System for Protecting People from Accidental and Terrorist Explosions in Underground Structures.

28 April, 2016

Center for Infrastructure Protection and Physical Security (CIPPS),
University of Florida 365 Weil Hall
Gainesville, FL 32611-6580, USA
Tel: (352) 273-0691
Fax: (352) 273-0186

The protective system is composed of: i) a wireless device for the detection of explosions and activation of a protective system; ii) a new design of a blast energy absorber with a pyrotechnic activation to ensure discharge of water mist to form a barrier in the path of the shock waves. Results of bench testing and of testing in an underground opening confirmed the envisioned potential of the proposed protective system.

The new high-speed suppression system activated at the command of the initiation signal produces tailored dispersing water mist with droplet sizes in the range of 25-400 micron along selected sections of a tunnel and that has the following properties:

- the time of absorber activation from the moment of blast: 11 ms;
- speed of a damping agent discharge from an absorber: 60-80 m/s;
- volume of discharge: 80-150 liter;
- reduction of shock wave overpressures by means of an absorber: 2.1-2.98 times ;
- the distance between a transmitter and a receiver in a direct tunnel - at least 150m; in a tunnel with a 900 bending - 50m;
- minimum overpressure for activation of an absorber: 12 kPa.

The presented protecting system can be effectively applied in:

1. motorway and railway tunnels;
2. subway tunnels;
3. coal mines under threat of methane explosion;
4. land- or sea-based oil platforms;
5. other petro-chemical plants;
6. long superstructures with limited cross sections that could be loaded by gas or dust explosions.

Development status: Prototype
Patent landscape: Protected by “know-how”

The development of the presented protective system was sponsored by NATO’s Public Diplomacy Division in the framework of ”Science for Peace”.

А -water mist generator for horizontal dispersal, В - for vertical dispersal.
1 - absorber control block, 2 - high pressure camera, 3 - water container, 4 - nozzles

The process of water discharge from the vertical absorber. A - after 12 ms from activation of an absorber; B - after 25 ms.

The process of water discharge from the horizontal absorber. A – after 12ms from absorber activation. B- nozzles P120 BETE