The following article was authored by Ed Davidson with Long Foundation Drilling Co. and originally published on LinkedIn.
** SEE THE VIDEO OF WHAT HAPPENED IN THE EMBEDDED POST BELOW. **
There ya have it folks...
Neglecting to consider weather conditions can be the tipping point toward your day ending in incident and or injury.
Harsh weather adds risk to lifting operations, and quick action may be needed to prevent accidents. To manage risk, the first step is knowing the exact wind conditions at all times. Based on crane specifications, operators and project managers can decide if a lift can proceed safely.
- Crane manufacturers must provide loading tables, derating factors and maximum wind speeds. Note that these specifications change depending on the type of load. *When this data is lacking, contractors can follow general safety protocols from construction associations.
- Wind direction is also important, since it determines how the crane will be loaded. For example, lateral winds have different effects than wind blowing from behind the crane.
- Turbulence intensity must also be considered, since it creates additional loads even when the average wind speed hasn’t changed.
Cranes have a loading limit, like any structure. The wind exerts a larger force when its speed increases, and the crane uses some of its loading capacity to withstand this force. As a result, the crane’s effective capacity is reduced.
Crane manufacturers should be contacted if the loading data is missing. This information should be available for everyone involved in the lift, especially the operator.
When a project involves different types of cranes, having specific information for each one is important, since loading characteristics may change. Also consider that wind conditions may change across small distances and heights, and they should be measured for every crane involved. A single weather station in a site with multiple cranes does not offer enough certainability.
There may be cases where a lift is already programmed, and some data from the crane manufacturer is still missing. If the lift cannot be postponed and specific crane load information is not available, contractors can follow general safety guidelines:
- 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.
Ultimately the crane operator may decide to take the crane out of operation at lower wind speeds due to the type of load being lifted or difficult to control it under wind pressure.
The forces exerted on a crane can change due to external factors, even if the load itself has not changed.
** SEE THE VIDEO IN THE EMBEDDED POST BELOW. **