SOME PROBLEMS FOR ASSESSMENT OF FIRE IN ROAD TUNNELS   SOME PROBLEMS FOR ASSESSMENT OF FIRE IN ROAD TUNNELS Professor Omar LANCHAVA Professor Nikolae ILIAS Dr Giorgi NOZADZE

These studies aim to clarify two issues: 1 What is the impact of natural and mechanical ventilation of tunnels on the spread of smoke, high temperature, carbon monoxide and other toxic combustion products? 2 How provide a rapid actions operational staff of tunnel for the estimation and the management of emergency situations in case of accident?

Description of the problem and novetly 1 The main component of the potential harm caused by fires are: human victims, deterioration their health and damage infrastructure of tunnel. 2 We suggest a criteria by which it are possible to evaluate of emergency situations in tunnels caused by fire. 3 Criteria will be characterize the negative transformation of the environment under the earth. This changing would be described in spatial and temporal scales.

Classical form developing of fire

Similar figures Experiment of Memorial Tunnel Fire Ventilation Test Program

Similar figures Experiments of Eureka Project

Growth HRR of fire for liquid fuel (e. g Growth HRR of fire for liquid fuel (e.g. a petrol and similar fuels) - Without the regimes increasing and diminishing in burning process. V-C fire (a fire controlled by ventilation - magnitude of fire and its HRR limited by the amount oxygen supplied to the situ of fire.

Scenario of fire developing for liquid fuel with diminishing zone F-C fire (fuel controlled fire – limited by the arrangement and the chemical nature of the fuel)

In this work there were performed various mathematical models of V-C fires. That is, for the most difficult conditions in the preservation of health and life of humans, so for their evacuation.

Damaging factors affecting on the human during fires: Toxic products (COx, NOx, SOx). Smoke (about 100 ingredients including products of incomplete combustion). High temperature. By the distribution of carbon monoxide it is possible to judge on the distribution of smoke and other toxic products. Therefore, the following simulation results are given for only the temperature and carbon monoxide.

The average time of occurrence hyper thermal shock 80 75 70 65 60 55 50 45 40 II 1 3 5 7 10 30 1000 14000 I- The ambient temperature, II- The limit of human endurance, min The average time for occurrence of toxic poisoning I 12000 11500-5500 5500-3500 3500-2500 2500-1800 1800-800 800-600 II 1-2 2-5 10-15 20-30 40-80 60-120 120-320 I- The concentration of CO, mg/m3 II- The limit of human endurance, min

HRR - Heat release rate during burning different vehicle Vehicle type and quantity Quantity of a fire, MW 1 passenger car 5 2-3 passenger cars or 1 mini-bus 8-15 1 small truck 15-20 1 bus or 1 truck with non-dangerous goods 20-30 1 loaded trailer 100 1 tanker with petrol 200-300

Starting conditions of models HRR – 5, 10, 20, 30, 50 MW. Pressure difference between portals - 0 Pa. Cross-section area of tunnel - 64 m2. Burning surface area of liquid fuel - 15 m2. Slope of tunnel - 0-6 ppm. Localization of fire – in center of tunnel.

View of starting model in soft Localization of the fire in the center, at a distance each 100 m on both areas from fire installed various sensors. Therefore, in a cross section we have a stratigraphic picture of the distribution of the calculated values. The following are only a part of the results - changing of temperature and concentration of carbon monoxide at a level which corresponds to the height of a person (1.8m).

The dynamics of temperature (Starting model, HRR 10 MW)

The dynamics of carbon monoxide in tunnel (Starting model, HRR 10 MW)

The dynamics of temperature (Starting model, HRR 30 MW)

The dynamics of carbon monoxide in tunnel (Starting model, HRR 30 MW)

The dynamics of heat release rate (HRR) in the situ of fire The dynamics of heat release rate (HRR) in the situ of fire. Magnitude 30 MW

The dynamics of temperature in the situ of fire. (HRR 30 MW)

The dynamics of temperature – localization 100 m from fire (HRR 30 MW)

The dynamics of temperature – localization 200 m from fire (HRR 30 MW)

The dynamics of temperature – localization 300 m from fire (HRR 30 MW)

The dynamics of concentration of carbon monoxide – localization 0 m from fire.

The dynamics of concentration of carbon monoxide – localization 100 m from fire.

The dynamics of concentration of carbon monoxide – localization 200 m from fire.

The dynamics of concentration of carbon monoxide – localization 300 m from fire.

The dynamics of temperature ( simulation time 360 second, magnitude of fire 30 MW): distance from the bottom of the tunnel to isotherms: 50 - 2 m; 70 - 3 m; 90 - 4 m.

The dynamics of carbon monoxide in tunnel (simulation time 360 s).

The change in temperature over the length of the tunnel according to the simulation results.

The dynamics of concentration of carbon monoxide in tunnel by the results of the simulation.

Dynamic of concentration of carbon monoxide in the characteristic points of the tunnel

Dynamic of temperature in the characteristic points of the tunnel

To assess the effect of the fire, we use the method of separation of hazards in the tunnel by the zones. These are spatial and temporal zones of damage factors in tunnel. Thus, the method takes into account a change spatial zones of damage factors (such are high temperature and concentration of carbon monoxide) in time.

Dividing of emergencies of space and time zones with consideration of damage The spatial scale , m length of the zone - L1 length of the zone – L2 length of the zone – L3 length of the zone – L4 length of the zone – L5 The time scale, min. T1<Tp T1<T2<Tp T2<T3<Tp T3<T4<Tp T4<T5<Tp The extent of damage Hardest Heavy Average Weak Negligible

Spatial dynamics of the temperature field from the start of the fire after 5 minutes

Spatial dynamics of the temperature field from the start of the fire after 25 minutes

CONCLUSIONS Based on the averaged experimental results and with computer simulation by means of models can be getting spatial and temporal criteria for evaluation of fire that are closely related to the dynamic processes of the spatial and temporal distribution of hazards. This will allow under the initial and boundary conditions of the fire to adequately determine the method and tactics of evacuation. According to the results of submissions temperature fields and carbon monoxide distribution can be concluded that relaxation of temperature fields along the length of the tunnel takes place faster than alignment of other damaging factors, particularly of concentration of carbon monoxide and smoke. The studies showed that in case of fire in the power range of 5 - 30 MW in the tunnels there is sufficient time to carry out the evacuation. In case of V-C fires with a magnitude of 30 MW or more, under the conditions of a standard longitudinal ventilation system, and within the scope of the starting model, damaging factors may develop to dangerous levels within 10 to 5 minutes at a distance of up to 300 m from the fire source.

Acknowledgment This work was supported by Shota Rustaveli National Science Foundation No AR 61/3-102/13