In today's Fire Science Show, we talk about how boundary conditions can make or break your fire simulation models. We'll explore boundary conditions' fundamental role in defining how simulations interact with their environments and how mastering these can lead to more accurate and reliable fire simulation models. I hope we break down some complex topics into manageable insights. Also, I hope we've turned something really boring into an interesting and fun episode. We discuss:1. Boundaries interacting with flow:pressure inlets/outlets [open];velocity boundary conditions [vents];mass flow inlets;fans and HVAC models.2. Boundaries containing the flow - walls:heat transfer at walls;shear at walls.And other minor boundaries such as symmetry and interior. The episode is largely based on my expertise with ANSYS Fluent, but I've tried to make it relatable to FDS as well, ensuring that the content is practical and valuable for your work in fire science and simulation modeling.----The Fire Science Show is produced by the Fire Science Media in collaboration with OFR Consultants. Thank you to the podcast sponsor for their continuous support towards our mission.