Review of heat exposure equipment and in-situ characterisation techniques for intumescent coatings

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.

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Intumescent Polymer Metal Laminates for Fire Protection

Polymers ◽

10.3390/polym10090995 ◽

2018 ◽

Vol 10 (9) ◽

pp. 995 ◽

Cited By ~ 6

Author(s):

Laura Geoffroy ◽

Fabienne Samyn ◽

Maude Jimenez ◽

Serge Bourbigot

Keyword(s):

Fire Protection ◽

Thin Layers ◽

Intumescent Coatings ◽

Thin Aluminum ◽

Thermal Measurements ◽

Polymer Metal ◽

Fire Barrier ◽

Steel Substrates ◽

Burn Through

Intumescent paints are applied on materials to protect them against fire, but the development of novel chemistries has reached some limits. Recently, the concept of “Polymer Metal Laminates,” consisting of alternating thin aluminum foils and thin epoxy resin layers has been proven efficient against fire, due to the delamination between layers during burning. In this paper, both concepts were considered to design “Intumescent Polymer Metal Laminates” (IPML), i.e., successive thin layers of aluminum foils and intumescent coatings. Three different intumescent coatings were selected to prepare ten-plies IPML glued onto steel substrates. The IPMLs were characterized using optical microscopy, and their efficiency towards fire was evaluated using a burn-through test. Thermal profiles obtained were compared to those obtained for a monolayer of intumescent paint. For two of three coatings, the use of IPML revealed a clear improvement at the beginning of the test, with the slopes of the curves being dramatically decreased. Characterizations (expansion measurements, microscopic analyses, in situ temperature, and thermal measurements) were carried out on the different samples. It is suggested that the polymer metal laminates (PML) design, delays the carbonization of the residue. This work highlighted that design is as important as the chemistry of the formulation, to obtain an effective fire barrier.

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In situ X-ray scattering evaluation of heat-induced ultrastructural changes in dental tissues and synthetic hydroxyapatite

Journal of The Royal Society Interface ◽

10.1098/rsif.2013.0928 ◽

2014 ◽

Vol 11 (95) ◽

pp. 20130928 ◽

Cited By ~ 16

Author(s):

Tan Sui ◽

Michael A. Sandholzer ◽

Alexander J. G. Lunt ◽

Nikolaos Baimpas ◽

Andrew Smith ◽

...

Keyword(s):

Heat Exposure ◽

Organic Matrix ◽

Material Design ◽

Ultrastructural Changes ◽

X Ray ◽

Ultrastructural Alterations ◽

Dental Tissues ◽

X Ray Scattering ◽

Ray Scattering

Human dental tissues consist of inorganic constituents (mainly crystallites of hydroxyapatite, HAp) and organic matrix. In addition, synthetic HAp powders are frequently used in medical and chemical applications. Insights into the ultrastructural alterations of skeletal hard tissues exposed to thermal treatment are crucial for the estimation of temperature of exposure in forensic and archaeological studies. However, at present, only limited data exist on the heat-induced structural alterations of human dental tissues. In this paper, advanced non-destructive small- and wide angle X-ray scattering (SAXS/WAXS) synchrotron techniques were used to investigate the in situ ultrastructural alterations in thermally treated human dental tissues and synthetic HAp powders. The crystallographic properties were probed by WAXS, whereas HAp grain size distribution changes were evaluated by SAXS. The results demonstrate the important role of the organic matrix that binds together the HAp crystallites in responding to heat exposure. This is highlighted by the difference in the thermal behaviour between human dental tissues and synthetic HAp powders. The X-ray analysis results are supported by thermogravimetric analysis. The results concerning the HAp crystalline architecture in natural and synthetic HAp powders provide a reliable basis for deducing the heating history for dental tissues in the forensic and archaeological context, and the foundation for further development and optimization of biomimetic material design.

