Intumescent Fire Protective Coatings Research Articles

Performance of different water-based resins in the formulation of intumescent coatings for passive fire protection

Performance of different water-based resins in the formulation of intumescent coatings for passive fire protection

Assessment Methods for Fire Durability of Intumescent Fire Protection Coatings

Fire durability of intumescent coatings is their ability to retain their fire-protective properties under fire conditions (under the influence of real temperature conditions of fire). The peculiarities of application of intumescent fire-protective coatings in single-storey buildings on the steel frame with account of fire load are considered. In this study, the fire hazard assessment of single-storey buildings on a steel frame with the use of sandwich panels as enclosing structures is made. The analysis of fire load values has been made. Numerical experiments on estimation of the indoor fire temperature regime have been carried out. For estimation of influence of temperature modes of fire on fire resistance of steel structures the software complex “Fire Dynamics Simulator” was used, which implements the field mathematical model. Various fire temperature modes (temperature-time dependencies) were obtained. Modelling of fire temperature modes was performed without taking into account active fire protection systems. The most critical and unfavourable by their consequences fire scenarios, used later for solving the heat engineering problem, have been chosen by experts. Numerical experiments on heating of steel structures were carried out by solving the heat engineering problem in conditions of non-stationary heat influence at standard temperature conditions according to ISO 834 and at fire temperature conditions obtained by modelling results. The estimation of equivalent fire duration on loss of bearing capacity for steel structures is made. ANSYS mechanical” computing complex was used for modelling the heating of steel structures, which allows us to perform heat engineering calculation of the structure on the basis of its software model.

Fire Resistance and Mechanical Properties of Intumescent Coating Using Novel BioAsh for Steel

Recent developments of intumescent fire-protective coatings used in steel buildings are important to ensure the structural integrity and safe evacuation of occupants during fire accidents. Flame-retardant intumescent coating applied to structural steel could delay the spread of fire and heat propagation across spaces and structures in minimizing fire risks. This research focuses on formulating a green intumescent coating utilized the BioAsh, a by-product derived from natural rubberwood (hardwood) biomass combustion as the natural substitute of mineral fillers in the intumescent coating. Fire resistance, chemical, physical and mechanical properties of all samples were examined via Bunsen burner, thermogravimetric analysis (TGA), carbolite furnace, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared (FTIR), freeze–thaw cycle, static immersion and Instron pull-off adhesion test. Sample BioAsh intumescent coating (BAIC) 4-7 incorporated with 3.5 wt.% BioAsh exhibited the best performances in terms of fire resistance (112.5 °C for an hour under the Bunsen burner test), thermal stability (residual weight of 29.48 wt.% at 1000 °C in TGA test), adhesion strength (1.73 MPa under Instron pull-off adhesion test), water resistance (water absorption rate of 8.72%) and freeze–thaw durability (no crack, blister and color change) as compared to other samples. These results reveal that an appropriate amount of renewable BioAsh incorporated as natural mineral fillers into the intumescent coating could lead to better fire resistance and mechanical properties for the steel structures.

Development of led-curable intumescent polymer coatings for fire protection of building constructions

The influence of reactive monomer on the properties of fire-protective intumescent composition and the final UV-curable coating was investigated; it was established that compositions based on isobornyl acrylate, mixture of hydroxyethyl methacrylate with dipropylene glycol, and cyclohexyl methacrylate form charred layers with sufficient fire-protective and mechanical properties.

Effects of Flame Retardant Nano Bio-Based Filler on Fire Behaviors of Intumescent Coating

The present work analyzed the fire protection performances, char formation and heat release characteristics of the thin film intumescent fire protective coatings that incorporate the eggshell (ES) waste as a renewable flame retardant nano bio-based filler. The fire performances of the coatings were evaluated using Bunsen burner and cone calorimeter. The fire behaviors of the samples in the condensed phase were conducted in accordance with the ISO 5660-1 standard. On exposure, the samples B and D reinforced with 3.30 wt.% and 2.75 wt.% of ES nano bio-filler, respectively showed a significant reduction in total heat rate, promoting thicker and more uniform char layer in protecting the steel structural. As a result, ES nano bio-filler composition has shown to be efficient in fire protective performance of the intumescent coatings.

