Not only have we had the hottest years since the weather was recorded, but also an accumulation of violent thunderstorms and rainfalls in the form of hail and torrential rain. Even tornadoes are being sighted more and more frequently. What demands do these weather phenomena make on the safety of your machines and systems?
Anyone who has ever sailed with a sailboat during a thunderstorm has probably also been instructed by the skipper to stay away from the mast and shrouds. Even if a lightening strike is rather rare, the consequences can be fatal. Lightning protection should therefore also be taken into account in the design. Particularly in the case of machinery which is used outdoors or has vents and exhaust systems to the outside, appropriate measures should be provided for the protection of the operators.
Nowadays, lightning alone can be conducted quite well with modern methods. However, the indirect consequences can weigh more heavily. Many control systems have been damaged by overvoltage, which can cause an abrupt failure of all systems. A resulting unplanned stop in production is certainly annoying and the effort to bring the system back to life can be long and expensive. However, the safety risks associated with such failures of possible unintended movements or movements that cannot be stopped can have severe consequences.
Some machines can actually be destroyed when there is no energy left for vital movements. In fire protection, systems already exist which allow the override of machine sections and fire doors to be closed despite power failure. If machines or even persons are endangered due to a power failure, an independent power supply or even redundant units should be considered. Surge and lightning protection should, however, always be or become part of any risk assessment.
Diversity would have helped!
Apart from lightning and thunder, water masses can also have significant consequences for people and the environment. Who doesn’t remember the consequences of the tsunami at the Japanese nuclear power plant in Fukushima? The safety requirements for power supply and cooling of a nuclear power plant are enormous anyway. However, what was not considered in this case was the location of the corresponding aggregates. The emergency generators located on the seaward side of the reactor buildings were all destroyed simultaneously by the wave. No redundancy helped there either. Diversity could actually have helped here – i.e. different technologies at different locations. In chemical plants or other critical production processes, a failure of cooling systems can also have massive consequences for people and the environment.
In the Austrian state of Vorarlberg, a small creek suddenly burst its banks due to heavy rainfall and flooded a cellar in which the switch cabinets of a production plant were located. Firefighters did their best, but were unable to prevent the switchgear from being destroyed. The result was a production stoppage lasting several weeks. After the incident and the new construction of the switchgear cabinets, they were of course not reinstalled in the cellar, but in a flood-safe area.
Some production processes cannot tolerate water at all. If water gets into an aluminium melt, the consequences are massive – for the plant as well as for the personnel. In such cases, not only the choice of location, but also the design of the buildings is a criterion that should not be underestimated.
Other forces of nature
Where there are thunderstorms, wind is to be expected – sometimes a lot of wind. Fallen trees and destroyed overhead lines are already part of the “natural” picture of destruction when storms sweep across the country. Collapsed wind turbines or cranes on construction sites and in harbours offer a rather frightening picture of the destructive forces of nature.
Material selection and stability requirements must be considered in the risk assessment and measures already taken should be reconsidered if necessary. At the same time, however, the requirements for escape routes are also increasing in order to be able to find a safe place in case of an emergency. Although Europeans are still a long way from having to plan “hurricane evacuation roads”, a meeting point can actually save lives in the event of storms.
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