Petr Lepík - Academia.edu (original) (raw)

Papers by Petr Lepík

Research paper thumbnail of Experimental investigation of consequences of LPG vehicle tank failure under fire conditions

Journal of Loss Prevention in the Process Industries, 2018

In case of a vehicle fire, an installed LPG (liquefied petroleum gas) tank with a malfunctioning ... more In case of a vehicle fire, an installed LPG (liquefied petroleum gas) tank with a malfunctioning safety device poses severe hazards. To investigate the consequences in case of tank failure, we conducted 16 tests with toroidal shaped LPG vehicle tanks. Three tanks were used for a Hydraulic Burst Test under standard conditions. Another three tanks were equipped with a statutory safety device and were subjected to a gasoline pool fire. The safety device prevented tank failure, as intended. To generate a statistically valid dataset on tank failure, ten tanks without safety devices were exposed to a gasoline pool fire. Five tanks were filled to a level of 20%; the remaining five were filled to a level of 100%. In order to gain information on the heating process, three temperature readings at the tank surface, and three nearby flame temperatures were recorded. At distances of l = (7; 9; 11) m to the tank, the overpressure of the shock wave induced by the tank failure and the unsteady temperatures were measured. All ten tanks failed within a time of t < 5 min in a BLEVE (boiling liquid expanding vapor explosion). Seven of these resulted directly in a catastrophic failure. The other three resulted in partial failure followed by catastrophic failure. A near field overpressure at a distance of l = 7 m of up to p = 0.27 bar was measured. All ten tests showed massive fragmentation of the tank mantle. In total, 50 fragments were found. These 50 fragments make-up 88.6% of the original tank mass. Each fragment was georeferenced and weighed. Fragment throwing distances of l > 250 m occurred. For the tanks with a fill level of 20%, the average number of fragments was twice as high as it was for the tanks that were filled completely.

Research paper thumbnail of Exfoliation Processes of Graphites

Příspěvek popisuje možné chemicko-mechanické cesty (mletí v kulovém mlýně, sonikace, mikrovlné zá... more Příspěvek popisuje možné chemicko-mechanické cesty (mletí v kulovém mlýně, sonikace, mikrovlné záření) exfoliace grafitu s cílem získat nanografen. Jsou uvedeny příklady morfologie a základní chemické analýzy produktů pomocí FTIR a schéma předpokládané exfoliace grafi tu působením sil při kulovém mletí. Dále byla u námi vyrobených produktů provedena termická analýza pomocí TGA a DSC křivek.The paper describes the possible chemical-mechanical ways (ball milling, sonication and microwave radiation) exfoliation of graphite to obtain nanographene. The examples of product morphology are presented and basic chemical analysis of the products by FTIR is given as well. This contribution introduces predicted diagram of exfoliation of graphite created by interaction of forces during a process of ball milling. Finally a thermal analysis of our manufactured products was made by using TGA and DSC curves

Research paper thumbnail of Uncontrolled and Controlled Destruction of Acetylene Pressure Cylinders

Applied Sciences

The risk of physical destruction of a pressure cylinder increases with increasing temperature loa... more The risk of physical destruction of a pressure cylinder increases with increasing temperature load. Acetylene is a significant hazardous gas in cylinders. If the destruction pressure is reached, the cylinder is torn into two or more pieces, followed by the gas release to the environment. The presence of ignition sources could lead to the formation of the fireball phenomenon. This phenomenon generally reaches approximately ten meters in diameter and can be accompanied by a blast wave and a spread of the cylinder’s fragments or surrounding objects. The consequences of this type of fire could be fatal. Shooting through the cylinder shell may lead to the mitigation, if not elimination, of the effects of the uncontrolled destruction mentioned above. As a result of the review of relevant publications, several states commonly use this method as a standard procedure. Internal gas is released through the resulting hole, the pressure drops down and the gas creates a fire jet or disperses to s...

Research paper thumbnail of The Verifi cation Process of Agitation of Wheat Flour on the Explosion Autoclave VA - 250

Článek se zabývá ověřením podmínek rozvíření pšeničné mouky ve výbuchovém autoklávu VA - 250. V p... more Článek se zabývá ověřením podmínek rozvíření pšeničné mouky ve výbuchovém autoklávu VA - 250. V práci je proveden rozbor rozviřovacích kuželů a s tím související podmínky rozviřování spolu s popisem zkušebního zařízení, kterým je výbuchový autokláv VA - 250. Dále jsou v práci uvedené výsledky získané měřením maximálních výbuchových parametrů pšeničné mouky, na kterém je ověřeno nastavení rozviřovacího kužele.The article deals with the verifi cation conditions in the agitation of wheat fl our explosion autoclave VA - 250. This work analyzed swirl cones and related conditions swirl along with a description of test equipment, which is the explosion autoclave VA - 250. Further, there are the results obtained by measuring the maximum explosion parameters of wheat fl our, which is verified at set swirl cone

