scholarly journals Influence of Constructional-Material Parameters on the Fire Properties of Electric Cables

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4569 ◽  
Author(s):  
Kaczorek-Chrobak ◽  
Fangrat
Keyword(s):  
Construction Material ◽  
Constructional Material ◽  
Standard Test ◽  
Fire Load ◽  
Material Parameters ◽  
Electric Cables ◽  
Fire Properties ◽  
Halogen Free ◽  
Electrical Cables ◽  
Relevant Factors

The significant number of cables of different materials and construction used extensively in building objects increases their fire load and, therefore, strongly influences safety in the case of fire. The purpose of the study was to identify relevant factors related to the construction of electrical cables, and perform a qualitative and quantitative assessment of their influence on specific fire properties, such as heat release and smoke production. Fifteen cables of different construction and materials were studied using the EN 50399 standard test. The analysis was focused on cable constructional-material parameters related to the chemical composition of non-metallic elements and the number and shape of conductors in the cable, as well as the concentric barrier as armor or the copper concentric conductor. The conclusions drawn from the experiments were: (1) Construction, the number of conductors, and the presence of armor or concentric metallic conductors improve the fire properties by forming a barrier against flame penetration through the cable; (2) the use of copper conductors resulted in a decrease of fire parameters compared to cables with aluminum conductors (peakHRRav parameter even four times lower for copper cable); (3) construction material based on non-plasticized poly(vinyl chloride) (PVC) significantly reduced the fire properties of cables more than halogen-free materials (LS0H) (peakHRRav parameter more than 17 times higher for the fully halogenated cable), which is due to the decomposition process of the material; and (4) no clear relationship between the fire parameters and the cable parameter, χ, was found.

Repair of Major Cracks in Central Spans of the 4 Span Continuous Bridge, India

2018 ◽  
Author(s):  
Dhananjay A. Bhide ◽  
Prashant Dongre
Keyword(s):  
Construction Material ◽  
Remedial Measures ◽  
Construction Technique ◽  
Box Girder ◽  
Material Parameters ◽  
National Highway ◽  
Major Crack

Varsova Bridge is across Vasai Creek, about 35 Km from Mumbai, India. It is on National Highway 48. Two bridges, 555.32m long, exist at the crossing, built in 1970 and 2004 respectively. Old bridge has central 4 spans, built in continuous PSC box girder su configuration of 57.3 + 2 x 114.6 + 57.3 construction technique. 114.6m span on Mumbai end developed a major crack, 4mm wi about 12m from mid span. Main c height in both webs. The paper describes the investigations made through analysis the probable reasons and deciding remedial measures as well as execution of the same. used four different models as per construction material parameters. Final repair measure crack locations.

scholarly journals Excellent Fireproof Characteristics and High Thermal Stability of Rice Husk-Filled Polyurethane with Halogen-Free Flame Retardant

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1587 ◽  
Author(s):  
Huong T.Q. Phan ◽  
Binh T. Nguyen ◽  
Lam H. Pham ◽  
Chi T. Pham ◽  
Thi Vi Vi Do ◽  
...  
Keyword(s):  
Rice Husk ◽  
Flame Retardants ◽  
Standard Test ◽  
Solid Particles ◽  
Cone Calorimetry ◽  
Thermal Stabilities ◽  
Pyrolysis Products ◽  
Halogen Free ◽  
Flame Retardancy Mechanism ◽  
Thermal Stability Of

The thermal stabilities, flame retardancies, and physico-mechanical properties of rice husk-reinforced polyurethane (PU–RH) foams with and without flame retardants (FRs) were evaluated. Their flammability performances were studied by UL94, LOI, and cone calorimetry tests. The obtained results combined with FTIR, TGA, SEM, and XPS characterizations were used to evaluate the fire behaviors of the PU–RH samples. The PU–RH samples with a quite low loading (7 wt%) of aluminum diethylphosphinate (OP) and 32 wt% loading of aluminum hydroxide (ATH) had high thermal stabilities, excellent flame retardancies, UL94 V-0 ratings, and LOIs of 22%–23%. PU–RH did not pass the UL94 HB standard test and completely burned to the holder clamp with a low LOI (19%). The cone calorimetry results indicated that the fireproof characteristics of the PU foam composites were considerably improved by the addition of the FRs. The proposed flame retardancy mechanism and cone calorimetry results are consistent. The comprehensive FTIR spectroscopy, TG, SEM, and XPS analyses revealed that the addition of ATH generated white solid particles, which dispersed and covered the residue surface. The pyrolysis products of OP would self-condense or react with other volatiles generated by the decomposition of PU–RH to form stable, continuous, and thick phosphorus/aluminum-rich residual chars inhibiting the transfer of heat and oxygen. The PU–RH samples with and without the FRs exhibited the normal isothermal sorption hysteresis effect at relative humidities higher than 20%. At lower values, during the desorption, this effect was not observed, probably because of the biodegradation of organic components in the RH. The findings of this study not only contribute to the improvement in combustibility of PU–RH composites and reduce the smoke or toxic fume generation, but also solve the problem of RHs, which are abundant waste resources of agriculture materials leading to the waste disposal management problems.

