FX-EML separates document options from local application settings. ## Options Tab The **Options** tab is saved with the project file. These values travel with the `.fxeml` project. ![[Images/Options-Tab.png]] General options: - **Author** - **Description** Georeferencing: - **True North**, declination between the canvas +Y axis and true north, deg - **Origin X**, X location of the georeferenced point, ft - **Origin Y**, Y location of the georeferenced point, ft - **Longitude of origin**, longitude of the Origin X location, deg - **Latitude of origin**, latitude of the Origin Y location, deg The georeferencing fields tie the document's local XY world (in feet) to real-world geographic coordinates. A single known point anchors the two systems: its local position is (**Origin X**, **Origin Y**) and its geographic position is (**Longitude of origin**, **Latitude of origin**). The local +Y axis is rotated from true north by the **True North** declination. With these set, FX-EML can convert any canvas location to and from longitude/latitude, projecting distances and bearings onto the WGS-84 ellipsoid. Weather parameters: - **Atmospheric Pressure**, psi - **Ambient Temperature**, degrees F - **Relative Humidity**, from 0 to 1 - **Solar Radiation Flux**, W/m2 - **Wind Speed**, mph - **Stability Class**, Pasquill A–F; default D (neutral) Surface parameters: - **Surface Type**, Concrete (default) or Dry Dirt - **Surface Temperature**, degrees F; default 68 - **Surface Roughness**, aerodynamic roughness length in cm; default 100 UDM uses wind speed at a measurement height of 10 m. Wind speed and surface roughness must be positive. Additional costs: - **Debris Removal Cost**, percent - **Other Additional Cost**, percent - **Inflation per Year**, percent - **Inflation Years** Additional costs are calculated from the total property damage before additional costs: - Debris removal cost = Total property damage * Debris Removal Cost / 100 - Other additional costs = Total property damage * Other Additional Cost / 100 - Inflation costs = Total property damage * ((1 + Inflation per Year / 100) ^ Inflation Years - 1) - Total loss = Total property damage + Debris removal + Other additional costs + Inflation costs Discharge calculation options: - **Droplet Method**, one of `Simple Rainout`, `Original CCPS`, `Modified CCPS`, or `DNV droplet JIP` - **Expansion Method**, one of `Isentropic`, `Momentum`, or `Closest to Initial` - **Velocity Capping Method**, either `Fixed Velocity` or `Sonic Velocity` - **Max Release Velocity**, ft/s The **Droplet Method** field selects the atomization model supplying the droplet size to UDM. The legacy **Simple Rainout** selection uses Modified CCPS atomization. All selections now defer rainout to UDM. The **Expansion Method** field selects the model used to expand the release to ambient pressure for gas and liquid sources. The **Velocity Capping Method** field allows you to choose the method used to set an upper limit on the calculated discharge velocity. If you choose **Sonic Velocity**, the upper limit is set by the sonic velocity for vapor under the discharge conditions. If you choose **Fixed Velocity**, the upper limit is set by the value in the **Max Release Velocity** field. Dispersion calculation options (UDM): - **Max Downwind Distance**, ft; default 164042 - **Minimum Conc of Interest**, ppm; default 10. This is a reported UDM endpoint; it does not stop the rainout calculation early. - **Pool Vapor Pickup**, Off, Max Rate (default), or Mean Rate - **Finite Duration Method**, Front Taper or Along-Wind Diffusion (default) Liquid releases with liquid remaining after expansion use full UDM dispersion (Contract B). Discharge supplies the full expanded flow, phase split, velocity, jet diameter, temperature, and droplet diameter. UDM calculates gross rainout and models its pool. Gas and fully flashed releases have no liquid rainout to calculate. Final mass to air is `(discharge rate − final-march UDM rainout rate + pool vapor pickup rate) × release duration`, where duration is limited by the available tank mass and maximum release duration. Pool Vapor Pickup selects the equivalent evaporation rate added to air: Off adds zero, Max Rate adds the maximum rate over the release duration, and Mean Rate adds the time-average rate. Gross rainout is retained for reporting the pool feed; final-march rainout is used for mass to air. Using Max Rate gives an equivalent steady-state mass estimate rather than an integrated pool mass balance, so final airborne mass is not capped at tank mass. The reported airborne aerosol contribution includes droplet material that evaporates in flight; it is not the liquid fraction at a particular downwind location. The release is horizontal, with concentration averaging time 18.75 seconds. Each source's **Max Pool Area** sets the rainout-pool spreading limit in ft²; zero (the default) means unbounded. A positive area represents a non-overflowable bund centered on the rainout point: the pool deepens instead of spreading beyond it. Surface, weather, dispersion, and source pool-area options are saved with the project; older files use the new defaults for missing values. Damage calculation options: - **Include Drift** - **Max Drift Distance**, ft - **Drift Step Size**, ft - **Damage Mapping**, either `Constant` or `Interpolate` **Constant** treats the damage contours as bands. A location between two damage-level radii receives the outer, lower damage percentage for that band. **Interpolate** linearly blends the damage percentage between adjacent damage-level radii, giving intermediate values between the defined damage levels. For both methods, locations inside the innermost contour receive the innermost damage percentage, and locations outside the outermost contour receive zero damage. Smaller drift step sizes can improve search resolution but increase solve time. ## Settings Tab The **Settings** tab is saved for the local user, not inside the project file. ![[Images/Settings-Tab.png]] Autosave: - **AutoSave** - **AutoSave Duration**, seconds Canvas: - **Grid Spacing** - **Show IDs** - **ID Font Size** - **Snap Angle** Solver: - **Log Level** - **Clear Log On Run** - **Short Pipe Equil. Model**, either `Omega` or `HDI` UI configuration: - **Asset Sorting**, either `Name` or `ID`