include a clear indication of the function of each control, for example, ‘Raise Platform’, ‘Lower Platform’, and ‘Emergency Stop’.
Man Baskets: Features and Requirements
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Definition
A platform attached to a vehicle-mounted crane for lifting people with the aim of performing work at height. It is often used in construction, maintenance, and industrial settings, where it provides a safe and efficient way to access elevated areas.
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Safety Systems
Must include anchorage points for safety harnesses, protected controls and emergency stop devices. These features ensure worker safety and prevent accidents in case of unexpected events, such as sudden equipment malfunctions or changes in environmental conditions.
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Stabilization
A system that prevents the operation of the stabilizing legs before the mobile arm is retracted. This ensures stability and prevents the basket from tipping over during operation.
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Capacity and Load Limits
Must be clearly identified and displayed on the basket. It specifies the maximum weight capacity and the number of people that can safely be lifted by the basket.
Safety Requirements for Attached Baskets
Anchoring
Must provide at least two secure anchor points for fall arrest harnesses, positioned strategically within the platform for easy accessibility.
Controls
Both upper and lower control panels should be equipped with emergency stop buttons, along with an anti-panic control system to prevent accidental activation.
Stabilizers
The stabilization system must include tilt indicators and a system that automatically prevents the operation of the stabilizing legs before the mobile arm is retracted.
Emergency
Emergency stop devices should be easily accessible from any point within the platform. In addition, a backup operating system must be in place in the event of a control system failure.
Suspended Baskets: Applications and Restrictions
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Application
Suspended baskets are a valuable tool for working at heights, but they should only be used when the use of aerial platforms, aerial baskets or attached baskets is technically unfeasible or represents a greater risk. This may include situations where the load capacity of an aerial platform is exceeded, or where the access point is too narrow for an aerial basket to maneuver. For example, if you are working near a fragile structure, or if there are overhead power lines present.
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Risk Analysis
The use of suspended baskets must be justified by a technical report and preceded by a risk analysis performed by a qualified professional. This risk analysis should consider factors such as the weight of the load, the height of the work area, the wind speed and direction, and the potential for falling objects. The analysis should also identify any potential hazards and develop mitigation strategies.
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Restrictions
Simultaneous movement of people and cargo is prohibited, except for tools and materials essential to the task. This means that no workers should be allowed to ride in the basket while it is carrying cargo. The exception to this rule applies to tools and materials that are necessary for the work being done, such as ladders, ropes, or hand tools. The movement of people and cargo should be carefully coordinated to ensure that the basket remains stable and safe at all times.
Planning and Technical Responsibility for Suspended Baskets
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Formal Planning
Includes a detailed risk analysis that considers the specific application, environment, and potential hazards, as well as material specification for the basket, hoist, and rigging. Also includes a comprehensive movement plan and operational procedures that ensure the safe operation of the suspended basket and the protection of workers and the public.
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Technical Responsibility
The design, installation, and operation of suspended baskets require a high level of technical expertise and must be the responsibility of a Legally Qualified Professional, such as a qualified engineer or inspector, who is responsible for ensuring the safety and compliance of the system.
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Supervision
A qualified Safety Engineer or Technician must be present and supervise the operation throughout. This individual is responsible for overseeing the adherence to safety procedures, responding to any emergencies, and ensuring the overall safety of the workers and the environment.
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Operation
A professional with experience in cargo handling and the operation of suspended baskets must be physically present during the entire operation. They are responsible for the safe loading, unloading, and movement of the basket, ensuring the secure and efficient movement of the basket, cargo, and personnel.
Technical Specifications of Suspended Baskets
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Minimum Capacity
The minimum capacity of a suspended basket should be at least 136 kg, which is the weight of the average worker and equipment.
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Height of the Protection System
The height of the protection system surrounding the basket should be a minimum of 990 mm to ensure the safety of the worker.
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Structure Material
The structure of the suspended basket must be made of metal for strength and durability.
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Floor and Protection Material
The floor and protection system of the basket must be made of metal for strength and durability.
Suspension System for Suspended Baskets
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Steel Cable
The steel cable used in suspended basket systems must be of a specific type and have a clear identification tag for easy tracking. Only steel cable is allowed, as chains or fiber ropes are not considered robust enough for this application. The cable should be regularly inspected for any signs of wear or damage, such as fraying, corrosion, or kinking. The cable's diameter should be appropriate for the load capacity of the suspended basket and the length should be sufficient to allow for safe operation. A clear identification tag on the cable is crucial for ensuring proper maintenance and replacement schedules.
