The paper analyses the breathing air consumption among participating firefighters during full-scale tests performed in the Tistbrottet mine in Sweden 2013. The availability of breathing air during firefighting has in earlier work been identified as a critical tactical factor in underground firefighting. Results from the tests show that there are differences in the breathing air consumption and that this depends on the methods used, equipment and the workload. The use of BA-teams, i.e. firefighters equipped with breathing apparatuses, is a complex group activity where the largest breathing air consumer will set the limits for the whole team. Light equipment and a structured command and control during the activities will enhance the endurance and the firefighting performance. Equipment and methods affect both firefighting performance and the durability of the firefighting activities. Examples of tested methods and equipment during the test series are: different variations of conventional hose lay-out; CAFS; cutting extinguisher; and trolley for equipment and complementary air. The aid of additional air supply and the use of trolleys will support the activities but is dependent on a large degree of preparation and training to function properly. Based on the tests, it is concluded that the larger model of air bottles should be considered for distances longer than 75 m.

An evacuation experiment was carried out at the Äspö Hard Rock Laboratory in March 2018 to investigate human behaviour during evacuation in underground facilities via escape routes with long ascending tunnels. The objective of the experiment was to collect data that could be used as a basis for evacuation risk and safety assessments in underground tunnels and other large infrastructure projects related to e.g., mining. In total, 32 participants individually ascended the 907Â m long tunnel with an inclination of 14%. During the evacuation, each participant’s walking speed, vertical walking speed, heart rate and estimated physical exertion was documented. The measured walking speeds were found to be higher than the walking speeds obtained in previous experiments, but the vertical walking speeds were lower. The strategy of 44% of the participants was to adjust their walking speed to a pace they thought could be maintained over a longer distance. The results of this experiment show that the walking speed decreased as the level of perceived exertion increased. Moreover, the results indicate that the walking speed and the level of perceived exertion stabilized during the movement along the tunnel.