Water Mist in Road Tunnels: The Key Standards, Guidelines, and a Practical Example from Delhi
The successful deployment of the FOGTEC high-pressure water mist system in Delhi’s Dwarka Tunnel demonstrates the effectiveness of properly designed fire-fighting systems in containing fires, ensuring safe escape and rescue conditions, and protecting critical transport infrastructure, as stipulated by international standards and guidelines.
When a car recently caught fire in the Dwarka Tunnel in Delhi, India, the FOGTEC system responded exactly as intended. The system was automatically triggered by the fire alarm, extinguishing the fire and limiting its spread while maintaining tolerable conditions in the tunnel until the fire brigade arrived.
This incident shows that: A fixed firefighting system (FFFS) that is properly planned and designed for emergencies, taking current research findings into account and meeting specified standards, will also prove effective in practice.
We are delighted to have contributed to the protection of this vital infrastructure link to Delhi Airport with one of FOGTEC’s most recent major turnkey installation projects. This is a tunnel where a prolonged closure would result in enormous overall economic losses in this part of India.
This successful operation highlights an international trend: water-based fixed fire-fighting systems are becoming an integral part of modern tunnel safety concepts worldwide. In recent years, numerous standards, guidelines, and technical recommendations have recognised their contribution to personal safety, infrastructure protection, and risk mitigation, as well as their compensatory potential.
Today, water-based fire suppression systems are included in many of the world’s leading tunnel safety documents. Let’s take a look at the most important standards and guidelines.
NFPA 502, USA
The NFPA 502 includes comprehensive guidance on design objectives, system integration and performance requirements. Annex E summarizes the latest research and documents the proven benefits of FFFS for life safety and infrastructure protection. As an active member of the NFPA 502 Technical Committee, FOGTEC contributes directly to the continuous development of this internationally recognized standard.
RABT and EABT 80/100, Germany
In Germany, the RABT and EABT 80/100 recommend considering fixed firefighting systems for specific tunnel types and design fire loads of 100 MW or higher. They have been replaced by the RE ING, which is taken the same safety approach for the FFFS topic. Their ability to limit fire development, support emergency response and reduce structural damage is recognized within the overall tunnel safety concept.
PIARC, worldwide
PIARC (World Road Association) has significantly strengthened its position on FFFS over recent years. Based on international experience, PIARC now recognizes fixed firefighting systems as an effective risk reduction measure that improves user safety, extends available evacuation time and protects tunnel infrastructure.
RVS 09.02.51, Austria
Austria’s RVS 09.02.51 guideline highlights additional advantages, including reduced radiant heat, lower smoke production and the potential to optimize other tunnel safety measures such as ventilation systems, emergency exit spacing and structural fire protection.
SOLIT² Engineering Guidance, worldwide
The German SOLIT² Engineering Guidance, endorsed by ITA-COSUF, provides a comprehensive framework covering fire testing, design, installation, operation and maintenance of tunnel fire protection systems. It also demonstrates how FFFS can positively influence the overall tunnel safety strategy through compensation of other safety measures. By now it has been taken into account for several tenders and installations all over the world.
UPTUN, Europe
Likewise, the European UPTUN project established important engineering guidance based on extensive full-scale fire testing, defining minimum requirements and best practices for water-based firefighting systems in tunnels.
Although national regulations might still deviate from country to country, the overall direction in the international tunnel industry is quite clear: Around the world, tunnel authorities and infrastructure owners increasingly rely on internationally recognized standards and engineering guidance when implementing Fixed Fire Fighting Systems. This short overview should also help those who might not have local standards and guidelines in their country but to think outside the box.
The successful activation of our water mist system in the Dwarka Tunnel is therefore more than just an isolated event, it is a confirmation of what international research, testing and standards have demonstrated for many years: well-designed High Pressure Water Mist Systems effectively control tunnel fires, improve life safety and protect critical infrastructure when every second counts.
