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/m^3]	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