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Brightness stability of eucalyptus-dissolving pulps: effect of the bleaching sequence

Holzforschung ◽

10.1515/hf-2016-0208 ◽

2017 ◽

Vol 71 (7-8) ◽

pp. 625-631 ◽

Cited By ~ 2

Author(s):

Jordan Perrin ◽

Dominique Lachenal ◽

Christine Chirat

Keyword(s):

Heat Exposure ◽

Dissolving Pulp ◽

Paramagnetic Resonance ◽

Bleached Pulp ◽

Alkaline Peroxide ◽

Elemental Chlorine ◽

Brightness Reversion ◽

Dissolving Pulps ◽

Ultraviolet Resonance Raman

Abstract The factors governing the brightness reversion (BR) of dissolving pulps under heat exposure are investigated. Carbonyl (CO) groups were artificially introduced on fully bleached pulp by sodium hypochlorite (NaClO) oxidation. It was demonstrated that the CO groups are responsible for loss of brightness stability (BS). These groups were partly eliminated by an alkaline extraction stage (E), which improved BS. However, an alkaline peroxide stage (P) was more efficient than E to improve BS, but without any additional CO loss. Moreover, an unbleached dissolving pulp was bleached in the laboratory by elemental chlorine free (ECF) and totally chlorine free (TCF) [ozone-based] sequences to the same brightness. The very low CO content was about the same in both cases. The ECF-bleached pulp showed substantially lower BS than the TCF pulp. These results are interpreted such that the chemistry of chromophores in the unbleached pulp also governs BS. In situ detection of phenolic and quinone chromophores in bleached dissolving pulp was performed by electron paramagnetic resonance (EPR) spectroscopy and ultraviolet resonance Raman (UVRR) spectroscopy. The content of these groups was bleaching-sequence-dependent, which may be related to the BS differences.

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Fire Intensity Assessment through the Analysis of Artifacts and Building Materials

Advances in Archaeological Practice ◽

10.7183/2326-3768.2.1.50 ◽

2014 ◽

Vol 2 (1) ◽

pp. 50-63 ◽

Cited By ~ 4

Author(s):

Takeshi Inomata

Keyword(s):

Building Materials ◽

Heat Exposure ◽

Fire Intensity ◽

Maya Lowlands ◽

Building Fire ◽

Intensity Assessment ◽

Different Types ◽

Tropical Lowlands ◽

Lines Of Evidence

AbstractDifferent types of artifacts and building materials react in varying manners to heat exposure, and the analysis of their degrees and patterns of thermal alterations provide important clues to the intensity of fire to which they were subjected. Such data allow researchers to examine the presence or absence of a building fire, the quantity of fuel, and the intentional or accidental nature of the fire. This approach is particularly important in the tropical lowlands, where evidence of fire in the forms of charcoal and ash may not be well preserved. At the rapidly abandoned site of Aguateca, Guatemala, the amount of charcoal and ash was small, but the examination of numerous artifacts left in situ and of building materials identified clear evidence that many buildings were burned at the time of abandonment. Similar lines of evidence were also found in artifact-poor, gradually abandoned structures at Ceibal, Guatemala. These results suggest the possibility that the burning of structures at the time of abandonment may have been more common in the Maya Lowlands than generally thought.

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In situ characterisation techniques used to test the biogenicity of biomorphic structures in 2.72Ga pristine drill core samples from the Tumbiana formation, Western Australia

Geochimica et Cosmochimica Acta ◽

10.1016/j.gca.2006.06.715 ◽

2006 ◽

Vol 70 (18) ◽

pp. A353

Author(s):

K. Lepot ◽

P. Philippot ◽

K. Benzerara ◽

M. Cotte

Keyword(s):

Western Australia ◽

Drill Core ◽

Core Samples ◽

Characterisation Techniques

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Development of in-situ trap characterisation techniques for EMCCDs

Journal of Instrumentation ◽

10.1088/1748-0221/13/02/c02025 ◽

2018 ◽

Vol 13 (02) ◽

pp. C02025-C02025 ◽

Cited By ~ 1

Author(s):

N. Bush ◽

D. Hall ◽

A. Holland ◽

R. Burgon ◽

D. Jordan ◽

...

Keyword(s):

Characterisation Techniques

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Advanced characterisation techniques: multi-scale, in situ, and time-resolved: general discussion

Faraday Discussions ◽

10.1039/d0fd90032j ◽

2021 ◽

Vol 225 ◽

pp. 152-167

Author(s):

Lee Brammer ◽

Andrew D. Burrows ◽

Samantha Yu-ling Chong ◽

Gavin Craig ◽

Jack Evans ◽

...

Keyword(s):

Time Resolved ◽

Multi Scale ◽

Characterisation Techniques

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Enhancements of the refractory submicron aerosol fraction in the Arctic polar vortex: feature or exception?

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-14-9849-2014 ◽

2014 ◽

Vol 14 (7) ◽

pp. 9849-9901

Author(s):

R. Weigel ◽

C. M. Volk ◽

K. Kandler ◽

E. Hösen ◽

G. Günther ◽

...