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Connections
Connections within the suspension system of suspended baskets are critical for ensuring secure attachment and preventing accidents. All connections should be made using high-quality thimbles, shackles with nuts and cotter pins, and hooks with safety latches. The thimbles are metal rings used to reduce wear and tear on the cable by preventing sharp bends. Shackles, which are U-shaped metal fasteners, are used to connect the cables to other parts of the suspension system. Nuts and cotter pins ensure that the shackles are securely fastened. Hooks with safety latches provide an additional layer of security by preventing accidental disengagement. Regular inspection of these connections is crucial for safety and should be performed before each use of the suspended basket.
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Backup Element
A backup element, such as a secondary sling or a safety chain, must be incorporated between the hoist hook and the main slings. This crucial element ensures that the basket remains supported in the event of a catastrophic failure of the primary suspension elements. It acts as a secondary safety measure, preventing the basket from dropping and ensuring the safety of the workers inside. The backup element should be designed to withstand a load equal to or greater than the weight of the basket and its occupants. This safety feature is critical for mitigating the risk of accidents and ensuring the overall safety of the suspension system.
Hoisting Equipment for Suspended Baskets
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Anemometer
Measures wind speed and emits an alarm when it exceeds 35 km/h, ensuring safe operation in windy conditions. This is a vital safety feature, as strong winds can pose a serious risk to the stability and control of suspended baskets. The anemometer should be positioned in a location where it can accurately measure wind speed and direction. It should also be regularly calibrated to ensure accurate readings.
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Limiters
These devices prevent the hoisting equipment from exceeding its safe operating parameters, including load moment, height, and travel speed. These parameters are determined by the weight of the suspended basket, its occupants, and the lifting capacity of the crane. The limiters work by automatically stopping the hoisting operation if any of these parameters are exceeded. This helps to ensure the stability and safety of the suspended basket and the workers within it.
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Safety Systems
Include hydraulic valves for controlled lowering, return-to-neutral controls that prevent accidental movement, and emergency stop buttons for immediate deactivation of the hoisting equipment. These systems are designed to minimize the risk of accidents and to provide an extra layer of safety in case of malfunctions. The hydraulic valves are essential for ensuring a controlled descent of the suspended basket, while the return-to-neutral controls help prevent accidental movement and ensure that the hoisting equipment only operates when intended. The emergency stop buttons provide an immediate means of deactivating the hoisting equipment in case of a dangerous situation or equipment malfunction.
Additional Requirements for Cranes
Limiters
Prevent overloading and over-extending the crane by limiting its maximum load, moment, travel distance, and height. This ensures that the crane operates within its safety limits and prevents potentially dangerous situations. These limiters typically trigger an alarm or shutdown system when the limits are reached.
Alarms
Provide immediate auditory alerts to operators in critical situations, such as approaching load limits, encountering obstructions, or exceeding wind speed thresholds. These alarms can be either mechanical or electronic and are designed to increase awareness and prompt operators to take corrective actions.
Signaling
Essential for safe operation in busy environments. They include load plates indicating allowable lifting capacity, obstacle lights signaling potential hazards, and visual indicators for the operator's current operating conditions. These signaling systems enhance visibility and communication between the crane operator and the surrounding workers.
Safety
Ensure secure lifting operations with features such as hook latches that prevent accidental release of the load, guide ropes that maintain the load in a controlled trajectory, and anti-escape devices that prevent the load from swinging out of control. These elements work together to minimize risks and ensure the safety of personnel and equipment.
Pre-Operational Safety Procedures
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Safety Meeting
Review the suspended basket operation plan, safety equipment and procedures, and the communication protocol with all team members.
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Equipment Inspection
Thoroughly inspect the suspended basket, including the hoisting cables, suspension system, and safety harnesses. Make sure to check the radio for proper functionality.
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Signal Confirmation
Verify that everyone understands the international hand signals and the radio communication procedures. Ensure that the team is familiar with any additional signals specific to the operation, as per the company's safety protocols.
Communication and Signaling during Operations
Radio Communicator
All team members must be equipped with radios operating on a dedicated frequency, ensuring clear communication.
Hand Signals
The team must adhere to the international hand signaling system, with the possibility of incorporating additional signals that are understood by all members.
