Summary

This paper discusses an extensive programme of tests and numerical analyses on vertical escape route smoke ventilation in multi-story buildings described on the project page www.bezpiecznaewakuacja.pl;. The purpose of the tests carried out by SMAY Sp. z o.o. in cooperation with experts from Scientific and Research Centre for Fire Protection – National Research Institute (CNBOP-PIB), the Warsaw University of Technology, the Silesian University of Technology and ARDOR, was to verify stairwell smoke extraction performance for various configurations under a fire hazard, and to develop and test an optimum set of tools for stairwell smoke extraction. In addition, the test programme provided an opportunity to gain better insight into fire development in a enclosed room, and to analyse the efficiency of rescue team actions in a fire hazard scenario.

Physical tests representing the basis for the conclusions were performed on a special test station erected in the test area, located in a decommissioned 9-storey office building in Sosnowiec. A room on the 4th floor of the building and a short corridor to the stairwell were selected for the tests. A set of measuring and monitoring devices was installed in the test room and the stairwell space including e.g.:

• temperature measurement devices in the test room (Fig. 1), enabling concurrent recording from 48 temperature sensing tracks. Example data obtained during the fire test from the temperature measurement device No. 5 are provided in chart 1.
• light transmittance measurement points in the stairwell located on floors 4, 5, 6 and 9.
• ongoing surveillance by CCTV cameras located at key points of the test station (Fig. 2)
• additional temperature, airflow and differential pressure measurement points at various stairwell locations, and a weather station recording ambient conditions.

The structure and technical equipment of the test station were used to conduct over 70 tests with hot marker gases and 5 fire tests (photo 1). An important preliminary conclusion from the comparison of fire and smoke test data was the high consistency of the results. The average temperature of marker gases flowing through the open door separating the stairwell space from the test floor was 70oC, which corresponds to the temperature at the same point measured during fire test 3 and 4. This means that the smoke tests accurately represent the smoke flow conditions during a fire spread. Thus, the results from tests checking, e.g. the efficiency of gravity stairwell smoke ventilation using various configurations of smoke and external wall smoke vents and the actual performance of smoke ventilation systems supported by mechanical air flow, can be regarded as reliable.

The test programme led to the formulation of a series of conclusions, not only on smoke ventilation systems, but also fire dynamics and actual evacuation and actions by rescue teams. The result showed e.g. that the spread of fire in a room fitted with modern furniture is abrupt, and leaves little time to respond (escape), while the spread rate and time of reaching the respective fire spread phases is closely linked to the integrity status of the room (volume of air supply), and flashover may take place even before fire fighters arrive.

Key conclusions focused on the performance of stairwell smoke ventilation systems. It was e.g. proven that the performance of gravity smoke ventilation systems has significant limitations and the system does not always perform up to the designed standard. The efficiency of gravity systems is closely linked to external environment parameters and the actual phase of fire spread. Particularly sensitive to wind changes are smoke ventilation systems provided with external wall smoke ventilation windows. The tests demonstrated excellent performance of the gravity smoke ventilation system when supported by mechanical air supply. It should be emphasized that, due to dynamic changes to the building structure (cracking of windows, change of open door configuration, fire separation door blocking, etc.), as well as variable external environment parameters (e.g. wind pressure), it is required to use adaptive mechanical air supply control to ensure maximum effect. Field tests combined with numerical analyses were used as the basis for a fully defined set of tools, with clear indication of interdependencies between its constituent components, and development of a new standard for the design of smoke ventilation system for vertical escape routes.

The results of the tests and numerical studies are the basis for the development of new guidelines for stairwell smoke ventilation system design. The work of the team of experts working on this document should be finalised by December 2016.

Below is a list of persons directly involved in the research part of the project, with whom I have had the pleasure to work and without whom the project would not have been developed.

• Brigadier Daniel Małozięć, M.Sc., Head of Fire and Explosion Laboratory Unit, CNBOP-PIB,
• Grzegorz Kubicki, Ph.D, Eng, researcher and teacher at the Warsaw University of Technology
• Małgorzata Król Ph.D, Eng, researcher and teacher at the Silesian University of Technology
• Senior Captain Marcin Cisek, M.Sc., researcher and teacher at the Main School of Fire Service
• Dariusz Ratajczak Ph.D, Eng, Independent Expert
• Grzegorz Sztarbała Ph.D, Eng, Ardor,
• Izabela Tekielak Skałka M.Sc., Head of Tests and CFD Analysis Department, SMAY Sp. z o.o.,
• Senior Captain Jacek Szczypiorski, M.Sc., Commander of Rescue and Firefighting Team 1 of Fire Department in Sosnowiec.