Total Heat Emission Research Articles

THE OPTIMAL IMPREGNATION AMOUNTS OF FLAME-RETARDANT FOR KOREAN LARCH AND JAPANESE CEDAR BUILDING MATERIALS

In Korea, in accordance with regulations MOLIT notice 2023-24 regarding the flame retardant performance of building finishing materials and fire spread prevention structure, it is mandated that flame-retardant materials have a total heat emission less than 8 MJ/m2. Consequently, our study aimed to determine the quantity of flame-retardant treatment required to meet MOLIT notice 2023-24 for Korean larch and Japanese cedar, as commonly used exterior materials in construction. To this end, we investigated using a cone calorimeter to observe changes in the THR (total heat released) depending on the SCFI (solid content of flame-retardant impregnation). Our simple linear regression analysis indicated that the SCFI needed to satisfy the prescribed flame-retardant standard of 8 MJ/m2 was 93.9 kg/m3 for Korean larch and 144.6 kg/m3 for Japanese cedar. As a result, we established optimal impregnation levels of flame retardant for both species.

화재 확산 방지를 위한 Biochar-황토 복합 건축자재의 난연성능 평가

The goal of this study was to develop and evaluate building finishing materials with excellent thermal and flame retardant performances using eco-friendly materials such as hwangtoh and biochar. The hwangtoh binder without biochar was found to have better thermal insulation performance than gypsum and higher heat storage than concrete.. The use of rice hull biochar was the most effective approach for weight reduction, and when 10% of the maximum weight was mixed, the density decreased by 60%. The results showed that the insulation performance could be improved by lowering the biochar mixture. Heat capacity analysis results showed a small decrease after mixing bamboo biochar; however, in most cases, it showed a higher heat storage capacity compared to concrete. Flame retardant analysis results showed that when 5% of each biochar was mixed, the total heat emission was higher than that of the hwangtoh binder, and there was a possibility of more than semi-incombustible performance; however, there was no ignition. The weight loss was up to 10.5%, and no significant change was found in the structureforming strength.

Evaluation of the Flame-Retardant Performance and Fire Risk of Cellulose Building Finishing Material Due to the Particle Size of Expandable Graphite

The burning of building finishing materials containing chemical substances can lead to the spread of fire with a large number of harmful substances. To prevent this, cellulose, an eco-friendly material that minimizes the generation of harmful substances, was chosen as the main material for building finishing materials. Wastepaper was recycled to extract cellulose, and a finishing material was manufactured by mixing in expandable graphite and magnesium hydroxide. The flame-retardant performance of the finishing material was evaluated by measuring the total heat emission rate using the ISO 5660-1 cone calorimeter, with the particle size of the expanded graphite as a variable. The measured physical properties value was used as the FDS parameter to evaluate the risk of fire. Results show that the cellulose-based building finishing material meets the life safety standard of NFSC 203 during the simulation time and has a FED value that does not exceed 0.001 at maximum. This confirms its effectiveness in providing safe egress time for residents.

Estimation of Heat Released from Fire Based on Combustible Load in Inner Mongolian Grasslands

The grasslands of Inner Mongolia are prone to wildfires, which can endanger the grassland ecosystem, as well as people’s lives and property. The amount of heat released by grassland fires must be determined for the quantitative evaluation of grassland fires. On the basis of a field survey of combustible load and an indoor heat release experiment, together with the acquisition of NDVI and fire area data, this study evaluated the amount of combustible load, plant heat release, potential heat release, and fire-caused heat release in Inner Mongolia grasslands. The following results were obtained: (1) The models for determining Inner Mongolia’s combustible load (Y) per unit area throughout the growing and nongrowing seasons were Yi = 412.74NDVIi1.5917 and Yj = −7.21tj + Y10 (i represents May–October of the growing season; j represents November–April of the following year). In the northern temperate zones, grasslands and meadows showed a decline in combustible load per unit area. The interannual combustible load variance increased between 2001 and 2016; (2) the per square meter average heat release of Stipa capillata, Cleistogenes squarrosa, Carex doniana, Leymus chinensis, and other plants was 0.51, 0.18, 0.17, 0.3, and 1.42 MJ/g, respectively. Unit weights were released at 2.13, 1.77, 2.06, 1.9, and 3.99 MJ/m2; (3) from 2001 to 2016, Inner Mongolia’s grassland fires predominantly occurred in northern temperate grasslands and meadows. Over the 16 year period, the total heat emission was 1.01 × 1012 MJ, with variable decreasing trends noted in spring and fall. The main practical objectives of this paper were to provide basic data for fire spread modeling and suggest more scientific and effective fire management methods for the future.