On the Impact Caused by Titanium Dioxide of Different Trademarks on the Properties of Intumescent Fire-Protective Coatings

The paper overviews the process of thermolysis of fire-retardants based on melamine, ammonium polyphosphate and pentaerythtritol and containing titanium dioxide of different trademarks. The role of titanium dioxide as a component of fire-retardants is revised. Titanium dioxide was perceived only as white pigment, but this paper states that the properties of a charred layer forming from an intumescent coating depend on the properties of titanium dioxide's species, such as surface treatment and crystalline structure. This statement is proven by using thermal analysis of intumescents with different titanium dioxide's trademarks; it shows that rutile titanium dioxide helps forming a charred layer with the highest thermal stability thus fire retardant efficiency grows up. It means that the knowledge of processes which occur in intumescents based on primary products with different qualities helps to create fire-protective compositions which will perform more reliable in case of fire.

Computer Tomography Based Structure Characterization of Expanded Intumescent Coatings for Fire Protection

Intumescent coatings are used to protect structural steel from fires. In this study, morphological characteristics of expanded and charred intumescent coatings, which is a key factor of its thermal insulating mechanisms, have been studied using a computer tomography (CT)-based analysis method. Specimens of the charred materials are prepared by a laboratory-scale mass-loss cone heating method for measuring thermal insulation performance. Three types of coatings are exposed to three constant incident heat fluxes (25 kW/m2, 50 kW/m2, and 75 kW/m2) for 2 h. The micro-CT scanning technology is applied on the charred materials to generate 3D reconstructed images with 20 µm resolution by ImageJ software. By using an image processing technique, the central region of each scanned 3D model is divided into three horizontal layers at different depths: top, middle and bottom. The morphological structure varies significantly with the type of coatings, the incident heat flux, and the depth in the char, but the median value of pore size (i.e. equivalent diameter) for all tested samples varies within a narrow range (0.352 mm to 0.424 mm). The qualitative morphological observations as well as the quantitative pore properties (i.e., 3D porosity, size distributions, and sphericity) are obtained. The present non-destructive structure analyses method is useful to assist in new formulation developments and to advance numerical modeling.

In situ thermal-conductivity measurements and morphological characterization of intumescent coatings for fire protection

Thermal insulating performance and char-layer properties have been studied for water-based intumescent coatings for structural steel fire protection using a new laboratory-scale mass-loss cone apparatus. A specimen (100 × 100 mm mild steel plate; the initial coating thickness: 0.3–2.0 mm) is placed horizontally and exposed to a constant incident radiant heat flux (25, 50, or 75 kW/m2). The apparent thermal conductivity of the expanding char layer is determined in situ based on real-time measurements of the temperature distribution in the char layer and the heat flux transmitted through the char layer. Three-dimensional morphological observations of the expanded char layer are made using a computed tomographic–based analytical method. The vertical variation of the porosity of the expanded char layer is measured. The measured heat-blocking efficiency is correlated strongly with the incident heat flux, which increases the expanded char-layer thickness, and porosity for sufficiently large initial coating thicknesses (>0.76 mm). For a thin coating (0.30 mm), violent off-gassing disrupts the intumescing processes to form a consistent char layer after abrupt exposure to higher incident heat fluxes, thus resulting in lower heat-blocking efficiency. Therefore, the product application thickness must exceed a proper threshold value to ensure an adequate thermal insulation performance.

The impact of the aging of intumescent fire protective coatings on fire resistance

The paper is aimed at determining fire resistance of various intumescent fire protective coatings intended for the protection of steel structures dependently on the simulated operating conditions and atmospheric factors having affected the materials for a certain period. Fire resistance was determined upon applying four methods. The first of them was a method of theoretical calculations. The other methods were experimental ones: a) the fire resistance was established upon using samples of steel double-T profiles covered with fire protective coatings; b) the fire resistance was established after aging the samples at a laboratory upon applying the cyclic freezing-thawing; and c) the fire resistance was established after aging the samples in outdoor shed for 12 months with subsequent heating of the samples according to the standard methodology. The statistical analysis of the obtained fire resistance data shows that there was practically no connection between the values of indicators of fire resistance of non-aged samples calculated theoretically and determined in the experimental way and the indicators of fire resistance of aged samples. The mechanism of material aging taking place as a result of simulated operating and climatic factors is similar for all coatings. However, different coatings are differently affected by aging due to their composition and complexity of the structure. Thus forecasting the fire resistance indicators for different coatings after their aging on the base of the values of the primary fire resistance indicator is impossible.However, a strong link had been obtained and an equation usable for forecasting the fire resistance time (determined according to the standard ISO 834 fire curve) after 12 months of operation of the coating in the outdoor shed according to the results of fire resistance of intumescent fire protective coatings after 60 artificial aging cycles at the laboratory had been deduced.

