scholarly journals CALCULATION METHODS OF HIGH TEMPERATURE DISTRIBUTION WITHIN STRUCTURAL COMPONENTS AND APPLICATION OF THESE METHODS TO FIRE RESISTANCE ASSESSMENT /AUKŠTŲ TEMPERATŪRŲ PASISKIRSTYMO STATYBINĖSE KONSTRUKCIJOSE SKAIČIAVIMO BŪDAI IR JŲ TAIKYMO ANALIZĖ ĮVERTINANT ATITVARŲ ATSPARUMĄ UGNIAI

2001 ◽  
Vol 7 (5) ◽  
pp. 391-396
Author(s):  
Romualdas Mačiulaitis ◽  
Kęstutis Lukošius
Keyword(s):  
High Temperatures ◽  
Fire Resistance ◽  
Material Properties ◽  
Thermal Conduction ◽  
Building Materials ◽  
Heat Exposure ◽  
Thermal Characteristics ◽  
Calculation Methods ◽  
Normal Environment ◽  
Temperature Conduction

Fire resistance of a building structure is one of important properties which describes the behaviour of the structure exposed to fire. Performance based on codes allows to use calculation methods. Given a satisfactory characterisation of the heat exposure, the designer may then compute how quickly temperatures will increase at various sections within the structural component. There are many calculation methods. They can divided into three groups (Fig 1): using experimental data, using both temperature conduction process and non-stationary thermal conduction. Thermal conduction, temperature conduction and thermal capacitance are general properties for temperature prediction methods. Usually building materials have thermal characteristics for normal environment, which can not exactly describe material properties at high temperatures. But many calculation methods lack accurate thermal characteristics describing building material properties at high temperatures. This article is intended for the analysis of this question.

scholarly journals FIRE PROTECTION OF STEEL ELEMENTS USING LIGHTWEIGHT HYBRID CEMENT MORTAR

2021 ◽  
Vol 30 ◽  
pp. 104-108
Author(s):  
Stanislav Šulc ◽  
Vít Šmilauer ◽  
Jakub Šejna ◽  
František Wald
Keyword(s):  
High Temperatures ◽  
Fire Resistance ◽  
Fire Protection ◽  
Material Properties ◽  
Cement Mortar ◽  
Positive Impact ◽  
Steel Structures ◽  
Cement Based Materials ◽  
Noticeable Reduction ◽  
Steel Surfaces

Material properties of steel structures are significantly reduced at high temperatures, so a fire protection has strong positive impact on the fire resistance of the structure. Fire resistance of steel elements can be increased using a layer of cement-based materials as a fire protection. Most of commonly used cement-based materials do not withstand high temperatures without noticeable reduction of mechanical properties. Hybrid cement showed some interesting properties in the way of resistance to high temperatures and adhesion to steel surfaces, thus its behavior during fire exposure should be investigated. One experimental analysis with numerical simulation is presented in this article. It examines thermal material properties of lightweight hybrid cement mortar with expanded perlite from a simple experiment with a lab gas burner.

Determination of Fire Resistance of Ceiling Structure Variant Design on the Basis of Timber Using Numerical Calculation Methods

2016 ◽  
Vol 820 ◽  
pp. 379-384
Author(s):  
Róbert Leško ◽  
Martin Lopušniak
Keyword(s):  
High Temperature ◽  
Numerical Calculation ◽  
Fire Resistance ◽  
Building Materials ◽  
Effective Alternative ◽  
Fire Tests ◽  
Calculation Methods ◽  
Variant Design ◽  
Temperature Impacts

Ability to resist of high temperature impacts during fire is not based exclusively on ignitability of building materials. At the present time, fire resistance is declared mainly through fire tests, but numerical procedures for the determination of fire resistance also represent an effective alternative in this field. Using calculation methods for the determination of ceiling structure fire resistance on the basis of timber is subject of the submitted paper. The main objective of this paper is to demonstrate the fact that timber, or products from it, are building materials capable to resist impacts of fully developed fire for the period of more than 60 minutes in spite of their flammability. Applicability of these results in selected countries of Europe can be seen from the list of requirements.