Flame retardancy of PET foams manufactured from bottle waste

Supercritical CO2-assisted extrusion technique was used to produce flame retarded foams from recycled poly(ethylene terephthalate) (rPET). Synergistic combination of aluminium-alkylphosphinate flame retardant (FR) and natural montmorillonite (MMT) was utilised to provide adequate flame retardancy at moderate loadings, i.e. with less than 9% of additives. Addition of FR was found to increase the rate of degradation during production (compounding and foam extrusion), which was effectively compensated by chain extender (CE) addition that ensured the melt strength required to obtain proper foam structure. The effects of the FR content and the CE addition on the viscosity of the rPET compounds and on the morphological, thermal, flammability and mechanical properties of the foam products were comprehensively investigated. When compared to injection moulded bulk materials of identical compositions, the highly porous structure of foams was found to increase flammability according to UL94 tests and LOI measurements but has not been shown to be detrimental to heat release rates as measured by cone calorimetry. It was concluded that with well-balanced composition, i.e. 8% FR + 1% MMT + 1% CE, low-density foams (with porosities higher than 70%) of uniform microcellular structure and prominent flame retardant characteristics (such as V0 rating according to UL94 standard, LOI of 28.5% and by 50% reduced peak of heat release rate and by 30% reduced total heat emission) can be manufactured even from rPET.

Influence of foam density on burning behavior of polymer bead foams

AbstractFoamed plastics are increasingly employed due to the high demand in functional materials with reduced weight. Bead foams in general offer low weight and excellent thermal insulation properties combined with extremely high freedom in design. Though foams show increased risk of ignition and heightened heat release, literature on burning behavior is rather limited. Therefore, this study investigates density‐dependent burning behavior of commercial bead foams like expanded polypropylene (EPP) and expanded modified polyphenyleneether (E‐mPPE) by cone calorimetry. The results are compared to existing studies on the density‐dependent burning behavior of different foams, mainly expanded polystyrene and foamed polyurethane. The importance of density as a characteristic is highlighted by the linear dependence of total heat emission on density for all investigated polymers, making a prediction of thermal loads possible. The peak heat release rate of flame‐retarded EPP and E‐mPPE was found not to be dependent on density, indicating an increased homogeneity by addition of flame retardant.

Estimation of microbiological contamination of maize seeds using isothermal calorimetry

The storage of maize seed intended for industrial purposes in foil silo bags is associated with microbiological contamination of the material by bacteria and fungi. This results in the loss of a part of the raw material or its deterioration and causes financial losses. In this paper, the relationship between the number of microorganisms colonizing maize seeds as well as changes in heat flow has been proved. For this purpose, the heat flow and total metabolic heat emission values (total heat) were analyzed. Calorimetric measurements of seed samples were made using the TAM III isothermal calorimeter. The seed samples with the same heat flow curves shape were homogenized, and microbial DNA was isolated from them. The quantitative real-time polymerase chain reaction (qPCR) was performed for detecting the main group of microorganisms colonizing maize seeds. It has been shown that in the case of seeds less affected by Bacillus and fungi (including yeast), the heat flow (in the range of 0–360 min) has a falling shape, while for more infected it grows almost linearly. The more infected maize seeds also show significantly higher values of total heat emission. The described research can be used to quickly assess the degree of seed contamination.

Fire Tests for Representative Combustibles in Residential Facilities for the Development of Field Commander Training Content

In this study, the fire patterns, heat emissions, and smoke generated by means of fire tests developed for representative combustibles in residential facilities were analyzed from among seven fire types. These combustibles were selected in a previous study to simulate real-world situations and professionalism required while dealing with these types of fires and develop the field commander training content. Consequently, the maximum heat dissipation was recorded as 728.6 kW, followed by the dissipation measured from the combination of a mattress and electric blanket, desk and chair, and TV and mattress. The total heat emission of sofas (226.2 MJ) and the combination of mattress and electric blanket (2,259.5 m<sup>2</sup>) was recorded. In this study, the scope of the tests was limited to the fire characteristics and characteristics of the combustibles, and it is expected that a simulation using various data acquisition methods and FDS would be performed and evaluated at a later stage.

