Practical experience: Use of water mist turbines in the waste disposal industry

In waste management, materials with large fire loads are often stored in halls and open spaces. Often, a small ignition source such as a thumb-sized lithium-ion battery or an aerosol can in a pile is enough to turn an undetected smoldering fire into a full fire in a short time, which even a fire brigade finds difficult to control. In this article, we report on our experiences with the use of water mist turbines in the waste management industry.

After a major fire incident, many recycling companies have great difficulty in maintaining their delivery obligations to end customers and other waste processing companies. Such situations lead to considerable financial losses and not infrequently to the bankruptcy of the company concerned.

Since waste management companies are at risk for fires due to the nature of their work, stationary fire protection to protect storage and production areas is an omnipresent issue. In the past, the waste management industry relied heavily on the use of sprinkler technology, but this is increasingly being replaced by more innovative technologies.

Paradigm shift: from the sprinkler system to fire monitor and water mist turbine

In recent years, more and more good experience has been gained in the use of automatic early fire detection by infrared cameras and extinguishing monitors in waste management storage areas. The advantages of these applications compared to traditional sprinkler technology lie in the earlier detection of a fire source by monitoring the surface temperature and in the targeted application of a hotspot by the extinguisher.

A sprinkler system will generally always be triggered later than the infrared cameras, due to the sprinkler vessels hanging from the ceiling of the warehouse. A fire monitor can apply a hotspot very precisely using the information from infrared detection. The sprinkler system in contrast wets a whole area.

Further development of the fire monitor is the FT10e water mist turbine. The turbine covers all the requirements and functions of a fire monitor and additionally throws water mist at a distance of up to 35m via a separate nozzle ring. Compared to conventional water jets, water mist has the central advantage that it reaches hidden sources of fire better and can cool and extinguish very efficiently with a smaller amount of water. 

Thanks to intelligent detection systems, it is possible to precisely target the hotspot with different spray patterns (water mist only, monitor jet only, combination of water mist & monitor jet). 

Of course, the firefighting turbine can also be controlled manually via a radio remote control or through a control panel. A separate feed via the fire brigade is also possible. The water mist turbine can also be controlled via conventional fire detection. 

Water mist turbines in practice

Water mist turbines provide the following added values compared to conventional systems:

1. The use of water mist for firefighting enables the reduction of impact quantities in the event of an incident due to the proven better extinguishing and cooling result compared to a conventional monitor jet.
2. Likewise, a reduction of extinguishing equipment may be possible because the water mist also reaches shaded areas better than traditional fire extinguishing systems.

In fire protection project solutions for storage and production halls for substitute fuels, automatic water mist turbine systems in combination with high-quality infrared detection have already been planned and implemented with the client's fire protection planner, which, according to experts, offers a higher level of protection against fire hazards than a traditional sprinkler system.

The application rates can be configured flexibly, depending on the fire load and the specifications of the fire protection planners. In the waste disposal industry, we usually use between 100 and 2,700 l/min.

However, there are also areas where firefighting turbines do not make sense. For example, in areas with a ceiling height of fewer than 4 meters: here the necessary parabola for the water mist cannot be formed. In small areas of 20-40 square meters, conventional nozzle systems are more suitable. Then there are areas that must not come into contact with water or water mist (e.g. server rooms, libraries, steelworks).

If a company is considering the use of water mist turbines, the planning basically starts with the company's existing fire protection concept or fire protection planning.

Conclusion

The possible spectrum of applications for water mist turbines in practice is large and ranges from the chemical sector (where, in addition to firefighting, the main focus is also on the precipitation of pollutants) to recycling plants and companies with storage areas with a high fire load (such as aircraft hangars, refinery tank farms, the wood-processing industry, etc.) or high-voltage power plants.

Installations, also with customized adaptations, are realized in customary market times of 4-12 months. Complete new technical developments have a longer lead time, as they are very carefully checked and tested for their specific suitability.