scholarly journals Combustible Material Content vs. Fire Properties of Electric Cables

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6172
Author(s):  
Katarzyna Kaczorek-Chrobak ◽  
Jadwiga Fangrat
Keyword(s):  
Heat Release ◽  
Combustion Process ◽  
Test Method ◽  
Zinc Borate ◽  
Infrared Analysis ◽  
Chemical Structures ◽  
Smoke Production ◽  
Outer Sheath ◽  
Electric Cables ◽  
Fire Properties

The fire load of buildings is significantly increased by means of electric cables, usually creating a long combustible base for fire to spread and in this way decreasing the fire safety of buildings. The aim of the study was to evaluate a relationship between the construction of the cables and their fire properties, especially the mass loss influence on other fire properties of cables. Six cables of different core numbers were tested by means of the standard test method EN 50399. Additionally, thermogravimetric analysis and Attenuated Total Reflection—Fourier Transform Infrared analysis were performed on the separate outer sheath, bedding, and core insulations in order to determine the similarity of the materials’ chemical structures. It was found that: (1) the construction of the cable strongly influences the fire behavior due to the creation of a barrier for flame penetration and emission of combustion effluents though inside the closed agglomeration of non-combustible metallic cores (conductors), and the intumescent structures formed from aluminum trihydrate/zinc borate fillers and fire retardants in outer sheath material during the self-sustained combustion process after ignition of cables; (2) the inhomogeneous distribution of non-combustible inorganic fillers or different contents of fillers and flame retardants within the polymer fraction cause an unobvious fire behaviors of cables; and (3) the use of bedding in multicore cable construction results in lower values of combustion parameters (maximum average heat release rate, total heat release, maximum average smoke production rate, total smoke production), e.g., better fire properties of cables.

scholarly journals Organic Aluminum Hypophosphite/Graphitic Carbon Nitride Hybrids as Halogen-Free Flame Retardants for Polyamide 6

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2323
Author(s):  
Chengxin Guo ◽  
Yongshuai Zhao ◽  
Guichen Ji ◽  
Chaosheng Wang ◽  
Zhihan Peng
Keyword(s):  
Gas Phase ◽  
Flame Retardants ◽  
Carbon Nitride ◽  
Solid Phase ◽  
Polyamide 6 ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
Aluminum Hypophosphite ◽  
Fire Properties ◽  
Halogen Free

The novel organic aluminum hypophosphite (ALCPA) and its hybrid (CNALCPA) with graphitic carbon nitride (g-C3N4) were successfully synthesized and applied as halogen-free flame retardants in polyamide 6 (PA6). Their structures, morphology, thermal stability, and fire properties were characterized. Results showed that both ALCPA and CNALCPA had good flame retardancy. PA6/CNALCPA composites achieved a high limited-oxygen-index (LOI) value of 38.3% and a V-0 rating for UL94 at 20 wt % loading, while PA6/ALCPA composites could reach a V-1 rating for UL94. The flame-retardant mechanism was also studied. On the one hand, the incorporation of g-C3N4 produced more gas-phase products, which indicated a gas-phase mechanism. On the other hand, g-C3N4 could catalyze the thermal degradation of ALCPA and PA6 to form a compact char layer that was evidence for a solid-phase mechanism. The tensile test of the PA6 composites also displayed good mechanical properties.

scholarly journals Fire behavior of halogen-free flame retardant electrical cables with the cone calorimeter

2018 ◽  
Vol 342 ◽  
pp. 306-316 ◽  
Author(s):  
Romain Meinier ◽  
Rodolphe Sonnier ◽  
Pascal Zavaleta ◽  
Sylvain Suard ◽  
Laurent Ferry
Keyword(s):  
Flame Retardant ◽  
Cone Calorimeter ◽  
Fire Behavior ◽  
Halogen Free ◽  
Electrical Cables

Investigation of Performance of Superplasticizing Admixtures Used in Hungarian Building Industry

2008 ◽  
Vol 589 ◽  
pp. 445-450
Author(s):  
Márton Takács ◽  
Ferenc Nemoda
Keyword(s):  
Construction Material ◽  
Research Work ◽  
Test Methods ◽  
Standard Test ◽  
New Materials ◽  
Compressive Test ◽  
Flow Table ◽  
Work Effect ◽  
The Eu ◽  
Chemical Materials

