Aim: The presentation of technical know-how associated with fire tests and the classification of glazed curtain walls. The determination of critical places for maximum temperature rise on the unexposed surfaces of curtain wall test specimens.

Introduction: A curtain wall is a type of wall which usually consists of vertical and horizontal structural members connected to each other and fixed to the floor-supporting structure of the building to form a lightweight space-enclosing continuous skin, which provides, by itself or in conjunction with the building construction, all the normal functions of an external wall, but doesn’t acquire any of the load-bearing properties of the building.The paper discusses the main issues related to the fire resistance of glazed curtain walls, including the testing methodology and the method of classification of this type of building element. Moreover, the paper presents an attempt to determine the weaknesses of aluminum glazed curtain wall test specimens regarding the maximum temperature-rise measurements, based on the fire-resistance tests performed in recent years by the Fire Research Department of the Building Research Institute (ITB). The paper analyses the results of the temperature rises on unexposed surfaces of 17 aluminum glazed curtain wall specimens tested for internal fire exposure in accordance with EN 1364-3:2006 and EN 1364-3:2014, which achieved the fire-resistance class of min. EI 15.

Methodology: The paper presents the results of the analysis of temperature rises on the unexposed surfaces of curtain wall test specimens during fire-resistance tests. The tests were conducted in accordance with the PN-EN 1364-3:2006 and EN 1364-3:2014 standards in the Fire Testing Laboratory of the Building Research Institute (ITB) in Warsaw and Pionki.

Conclusions: The highest temperature rise was recorded on the mullion and transom connections, and these places can be regarded as critical. The significant increase in temperature in those junctions can be explained by the large deformations of the glazed curtain wall specimens during the fire test. Such deformation causes the destruction of beam-to-column connections, which facilitates the flow of hot gases. Additionally, special connectors often occur in these places, which constricts the space of insulation inserts. An interesting phenomenon is the fairly high temperature rise on the glass panes, 20 mm from the mullions or transoms. Requirements regarding temperature measurements in these places were established no earlier than in the new version of the standard issued in 2014 and, as can be observed, this was the correct decision, because these places, in terms of fire resistance, can also be the weakness of glazed curtain wall specimens.

Keywords: ire safety, fire resistance, fire insulation, curtain wall, fire tests

Type of article: short scientific report