Mass Loss Calorimeter Research Articles

Small-scale experimental study on EPS ETICS and flame-retardant coating reaction-to-fire performance

External thermal insulation composite systems (ETICS) are a common and energy-efficient cladding system. Thermoplastic expanded polystyrene (EPS) is widely used as an insulation core. However, such combustible material has aggravated fire incidents in recent years, thus it is essential to improve its fire behavior. To evaluate the performance of EPS ETICS, a series of specimens with different flame-retardant (FR) coatings were tested using a small-scale bench and a mass loss calorimeter with a maximum heat flux of 40 kW/m2. When untreated EPS ETICS are exposed to heat, the EPS foam degrades, releases a large volume of combustible gases, and ignites. Applying FR agents such as FR surface paint and expandable graphite blended coating can stop flame propagation, reduce total heat release by approximately 50%, and preserve about 50% of the EPS foam during heat exposure. This enhances significantly the fire safety of EPS ETICS.

OVERVIEW OF COMMON METHODS FOR FIRE TESTING

Fire testing is critical for assessing the behavior of building materials under fire conditions, providing indispensable insights into important variables such as flammability, heat release rate, and smoke production. This paper provides an overview of common fire testing methods, including the procedures for test selection, sample preparation, data collection, and analysis. These fire testing methods are outlined in standards issued by world-respected standardization bodies such as ISO, EN, ASTM, and UL. These standards guarantee and ensure the consistency and reliability of prescribed methods. Moreover, this paper presents a detailed description of a custom-made installation hosted at the Fire Protection Laboratory at the Faculty of Occupational Safety, University of Niš, used for evaluating the flammability parameters of a broad spectrum of materials. This hyphenated installation, comprising a mass loss calorimeter and an FTIR gas analyzer, can be used for comprehensive and simultaneous real-time measurement of flammability parameters and fire effluent analysis.

Eco‐friendly flame‐retardant based on sap from banana plant pseudostems

AbstractSociety's need for safe flame‐retardant technologies in passive fire protection is undeniable. To address this concern, this paper presents an experimental investigation of the fire‐retardant properties of slash pine wood treated with banana plant pseudostem sap, obtained from a cultivated banana plant variety widely grown in Brazil. The natural sap extract was characterized through X‐Ray Fluorescence spectrometry and Fourier Transform Infrared Spectroscopy techniques, revealing the presence of key components, including water, potassium chloride, sodium chloride, sodium silicate, calcium phosphate, sodium phosphate, lignin and tannins. The authors explored different treatment parameters, including various sap impregnation times, number of impregnations and use of natural versus various levels of concentrated sap. First, a horizontal burning test, similar test to UL 94 HB, was used to obtain an initial assessment of the suitability of sap as a flame retardant for slash pine wood. Subsequently, the Mass Loss Calorimeter equipment with thermopile attachment described in ISO 13927:2015 was used to measure various heat release rate parameters. The findings suggest that reducing the water content in sap and increasing the number of repeat treatments results in a more effective treatment for slash pine wood. More specifically, the results indicate that the most efficient treatment involves three impregnations with high‐concentration (1/10 volume reduction) sap. Future work to improve the efficacy of the concentrated sap impregnation process could explore the use of pressure treatment instead of soaking.

The effect of veneer-surface modification with fumed nanosilica on the selected properties of water-resistant plywood

ABSTRACT The aim of the presented research was to investigate the effect of veneer modification with both 2% aqueous dispersion of fumed nanosilica and dispersion of fumed nanosilica containing additional 5% of wood fire retardant, on bonding quality and the flammability parameters of water-resistant plywood. The veneer modification was evaluated using SEM images. The bonding quality was determined through shear strength tests conducted post-aging procedures. Flammability tests were conducted using a mass loss calorimeter and the French method. Parameters such as heat release rate, average rate of heat release, mass loss, time to ignition, time of flameout, total heat release, burned surface area were determined to assess the fire resistance. The results showed that the modification of veneers with nano-SiO2 did not affect the bonding quality, however, the application of a dispersion containing a small amount of fire retardant resulted in a significant reduction in the shear strength. Significantly shorter ignition time was recorded for both modification methods, but at the same time, a reduction in a mass loss and an amount of heat released was also observed. The obtained results indicate the potential of veneer’s surface modification with fumed silica to increase fire resistance of plywood with high bonding quality.

