What Crane Hire & Operators Should Know

Introduction

As mentioned in the CPA's Good Practice Guide, most wind speed forecasts are taken at 10m above ground, which will not reflect the conditions a crane is under, considering it can reach heights between 200m and 250m. Additionally, most wind forecasts also ignore important details, such as nearby buildings and obstacles, which will change how wind behaves. These are a couple of reasons why having a wind forecast specific to the crane in question is so important, and why that information needs to be accessible to everyone working on that project.

Understanding wind allows you to be in control and plan for stability

Wind creates a sideways load on the crane itself and on the load it is carrying. Normally, the lighter the load that the crane is carrying, the more dangerous it might be. This is because of the relationship between wind speed and the force exerted on the crane; for example, if the wind speed doubles, the force exerted on the crane will increase 4 times, which could lead the crane to be at risk of tipping over. 

The wind forecast will most often not represent the forces acting on the crane

Many forecasts report 1-hour mean average winds, but site decisions should use the gust at crane height. To make better-informed decisions, WINDCRANE keeps a record of the highest wind speed measured plus the average and standard deviation for turbulence analysis, which means a shared real-time visibility of what the operator sees.  This is important as the crane operator and lifting team have the final say on whether an operation proceeds. Lifting operations should be planned using short-term forecasts and discussed at daily briefings.

Furthermore, two cranes on the same site can be affected by wind in that same area very differently, because of parameters such as height, shielding, funnelling, vortices, etc. 

The lift plan must include two limits: the crane limit and the load limit

It is worth noting that different cranes have different wind tolerances. OEM data gives a specific wind limit for each crane configuration. Once that is established, you need to set the load’s limit in relation to excessive wind load.

There are some suggested wind limits in the table below (these are rule-of-thumb suggestions, but you should always check the OEM instructions).

Please note that wind limits may be lower when lifting people, operating near crane capacity, or when using specialist lifting equipment. Ultimately, cranes must be winded off immediately when the in-service wind speed limit is reached at the crane's anemometer.

Location and terrain roughness for wind forecasting

It is important to note that wind speeds increase with height and vary by terrain roughness, meaning that in rural areas, there is low roughness, and in urban environments, there is high roughness (class 3.5+). Inaccurate roughness assumptions will lead to inaccurate wind predictions, which is why it is so important to consider each location individually. This is another aspect that WINDCRANE can help with, as our wind forecasting takes terrain roughness and the specific location of the considered crane into account.

Taglines and remote load control

The CPA treats load-control methods as a core planning factor, such as taglines, push-pull poles (manual), and remote electro-mechanical below-hook devices (for orientation control). These are good tools, but the lift still needs to be safe within wind limits nonetheless.

Information mismatch is a hidden productivity killer

In order to be able to make correctly informed decisions, everyone needs to be considering the same correct data. On multi-stakeholder jobs (PC, crane supplier, AP, lifting supervision, operator, HSQE, client), delays and arguments often come from everyone looking at different wind data:

• The operator sees instantaneous live maximum wind speed data at the control station (typically sampling every second) and must obey it. 
• Online platforms often show 1-hour mean average and gust wind speeds and may update every 1 hour, introducing time-lag and confusion if people assume it’s “live right now”.
• Some sites install an anemometer repeater in the site office to mirror the operator’s display, while keeping the operator as the final authority.  

This is exactly where remote monitoring (e.g., such as WINDCRANE) becomes a productivity and  safety tool:

• A single source of truth for the whole team (clearly stating the maximum wind speed and mean wind speed).
• Offers better real-time coordination, allowing for more informed stand-down or resume decisions, continuing work around calmer windows of time.
• A record of forecast data used in all decisions (useful for planning reviews, lessons learned, and commercial conversations) with the option to correct to different heights and terrain roughness.

Site Checklist

 Use the max or wind gust at crane height for decision-making.

 Have the team check the weather forecast for the specific location of operations at the right height and terrain roughness.

 Use the forecast to formulate a plan for operations.

 Agree that the lowest limit wins  (if the load limit is lower than the crane limit, the maximum wind speed to safely operate will be dictated by the load limit).

 Agree on who calls the wind-off.

 Agree on crane restart conditions.