A Study on Fire Spread and Evacuation Risk of Conduit Combustion in Ceiling Hiding Place

In this study, the ISO 5660 and ISO 5659 combustion tests were conducted with synthetic resin conduits (CD, VE) and metal conduit (ST) used for wiring work in electrical facilities, which can be installed in ceiling concealed places. Then, fire spreading and evacuation risks were analyzed based on the measured data. In the ISO 5660 test, CD of 120.5 MJ/㎡, VE of 81.9 MJ/㎡, and ST of 4.9 MJ/㎡ were measured. In the ISO 5659 test, the CD 1320, VE 731, and ST 102 were measured, and then the maximum smoke densities were measured for CD 605 s, VE 740 s, and ST 1,200 s. In terms of fire spreading and evacuation risk, the CD conduit, VE conduit, and ST conduit were in order. In the fire spreading risk analysis, total heat emission was calculated as 4,820 MJ/㎡, 4,267 MJ/㎡, and 196 MJ/㎡ for CD, VE, and ST, respectively. Evacuation risk analysis shows at transmittance of 89%, CD is 127 s, VE is 35 s, and ST is 969 s. At transmittance of 79%, representing almost invisible concentration, CD is 157 s and VE is 50 s. The CD and VE conduits had a high fire spreading and evacuation risks, while the ST conduit had little effect on fire spreading and evacuation risk.

Flame retarded self-reinforced poly(lactic acid) composites of outstanding impact resistance

Impact resistant all-poly(lactic acid) composites were prepared by film-stacking of highly crystalline poly(lactic acid) (PLA) fibres with fully amorphous PLA films. The flammability of the self-reinforced PLA composites (PLA-SRCs) was effectively reduced by incorporating ammonium polyphosphate based flame retardant (FR) additive and montmorillonite clays in a weight ratio of 10 to 1 into the matrix layers. As low as 16wt% FR content proved to be sufficient for achieving self-extinguishing behaviour, i.e. UL94 V-0 rating, and to achieve 50% and 40% reduction of peak of heat release rate and total heat emission, respectively. The introduction of FR additives improved also important mechanical properties compared to the FR-free all-PLA composite. The stiffness of the PLA-SRCs increased steadily with the FR contents of their matrix layers, furthermore, owing to the improved fibre–matrix bonding, prominent energy absorption capacity (impact perforation energy as high as 16J/mm) was determined for the effectively flame retarded PLA-SRC.

The significance of the anthropogenic heat emissions of London's buildings: A comparison against captured shortwave solar radiation

This study addresses the anthropogenic heat emissions from buildings in London, i.e. the total energy delivered to buildings, all of which will ultimately end up as heat energy. The study was undertaken in an attempt to understand the significance of these emissions with regards to the impact on the local climate in London. In order to place the emission of this anthropogenic heat in context, it was thus compared against the net short wave solar radiation captured within the urban environment. This study provides a preliminary analysis of the spatial and temporal anthropogenic heat emissions from buildings across London as part of the urban climate modelling element of the LUCID (‘The Development of a Local Urban Climate Model and its Application to the Intelligent Design of cities’) project. Four urban environment models, representative of the range of urban density found in central London, were developed for the comparison of the anthropogenic heat emissions and the net shortwave solar radiation. It was found that the annual average anthropogenic heat emission from the built environment across London was approximately 9 W/m 2 (ground area). However, this average value conceals a significant spatial and temporal range. In those urban areas with deep canyons and high densities, the anthropogenic heat constitutes a significant portion of the total energy input. A comparison indicates that the total heat emission from buildings during a winter day ranges between 3 and 25 times greater than the incident solar radiation, and during a summer day between 0.04 and 0.4 times, depending on built form density.