Production and characterization of flame-retardant poly (butylene terephthalate) composites containing boron compounds

ABSTRACT Within the scope of this work, flame retardant polybutylene terephthalate (PBT) was produced using boron compounds, namely, anhydrous borax (BX), colemanite (C), and zinc borate (ZnB) in three different concentrations of 40, 50, and 60 wt%. The thermal, flame retardant, and tensile properties of PBT composites were systematically investigated using thermogravimetric analysis (TGA), limiting oxygen index (LOI), vertical UL 94 test (UL-94V), mass loss calorimeter (MLC), and tensile tests. The thermal stability of PBT slightly enhanced with the use of BX, whereas the use of C and ZnB reduced the thermal stability. Improvement in LOI value, a reduction in peak heat release rate (pHRR), and total heat release (THR) values were observed with the use of all boron compounds. The improvement in UL-94V rating was observed only with the use C. The addition of all boron compounds deteriorates the tensile strength of the composites. In brief, the highest flame retardant performance with V0 rating (UL-94 V), 33.5% (LOI), and 48 Kw·m−2 (pHRR) was achieved with the use of C.

Fire Properties of Paper Sheets Made of Cellulose Fibers Treated with Various Retardants.

This article presents the results of flame-retardancy tests conducted on cellulose sheets produced using a Rapid Köthen apparatus treated with retardants. The agents used were potassium carbonate (PC) K2CO3 (concentrations of 20; 33.3; and 50% wt/wt), monoammonium phosphate (MAP) NH4H2PO4 (concentrations of 35% wt/wt), diammonium phosphate (DAP) (NH4)2HPO4 (concentrations of 42.9% wt/wt), and bisguanidal phosphate (FOS) C2H10N6 (concentrations of 22.5% wt/wt). The agents were used to improve Kraft cellulose-based sheets' flame-retardant properties and compare their performances. As part of the study, the flammability of the materials was determined by the following methods: an oxygen index (OI) test, a mass loss calorimeter (MLC) test, and a mini fire tube (MFT) test. All formulations showed an increase in flame retardancy compared to the control test. All protected samples were non-flammable for OI determinations, and DAP-protected samples showed the highest OI index. For the MLC test, DAP-protected and MAP-protected samples showed the best heat-release rate (HRR), total heat release (THR), and average heat-release rate (ARHE) (samples did not ignite for 600 s). In the MFT test, all treated samples had comparably reduced weight loss. The best parameter was achieved for MAP and DAP (15% weight loss).

Multi-technique characterization and thermal degradation study of epoxy modified resins designed for multifunctional applications

Tetraglycidyl methylene dianiline (TGMDA) was mixed with 1,4-Butanediol diglycidyl ether (BDE) (in a 4:1 mass ratio) and with a stoichiometric amount of the curing agent diaminodiphenyl sulfone which was solubilized at 120 °C for 20 min in the liquid mixture TGMDA + BDE. The so obtained unfilled epoxy resin matrix, denoted as ER, was blended with glycidyl polyhedral oligomeric silsesquioxane and carbon nanotubes in suitable proportions to obtain binary and ternary mixtures. Characterization of the formulated materials was performed using different experimental techniques, such as Dynamic mechanical analysis, Thermogravimetry (TG), Field emission scanning electron microscopy. Furthermore, the investigation of the flame behavior was carried out by the limiting oxygen index and mass loss calorimeter measurements. Direct current measurements and investigation by Tunneling atomic force microscopy of the conductive nanodomain map allowed the evaluation of the electrical properties of the developed nanofilled systems. The TG data related to thermal decomposition of ER and its binary and ternary mixtures were processed according to isoconversional kinetic analysis by assuming a non-Arrhenian behavior of the temperature function, and lifetime prediction was estimated at suitable relatively low temperatures and possible relation between the thermal stability and the presence of each component was discussed. This method of kinetic analysis paves the way for the possibility of evaluating in a more realistic way, on the basis of thermal stability, the potential application of structural resins with primary load functions in contact with hot areas of aeronautical aircraft engines.

