scholarly journals Material properties and the energy balance in standardized fire testing

2018 ◽  
Vol 163 ◽  
pp. 07004 ◽  
Author(s):  
Wojciech Węgrzyński ◽  
Piotr Turkowski

The origins of standardised fire testing can be traced back to 1870’s, and the origin of the standard temperature-time curve to 1917. This approach, based on a 19th-century intuition is still in use up to this day, to design the 21st-century structures. Standardized fire-testing ultimately disregards the conservation of energy in the fire, as in every test the resulting temperature of the test must be the same (precisely as the temp.-time curve). To maintain this, different amount of heat is required in every test, which means that every time a different fire is modelled within the furnace. The differences between furnace fire sizes are ignored in the certification process, but can be interesting for fire researchers to understand how different materials behave in fire conditions. In this paper, Authors explore this topic by investigating the energy balance within the furnace, and comparing different fire tests together.

2018 ◽  
Vol 174 ◽  
pp. 01019
Author(s):  
Joanna Kaliszuk ◽  
Elżbieta Grochowska

The paper presents a sensitivity analysis of design bending resistance of a composite slab rib in a fire situation to a change of the value of basic variables. The analysis was carried out for a composite slab being an element of a supporting structure of a reinforced floor referred to in [1, 2]. The calculations were made for a simple calculation model and the standard temperature-time curve according to [6, 7]. The set of basic variables was limited to X1 = {(y, z), h1, fy,a, fy,s, fc}.


2011 ◽  
Vol 250-253 ◽  
pp. 2477-2480
Author(s):  
Guang Yong Wang ◽  
Yu Mei Li

An experimental study on the fire performance of reinforcing concrete beam-column joints under ISO834 standard temperature-time curve was carried out, and the main parameters including the load ratio of the beams and axial compression ratio of the columns were chosen to study the performance of the joints. The deformation, the explosive spalling of concrete, the fire resistance and the collapse mechanism of the joints in fire are observed carefully, and several conclusions are drawn in the end.


2013 ◽  
Vol 423-426 ◽  
pp. 714-719
Author(s):  
Ji Wang ◽  
Wen Hua Song ◽  
Zhong Jun Shu ◽  
Miao Zhang

The failure time of polyvinylchloride (PVC) insulated power cables was studied using an infrared radiation heating furnace and insulation resistance measurements. The temperature-time curve inside the furnace was similar to that of the ISO 834 standard. Two popular fire protection methods were employed for the cables; one method applied fire-retardant coatings directly on the cable surface, and the other inserted the cables into metal conduits coated with structural steel fire-retardant coating. The results showed that for both protection methods, the failure time of the cable increased with the thickness of the coating. However, if the cable coatings were thicker than 1.5 mm, the coating will crack in the case of cable movement. When the steel structural coating was thinner than 1 mm or thicker than 3 mm, the protective effect was not remarkable for the relatively small expansion multiple. For the longest failure time of the cables, less than 10 minutes in these tests, neither of the two methods was effective in protecting the electrical cables that supply power (on transmit a signal) to equipment required to operate over a relatively long duration in fire conditions.


1979 ◽  
Vol 44 (12) ◽  
pp. 3425-3433 ◽  
Author(s):  
Miloš Smutek ◽  
Slavoj Černý

An analysis was performed of various estimates of the adiabatic temperature Ttot that corresponds to the total heat liberated by a gas dose adsorbed on a metal film in the calorimeter for measurement of chemisorption enthalpies. Besides the two common procedures consisting either in the construction of the adiabatic temperature-time curve or in the extrapolation of the single-exponential cooling part of the actual temperature-time curve to zero time, we have examined estimates of Ttot by extrapolating the cooling exponential to the mid-point between zero time and the temperature maximum (t = tmax/2). Model calculations have shown the merit of the latter extrapolation, particularly in the cases of slow heat evolution. This has been verified on the data measured in the chemisorption of methane and ethane on molybdenum films. Extrapolation to tmax/2 has turned out to be a simple and reasonably reliable procedure for handling the data obtained in film calorimeters.


2012 ◽  
Vol 628 ◽  
pp. 156-160
Author(s):  
In Kyu Kwon ◽  
Hyung Jun Kim ◽  
Heung Youl Kim ◽  
Bum Yean Cho ◽  
Kyung Suk Cho

Structural steel has been used since the early 1970’s in Korea as primary structural members such as columns, beams, and trusses. The materials have much higher strength such as fast construction, high load bearing capacity, high construction quality but those have a fatal weakness as well. Load-bearing capacity is going down when the structural members are contained in fire condition. Therefore, to protect the structural members made of steels from the heat energy the fire resistance performance required. Generally, the fire resistance performance have evaluated from the exact fire tests in fire furnaces. But the evaluation method takes much more time and higher expenses so, the engineering method requires. The engineering method not only adopts a science but also an engineering experience. In this paper, to make various data-bases for evaluation of structural members such as columns(H-section, RHS), beams, loaded fire tests were conducted and derived not only each limiting temperature but also fire resistance respectively.


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