Hideki Yoshioka

Experimental Study on Fire Performance of Weathered Cedar

ABSTRACT Historic buildings have significant cultural, scientific, and aesthetic value, and show the accomplishments of past eras. Unfortunately, many of wooden historic buildings are destroyed by fire disasters. The reaction-to-fire performance of timber was changed after several hundred years of natural weathering. In this study, the effect of weathering on the reaction-to-fire performance of untreated and fire retardant treated timber are investigated. The conventionally treated cedars were weathered in accordance with a standard construction material durability test method (JSTM J7001), three accelerated weathering test methods (J60, J20 and J4), and a standard weathering method (NT FIRE 053 Method A), respectively. Then, the effect of weathering on phosphoric acid and paraffin treated timber samples was examined by comparing the reaction-to-fire performance of chemically treated timber before and after weathering. The results show that the use of fire retardant can reduce the ignition time, the peak heat release rate (pHRR) and total heat release (THR). The weathering process increases both the pHRR and THR, but reduces the ignition time, which infer a relationship between the two processes of sufficient pyrolysis.

Verification Methodology of Vertical Fire Spread to the Upstairs Room via Openings and Facade Wall

The authors conducted an ISO 13785-2 modified large-scale facade fire tests in Tokyo University of Science and tentatively proposed the draft for the calculation method for vertical upstairs fire spreading based on those fire test results, prior to this study. And in this research, several modifications were carefully added to past calculation methods, especially regarding the calculation of temperature in the fireroom, detailed method of unifying multiple openings on the same floor for calculation, and the criteria for the occurrence of upstairs fire spreading. Detailed calculation methods are proposed for two different situations depending on the existence of an eave above the opening at the fireroom, respectively. Also, two different criteria for verification of vertical upstairs fire spreading were proposed, one of which is based on the maximum heat flux to the upstairs room (Method 1), while the other is based on the integrated value of heat flux over time of fire duration (Method 2). Using this newly modified calculation method, the effectiveness of 90 cm spandrel and 50 cm eave is demonstrated, respectively, in terms of practically preventing the occurrence of vertical upstairs fire spreading. Improved verification calculation methods (both Methods 1 and 2) are applied to four exiting office buildings in Japan and seven rooms of fire origin considered. Verification methods using calculation proposed in this study are proved to be able to practically evaluate the occurrence of vertical upstairs fire spreading, especially regarding noncombustible facades with openings in there.

Experimental Study on Confluence of the Emerged Flames Ejected from Two Adjacent Openings

A considerable number of studies on emerged flames have been done in the past. However, since these studies were implemented using a single opening, the same conditions applied to multiple openings in close proximity to each other are yet to be determined.