Improvement of heat release methodologies using mass loss calorimeter and oxygen consumption hood to assess flammability of wood plastic composites

The mass loss calorimeter provides a robust method for evaluating flammability of very sooty materials such as wood plastic composites as a lower cost and rugged alternative to the reliable and effective cone calorimeter. The high amounts of smoke and carbon monoxide associated with these materials resulted in a much-reduced heat release rate, resulting in incomplete combustion of the diffusion flame, which required modifications to the standards in measuring heat release rate via oxygen consumption or carbon dioxide production or thermopiles. In addition to liquid fuels of ethylene glycol and methanol, the solids polystyrene and polymethyl methacrylate were used as calibration materials for the mass loss calorimeter and the instrumented heat release rate hood. Because of concerns about the flue gas thermopile methodology for heat release rate measurements, a second thermopile was attached to the exterior of the metal pipe chimney typically used for heat release rate calculations in the mass loss calorimeter. A heat balance analysis indicated that this is an effective design compared with alternative designs. Estimates of flaming heat release rate are reported using both signals from the thermopiles for calculation of heat release rates and confirmed with the updated oxygen consumption analysis under an instrumented hood. This special fire test arrangement was used to assess the flammability of four different wood plastic composites, some with fire-retardant treatments, such as ammonium polyphosphate and brominated, all of which tended to have high smoke production leading to high-radiant energy losses. The reduction of heat release rate with 10% by content of fire-retardant treatment was confirmed by both heat release rate measures. The average heat release rate decreased 19% to 39% when fire retardants were added, relative to this wood flour–polyethylene composite.

Combined treatment of wood with thermosetting resins and phosphorous flame retardants

Wood modification with thermosetting resins results in improved dimensional stability and durability. However, the treatment does not enhance fire resistance. To address this, Scots pine sapwood (Pinus sylvestris L.) was impregnated with thermosetting resins such as 1,3-dimethylol-4,5-dihydroxyethyleneurea, phenol-formaldehyde resin and melamine-formaldehyde resin, along with a phosphorus polyol as the flame retardant. Both weight percent gain and cell wall bulking were measured to investigate the deposition of resin and phosphorus polyol. Fire resistance was assessed through thermogravimetric analysis, Bunsen burner test and mass loss calorimeter. The inclusion of a phosphate polyol improved thermal stability, reduced flammability and heat release. Melamine-formaldehyde resin combined with phosphorus polyol demonstrated self-extinguishing capability with the heat release rate comparable to non-combustible materials inside 400 s. Moreover, the total heat release within 600 s shows an 84% reduction compared to untreated wood.

The effect of phosphorus based flame retardants on the thermal and fire retardant properties of chicken feather/thermoplastic polyurethane composites

The aim of the study was to enhance the flame-retardant properties of chicken feather (CF) reinforced thermoplastic polyurethane (TPU) composites by incorporating three different phosphorus-based flame retardants, namely aluminum hypophosphite (AHP), ammonium polyphosphate (APP), and aluminum diethyl phosphinate (AlPi), at concentrations of 5, 10, and 20 wt%. The effectiveness of the additives was evaluated through various tests, including limiting oxygen index (LOI), vertical burning test (UL 94 V), thermogravimetric analysis (TGA), and mass loss calorimeter test (MLC). The results indicated that all three additives exhibited flame retardant properties in both the condensed and gas phases, but APP and AHP performed better than AlPi due to their enhanced char formation capabilities. The flame retardant effectiveness of the additives decreased in the order of APP > AHP > AlPi.

Influence of boron bearing fillers on flame retardancy properties of huntite hydromagnesite filled ductile PLA biocomposites

In this work, the flame retardant influences of colemanite and boron oxide are investigated in huntite-hydromagnesite (HH) containing plasticized poly (lactic acid) (PLA) biocomposites. The composites are characterized using limiting oxygen index (LOI), horizontal (UL 94 HB) and vertical (UL-94 V) burning tests, mass loss calorimeter and thermo gravimetric analysis (TGA). The addition of colemanite causes enhanced fire retardant performance with higher UL-94 V rating and LOI value and lower pHRR value. V0 rating and the highest LOI value is observed with the addition 1 wt % colemanite. When the concentration of colemanite reaches to 3 and 5 wt %, the samples get V1 rating. When the concentration of colemanite reaches to 5 wt %, pHRR and avHRR values are lower than those of the reference sample. The addition of boron oxide caused only improvement in LOI value. The highest LOI value (33.2) is observed in 5 and 10 wt % boron oxide containing samples.

