New Calculation Technique for Assessment of Smoke Layer Interface in Large Buildings in Connection with the Design of Buildings in the Czech Republic

The sustainability of the indoor environment of buildings is also related to the conditions that arise in the case of fires. Fires in buildings are characterized by the formation of combustion products, which can significantly endanger the life and health of people. One of the major sources of danger is smoke. If there is no smoke exhaust into the outside environment during the development of the fire, the building is gradually filled with smoke. The important characteristic of the smoke layer is the level of the smoke layer, which changes over time. Several methods have been derived for determining the descent of the smoke layer in an enclosed area of space, which mainly differ in terms of the application area and limits of use. The methods used in the Czech Republic for the assessment of smoke layer descent in the case of fires do not have a clear rationale and in many cases lead to completely misleading results. For this reason, in connection with the standards for the assessment of the buildings in the Czech Republic, a new calculation technique (CSN) has been derived, which has been compared with the selected simple calculation techniques in large buildings. The deviations between the results have been evaluated by the percentage bias method (PBIAS), while the largest deviation, compared to the ISO standard technique, did not exceed 20%. The CSN calculation technique shows a favourable compliance with the technique presented by the ISO standard, where the deviation did not exceed 1.6%. In response to the proposed standards in the Czech Republic, the CSN calculation technique enables the assessment of safe evacuation in relation to the smoke layer interface and can be a considered perspective.