Abstract This study identifies the parameters that influence the development of thermal conditions during live fire training evolutions within burn facilities。 As part of a previous study, tests were conducted on the third floor of the live fire training building at the Maryland Fire and Rescue Institute (MFRI)。 The principal measurements obtained during the training evolutions were temperatures and heat flux in the burn room。 A model replicating the tests conducted in the MFRI training facility was created using CFAST version 6 and a validation was performed by comparing temperature and heat flux measurements from the test to the model’s estimation。 Then, the MFRI CFAST model was used to simulate twenty one scenarios that examine the effects various fuel packages, ventilation strategies, room sizes and time between sequential burn evolutions have on the thermal conditions inside a firefighter training burn room。 There are many fuel packages commonly burned during live-fire training。 This study was only able to analyze fuel packages in which there is heat release rate data available, which include; stacked pallets, triangular pallets & excelsior, excelsior pile, flat pallets & excelsior, and upright pallets & excelsior (see Table 8 for more details regarding the fuel packages)。 Results show that of the fuel packages analyzed, the ones configured vertically (stacked pallets and the upright pallets & excelsior) have the greatest heat release rate and create the most severe thermal conditions, while triangular configured fuel packages create moderate thermal conditions and lastly, horizontally configured fuel package (flat pallets & excelsior) create the least severe thermal conditions。 Horizontal ventilation causes a quick decrease in thermal conditions, while leaving remote vents open during a burn evolution limits the development of thermal conditions within the burn room。 According to the model simulations where the same fuel package is burned in rooms that vary in size, the burn evolutions that occur in small rooms produce hotter conditions than ones that occur in larger burn rooms。 Also, as multiple sequential burn evolutions occur over the course of training, the initial ambient temperatures inside the facility continually rise to yield thermal conditions that are even more severe than the previous evolution。 When minimal time is taken between burn evolutions, conditions can become very severe after multiple evolutions。 Taking more time between burn evolutions can allow the facility to cool down and reduce the severity of thermal conditions。 Based on the results of this simple study, it is recommended that NFPA 1403 be modified to include a hazard assessment procedure that can enable fire instructors to properly account for the principal factors affecting the severity of the thermal conditions produced in burn evolutions。82321

Executive Summary

Live fire training facilities are built to endure repeated burn evolutions so that firefighters can train in an environment that mimics the conditions of a real building fire。 These training facilities generally have well insulated burn rooms。 When a fuel package is burned in these structures, thermal conditions can become extreme, potentially threatening the tenability of firefighters wearing personal protective equipment。 NFPA 1402 does not mandate a specific *size for burn rooms in live fire training facilities and NFPA 1403 does not provide quantitative guidance to fire instructors on the types of fuel packages that are safe to burn, methods to properly ventilate and how to conduct sequential burn evolutions。 This report conducts a first order analysis by using a simplified zone fire model, CFAST to replicate tests conducted in the MFRI live fire training facility and simulate various scenarios to assess the relative impact of four parameters on the thermal conditions that may develop within a burn room of a live fire training facility。 The key components that determine the thermal conditions within a training facility, during a live burn are: the fuel package, ventilation strategy, room size and duration between burn evolutions。 A detailed methodology for conducting a fire hazard assessment for a live fire training evolution does not exist。 The analysis documented in this report should provide some assistance to fire instructors in appreciating which parameters are the most influential in dictating thermal conditions which are generated。