Combination effect of zinc borate in intumescent polybutylene succinate systems: Study of the carbonaceous structures using solid-state NMR

Inspired by the concept of intumescence, this research proposed and exemplified a strategy for reinforcing the carbonaceous structures to improve the fire retardancy of intumescent polybutylene succinate (PBS). Herein, intumescent PBS formulations were fabricated by incorporating ethylenediamine phosphate (EDAP) and melamine (MEL) or melamine cyanurate (MCA) as well as zinc borate (ZnB) into PBS at a relatively low loading (10 wt%). The reaction to fire of PBS formulations were assessed by mass loss calorimeter (MLC) and the reinforcement mechanism of the condensed phase was investigated by solid-state NMR technique. Compared to PBS/EDAP&MEL(5:1,10%) and PBS/EDAP&MCA(5:1,10%), the synergistic combination of ZnB and EDAP&MEL (or EDAP&MCA) significantly reduced the peak of heat release rate (pHRR) of PBS/EDAP&MEL(5:1,8%)/ZnB(2%) and PBS/EDAP&MCA (5:1,8%)/ZnB(2%) by 61% and 53%, respectively, exhibiting high degrees of intumescence. Meanwhile, the fire growth rate index (FIGRA) were reduced by 48.8% and 39.5%, respectively, and the maximum average rate of heat emission (MARHE) decreased by 47.9% and 53.3%, respectively. Moreover, the flameout time increased by 428 s (from 507 to 935 s) and 444 s (from 509 to 954 s), respectively. Those phenomena suggested a synergistic flame retardant effect of ZnB and intumescent additives on PBS. Solid-state NMR of 11B, 13C and 31P of the top and bottom of chars after MLC test demonstrated the strengthening of the protective char by the formation of borophosphate and other phosphate glasses, limiting cracking and increasing the char cohesion.

Performance evaluation of melamine derivatives as flame retardant additive in chicken feather containing thermoplastic polyurethane biocomposites

The objective of this research is to examine the potential use of melamine derivatives namely melamine cyanurate (MC), melamine phosphate (MP), and melamine polyphosphate (MPP) as flame retardant additives in chicken feather (CF) containing thermoplastic polyurethane (TPU). The performances of the composites are evaluated using limiting oxygen index (LOI), vertical UL-94 (UL-94 V), and mass loss calorimeter (MLC) tests. The V0 rating is achieved with the addition of 10 wt% MC, 20 wt% MP, and MPP. The performances of the additives are ranked in the ascending order of MC, MP, and MPP in LOI test. MP and MPP show distinct better performance than MC in the condensed phase. However, the gas phase action of MC is much better. than MP, and MPP. The lowest pHRR (103 Kw/m2), THE (39 MJ/m2), and THE/TML ratio (1.4 MJ/m2g) are observed with the use of 20 wt% MPP, MP, and MC, respectively.

The influence of expandable graphite on the thermal, flame retardant and mechanical characteristics of short carbon fiber reinforced polyamide composites

The fire retardant performance of carbon fiber (CF) reinforced polyamide 6 (PA 6) composites plays an important role in their novel application fields. Thus, expandable graphite (EG) is integrated into CF containing PA 6 composite system to donate halogen-free flame retardant property based upon intumescence. The effect of EG amount on the thermal, flame retardant, and mechanical properties of CF reinforced PA 6 composites is examined. The properties of the composites are investigated using thermogravimetric analysis (TGA), limiting oxygen index (LOI), vertical burning test (UL-94 V), mass loss calorimeter (MLC), tensile, and impact tests. According to the test results, thermal stability reduces as the added amount of EG increases. The addition of EG improves fire performance and reduces the flammability characteristics of CF containing PA6 composites. The highest LOI value (36.4%), UL-94 V rating (V0), and the lowest peak heat release rate (pHRR) (74 kW/m2), total heat evolved (THE) (23.9 MJ/m2) values are observed with the inclusion of 30 wt% EG. The impact strength increases at 10 wt% EG addition, whereas negligible change is observed at higher EG loadings with respect to the reference sample. The increase in tensile modulus and the reductions in tensile strength and percentage elongation are observed as the added amount of EG increases. In brief, CF reinforced PA6 composites gain multifunctional characteristic with the help of interaction between EG and CF based on condensed phase fire-proofing behavior.

