If a crane’s load moment indicator (LMI) suggests that the wind speed is within acceptable limits but the crane still raises concerns, there could be several possible reasons for this discrepancy. Ensuring the safety and proper operational procedures of the crane during lifting and rigging operations is essential to addressing this issue promptly.
LMI devices gauge the force acting on the boom. Pressure sensors on the rod and bore side of the boom lift cylinder are typically used for this on telescopic boom cranes. The hoist line tension is directly measured by RCI systems. This is usually accomplished with a dynamometer, pin, or load link.
Here are some potential reasons why a crane may pose a risk despite the LMI indicating that the wind speed is within limits:
- Sensor Malfunction: The crane’s wind speed sensor may be faulty or provide inaccurate readings. This could be due to a damaged sensor, faulty wiring, or calibration issues. Checking and inspecting the wind speed sensor is crucial to ensuring it is functioning correctly. If necessary, recalibrating or replacing the sensor may be required to provide accurate wind speed readings to the LMI.
- System Error: There could be a systemic error within the crane’s LMI system, causing it to misinterpret the data related to wind speed. This may result from software glitches, communication errors between components, or other technical issues. Conducting a comprehensive examination of the LMI system, including software and hardware components, can help identify and resolve any potential errors causing false alarms.
- Overrides in Safety Features: Some cranes come equipped with safety features that automatically trigger alarms or shut down operations if specific conditions are not met, regardless of LMI readings. These safety features are designed to operational safety and can be activated by factors such as sudden gusts of wind, changes in wind direction, or disturbances near the crane. Reviewing and adjusting the crane’s safety features and settings is important to ensure they are working as intended and not generating false alarms.
- External Factors: While the LMI may indicate that the wind speed is within limits, external factors such as sudden gusts, changes in wind direction, or disturbances in the crane’s vicinity can affect its stability and trigger alarms. Assessing the real-time environmental conditions around the crane and installing anemometers or additional wind speed indicator devices at strategic locations can provide supplementary data to complement LMI readings.
- Intervention or Environmental Conditions: Electronic systems, including LMI and other electronic components of the crane, can be sensitive to electromagnetic fields, radio frequency signals, or other environmental conditions that may interfere with their accuracy. Conducting an environmental assessment and identifying potential sources of interference can help mitigate risks and improve the reliability of LMI readings.
How does LMI-RCI Crane Care Risk work?
In addition to resolving issues related to the LMI and crane components, actively addressing risks assessment associated with lifting and rigging operations by implementing additional safety protocols, planning for lifting operations with consideration to wind conditions, and temporarily suspending operations until the issue is resolved can contribute to overall safety on the job site. It is crucial to involve qualified technicians or engineers with expertise in crane operation and safety to conduct thorough inspections, calibrations, and troubleshooting.
Finally, identifying the underlying reasons for the discrepancy between LMI readings and crane alarms and addressing them requires a systematic approach. By prioritizing safety and involving competent professionals in comprehensive issue resolution, organizations can ensure the reliability and accuracy of crane safety systems, including responses to air conditions during lifting and rigging operations.
What is the permissible maximum wind speed for crane operations?
For safe crane operation, the permissible wind speed is approximately 25 miles per hour (40.23 km/h) or 11.18 meters per second—winds should not exceed 35 miles per hour. Operators should verify the recommended limits based on the manufacturer’s guidelines for precise wind speed readings.
What does LMI RCI stand for on a crane?
LMI stands for Load Moment Indicator. It is a device installed on lattice cranes, mobile cranes, or tower cranes, commonly known as a Rated Capacity Indicator (RCI). This tool alerts the crane operator when the lifted load exceeds the manufacturer’s recommended lifting capacity.
What is the maximum allowable wind speed for lifting by crane?
When the wind speed on the working platform exceeds 20 miles per hour (continuous or gusts), it is unsafe to lift. If this is the case, lifting operations should not commence or, if already underway, should be halted.
What is a Safe Load Moment Indicator (SLI) ASLI for a crane?
Crane operators are responsible for ensuring the safe operation of cranes, relying on various safety devices, one of which is the Load Moment Indicator (LMI). The crane’s load moment indicator measures the weight and angle of the boom, monitoring its conditions for safe operation.
Two types of device system in crane cabin:
1. SLI} Safe Load Indicator.
2. ASLI} Automatic Safe Load Indicator.
What is the wind speed indication for a crane?
Anemometers provide wind speed measurements to ensure safe crane operation. Cranes are restricted from operating at high wind speeds. Typically, an anemometer (wind sensor) is installed on the crane to measure the wind speed around the crane.
What is the difference between LMI and RCI?
Several different sensors and designs are used for this information. T he LMI system measures the force on the hoist line. Typically, it is installed on telescopic boom cranes and works with pressure sensors on the rod and bore sides of the boom lift cylinder. The RCI system measures the tension in the luffing line.
What are LMI and A2B in a crane?
Load Moment Indicator (LMI) and Anti-Two Block (A2B) are safety systems for cranes. The LMI alerts the operator when the crane is approaching or exceeding its safe load capacity, while A2B prevents the crane from operating if the hook and block are too close to each other.
Anti-tow block: what will happen if you are not in crane?
In conclusion, a holistic approach is essential for identifying and resolving the underlying causes of discrepancies between LMI readings and crane alarms. By prioritizing safety and implementing comprehensive issue resolution involving qualified professionals, organizations can ensure the reliability and accuracy of crane safety systems, including responses to air conditions during lifting and rigging operations.