# Sources and TNT Models Sources define chemical release conditions. Consequence models attached to a source calculate the resulting hazard and damage effects. ## Add a Source 1. Right-click **Sources**. 2. Choose **Add Source**. 3. Pick the source location on the canvas or enter the coordinates. 4. Fill in the source inputs. Important source properties: ![[Images/Source-Property-Grid.png]] - **Name** and **ID** - **Enabled** - **Color**, **Shape**, and **Width** - **Point** - **Material** - **Process Pressure**, in psig - **Process Temperature**, in degrees F - **Phase**, calculated from material, pressure, and temperature - **Hole Diameter**, in inches - **Leak Type**, either `Orifice` or `ShortPipe` - **Tank Volume**, in gallons - **Max Release Duration**, in minutes - **Elevation**, in feet Use the ellipsis button on **Material** to open the chemical picker. Filtering in the chemical picker helps locate a chemical by name or CAS number. ![[Images/Chemical-Picker.png]] ## Leak Type Use **Orifice** for homogeneous, non-equilibrium release behavior. Use **ShortPipe** for equilibrium flow typical of pipe lengths greater than about 10 cm. The short-pipe equilibrium method is selected in **Settings**. ## Add a TNT Model 1. Right-click a source. 2. Choose **Add TNT Model**. 3. Review or edit the model inputs. Important TNT model properties: ![[Images/TNT-Property-Grid.png]] - **Name** - **Enabled** - **TNT Yield**, as a percent - **TNT Heat of Combustion**, in kJ/kg When a TNT model is added, FX-PML attempts to apply a TNT yield value based on the source material data when available. ## Result Location The TNT model starts from the source point. If drift is enabled, the solver can displace the consequence location during the calculation based on the drift search settings.