Flame‐retardant features of various boron compounds in thermoplastic polyurethane and performance comparison with aluminum trihydroxide and magnesium hydroxide

SummaryThe objective of this research was to examine and compare the flame‐retardant properties of boron compounds with respect to conventional mineral fillers, namely aluminum trihydroxide (ATH) and magnesium hydroxide (MH) in thermoplastic polyurethane (TPU). Seven different boron compounds including zinc borate (ZnB), colemanite (C), boron oxide (BO), anhydrous borax (BX), melamine borate (MB), imidazolium borate (IB), and guanidinium borate (GB) were used as flame‐retardant additive. The flame‐retardant characteristics of the composites were investigated using limiting oxygen index (LOI), vertical and horizontal UL‐94 tests, and mass loss calorimeter (MLC) tests. According to the flammability test results, the highest LOI value (33.5%) was obtained with the use of 60 wt% ATH and BO. All samples got HB rating in UL‐94 HB test. The highest UL‐94 V rating of V0 was achieved with the use of ATH (60 wt%), BO (60 wt%), and GB (50 wt%). According to MLC test results, C, BO, and IB showed distinct better performance than ATH and MH. The other ones showed almost the similar fire performances. The lowest pHRR (37 kW/m2) and THE (16.2 MJ/m2) values, which were corresponded to 62% and 20% reduction with respect to those of ATH containing one, were achieved with the use of 60 wt% BO. In brief, all studied additives exerted different levels of fire retardancy depending upon their type and BO showed the highest performance in terms of flammability and fire‐retardant properties.

The effect of a phosphorus-based FR on the fire performance and flammability properties of basalt fiber-reinforced acrylonitrile-butadiene-styrene composites.

This study focuses on the improvement in fire performance, and flame retardancy (FR) properties of chopped basalt fiber-reinforced acrylonitrile-butadiene-styrene (ABS) composites. For this purpose, different amounts of aluminum diethyl phosphinate (AlPi) compound (5, 10, and 15 wt%) were incorporated in the composites. The FR properties of the composites were examined via limiting oxygen index (LOI), UL-94 standard, and mass loss calorimeter tests. Thermogravimetric analysis was carried out to analyze the decomposition behavior of the composites. SEM inspection was also performed to examine the char surfaces of the composites. The results and findings showed that the introduction of AlPi compound into the composite structure leads to promotion in the char yield and improves the fire performance of the ABS matrix. As the added amount of AlPi into the composite increased, the LOI value of the composite increased. The addition of 15 wt% AlPi resulted in a UL-94 rating of V1 and the LOI value of 31.4%.

Experimental evaluation of tri‐hydrated aluminium in fire‐retardant properties of glass fibre reinforced polymers

SummaryThis paper presents an experimental investigation of alumina trihydrate (ATH) in glass fibre reinforced polymers (GFRP), aiming to determine the influence of ATH concentration on improved flame‐retardant properties. For this research, different concentrations of ATH: 37 phr (parts per hundred resin), 40, 47.5, 50 and 55 phr, were added in isophthalic polyester matrix composites reinforced with E‐glass fibre through a pultrusion process. These composites were tested for flammability and flame propagation using the mass loss calorimeter cone (MLCC), limiting oxygen index (LOI) and glow wire tests. Simultaneous thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) was performed to evaluate the thermal stability and enthalpy. These analyses assessed the effectiveness and influence of each ATH concentration. It was observed in the MLCC tests that the ATH concentration of 40 phr reduced the peak heat release rate (PHRR) by 27% compared to a composite with 37 phr. All specimens showed the desired commercial result for wires and cables in the glow wire test since the composites reached the maximum glow wire flammability index (GWFI) of 960 °C and a glow wire ignition temperature (GWIT) above 900 °C. Thus, the addition of ATH above 40 phr leads to an improvement in the flame‐retardant properties of glass fibre reinforced polymers.