Heat exposure and workers’ health: a systematic review

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Junhyeong Lee ◽  
Yong Ho Lee ◽  
Won-Jun Choi ◽  
Seunghon Ham ◽  
Seong-Kyu Kang ◽  
...  
Keyword(s):  
Systematic Review ◽  
Health Status ◽  
Health Effects ◽  
High Temperatures ◽  
Reproductive System ◽  
Health Effect ◽  
Heat Exposure ◽  
Urinary System ◽  
Psychological System ◽  
Meta Analyses

Abstract Objectives Several studies on the health effects of heat exposure on workers have been reported; however, only few studies have summarized the overall and systematic health effects of heat exposure on workers. This study aims to review the scientific reports on the health status of workers exposed to high temperatures in the workplace. Methods We reviewed literature from databases such as PubMed and Google Scholar, using Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines to identify studies that address health effects of heat exposure among workers. Results In total, 459 articles were identified, and finally, 47 articles were selected. Various health effects of heat exposure on workers have been reported, such as heat-related diseases, deaths, accidents or injuries, effects on the urinary system, reproductive system, and on the psychological system. Conclusions Our review suggests that many workers are vulnerable to heat exposure, and this has a health effect on workers.

The Effect of Heat Treatment on Mechanical Properties of Car Interior Fabric Used for Injection Molding

2012 ◽  
Vol 532-533 ◽  
pp. 234-237
Author(s):  
Wei Lai Chen ◽  
Ding Hong Yi ◽  
Jian Fu Zhang
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
High Temperature ◽  
Injection Molding ◽  
High Temperatures ◽  
Material Properties ◽  
Injection Molding Process ◽  
Molding Process ◽  
Composite Fabrics

The purpose of this paper is to study the effect of high temperature in injection molding process on mechanical properties of the warp-knitted and nonwoven composite fabrics (WNC)used in car interior. Tensile, tearing and peeling properties of WNC fabrics were tested after heat treatment under120, 140,160,180°C respectively. It was found that, after 140°C heat treatment, the breaking and tearing value of these WNC fabrics are lower than others. The results of this study show that this phenomenon is due to the material properties of fabrics. These high temperatures have no much effect on peeling properties of these WNC fabrics. It is concluded that in order to preserve the mechanical properties of these WNC fabrics, the temperature near 140°C should be avoided possibly during injection molding process.

Influence of Heat on Seed Germination of Cistus Laurifolius and Cistus Ladanifer

1992 ◽  
Vol 2 (1) ◽  
pp. 15 ◽  
Author(s):  
L Valbuena ◽  
R Tarrega ◽  
E Luis
Keyword(s):  
Seed Germination ◽  
High Temperatures ◽  
Exposure Time ◽  
Germination Rate ◽  
Heat Exposure ◽  
Cistus Ladanifer ◽  
Different Temperatures ◽  
Petri Dishes ◽  
Germinated Seeds

The influence of high temperatures on germination of Cistus laurifolius and Cistus ladanifer seeds was analyzed. Seeds were subjected to different temperatures for different times, afterwards they were sowed in plastic petri dishes and monitored for germinated seeds over two months.The germination rate observed in Cistus ldanifer was greater than in Cistus laurifolius. In both species, heat increased germination percentages. For Cistus laurifolius higher temperatures or longer exposure times were needed. Germination percentages of Cistus ladanifer were lower when heat exposure time was 15 minutes.It must be emphasized that germination occurred when seeds were not treated, while seeds exposed to 150�C for 5 minutes or more did not germinate.

scholarly journals Effect of perspired moisture and material properties on evaporative cooling and thermal protection of the clothed human body exposed to radiant heat