Concrete is the strongest candidate to be the most important construction material of the 21st century. This can be ensured by the continuous research and development of new materials and technologies regarding concrete construction. Properties of concrete can be expediently modified by adding special chemical materials called admixtures. In this research work effect of type and dosage of different superplasticizing admixtures available in Hungary were investigated in detail. Standard test methods such as flow table test and compressive test were applied to obtain effectiveness of the admixtures. Regarding the examinations done in the course of the research, we refer to the regulations of the EU harmonized admixture standard currently valid in Hungary MSZ EN 934-2:2002. In connection to that we will precisely quote the requirements specified in the standard regarding superplasticizers and will also mention the main differences compared to the plasticizer additives. Types, properties and use of superplasticizers are introduced in detail, too. Experimental results are evaluated to rate the efficiency in compliance with the requirements of the standard.

scholarly journals Corrosion Effect of 65% Nitrate Acid on X4CrNi1812 at 333 K

2019 ◽  
Vol 1 (1) ◽  
pp. 425-432
Author(s):  
Tomasz Lipiński ◽  
Dariusz Karpisz
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Austenitic Stainless Steel ◽  
Construction Material ◽  
Austenitic Stainless Steels ◽  
Steel Corrosion ◽  
Constructional Material ◽  
Design Stage ◽  
Roughness Parameters ◽  
Aggressive Environment

Abstract Austenitic stainless steels are often used for a materials in the construction of machines and equipment for agricultural and for industrial construction. One of the most important factors constructional material is corrosion resistance. Equipment with austenitic stainless steel can be easy join by quickly welding at a not to high construction price, but one with the serious problem in aggressive environment is their corrosion resistance. A few corrosion processes in crevices and awkward corners can be avoided at the design stage (low roughness parameters, round-section and other). But still the construction material is exposed to corrosion. These steels often come into contact with an aggressive environment based on nitric acid. The main aim of this research is to investigate corrosion resistance in different time (48, 96, 144, 192, 240, 288, 336 hours). For this used weight loss of test samples and its profile roughness. The research was conducted on austenitic stainless steel in grade in Nitrate acid at 333 K. Corrosion tests confirmed that the research this steel in 65% nitrate acid as a corrosive environments is characterized through proportionate to time corrosion process whose measure may be surface roughness. In industrial practice roughness parameters for all the research times can be used for determine the stage and size of steel corrosion.

Study of a Model for the Evaluation of the Heat Losses from Electric Cables Buried According to the Norm Standard

2013 ◽  
Vol 650 ◽  
pp. 437-442 ◽  
Author(s):  
R. de Lieto Vollaro ◽  
A. Vallati
Keyword(s):  
Cross Section ◽  
Soil Characteristics ◽  
Heat Losses ◽  
Forecasting Model ◽  
Correction Factors ◽  
Underground Cable ◽  
Electric Cables ◽  
Electrical Cables ◽  
Measurement Campaigns

The capacity of electrical cables buried in the same cross section depends on the capacity to dispose of heat into the ground around him. This depends on many factors: soil characteristics, moisture, installation mode etc. The CEI 20-21 regarding the uses expressions that sometimes are not very cautious and dimensioning of insufficient capacities for cables. This work has been done a study of the behavior of underground cable based on using a forecasting model that uses the techniques of cfd. This model was validated with a physical model in miniature, made from data collected in situ measurement campaigns carried out in underground conduits in the province of Foggia (Italy) that allowed the choice of the mesh to get more 'correct solution to of the problem. Thus it was possible to evaluate the differences with the CEI and attribute the correction factors that lead to more realistic values.

scholarly journals Improving Mechanical Properties and Reaction to Fire of EVA/LLDPE Blends for Cable Applications with Melamine Triazine and Bentonite Clay

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2393 ◽  
Author(s):  
Sanchez-Olivares ◽  
Sanchez-Solis ◽  
Manero ◽  
Pérez-Chávez ◽  
Jaramillo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bentonite Clay ◽  
Ethylene Vinyl Acetate ◽  
Elongation At Break ◽  
High Performing ◽  
Copolymer Blends ◽  
Property Evaluation ◽  
Electric Cables ◽  
Halogen Free ◽  
Acetate Copolymer

The high flame-retardant loading required for ethylene-vinyl acetate copolymer blends with polyethylene (EVA-PE) employed for insulation and sheathing of electric cables represents a significant limitation in processability and final mechanical properties. In this work, melamine triazine (TRZ) and modified bentonite clay have been investigated in combination with aluminum trihydroxide (ATH) for the production of EVA-PE composites with excellent fire safety and improved mechanical properties. Optimized formulations with only 120 parts per hundred resin (phr) of ATH can achieve self-extinguishing behavior according to the UL94 classification (V0 rating), as well as reduced combustion kinetics and smoke production. Mechanical property evaluation shows reduced stiffness and improved elongation at break with respect to commonly employed EVA-PE/ATH composites. The reduction in filler content also provides improved processability and cost reductions. The results presented here allow for a viable and halogen-free strategy for the preparation of high performing EVA-PE composites.

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