A Model For Prediction Of Temperature In Steel Structure Protected By Intumescent Coating, Based On Tests In The Cone Calorimeter

Abstract

Intumescent coating is an important fire protection method for steel structures. Traditionally its fire properties have been evaluated by performing furnace tests using a standardized test procedure and following a standardized time-temperature curve. This procedure is restrictive in performance based fire safety engineering design since it limits the fire condition to the standard one only. In this paper, a model is outlined that can take into account the different fire protection abilities of intumescent coating that will occur depending on what type of fire the coating is subjected to. The model is based on a experimental study, containing about 50 tests, performed in the Cone Calorimeter. Some test results are presented as well as an analysis model of the test results.

Thermal Boundaries in Cone Calorimetry Testing

“…(2) the formulation of an energy equilibrium model assigning the role of a single effective factor to the coefficient h, which represents convection transfers, as well as the uncertainties regarding the other heat transfer mechanisms developed [4,[18][19][20]; and (3) the application of parameter values from previous studies [3,7,8,21,22].…”

“…This boundary condition has often been adopted in testing intumescent coatings [7][8][9]. The literature does not report the heat transfer occurring on side surfaces, since this was conventionally regarded as less significant than that generated on the top surface.…”

“…Under the circumstances, h top remained in the range of approximately 4.25 to 15.48 W/m 2 K during the transient and steady periods. Table 2 shows the coefficient values used in prior analytical studies [3,4,7,8,[16][17][18][19][20][21][22] that assessed the reliability of the values predicted in this work; most of the data are for h top , whereas the values with the superscript "a" are from tests used to examine the effect of vertical burning with samples rotated through 90 • . The ranges of the coefficient values determined in this work overlapped with those having been commonly used in fire safety engineering.…”

STRUCTURAL FIRE SAFETY OF EXISTING STEEL BUILDINGS, Possible general approach and application to the case of the intumescent coatings

“…Moreover, as it is an existing structure, the number of samples should be defined, to balance the requirement of an adequate characterization of paints and the need to limit the invasiveness of the investigations on the existing structure. The tests in furnace should be properly designed, through models (Wang et al, 2005) and analysis with dedicated software, to try to predict the temperatures reached in the elements subjected to the fire test (Schaumann et al, 2014). Finally, enough thermocouples should be applied on each sample in order to catch any signs of localized detachment of the paint.…”

Fundamentals of thin intumescent coatings for the design of fire-safe structures

“…Char structural changes (char degradation zone) -the carbonaceous char is oxidised and CO 2 is released: the black and compact char structure slowing changes into a white brittle dusty foam at the exposed surface. The classification of stages and zones and their respective threshold temperature have been reported to occur within a range of temperatures ( Figure 2.3), influenced by variation in coatings formulations and fire testing procedures adopted by different researchers [19,33,35,36,[38][39][40][41][42][43][44][45][46][47][48]. The evolution of the four stages is strongly dependent on the composition of the chemicals and their mixture.…”