2018 ◽  
Vol 89 (18) ◽  
pp. 3663-3676 ◽  
Author(s):  
Manhao Guan ◽  
Agnes Psikuta ◽  
Martin Camenzind ◽  
Jun Li ◽  
Sumit Mandal ◽  
...  
Keyword(s):  
Human Body ◽  
Material Properties ◽  
Heat Dissipation ◽  
Thermal Protection ◽  
Evaporative Cooling ◽  
Thermal Characteristics ◽  
Radiant Heat ◽  
Physiological Effect ◽  
Heat Gain ◽  
Active Liquid

Perspired moisture plays a crucial role in the thermal physiology and protection of the human body wearing thermal protective clothing. Until now, the role of continuous sweating on heat transfer, when simultaneously considering internal and external heat sources, has not been well-investigated. To bridge this gap, a sweating torso manikin with 12 thermal protective fabric systems and a radiant heat panel were applied to mimic firefighting. The results demonstrated how the effect of radiant heat on heat dissipation interacted with amount of perspired moisture and material properties. A dual effect of perspired moisture was demonstrated. For hydrophilic materials, sweating induced evaporative cooling but also increased radiant heat gain. For hydrophilic station uniforms, the increment of radiant heat gain due to perspired moisture was about 11% of the increase of heat dissipation. On the other hand, perspired moisture can increase evaporative cooling and decrease radiant heat gain for hydrophobic materials. In addition to fabric thermal resistance ( Rct) and evaporative resistance ( Ret), material hydrophilicity and hydrophobicity, emissivity and thickness are important when assessing metabolic heat dissipation and radiant heat gain with profuse sweating under radiant heat. The results provide experimental evidence that Rct and Ret, the general indicators of the clothing thermo-physiological effect, have limitations in characterizing thermal comfort and heat strain during active liquid sweating in radiant heat. This paper offers a more complete insight into clothing thermal characteristics and human thermal behaviors under radiant heat, contributing to the accurate evaluation of thermal stress for occupational and general individuals.

Drywall Thermal Properties Exposed to High Temperatures and Fire Condition

2013 ◽  
Vol 62 (1) ◽  
Author(s):  
Md Azree Othuman Mydin
Keyword(s):  
Thermal Properties ◽  
High Temperatures ◽  
Fire Resistance ◽  
Residential Buildings ◽  
Cost Effective ◽  
Standard Fire ◽  
Performance Requirements ◽  
Cost Effective Technique ◽  
Fire Barrier ◽  
In Fire

Drywall is a widespread fire barrier used in house and general building construction. Drywall partitions and ceiling membranes are possibly the most common fire resistant construction approach employed in an extensive range of building types. The utilization of drywall board as prime fire protection of light-flame wood or steel construction is ubiquitous. Drywall board based systems are among those now broadly used, as walls or ceilings and it is principally employed as lining material in light-weight construction, which is a competent and cost effective technique of providing flexible partitioning assemblies in commercial and residential buildings. The thickness of the drywall board lining and the configuration of the framing can be flexibly changed to meet specified fire performance requirements. The use of such systems is increasing every day and there demands to be more research on their properties and behaviour. This paper will presents the properties of drywall board which will includes the assemblies and standard fire tests and the thermal properties of drywall in general and includes suggested properties of drywall by different researchers. Drywall boards shrink and crack at high temperatures, and this leads to collapse of parts of the drywall boards in fire. Fall-off of gypsum in fire affects the fire resistance of the assembly considerably, and cannot be overlooked when evaluating the fire resistance of drywall assemblies

Research of Fire Resistance of Tunnel Lining Concrete

2016 ◽  
Vol 249 ◽  
pp. 14-20
Author(s):  
Adam Hubáček ◽  
Veronika Ondryášová
Keyword(s):  
High Temperatures ◽  
Fire Resistance ◽  
Present Knowledge ◽  
Tunnel Lining ◽  
Fire Prevention ◽  
Resistance Improvement

The article is involved with study of fire resistance of concrete for tunnel linings. It summarises the problems of present knowledge of concrete resistance in tunnels and deals with behaviour of concrete particular parts at exposure to high temperatures. Further possibilities of fire resistance improvement for production of concretes together with fire prevention are described in this paper.

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