Estimation of anthropogenic heat emission in the Gyeong-In region of Korea

The anthropogenic heat emission in the Gyeong-In region of Korea in 2002 is estimated based on the energy consumption statistics data. The energy consumption over the region is categorized into four energy sectors: electricity use, transportation, point sources, and area sources. The estimated annual mean anthropogenic heat emissions in Seoul, Incheon, and Gyeonggi are found to be 55, 53, and 28 W m−2, respectively. A major contributing energy sector to anthropogenic heat emission in the Gyeong-In region is area sources including the residential, commercial, and small industrial sectors, which account for 40% of the total heat emission from the three administrative districts, and transportation and electricity use follow. The distributions of the annual, monthly, and hourly mean anthropogenic heat emission for all energy sectors are presented in the 0.01° longitude × 0.01° latitude grid domain. The presently estimated anthropogenic heat emission data can be used in mesoscale meteorological and environmental modeling in the Gyeong-In region.

Heat emission by the honey bee Apis mellifera L. Brood (Hymenoptera, Apidae)

Heat emission by the honey-bee larvae, prepupae, and pupae was investigated by microelectrocalorimetry. A correlation between changes in the environment temperature and heat emission was found. Within the vital range of air temperature (29–37.5°C), an increase in temperature by 1° stimulated an average heat emission increase of 0.5 mW/g in the larvae, 0.05 mW/g in the prepupae, and 0.2 mW/g in the pupae. At the optimum air temperature (34 ± 1°C), the increase in the larval body mass was followed by that in the total heat emission, but the heat emission to body mass ratio dropped. In the pupae, heat emission grows toward the end of the postembryonic development, the lowest value being observed in the prepupae.

1974 activity of chokai volcano, Japan

Shallow intrusion of magma caused phreatic explosions and mud flows at the snow-covered summit of Chokai volcano, northeast Honshu, Japan, after 153 years of dormancy. Total heat emission by the eruption is estimated at more than 3.0 × 1021 erg. Equivalent amount of magma is about 2.2 × 108 ton. Focal mechanisms of the associated volcanic earthquakes, which had been variable during the period of eruption. became stable after the cessation of the surface activity with pressure axis in a NW direction which is also the strike of the epicenter distribution. This temporal change of focal mechanisms may be interpreted as the result of propagation of increased pore pressure in the direction of the maximum pressure in the post eruptive period. The magmatic pressure which certainly predominated during the eruption period and caused carthquakes with variable mechanisms, decreased through surface activity.

The Heating Effect of the γ Rays from Radium

IN a recent communication to the Physikalische Zeitschrift (No. 18, September) Paschen has described some experiments which indicate that the γ rays from radium supply a large proportion of the total heat emission. It is known that the heating effect of radium when surrounded by an envelope of sufficient thickness to absorb both the α and β rays is about 100 gram calories per hour per gram. Paschen, however, found that if the radium was surrounded by a sufficient amount of lead to absorb completely the γ rays the heating effect was increased 2.26 times. This large heating effect of the γ rays was so unexpected, and of such great importance in connection with the nature of these rays, that we decided to verify this result by an independent method. In Paschen's experiments, the heating effect was determined in a special Bunsen ice calorimeter, in the central tube of which the radium, surrounded by a lead cylinder about 4 cm. in diameter, was placed. In order to correct for the natural melting of the ice mantle a differential method was employed. In our experiments we decided to use a differential air calorimeter, similar to the one described in our previous work on the heating effect of radium and its emanation (Phil. Mag., February). In each flask of the differential air calorimeter there was placed a narrow glass tube, closed at the lower end and extending to about the centre of the flask. The radium bromide weighing 23.7 milligrams was enclosed in a small metal capsule supported by a thread, and was inserted alternately in the glass tubes. The flasks, originally at atmospheric pressure, were immersed in a water bath kept in a constant temperature room, and were connected by a xylene tube which served as a manometer. The heating effect was measured by the movement of the xylene column, observed by a telescope with micrometer oeye-piece, and the scale was calibrated by a small heating coil of approximately the same dimensions as the radium. Two sets of experiments were carried out, in one of which the ends of the glass tubes were inserted in lead cylinders 3 cm. in diameter and 3 cm. high, and in the other with aluminium cylinders of exactly the same dimensions.