In our last newsletter, we introduced you to the Dwarka Tunnel in Delhi. It is part of the Dwarka Expressway, one of India’s most ambitious infrastructure projects and, with its eight lanes, is one of the widest road tunnels in Asia. FOGTEC has equipped the tunnel with a modern high-pressure water mist firefighting system.
In contrast to many other projects outside Germany, FOGTEC not only carried out the planning and design for this order, but also the complete installation on site together with our Indian subsidiary, FOGTEC India. The close cooperation between the FOGTEC team and the local partner was an exciting experience and offered both sides the opportunity to expand their intercultural skills and learn from each other.
The system in detail
The project was not only special from a collegial point of view, it was also a technical challenge for our team. The high-pressure water mist system in the Dwarka Tunnel was designed entirely in accordance with the SOLIT guidelines and is based on a system that has already been successfully tested in full-scale fire tests.
The central main pipework is made of robust duplex steel. The individual pipe segments are precisely welded to ensure the longevity of the system. Much of the pipework was prefabricated to reduce on-site installation time.
The nozzles were selected based on the worst case scenario for a tunnel of this type: a lorry fire. FOGTEC drew on experience from other international tunnel projects and used nozzles that had been fire-tested and installed in many other tunnel projects.
Two separate pumping stations with high-pressure plunger pumps, each with a redundant unit, ensure a reliable water supply in the event of a fire.
Customised solution for special installation conditions
The height of the tunnel placed special demands on the installation. Due to the high ceiling, long brackets were used for the nozzles. Considerable air turbulence is created in the tunnel, especially when there is heavy traffic, for example from fast-moving lorries. These currents act directly on the system’s brackets and can cause vibrations that would affect stability in the long term.
The challenge was to secure these brackets in such a way that they would remain permanently stable on the ceiling, even under dynamic loads. FOGTEC developed an engineering-based solution by simulating and analysing real load scenarios – such as a truck travelling at high speed – based on detailed force calculations. This resulted in clear requirements for the design. The necessary strength was achieved with additional brackets and struts, so that the system remains reliable and secure even in the event of strong air movements.
Next part: Quality at a glance
In the next newsletter, we will focus on quality control of the finished system – from X-ray and functional testing to final acceptance. Stay tuned.