Research paper thumbnail of Comparison of Normative Requirements for Determination of the Minimum Ignition Energy of Combustible Dusts

Citlivost hořlavých prachů k iniciaci elektrickou jiskrou je charakterizována hodnotou minimální ... more Citlivost hořlavých prachů k iniciaci elektrickou jiskrou je charakterizována hodnotou minimální iniciační energie (MIE). Hodnota MIE je důležitou požárně-technickou charakteristikou prachu, na základě které je možné navrhnout vhodná bezpečnostní opatření. V České republice jsou platné dvě normy zabývající se stanovením MIE prachů, a to ČSN IEC 1241-2-3 a ČSN EN 13821, které se vzájemně liší. K měření MIE mohou být použita různá zkušební zařízení splňující podmínky příslušné normy. Příspěvek je zaměřen na srovnání těchto postupů a na popis zařízení, které se v praxi pro stanovení MIE hořlavých prachů používají.The sensitivity of combustible dusts to be ignited by electrical spark is characterized by value of minimum ignition energy (MIE). The value of MIE is an important fi re-technical characteristic of dust according to which it is possible to optimise measures for explosion prevention. In the Czech Republic, there are two different valid standards dealing with MIE of dust determi...

Research paper thumbnail of Procesy exfoliace grafitů

Sdružení požárního a bezpečnostního inženýrství, 2017

Research paper thumbnail of The Resistance of Surface Coatings Exposed to Thermal Load

Proceedings of the 29th European Safety and Reliability Conference (ESREL), 2019

Research paper thumbnail of Inert Substances and Explosion Limits of Hybrid Mixtures

Chemical Engineering Transactions, 2013

Problems of formation of hybrid mixtures are a rather neglected hazard to the manufacturing proce... more Problems of formation of hybrid mixtures are a rather neglected hazard to the manufacturing process. With the origin of such mixtures a necessity of minimizing possible risks that may accompany the formation of hybrid mixtures is connected as well. The article focuses especially on problems of possible inerting of hybrid mixtures.

Research paper thumbnail of Study of Influence of Combustible Gas on Explosion Parameters of Black Coal Dust

Chemical Engineering Transactions, 2012

The article focuses on the matters of explosion parameters of coal dusts and the effect of the ad... more The article focuses on the matters of explosion parameters of coal dusts and the effect of the addition of small amount of combustible gas methane on them. This work presents laboratory tests of the influence of the addition of various amount of methane to the mixture of coal dust with air and its effect on maximum pressure and maximum rate of pressure rise.

Research paper thumbnail of Development of Special Explosive Charges for the Reconstruction of Unstable Damaged Buildings

WIT Transactions on The Built Environment, 2017

Buildings or properties seriously damaged due to detonation of explosives, gas explosions, techno... more Buildings or properties seriously damaged due to detonation of explosives, gas explosions, technological accidents, and other emergency's threaten their surroundings with their instability. Their damage is usually so significant that no repair or reconstruction is ever considered, demolition is inevitable. In such hazardous situations, use of special charges could be the possible solution for a safe disposal of damaged and statically unstable structures. Use of this emergency pyrotechnic instrument could eliminate or considerably reduce the possibility of health hazards of intervening people, rescue equipment and surrounding properties during the disposal process of extremely damaged buildings in a very short time, mainly in neighbourhoods. A System of special sequentially timed charges use the increase of efficiency of external charges and cover with water-bags together with the increase of efficiency of the whole system due to their timing. Developed charges increase the operability and safety of rescue units of IRS (Integrated Rescue System).

Research paper thumbnail of Vliv počáteční teploty a tlaku na výbuchové parametry prachovzdušných směsí

Disertacni prace se zabýva problematikou stanoveni výbuchových parametrů (dolni meze výbusnosti, ... more Disertacni prace se zabýva problematikou stanoveni výbuchových parametrů (dolni meze výbusnosti, maximalniho výbuchoveho tlaku a maximalni rychlosti narůstu výbuchoveho tlaku) prachovzdusných směsi při nestandardnich pocatecnich podminkach, kterými jsou v ramci teto prace mysleny zvýsena pocatecni teplota a změněný pocatecni tlak (podtlak a přetlak). Problematiku stanoveni výbuchových parametrů řesi řada norem CSN EN 14 034 – Stanoveni výbuchových charakteristik rozviřeneho prachu. Postupy vychazejici z těchto norem definuji proceduru, jak postupovat při stanoveni výbuchových charakteristik rozviřeneho prachu při standardnich laboratornich podminkach (pocatecni teplota ti = 20°C a pocatecni tlak pi = 1 bar). V praxi se vsak hořlavý prach může vyskytovat v prostředi, ktere neodpovida standardnim laboratornim podminkam. Může se jednat o zvýsenou teplotu např. při susicich ci jiných technologických procesech nebo při změněných tlakových podminkach, ať už se jedna a snižený tlak (podtla...