Designated Signaler
At least one person inside the suspended basket must be trained in the standardized hand signal code, ensuring effective communication.
Restrictions and Prohibitions in Operations
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Weather Conditions
Work is prohibited during storms with electrical discharges or in adverse weather conditions, such as strong winds, heavy rain, or fog. The team should consult local weather reports and adhere to safety protocols before commencing operations.
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Energized Networks
It is necessary to ensure the distance of the suspended basket from energized networks. This distance should be at least the minimum specified in the safety regulations and should be checked regularly, especially when working near electrical infrastructure.
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Simultaneous Movement
The movement of suspended loads on the hook and people in the basket at the same time is prohibited. This includes situations where the basket is being lowered or raised while a load is being transported. Separate procedures must be in place for both operations.
Documentation and Records
Archiving
Documentation related to offshore platform operations must be kept at the worksite for a minimum of 5 years. This includes, but is not limited to, safety procedures, inspection records, and any permits obtained for work on the platform.
Access
Documentation must be available for access by Labor Auditors, representatives of the CIPA (Internal Commission for the Prevention of Accidents) and Trade Unions. The platform operator should have a designated location for storing documentation where it can be easily accessed by authorized personnel.
Inspection Records
Daily inspections must be recorded in specific documents, which may be electronic. These records should include details of the inspection, the date, the time, the name of the inspector, and any findings or corrective actions taken. Additionally, specific documents may be required by the Brazilian Navy's Directorate of Ports and Coasts for suspended basket operations, as well as any other regulatory bodies involved.
Specific Operations on Offshore Platforms
Transfer Basket
The transfer basket must be approved by the Brazilian Navy's Directorate of Ports and Coasts. The basket must be inspected by a qualified technician before each use. This inspection includes verifying the integrity of the safety harness, brakes and all other components of the basket.
Team Training
The team must have completed the Basic Platform Safety Course (NORMAM 24) and training on the use of life jackets. This training includes the use of life jackets in the transfer basket and emergency procedures in case of a fall into the water.
Procedures
It is necessary to assess environmental conditions, ensure that the vessel is adequate and verify the availability of free area on deck. The procedures for this operation include a pre-operation meeting with the team on board the vessel and on the platform, to review the safety procedures, communication plan, and emergency responses.
Transfer between Dock and Vessel
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Work Permit
Prior to transferring personnel between a vessel and a dock, a work permit must be obtained and reviewed by the designated safety officer. It is essential to confirm the maximum validity period of the permit, which is typically one working day.
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Record
To ensure accountability and safety, it is crucial to maintain an accurate record of each transferred person's name. This information should be documented in the work permit or a separate log for tracking purposes.
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Safety Instruction
Prior to the transfer, safety instruction must be delivered to all involved personnel. This instruction must cover the specific procedures for using the transfer basket, addressing emergency procedures, and emphasizing the importance of following established safety protocols.
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Safety Equipment
To mitigate the risk of personnel falling overboard, the use of approved life jackets is mandatory for all individuals participating in the transfer between the vessel and dock.
Maintenance on Energized Installations
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Applicable Standards
NR-10, the Brazilian Standard for Safety in Electrical Installations, outlines the specific requirements for work on energized transmission lines and busbars.
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Work at Potential
To perform services on energized installations, it is necessary to use specific equipment and procedures to equalize the worker's potential to that of the network. This may involve using insulated tools, grounding equipment, and specific work techniques to minimize the risk of electric shock.
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Insulation
Safety requires the use of equipment with a degree of insulation suitable for the voltage of the installation. This may include insulated gloves, mats, tools, and specialized aerial work platforms.
Final Considerations and Regulatory Updates
Continuous Updating
Safety standards and procedures must be constantly reviewed and updated, keeping pace with advances in technology and safety practices. For example, new regulations may be introduced regarding the use of drones for inspection, or changes in the use of personal protective equipment may be required due to advancements in materials and design.
Training
Continuous worker training is crucial to ensure that they are familiar with the latest safety standards and procedures. This can include training on new technologies, updates to existing procedures, and the proper use of new safety equipment.
Inspection
Regular inspection is essential to ensure compliance with established safety standards, promoting a safe work environment for everyone. Inspections should be conducted by qualified personnel, using appropriate tools and methods. These inspections may include visual checks, functional tests, and documentation reviews.