Assessing the performance of intumescent coatings using bench‐scaled cone calorimeter and finite difference simulations

Bartholmai, Matthias; Schartel, Bernhard

doi:10.1002/fam.933

Cited by 54 publications

(59 citation statements)

References 15 publications

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“…In PP/APP the maximum temperature was almost 200 °C lower than the maximum temperature of PP. A direct correlation between insulating properties and the thickness of intumescent layers has also been reported for intumescent coatings on steel plates [51,52].…”

Section: Pyrolysismentioning

confidence: 62%

Flame-Retardancy Properties of Intumescent Ammonium Poly(Phosphate) and Mineral Filler Magnesium Hydroxide in Combination with Graphene

et al. 2014

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Thermally reduced graphite oxide (TRGO), containing only four single carbon layers on average, was combined with ammonium polyphosphate (APP) and magnesium hydroxide (MH), respectively, in polypropylene (PP). The nanoparticle's influence on different flame-retarding systems and possible synergisms in pyrolysis, reaction to small flame, fire behavior and mechanical properties were determined. TRGO has a positive effect on the yield stress, which is decreased by both flame-retardants and acts as a synergist with regard to Young's modulus. The applicability and effects of TRGO as an adjuvant in combination with conventional flame-retardants depends strongly on the particular flame-retardancy mechanism. In the intumescent system, even small concentrations of TRGO change the viscosity of the pyrolysing melt crucially. In case of oxygen index (OI) and UL 94 test, the addition of increasing amounts of TRGO to PP/APP had a negative impact on the oxygen index and the UL 94 classification. Nevertheless, systems with only low amounts (≤1 wt%) of TRGO achieved V-0 classification in the UL 94 test and high oxygen indices (>31 vol%). TRGO strengthens the residue structure of MH and therefore functions as a strong synergist in terms of OI and UL 94 classification (from HB to V-0).

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Section: Pyrolysismentioning

confidence: 62%

Flame-Retardancy Properties of Intumescent Ammonium Poly(Phosphate) and Mineral Filler Magnesium Hydroxide in Combination with Graphene

et al. 2014

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“…These include bench-scale cone calorimeter tests and small-scale furnace tests on coated plates [11,12], and furnace tests on cellular beams [13]. The first authors conducted studies on typical water-based and solvent-containing intumescent systems [10] and later on a high-performance material, i.e., epoxy resin containing boric acid and phosphate-based flame retardant [12]. The results from the former showed a significant slow down of temperature increase between 200-300C, due to intumescence, i.e.…”

Section: Materials Propertiesmentioning

confidence: 99%

“…An approximate calibration has been performed by comparison with test data, including the results of Bartholmai [12] giving a value of n=2. Taking an approximate temperature range from the DTG results of the latter study, and assuming R f =10, gives the following curve: The key parameter for the thermal model is the conductivity, or its scaled value, i.e.…”

Section: Materials Propertiesmentioning

confidence: 99%

“…k/d. The conductivity itself is affected by fundamental changes in the material as it intumesces [11,12,15]. Unfortunately, the effect is non-linear and very dependent on initial thickness, and most pronounced at the smaller thicknesses typical of real applications; hence, there would appear to be no substitute for its direct experimental determination.…”

Section: Materials Propertiesmentioning

confidence: 99%

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Development of an Engineering Methodology for Thermal Analysis of Protected Structural Members in Fire

Hong¹,

Welch²

2010

Volume 6 Number 1

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A novel CFD-based methodology for thermal analysis of protected steelwork in fire has been developed to overcome the limitations of existing methodologies. This is a generalised quasi-3D approach with computation of a "steel temperature field" parameter in each computational cell. It accommodates both uncertainties in the input parameters and possible variants to the specification by means of many simultaneous thermal calculations. A framework for the inclusion of temperature/time-dependent thermal properties, including the effects of moisture and intumescence, has been established. The method has been implemented as the GeniSTELA submodel within SOFIE RANS CFD code. The model is validated with respect to the BRE large compartment fire tests. Sensitivity studies reveal the expected strong dependencies on certain properties of thermal protection materials. The computational requirements are addressed to confirm the practicability of the tool in simultaneously running a large number of parametric variants. Ultimately, the steel temperature field prediction provided by GeniSTELA provides far more flexibility in assessing the thermal response of structures to fire than has been available hitherto; hence it could be further used for the structural response analysis, demonstrating the potential practical use of the method to improve the efficiency and safety of the relevant structural fire safety design.Keywords: CFD; thermal analysis; quasi-3D; GeniSTELA; SOFIE INTRODUCTIONIncreasing interest in assessing the performance of structures in fire is driving the development of an array of modelling methodologies to be used in fire safety engineering design. Whilst traditionally most code-based design has been based on simple calculations, referencing measured fire performance in standard tests, the progressive shift towards performance-based design has opened the door to use of advanced methods based on numerical models. These approaches will not replace standard testing, but they can already be used in a complementary fashion, to extend the application of test data.Some simplified modelling methods have also been established, such as the protected member equation in Eurocode 3 (EC3) [1], but as with all semi-empirical methods the results will tend to be conservative and there are of necessity a number of simplifying assumptions. CFD-based methodologies can in principle provide a much more detailed description of the thermal environment and the effects of localised heating, which could be used in conjunction with thermal analysis models to examine structural performance.There are currently various approaches used to link the CFD-based models and the thermal analysis models. For example a range of advanced methodologies have been developed to couple the CFD model with the thermal and structural model, such as those examined in the FIRESTRUC [2] project with code pairs ANSYS-CFX, FDS-ANSYS, VESTA-STELA etc. All these implementations have certain aspects of pros and cons.

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“…The models proposed in other studies, () as well as several others, include the assumption of a given final thickness of the coating. This is often expressed as a constant ratio of final and initial thickness, called “factor of expansion,” and assumed to be independent of the parameters like the initial thickness, the temperature, the heating rate, and the heating source.…”

Section: Introductionmentioning

confidence: 99%

On a planar thermal analysis of intumescent coatings

2017

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Summary The paper discusses a complex model for a nonstationary planar thermal analysis of expandable intumescent coatings. Following the existing one‐dimensional models, we develop novel and improved equations for the two‐dimensional thermal analysis of intumescent coatings. A progressive expansion due to chemical reactions, phase changes, and the time and temperature‐dependent thermal properties of the coating are considered. In the heating process, the coating may locally experience virgin, intumesced, or charred phases, and their transition with time. The rate of the density loss due to the pyrolysis reaction is described with the Arrhenius equation. The thickness of the coating is assumed to increase enormously during the pyrolysis. Consequently, the energy and mass equilibrium equations are formulated with respect to both the deformed and undeformed configuration. Since most of material properties of commercial products are not given by manufacturers, an innovative procedure is proposed to determine the time‐dependent thermal conductivities and remaining fundamental properties of the coating from the set of measured temperatures. This, together with the two‐dimensional formulation of the thermal equations with respect to the undeformed configuration, makes the present model unique and appropriate for the thermal analyses of an arbitrary steel cross section protected with intumescent coatings.

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Assessing the performance of intumescent coatings using bench‐scaled cone calorimeter and finite difference simulations

Cited by 54 publications

References 15 publications

Flame-Retardancy Properties of Intumescent Ammonium Poly(Phosphate) and Mineral Filler Magnesium Hydroxide in Combination with Graphene

Flame-Retardancy Properties of Intumescent Ammonium Poly(Phosphate) and Mineral Filler Magnesium Hydroxide in Combination with Graphene

Development of an Engineering Methodology for Thermal Analysis of Protected Structural Members in Fire

On a planar thermal analysis of intumescent coatings

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