Research paper thumbnail of Vliv turbulence na výbuchové parametry

Diplomova prace se zabýva vlivem turbulence na maximalni výbuchove parametry vybraných hořlavých ... more Diplomova prace se zabýva vlivem turbulence na maximalni výbuchove parametry vybraných hořlavých prachů. Prvni kapitola obsahuje použite terminy a definice. Druha kapitola podava přehled o statistice výbuchů v CR a výbusich prachu v minulosti. Třeti kapitola představuje zakladni informace o teorii výbuchu. Ctvrta kapitola se věnuje turbulenci. Pata kapitola je zaměřena na připravu vzorků. V seste kapitole jsou uvedeny výsledky měřeni sitových analýz, sypných hustot, optimalnich koncentraci zvolených prachových vzorků a dale se věnuje urceni turbulence a vlivu turbulence na maximalni výbuchove parametry.

Research paper thumbnail of Porovnání právních předpisů z oblasti stavebního práva a požární ochrany

LEPIK, P.: Porovnani pravnich předpisů z oblasti stavebniho prava a požarni ochrany. Bakalařska p... more LEPIK, P.: Porovnani pravnich předpisů z oblasti stavebniho prava a požarni ochrany. Bakalařska prace. Ostrava: VSB – TU Ostrava, Fakulta bezpecnostniho inženýrstvi. 2009. 42 s.Bakalařska prace se zabýva porovnanim pravnich předpisů z oblasti stavebniho prava a požarni ochrany a vytipovani rozdilných přistupů. Hlavni cast prace je věnovana výkonu statniho požarniho dozoru a s tim souvisejicim povinnostem. Dale jsou uvedeny možnosti projektanta postupovat odlisně od postupu stanoveneho ceskou statni normou.

Research paper thumbnail of Experimental investigation of deflagration characteristics for venting of gas explosion and their verification of CFD analysis

Α set of 44 experiments on vented methane-air mixture explosions with various concentration value... more Α set of 44 experiments on vented methane-air mixture explosions with various concentration values was executed. In terms of experiments, concentration of explosive mixture was changed in the range from lower explosive limit (LEL) to upper explosive limit (UEL). Measurements were carried out in the compact enclosure with a volume of 250 dm 3 at ambient conditions. Together with experiments, modelling of these processes was carried out by the codes based on computer fluid dynamic (CFD) using numerical tool FLACS (Flame Acceleration Simulator). Results of experiments and CFD models are analysed and compared to each other putting the accent on the compliance of calculated pressure-time curves and experimental pressure traces.

Research paper thumbnail of Influence of the Pyrotechnic Igniter Composition Aging on Explosion Parameters of Dispersed Dusts

Applied Sciences, 2021

A commercially available pyrotechnic igniter was used according to the EN 14034 and ASTM E1226a S... more A commercially available pyrotechnic igniter was used according to the EN 14034 and ASTM E1226a Standards to study the explosiveness of dispersed dusts. Its pyrotechnic composition consists of 1.2 g of zirconium (40% wt.), barium peroxide (30% wt.) and barium nitrate (30% wt.). The energy released during the combustion of that amount of composition is 5 kJ. The article investigates the influence of aging of the pyrotechnic composition in the igniter on its initiation parameters. In the study, igniters of different years from date of manufacture were used: Igniter 1, manufactured in 2021 (less than 1 year from date of manufacture), and Igniter 2 (more than 2 years from date of manufacture). The study was performed in the KV 150M2 explosion chamber with a volume of 365 L and the 20 L sphere chamber with a volume of 20 L. A standard sample of Lycopodium clavatum was used in the KV 150M2 explosion chamber. Magnesium and benzoic acid were used as the samples in the 20 L sphere explosion ...

Research paper thumbnail of Phytotoxicological Tests - Applications of Foils Based on Graphene (Graphene Oxide)

TRANSACTIONS of the VŠB – Technical University of Ostrava, Safety Engineering Series, 2016

This paper discusses the problematics of phytotoxicity of chemicals. It mainly focuses on the phy... more This paper discusses the problematics of phytotoxicity of chemicals. It mainly focuses on the phytotoxicity of nanomaterials made of graphene. It describes phytotoxicological tests performed with foils from materials belonging to the graphene family. It also describes testing the influence of plants on these films. Furthermore, the paper discusses the issues of mutual influence between plants and tested nanomaterials.