PECULIARITIES OF DESTRUCTION MECHANISM OF POLYMERIC INTUMESCENT FIRE PROTECTIVE COATINGS

The article describes the destruction mechanism of intumescent fire protective paint coatings at the time of their aging under the impact of simulated climatic factors. Steel plates covered in anti-corrosion varnishes and intumescent fire protective paint coatings of several types and different composition were used in the research, while certain samples were also additionally covered in protective coatings protecting from environmental effects. SEM, DTA and FT-IR researches were conducted on control samples and samples after aging. Aging was performed in 3 ways: according to regimes I and II in the laboratory and having stored them for 12 months under the outdoor conditions under the roof. The aging mechanism of materials was determined to be very similar when using different methods of aging: with increasing number of cycles, the extent of damage to the surfaces and their diversity increase. In all cases, chemical material changes were observed after artificial aging cycles compared to control samples. In aged samples, there were some new connections occurring, while others changed or disappeared judging from the number of waves and intensity of peaks, which shows that certain compounds form, while others change and disintegrate under the influence of environmental heat and mass exchange.

Design of Nanomodified Intumescent Polymer Matrix Coatings: Theory, Modeling, Experiments

Thermoset-based polymer matrix composites are widely used for production of intumescent fire protective coatings; many operational properties of such coatings can be further enhanced by means of nanoscale layers between matrix and disperse phases. The dependence between temperature of processing and temperature of glass transition of thermosetting matrix allows to produce gradient of glass transition temperature along the depth of the coating and lower exfoilation of char residue from steel substrate. In the present article we have offered the novel design scheme for such coating. Several results of laboratory and numerical experiments that are within the framework of the offered scheme are also presented. Application of the offered scheme allows to develop efficient fire protective coatings in purposely and precisely controlled manner.

Performance of Palm Oil Clinker as a Bio-Filler with Hybrid Fillers in Intumescent Fire Protective Coatings for Steel

Intumescent coatings are an effective method for fire protection of steel structures. The search for more environmental friendly intumescent coatings has led to the utilization of palm oil clinker (POC) as a bio-filler in solvent-borne intumescent coatings in order to improve fire protection performance, mechanical strength and water resistance of steel structures. In this research, POC and hybrid fillers are mixed with an acrylic binder and then blended with flame-retardant additives in order to produce intumescent coatings. The samples were tested using Bunsen burner test, thermogravimetry analysis, surface spread of flame test, field emission scanning electron microscopy, static immersion test, and adhesion strength test. It was found that the optimum composition of POC and hybrid fillers gives the best fire protection performance with the lowest equilibrium temperature (171.3°C), high thermal stability, good water resistance and excellent mechanical properties. The results of the surface spread of flame test show that Sample A3, A4, and A6 were classified as Class 1, which is the best classification. For Sample A6 (a hybrid formulation), the addition of aluminium hydroxide gives better water resistance with the lowest rate of weight change (<0.2%), while the addition of magnesium hydroxide enhances the bonding strength of the coating up to 125% compared with Sample A1 which only has a single filler POC. It can be concluded that the optimum composition of POC and hybrid fillers results in intumescent coating with the greatest fire protection performance.

Engineering model for intumescent coating behavior in a pilot‐scale gas‐fired furnace

In the event of a fire, intumescent fire protective coatings expand and form a thermally insulating char that protects the underlying substrate from heat and subsequent structural failure. The intumescence includes several rate phenomena, which have been investigated and quantified in the literature for several decades. However, various challenges still exist. The most important one concerns mathematical model validation under realistic exposure conditions and/or time scales. Another is the simplification of advanced models to overcome the often‐seen lack of a complete set of input and adjustable model parameters for a given coating, thereby providing models for industrial applications. In this work, these two challenges are addressed. Three experimental series, with an intumescent coating inside a 0.65 m3 gas‐fired furnace, heating up according to so‐called cellulosic fire conditions, were conducted and a very good repeatability was evident. The experiments were run for almost 3 h, reaching a final gas temperature of about 1100°C. Measurements include transient temperature developments inside the expanding char, at the steel substrate, and in the mineral wool insulation placed behind the substrate. A mathematical model, describing the intumescent coating behavior and temperatures in the furnace using a single overall reaction was developed and validated against experimental data. By including a decomposition front movement through the char, a good qualitative agreement was obtained. After further validation against experiments with other coating formulations, it has potential to become a practical engineering tool. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3947–3962, 2016

Mieszanina hydroksymetylowych pochodnych melemu jako potencjalny komponent termopęczniejących powłok stosowanych w ochronie przeciwpożarowej

