Research Article
Improved Modelling and Assessment of the Performance of Firefighting Means in the Frame of a Fire PSA
Table 1
Epistemic parameters and specified probability distributions.
| Epistemic parameter | Reference value | Distribution | Distribution parameters |
| Value of optical density at which emerging smoke is visible under fire compartment door [1/m] | 0.3 | uniform | Min = 0.2, Max = 0.4 | Response time index for activation temperature of fire dampers [ | 125 | uniform | Min = 50, Max = 200 | Threshold of optical density below which fire compartment can be entered [1/m] | 0.4 | uniform | Min = 0.3, Max = 0.5 | Fraction of fuel mass (oil) converted into smoke | 0.097 | uniform | Min = 0.095, Max = 0.099 | Time to reach 1 MW heat release rate [s] | 425 | uniform | Min = 250, Max = 700 | Conductivity of cable [W/mK] | 0.275 | uniform | Min = 0.15, Max = 0.4 | Specific heat of cable [kJ/kgK] | 1.225 | uniform | Min = 0.95, Max = 1.5 | Depth of cable isolation [m] | 0.0016 | uniform | Min = 0.0012, Max = 0.002 | Cable density [kg/m3] | 1131 | uniform | Min = 833, Max = 1430 | Specific heat of concrete [kJ/kgK] | 0.65 | uniform | Min = 0.5, Max = 0.8 | Conductivity of concrete [W/mK] | 1.75 | uniform | Min = 1.4, Max = 2.1 | Thickness of concrete walls in the fire compartment [m] | 0.37 | uniform | Min = 0.32, Max = 0.42 | Probability that a fire door falsely stays open | 0.005 | beta | = 1.5, = 236.5 | Probability that fire damper fails to close | 0.01 | beta | = 1.5, = 117.5 | Failure temperature of I&C cables [°C] | 170 | uniform | Min = 145, Max = 195 | Critical time periods [s] with temperatures of I&C cables | | | | ≥145°C | 420 | uniform | Min = 360, Max = 480 | ≥150°C | 300 | uniform | Min = 240, Max = 360 | ≥160°C | 215 | uniform | Min = 180, Max = 250 | ≥170°C | 160 | uniform | Min = 120, Max = 200 | ≥180°C | 80 | uniform | Min = 40, Max = 120 |
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