Generally speaking, cranes should proceed with extreme caution when winds are between 0-20 mph. Capacity deductions vary based on crane model and boom length between 20-39 mph. All crane operations must be shut down and the boom retracted and lowered to horizontal when wind speeds exceed 40 mph.
At what wind speed should a crane stop working?
A common “rule of thumb” is considering stopping the crane if the wind speed reaches 20 mph. Project managers and Appointed persons should reconsider lifts if the wind speed increases dangerously, even before it reaches 20 mph.
What does OSHA consider high winds?
Note to the definition of “high wind”: The Occupational Safety and Health Administration normally considers winds exceeding 64.4 kilometers per hour (40 miles per hour), or 48.3 kilometers per hour (30 miles per hour) if the work involves material handling, as meeting this criteria, unless the employer takes …
How does wind affect cranes?
Strong winds impose extra loads on a crane and may affect the crane’s stability. A maximum permissible operational wind speed will be included in the tower crane design but this may not apply for operational purposes—for example when a crane operator is at the controls and in the process of lifting a load.
Do construction cranes swing in the wind?
Cranes are weathervaned by removing the slew brake or parking brake when high winds or a storm is expected. The front jib is longer and heavier, meaning that it will move in the direction of the wind, helping to reduce the pressure put on the tower.
What is the safe wind speed for working at height?
Under BS EN280:2001+A2:2009 (Mobile elevating work platforms – Design calculations – Stability criteria – Construction – Safety – Examinations and tests) the maximum design wind speed in which a MEWP can work is 12.5 m/s (28 mph).
At what speed are winds dangerous?
“An Extreme Threat to Life and Property from High Wind.”
“Damaging high wind” with sustained speeds greater than 58 mph, or frequent wind gusts greater than 58 mph. Damaging wind conditions are consistent with a high wind warning.
What is the OSHA rule for lightning?
Lightning is likely to strike the tallest objects in a given area—you should not be the tallest object. Avoid isolated tall trees, hilltops, utility poles, cell phone towers, cranes, large equipment, ladders, scaffolding, or rooftops. Avoid open areas, such as fields. Never lie flat on the ground.
Do tower cranes move in the wind?
The tower cranes are left free to rotate (windmill) in the wind in order to reduce needless wind loading on the crane tower structure. The wind will naturally cause the jib to lay along the direction of the wind thus reducing the resistance of the jib.
When it is difficult for an operator to determine power line clearance by visual means an observer?
When it is difficult for an operator to determine power line clearance by visual means, an observer is not necessary.