Research paper thumbnail of Determination Of The Minimum Ignition Energy On Different Devices

TRANSACTIONS of the VŠB – Technical University of Ostrava, Safety Engineering Series, 2015

This article focuses on determination of the minimum ignition energy of dust. For the measurement... more This article focuses on determination of the minimum ignition energy of dust. For the measurement of the minimum ignition energy of dust are available device from different manufacturers. In this article, the comparison device from three manufacturers - Chilworth, Kühner and Anko are executed. For the experimental measurement of the minimum minimum ignition energy was chosen 5 dust samples so that they are represented sample of organic dust, synthetic organic dust and coal dust. The article briefly introduces each apparatus for determining the minimum ignition energy and there is a comparison of the results obtained with individual devices. Finally, it is an assessment the results obtained and used test equipment.

Research paper thumbnail of Experimental determination of deflagration explosion characteristics of methane–air mixture and their verification by advanced numerical simulation

WIT Transactions on The Built Environment, 2012

Venting is a widely applied method to protect buildings and technological equipment from effects ... more Venting is a widely applied method to protect buildings and technological equipment from effects of internal explosion. The key problem in venting is the adequate design of vent area and an effective material of venting element. Α set of 76 experiments on partly confined methane-air mixture explosions with various parameters was processed. In terms of experiments, vent areas and venting elements with variable values of static activation pressure were changed. During measurements, certain items were determined at steady stoichiometric mixture concentration and atmospheric conditions: reduced explosion pressures, rates of reduced explosion pressures rise, temperatures, flame lengths and deformations of experimental equipment enclosure. Together with experiments, modelling of these processes was carried out by the codes based on computer fluid dynamic (CFD) using numerical tool FLACS (Flame Acceleration Simulator). Results of experiments and CFD models are analysed and compared to each other.

Research paper thumbnail of Effect of temperature on the concentration explosion limits of combustible liquids

Safety and Security Engineering V, 2013

The contribution is focused on the theoretical calculations of the influence of the temperature o... more The contribution is focused on the theoretical calculations of the influence of the temperature on the concentration explosive limits of flammable liquids using empirical formulas. The first part of the paper is concerned with the theoretical basis of computation according to empirical formulas. The other part deals with experimental verification of the theoretical assumption of the calculation of the influence of the temperature on the concentration explosive limits of flammable liquids.

Research paper thumbnail of Explosion limits of industrial spirit and their affecting by temperature

Process Safety Progress, 2014

The article deals with the determination of industrial spirit's explosion limits and their af... more The article deals with the determination of industrial spirit's explosion limits and their affecting by temperature. It describes the determination of explosion limits and the influence of temperature by correlation equations available in professional literature, as well as the validation of these data by means of experiments in explosion autoclave and explosion chamber. © 2014 American Institute of Chemical Engineers Process Saf Prog 33: 380–384, 2014

Research paper thumbnail of Experimental investigation of consequences of LPG vehicle tank failure under fire conditions

Journal of Loss Prevention in the Process Industries, 2018

In case of a vehicle fire, an installed LPG (liquefied petroleum gas) tank with a malfunctioning ... more In case of a vehicle fire, an installed LPG (liquefied petroleum gas) tank with a malfunctioning safety device poses severe hazards. To investigate the consequences in case of tank failure, we conducted 16 tests with toroidal shaped LPG vehicle tanks. Three tanks were used for a Hydraulic Burst Test under standard conditions. Another three tanks were equipped with a statutory safety device and were subjected to a gasoline pool fire. The safety device prevented tank failure, as intended. To generate a statistically valid dataset on tank failure, ten tanks without safety devices were exposed to a gasoline pool fire. Five tanks were filled to a level of 20%; the remaining five were filled to a level of 100%. In order to gain information on the heating process, three temperature readings at the tank surface, and three nearby flame temperatures were recorded. At distances of l = (7; 9; 11) m to the tank, the overpressure of the shock wave induced by the tank failure and the unsteady temperatures were measured. All ten tanks failed within a time of t < 5 min in a BLEVE (boiling liquid expanding vapor explosion). Seven of these resulted directly in a catastrophic failure. The other three resulted in partial failure followed by catastrophic failure. A near field overpressure at a distance of l = 7 m of up to p = 0.27 bar was measured. All ten tests showed massive fragmentation of the tank mantle. In total, 50 fragments were found. These 50 fragments make-up 88.6% of the original tank mass. Each fragment was georeferenced and weighed. Fragment throwing distances of l > 250 m occurred. For the tanks with a fill level of 20%, the average number of fragments was twice as high as it was for the tanks that were filled completely.

