Does wind turbulence affect construction sites?

The weather is one of the main threats in construction, and only a monitoring system can tell if wind conditions are safe for work. Human perception of the weather is subjective, and project risks cannot be managed based on perception. High-rise constructions and projects with tower cranes are especially vulnerable to strong winds.

Meteorologists measure three main attributes that characterise the wind: Speed, direction and turbulence. Wind measurements in sensitive applications must follow stringent standards, such as the IEC 61400 for wind turbines and the BSI EN 13000 for tower cranes.

What Does Turbulence Intensity Mean in Weather Monitoring?

Understanding the difference between wind speed and turbulence is very important. While speed simply tells how fast the wind is moving, turbulence describes how steady or chaotic the wind is:

•  A 10 mph wind that changes little can be described as steady, or having low turbulence.
• On the other hand, a 10 mph wind that constantly changes can be described as chaotic, or having high turbulence.
• The average wind speed is the same in both cases, but not the turbulence intensity.

Wind speed and direction are evident, since they are measured directly: anemometers measure speed, while weather vanes measure wind direction. Measuring turbulence is not so simple, since it must be calculated from ongoing changes in wind speed.

You need a weather monitoring system with computing power to calculate wind turbulence. Knowing that a 10 mph wind is blowing from the north is useful, but also knowing that the turbulence intensity is 15% is even better.

How does wind turbulence affect construction projects?

There is no doubt that a strong wind is dangerous for construction workers, and even for cranes and unfinished structures. However, turbulence gets less attention, but it also creates risks:

• You may have noticed how repetitive forces break objects more easily - a piece of wire that is bent back and forth will eventually break.
• The same principle applies with turbulent wind, since it causes repetitive forces on cranes and structures.
• Even if a crane withstands the wind, the load and hook line tend to oscillate more with turbulence. This increases the risk of injuring workers or damaging the structure.

Wind measurements improve safety in construction sites. However, you can only get full protection by using a wind monitor that calculates turbulence intensity, such as WINDCRANE.

At what height should I measure wind?

When a project involves cranes or any type of work at height, consider that wind speed and turbulence change with altitude.

•     Turbulence tends to decrease with height, since there are more obstacles disrupting the wind near the ground. These include vegetation, other constructions, and uneven terrain.
• On the other hand, wind speed tends to increase with altitude. Since there are fewer obstacles as you go higher, the wind can achieve a greater speed.
• In construction we have both, high heights = high wind speeds and more obstacles like temporary structures = high turbulence

Wind speed can be estimated at any height based on a few measurements, but this is not possible for turbulence, due to its random and chaotic nature. Turbulence must be monitored directly at every point of interest, based on the variation of wind speed.

We are always happy to talk about wind and weather, if you want to discuss any aspects of it or wondering if your project could benefit from a more advanced wind monitoring system, have a chat with us. We’ll help as much as we can regardless of any business.