MCS0: Monte Carlo Simulation Method 0

Input parameters

The following table summarises the parameters that are required by sfeprapy.mcs0 module.

Non-Optional Miscellaneous Parameters

case_name: str

A name for the case/compartment. Should be unique
among all cases. This may be used in post-processing when combining time equivalence results.

fire_mode: int

Should be an integer from 0 to 4, inclusive. To define what design fires to use:
0 - EC parametric fire only;
1 - Travelling fire only;
2 - EC parametric fire, German Annex;
3 - Option 0 and 1 as above; or
4 - Option 2 and 1 as above.

n_simulations: int

Should be an integer greater or equal to 1.
The number of simulations that will be running. A sensitivity analysis should be carried out to determine the appropriate number of simulations.

probability_weight: float

Should be a real number between 0 and 1, inclusive.
The fire occurrence probability weight of this specific case (i.e. compartment) among all cases (i.e. entire building).
This parameter is not used in any calculation. sfeprapy.mcs0 reference this parameter in its output for each single iteration and can be used during post-processing to combine time equivalence curves based on their probability weight to the entire building.

Compartment Parameters

room_breadth: float

[m]
Breadth of room (the shorter dimension).

room_depth: float

[m]
Depth of room (the greater dimension).

room_height: float

[m]
Height of room (floor slab to ceiling slab).

room_wall_thermal_inertia: float

[J/m²/K/√s]
Compartment lining thermal inertia.

window_width: float

[m]
Total width of all opening areas for a compartment.

window_height: float

[m]
Weighted height of all opening areas.

beam_position_vertical : float

[m]
Height of test structure element within the compartment for TFM. This can be altered to assess the influence of height in tall compartments. Need to assess worst case height for columns.

beam_position_horizontal: float

[m]
Minimum beam location relative to compartment length for TFM - Linear distribution.

Windows/Natural Vent

window_open_fraction: float

Dimensionless.
Glazing fall-out fraction.

window_open_fraction_permanent: float

Dimensionless.
Use this to force a ratio of open windows. If there is a vent to the outside this can be included here.

Design Fire Parameters

fire_tlim: float

[hour]
Time for maximum gas temperature in case of fuel-controlled fire, value options can be found in Annex A EN 1991-1-2. Slow: 25/60 Medium: 20/60 Fast: 15/60

fire_time_step: float

[s]
Time step used for the model, all fire time-temperature curves and heat transfer calculation. This is recommended to be less than 30s.

fire_time_duration: float

[s]
End of simulation. This should be set so that output data is produced allowing the target reliability to be determined. Normally set it to 4 hours and longer period of time for greater room length in order for travelling fire to propagate the entire room.

fire_load_density: float

[MJ/m²]
Fire load density. This should be selected based on occupancy characteristics. See literature for typical values for different occupancies.

fire_hrr_density: float

[MW/m²]
Heat release rate. This should be selected based on the fuel. See literature for typical values for different occupancies.

fire_spread_speed: float

[m/s]
Min spread rate for travelling fire.

fire_nft_limit: float

[K]
TFM near field temperature.

fire_combustion_efficiency: float

Dimensionless.
Combustion efficiency.

fire_gamma_fi_q: float

Dimensionless.
The partial factor for EC fire (German Annex).

fire_t_alpha: float

[s]
The fire growth factor.

Structural Element Section Properties

beam_cross_section_area: float,

[m²]
Cross sectional area of the section.

beam_rho: float

[kg/m³]
Density of the structural member.

beam_temperature_goal: float

[K]
Structural element (steel) failure temperature in Kelvin for goal seek.

protection_protected_perimeter: float

[m]
Heated perimeter.

beam_protection_thickness: float

[m]
Thickness of protection.

protection_k: float

[W/m/K]
Protection conductivity.

protection_rho: float

[kg/m³]
Density of protection to beam.

protection_c: float

[J/kg/K]
Specific heat of protection

Solver Settings (for Time Equivalence)

solver_temperature_goal: float

[K]
The temperature to be solved for. This is critical temperature of the beam structural element, i.e. 550 or 620 °C.

solver_max_iter: float

Dimensionless.
The maximum iteration for the solver to find convergence. Suggest 20 as most (if not all) cases converge in less than 20 iterations.

solver_thickness_lbound: float

[m]
The smallest value that the protection thickness can be. This is used to solve the maximum steel temperature at solver_temperature_goal.

solver_thickness_ubound: float

[m]
The greatest value that the protection thickness can be. This is used to solve the maximum steel temperature at solver_temperature_goal.

solver_tol: float

[K]
Tolerance of the temperature to be solved for. Set to 1 means convergence will be satisfied when the solved value is greater than solver_temperature_goal-1 and less than solver_temperature_goal+1.

phi_teq: float

Dimensionless.
Model uncertainty factor multiplied with the evaluated characteristic time equivalence value to get the design time equivalence value.

Timber Properties

timber_exposed_area: float

[m²]
Exposed timber surface within the compartment. Set timber_exposed_area to ‘0’ to omitt timber involvement.

timber_charring_rate: float

[mm/min]
Timber constant charring rate. This is currently independent of temperature or heat flux.

timber_hc: float

[MJ/kg]
Heat of combustion of timber.

timber_density: float

[kg/m³]
Density of timber.

timber_solver_ilim: float

Dimensionless.
The maximum number of iterations that the solver can run. timber_solver_iter in the output file should be inspected to determine appropriate value for timber_solver_ilim. Consider to increase timber_solver_ilim (or increase timber_solver_tol) if many solved values have timber_solver_iter == timber_solver_ilim.

timber_solver_tol: float

[s]
Tolerance of the solver. Convergence is sought if change in time equivalence is less than timber_solver_tol.
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