Mieszanina hydroksymetylowych pochodnych melemu jako potencjalny komponent termopęczniejących powłok stosowanych w ochronie przeciwpożarowej

Solving Heat Conduction Problems in Movable Boundary Domains under Intensive Physical-Chemical Transformation Conditions

Results of solving problems of simulating temperature fields in domains with movable boundaries of characteristic zones of intensive physical-chemical and thermomechanical transformations to be realized in materials upon high-temperature heating have been presented. Intumescent fire-protective coatings based on organic and mineral materials are the object of study. Features of numerical realization of input equation systems taking into account, in particular, a dynamics of considerable increase and subsequent decrease of the intumescent layer thickness have been considered. Example calculations for structures of metal and wood protected with various coatings are given. Results of calculating two-dimensional temperature fields in polymer composite square-shaped structures with internal cruciform load-bearing elements have been presented. The intumescent coating is arranged on the external surface of a structure. The solution of the above-listed problems is of important significance to provide fire protection of different-purpose structures and products.

Numerical and Experimental Analysis of Reactive Fire Protection Systems Applied to Solid Steel Rods in Tension

The application of intumescent coatings for fire protection of steel constructions is increasing. Thanks to the relative thin thickness of the coatings, the typical visual appearance of the structures can remain essentially unchanged. In Germany, the applicability of the systems is regulated by the national as well as European technical assessments. According to the approvals, the application on steel members in tension is only allowed with limitations. Especially, the application on solid steel rods in tension is currently excluded from the approval. The paper explains the actual state of the art of the application of reactive fire protection systems applied to steel structures. Physical and technical background information are provided. Furthermore, the latest scientific results of an on-going research project funded by the German National Institute of Building Technology (DIBt) and conducted by the Federal Institute for Materials Research and Testing (BAM) will be described.

Fire propagation performance of intumescent fire protective coatings using eggshells as a novel biofiller.

This paper aims to synthesize and characterize an effective intumescent fire protective coating that incorporates eggshell powder as a novel biofiller. The performances of thermal stability, char formation, fire propagation, water resistance, and adhesion strength of coatings have been evaluated. A few intumescent flame-retardant coatings based on these three ecofriendly fire retardant additives ammonium polyphosphate phase II, pentaerythritol and melamine mixed together with flame-retardant fillers, and acrylic binder have been prepared and designed for steel. The fire performance of the coatings has conducted employing BS 476: Part 6-Fire propagation test. The foam structures of the intumescent coatings have been observed using field emission scanning electron microscopy. On exposure, the coated specimens' B, C, and D had been certified to be Class 0 due to the fact that their fire propagation indexes were less than 12. Incorporation of ecofriendly eggshell, biofiller into formulation D led to excellent performance in fire stopping (index value, (I) = 4.3) and antioxidation of intumescent coating. The coating is also found to be quite effective in water repellency, uniform foam structure, and adhesion strength.

Effect of Epoxy Binder on Fire Protection and Bonding Strength of Intumescent Fire Protective Coatings for Steel

This study focuses on the effect of epoxy emulsion, a binder for producing water-borne intumescent fire protective coating for steel structures. The influence of binder on the fire resistive performance, char formation, thermal stability and bonding strength of the coatings were investigated in detail by using Bunsen burner test, thermogravimetry analysis (TGA), field emission scanning electron microscopy (FESEM) and Instron microtester. It was found that the fire protection performance and foam structure of coating sample D2 was significantly improved by adding 10wt% of epoxy resin which produced the greatest thickness of char layer. In addition, TGA results showed that the residue weight of coating D2 was higher than coating sample D3 with 15wt% of epoxy. This indicated that sample D2 has better anti-oxidation and thermal stability. The results of Instron microtester indicated that the bonding strength of the coatings was improved with the increase of epoxy content.

A Brief Review of Intumescent Fire Retardant Coatings

Development and application of intumescent coatings for fire protection are reviewed with the associated chemical aspects discussed. Different types of intumescent coatings and their mechanisms are outlined. Intumescent coatings with special properties such as resistant to high temperature, mildew and rot, transparent as well as multi-functional are summarized. Survey of several products available in the market and their applications are outlined.

Mathematical Simulation of Thermophysical and Thermochemical Processes During Combustion of Intumescent Fire–Protective Coatings

A mathematical model of combustion of intumescent fire–protective materials is presented, which takes into account the basis physicochemical processes during combustion of such materials. The model employs the minimum number of empirical constants determined under conditions close to simulated ones. The results of numerical analysis are in good agreement with the experimental values of temperatures at the boundary between the intumescent material and the protected construction.