Keyword(s):

Total Mass ◽

Lower Stratosphere ◽

Heat Exposure ◽

Dynamical Evolution ◽

The Arctic ◽

Late Winter ◽

Air Masses ◽

Submicron Aerosol ◽

Mixing Ratios

Abstract. In situ measurements with a 4-channel stratospheric condensation particle counter (CPC) were conducted at up to 20 km altitude on board the aircraft M-55 Geophysica from Kiruna, Sweden, in January through March (EUPLEX 2003; RECONCILE 2010) and in December (ESSenCe, 2011). During all campaigns air masses from the upper stratosphere and mesosphere were subsiding inside the Arctic winter vortex, thus transporting refractory aerosol into the lower stratosphere (Θ<500 K) by vertical dispersion. The strength and extent of this downward transport varied between the years depending on the dynamical evolution of the vortex. Inside the vortex and at altitudes of potential temperatures Θ ≥ 450 K as many as eight of eleven particles per cm3 contained refractory material, thermally stable residuals with diameters from 10 nm to a few μm which endure heat exposure of 250 °C. Particle mixing ratios (up to 150 refractory particles per milligram of air) and fractions of non-volatile particles (up to 75% of totally detected particles) reach highest values in air masses with lowest content of nitrous oxide (N2O, down to 70 nmol mol−1). This indicates that refractory aerosol originates from the upper stratosphere or the mesosphere. From mixing ratios of the long lived tracer N2O (simultaneously measured in situ) an empirical index was derived which serves to differentiate air masses according to their origin from inside the vortex, the vortex edge region, and outside the vortex. Previously, observed high fractions of refractory submicron aerosol in the 2003 Arctic vortex were ascribed to unusually strong subsidence during that winter. Measurements under perturbed vortex conditions in 2010 and during early winter in December 2011, however, revealed similarly high values. Thus, the abundance of refractory aerosol at high levels appears to be a feature rather than the exception for the Arctic vortices. During December, the import from aloft into the lower stratosphere appears to be developing; thereafter the abundance of refractory aerosol inside the vortex reaches its highest levels until March. A measurement-based estimate of the total mass of refractory aerosol inside the vortex is provided for each campaign. Based on the derived increase of particle mass in the lower stratospheric vortex (100–67 hPa pressure altitude) on the order of 32 × 106 kg between early and late winter and assuming a mesospheric origin, we estimate the total mass of mesospheric particles deposited in the Arctic vortex and compare it to the expected atmospheric influx of meteoritic material (110 ± 55 × 103 kg per day). Such estimates at present still hold considerable uncertainties which are discussed in detail. Nevertheless, the results strongly suggest that the Arctic vortex easily achieves the drainage of all meteoric material deposited on the upper atmosphere.

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Fitness for Service Assessment of a Propylene Heat Exchanger Subjected to Fire Damage

Volume 1: Codes and Standards ◽

10.1115/pvp2020-21342 ◽

2020 ◽

Author(s):

Shanshan Shao ◽

Luowei Cao ◽

Guodong Jia ◽

Zhiyuan Han

Keyword(s):

Heat Exchanger ◽

Construction Material ◽

Heat Exposure ◽

The Finite Element Method ◽

Hardness Testing ◽

Fire Event ◽

Exposure Temperature ◽

Magnetic Particle Testing ◽

Fire Accident

Abstract Pressurized equipments maybe deform partially or wholly, and the mechanical properties of the construction material would be degraded due to a fire event. Fitness for service assessment can help to minimize reconstruction costs and allow safe resumption of unit operation as fast as possible. A propylene heat exchanger was exposed to overheating for about 3 hours due to a fire accident five or six meters far away. A fitness for service assessment was conducted according to API 579-1/ASME FFS-1. The material of the propylene heat exchanger is 09MnNiDR. The possible damage was examined by dimensional checks, hardness testing, in-situ field metallography, ultrasonic testing and magnetic particle testing. The heat exposure temperature of the propylene heat exchanger during the fire accident was estimated through the comparison between the results of in-situ field metallography examination and heat exposure simulation experiments. The heat exposure zones were identified based on the results of visual inspection and conjectural heat exposure temperature. The level 2 assessment was adopted to evaluate the heat exposure zones of V and VI. The approximate ultimate tensile strengths for the shell and the eastern head were converted from the hardness testing results. The caculated MAWP of the shell side is higher than the design pressure of the heat exchanger. The finite element method was adopted to evaluate the influence of the bulge in the upper part of the shell. The analytical results showed that the bulge had no significant effect on the operation of the heat exchanger before next inspection.

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