Frozen cranes

Does temperature affect lifting cranes operation? Can temperature really stop a tower or mobile crane?
 
Steel is characterised not only by its high strength, but also by its ability to bend without breaking. When the loading capacity of a steel component is exceeded, it starts to deform instead of breaking suddenly. This provides a visible sign of overloading, and quick action can prevent an accident.
For comparison, concrete does not have this property: it breaks suddenly when overloaded, and this is precisely why concrete is reinforced with steel bars.

With low temperature, many materials start to experience a ductile-to-brittle transition. This means they become less capable of bending when overloaded, and they tend to fracture like brittle materials. You may have seen videos of how easily objects break when they have been exposed to liquid nitrogen. As outdoor temperatures drop, steels starts to suffer this effect:

• When a crane operates at low temperature, it becomes more vulnerable to impact loads. There is a higher chance that crane components will fracture with a strong impact, instead of bending.

• Fracturing is more dangerous than bending, since the whole crane or load can collapse if a critical component fails suddenly.

• Hydraulic components are also susceptible to low temperature, since there is a higher risk that they will jam or freeze. If the lifting operation is critical and cannot be postponed, hydraulic elements should be inspected carefully.

Just like cranes are derated for high wind speed, they should also be derated for temperature. Manufacturers should provide the specific derating procedure, but the following is a common practice in the crane industry:

•     Derating the crane by 25% at -15°C.

•     Derating the crane by 40% at -30°C.

•     Ceasing all crane activities at -40°C, unless it is strictly necessary during an emergency.

Don't forget personnel during lifting operations

Low temperatures are also dangerous for personnel, especially when they are combined with strong wind. Workers can experience skin irritation, eye irritation and joint pain, leading to exhaustion, distractions and potentially accidents.

The OSHA 1926.1425 standard provides communication guidelines to minimise the risk of accidents during a lift. In general, a lift should only proceed if clear communication is possible between the crane operator and the person directing the lift, apportioned person [A.P] or ultimately the project manager [P,M.]

Are wind and temperature the only weather factors to take into account during crane operation?

When weather risks for cranes are considered, wind tends to get the highest priority. This is justified, since gusts are among the main causes of crane collapse. However, contractors cannot afford to ignore other weather factors, like low temperatures, visibility and even air pollution.  

If you would like to learn more about the ways to monitor the weather at construction sites and have remote real time feedback, give us a call or send us an email. We will be glad to help!

Also, did you know that WINDCRANE is a complete weather station that can measure all the risk factors discussed here?