Water Mist at Codelco Ventanas Plant in Chile
Meeting eco-friendly sustainability targets
Codelco Ventanas (DVEN), being a copper smelter and refinery plant in Chile, attaches great attention to employees and environmental safety as business continuity. High risk areas, such as substations, process control rooms, electrical rooms, cable tunnels and fuel storage areas are already protected by automatic fire protection systems.
DVEN is currently developing initiatives with the objective of improving the fire safety infrastructure, which includes the implementation of fire detection and extinguishing systems in operational areas. The hydraulic and lubrication systems, utilizing mineral oils, represent fire risks with high heat release and fume generation, potentially damaging critical equipment and facilities such as the pump room and lubrication of the acid plant, the air compressor of the oxygen plant and the hydraulic systems of the casting areas.
Based on risk assessments, an action plan for improvement of fire protection foresees the installation of fixed automatic fire protection systems for the lubrication and hydraulic systems in the areas mentioned above. FOGTEC’s local partner RMC Engineering Solutions is in the process of implementing FOGTEC high pressure water mist systems to these areas. This will minimize the risk of damage to people, the equipment and to the facilities by fire.
FOGTEC fire detectors for another world record holder
Cog railway in the Wengen Oberland, Switzerland
We have already reported in our summer newsletters that FOGTEC has equipped the world's highest cog railway in Colorado, USA and the steepest cog railway, in Switzerland, with FOGTEC fire detection technology. Now the next world record holder will be the Wengeneralpbahn (WAB), also in Switzerland.
With its almost 19 km long track, the WAB is the longest cog railway worldwide. It is named after the village of Wengen, one of four stations on its route. The railroad provides, among other things, passenger transport as well as the supply of goods for the car-free health resort of Wengen.
During the annual FIS SKI World Cup in the Bernese Oberland, the railroad performs a great deal: athletes, organizers, coaches and spectators are brought from Lauterbrunnen to Wengen. All goods such as race material, grandstands, tents, sponsor articles etc. are also transported step by step to 1,274 meters above sea level and distributed from there. A spectacular backdrop is provided by the bridge "Wasserstation" on which the WAB runs when the skiers race under it at speeds between 80 - 100 km/h. From now on the WAB is equipped with FOGTEC smoke and heat detectors.
How warm does it get in a tunnel smoke extraction duct when a water-mist FFFS is activated?
Results from the SOLIT² research project
Within the SOLIT² research project, numerous full scale fire tests were carried out in a test tunnel. For the first time, fire tests with a water-mist FFFS and a semi-transversal ventilation, including installation of a false ceiling in the test tunnel, were implemented. To cover several fire scenarios, both solid fires (Class A) and liquid fires (Class B) with different fire sizes were tested. To determine the temperatures in the smoke extraction duct, thermocouples were installed in the false ceiling at a height of 0.5m and 1.5m.
Figure: Temperatures in the exhaust duct with a 150 MW solid fuel fire and activated water mist FFFS
Although the ventilation in the test tunnel is only dimensioned for a fire size of 30 MW HRR, in fire tests with a significantly higher fire load, the amount of smoke gas could be discharged through the exhaust air duct after activation of the FFFS. The amount of smoke gas was also greatly reduced after activation. An exemplary evaluation of the duct temperatures with a 150 MW solid fuel fire (truck mock-up) and a semi-transverse ventilation with 120 m³/s at 3 m/s wind speed looks as follows:
Figure: Temperatures in the exhaust air duct with a 150 MW solid fuel fire and activated water-mist FFFS
The red bar marks the activation of the FFFS. The FFFS was activated very late (about 8 minutes after ignition) to represent a worst-case scenario. It is recognisable that shortly after activation of the FOGTEC FFFS, temperatures did not exceed 50°C and settled at less than 40°C, thus once again demonstrating the enormous cooling effect of water mist.
Increasingly water-mist FFFS are used for compensatory purposes in tunnels. One possibility is the compensation of structural fire protection to protect the structure. Fire tests have shown that temperatures can also be considerably reduced in the exhaust air duct, which means that structural measures such as fire protection panels and PP fibres can be dispensed with. It was also shown that ventilation systems that are designed too weak – as it is the case with many older tunnels - can be compensated by using water-mist FFFS.
If the safety systems are coordinated, such compensatory measures can be very cost-effective. The simple implementation of a water-mist FFFS can thus preserve against expensive construction measures. Furthermore, the overall safety level in the tunnel will be increased.
For further information on temperatures in exhaust air shafts or FFFS in tunnels, please contact firstname.lastname@example.org.