Flame retardancy effect of phosphorus graphite nanoplatelets on ethylene‐vinyl acetate copolymer: Physical blending versus chemical modification

AbstractA novel modified exfoliated graphite nanoplatelets (GNP‐g‐APP), resulting from grafting ammonium polyphosphate (APP) on exfoliated graphite nanoplatelets (GNP) was prepared and evaluated as flame retardant for ethylene‐vinyl acetate copolymer (EVA). The effect of modification on the thermal stability and flame retardancy of EVA was discussed. Thermogravimetric analysis (TGA), UL‐94, pyrolysis combustion flow calorimeter (PCFC), and mass loss calorimeter (MLC) analyses were employed for the evaluation of the thermal stability and flame retardancy of composites. The introduction of 20 wt.% GNP‐g‐APP into EVA resulted in significant enhancement in flame retardant properties with respect to the system containing physical mixture of GNP and APP. The former blend exhibited 57% decrease in the peak of heat release rate (pHRR), and 35% reduction in the total heat release (THR) than the latter one in MLC test. Thus, pHRR was decreased from 940 kW.m−2 for neat EVA to 403 kW.m−2 for EVA containing GNP‐g‐APP. V0 rating (auto‐extinguishable behavior) was also observed in UL 94 chemically modified sample. According to the present study, chemical modification of GNP with APP is more effective than a physical mixing of GNP and APP in improving the flame retardant properties of EVA.

Do cone age and heating mode determine the opening of serotinous cones during wildfires? A new bench scale approach applied to Pinus halepensis Mill.

Serotiny is a well-known fire adaptive trait in some species, as the Mediterranean conifer Pinus halepensis. However, information about cone opening mechanisms during wildfires and consequences on post fire dispersal is scarce. In addition, standardized methods allowing a realistic simulation of heating modes at bench-scale are not available. In this study, we address for the first time the interacting effects of radiation, convection and direct flame on the opening and seed release of serotinous cones, following a novel repeatable methodology. Using a Mass Loss Calorimeter (MLC) device and a wide range of heat exposures (between 5 and 75 kW m−2) with or without ignition, we intended to simulate realistic cone heating during surface and crown fires in laboratory conditions. Additionally, we included the effect of contrasting serotinous cone ages interacting with heating mode and considering the random individual variation. The proposed methodology has shown a high potential to simulate the complex process of crown fires in relation to cone opening under controlled conditions, detecting a threshold of heat exposure (25–30 kW m−2) for cone opening. We confirmed that heating mode had a highly significant effect in cone opening, interacting with cone age, while cone age effect on its own was marginal. Particularly, ignition significantly increased the efficacy of cone opening and seed release. Moreover, young and old cones behave differently in seed release, both in surface and crown fire simulations. Implementing and adjusting this methodology in other species will allow more realistic and reliable quantitative comparisons than previously attained.

Calcium carbonate and ammonium polyphosphate flame retardant additives formulated to protect ethylene vinyl acetate copolymer against fire: Hydrated or carbonated calcium?

AbstractIn this study, the effect of the chemical nature of different calcium (Ca)‐based minerals as flame retardant additives in combination with ammonium polyphosphate (APP), in 1:1 proportions, on the flame retardancy behavior and performance of ethylene vinyl acetate copolymer was discussed. Combining APP with partly and completely hydrated calcium oxide led to superior flame‐retardant function detected in mass loss calorimeter measurements with respect to the corresponding system containing carbonated calcium. This privileged character was attributed to the higher reactivity of hydrated Ca‐based fillers toward APP in comparison with Ca carbonate, which induced the formation of an intumescent residue. The difference between reactivity potential of hydrated and dry Ca was demonstrated by the newly formed thermally stable species, and further evidenced by thermogravimetric analysis performed on APP/fillers blends. Moreover, the presence of more crystalline domains in the Ca/phosphorus‐based compounds was evidenced by XRD analysis of the mass loss calorimeter test residues. The results of this work highlight the role of blend additive systems on the performance of flame retardancy of polymer materials.