In episode 48, my guest Mike Spearpoint said that in mid '90s, he participated in experiments on vehicle fires, as at that time, there were doubts if the design fires of that time (developed in the '80s) were representative of modern cars. Fast forward 30 years ahead, and we seem to be in a very similar situation. We have limited knowledge on vehicle fires, most coming from very old studies that have used even older vehicles... And we have a fleet that consists of larger vehicles, gravitating to alternative fuels and batteries. We urgently need a new design fire, and in my opinion not just that - we need a new design fire paradigm for the car parks. In this episode, I'm explaining the struggles we had choosing a design fire for our NCN OPUS grant on the multiparametric study of fire risk in wind conditions financed by the National Centre of Science in Poland. We have went through the literature, and looked through all of the available data, to figure out some data points we could implement in our studies. In the episode, I will share those data points (and you may refer to a paper which I will link as soon as it is published), but also cover my ideas related to: how do we carry out experiments on vehicles, and how does the experimental setup change the outcome;what is the design fire, and why do we need one?what are the goals of our design and why design fire should start with the goals in mind.The design fire is not a representation of a real fire. It is a test scenario that allows us to carry useful engineering judgement. This episode is all about this idea, and how I am making sure that my current assumptions reflect the changes in the modern car fleet. Enjoy! Some additional resources: Mohd Tohir's PhD thesis that gives the best overview of data up to 2014Our paper from 2014 which explains some assumptions for the car park smoke control design and summarizes experiments (in Polish)Badania przedstawione w odcinku podcastu przeprowadzono w projekcie realizowanym an podstawie umowy UMO-2020/37/B/ST8/03839 do projektu badawczego nr 2020/37/B/ST8/03839 pt. Skutki oddziaływania wiatru na pożary budynków w wieloparametrycznej ocenie ryzyka z wykorzystaniem metod numerycznych.