Research paper thumbnail of Exfoliation Processes of Graphites

Příspěvek popisuje možné chemicko-mechanické cesty (mletí v kulovém mlýně, sonikace, mikrovlné zá... more Příspěvek popisuje možné chemicko-mechanické cesty (mletí v kulovém mlýně, sonikace, mikrovlné záření) exfoliace grafitu s cílem získat nanografen. Jsou uvedeny příklady morfologie a základní chemické analýzy produktů pomocí FTIR a schéma předpokládané exfoliace grafi tu působením sil při kulovém mletí. Dále byla u námi vyrobených produktů provedena termická analýza pomocí TGA a DSC křivek.The paper describes the possible chemical-mechanical ways (ball milling, sonication and microwave radiation) exfoliation of graphite to obtain nanographene. The examples of product morphology are presented and basic chemical analysis of the products by FTIR is given as well. This contribution introduces predicted diagram of exfoliation of graphite created by interaction of forces during a process of ball milling. Finally a thermal analysis of our manufactured products was made by using TGA and DSC curves

Research paper thumbnail of Uncontrolled and Controlled Destruction of Acetylene Pressure Cylinders

Applied Sciences

The risk of physical destruction of a pressure cylinder increases with increasing temperature loa... more The risk of physical destruction of a pressure cylinder increases with increasing temperature load. Acetylene is a significant hazardous gas in cylinders. If the destruction pressure is reached, the cylinder is torn into two or more pieces, followed by the gas release to the environment. The presence of ignition sources could lead to the formation of the fireball phenomenon. This phenomenon generally reaches approximately ten meters in diameter and can be accompanied by a blast wave and a spread of the cylinder’s fragments or surrounding objects. The consequences of this type of fire could be fatal. Shooting through the cylinder shell may lead to the mitigation, if not elimination, of the effects of the uncontrolled destruction mentioned above. As a result of the review of relevant publications, several states commonly use this method as a standard procedure. Internal gas is released through the resulting hole, the pressure drops down and the gas creates a fire jet or disperses to s...

Research paper thumbnail of The Verifi cation Process of Agitation of Wheat Flour on the Explosion Autoclave VA - 250

Článek se zabývá ověřením podmínek rozvíření pšeničné mouky ve výbuchovém autoklávu VA - 250. V p... more Článek se zabývá ověřením podmínek rozvíření pšeničné mouky ve výbuchovém autoklávu VA - 250. V práci je proveden rozbor rozviřovacích kuželů a s tím související podmínky rozviřování spolu s popisem zkušebního zařízení, kterým je výbuchový autokláv VA - 250. Dále jsou v práci uvedené výsledky získané měřením maximálních výbuchových parametrů pšeničné mouky, na kterém je ověřeno nastavení rozviřovacího kužele.The article deals with the verifi cation conditions in the agitation of wheat fl our explosion autoclave VA - 250. This work analyzed swirl cones and related conditions swirl along with a description of test equipment, which is the explosion autoclave VA - 250. Further, there are the results obtained by measuring the maximum explosion parameters of wheat fl our, which is verified at set swirl cone

Research paper thumbnail of Comparison of Normative Requirements for Determination of the Minimum Ignition Energy of Combustible Dusts

Citlivost hořlavých prachů k iniciaci elektrickou jiskrou je charakterizována hodnotou minimální ... more Citlivost hořlavých prachů k iniciaci elektrickou jiskrou je charakterizována hodnotou minimální iniciační energie (MIE). Hodnota MIE je důležitou požárně-technickou charakteristikou prachu, na základě které je možné navrhnout vhodná bezpečnostní opatření. V České republice jsou platné dvě normy zabývající se stanovením MIE prachů, a to ČSN IEC 1241-2-3 a ČSN EN 13821, které se vzájemně liší. K měření MIE mohou být použita různá zkušební zařízení splňující podmínky příslušné normy. Příspěvek je zaměřen na srovnání těchto postupů a na popis zařízení, které se v praxi pro stanovení MIE hořlavých prachů používají.The sensitivity of combustible dusts to be ignited by electrical spark is characterized by value of minimum ignition energy (MIE). The value of MIE is an important fi re-technical characteristic of dust according to which it is possible to optimise measures for explosion prevention. In the Czech Republic, there are two different valid standards dealing with MIE of dust determi...

Research paper thumbnail of Procesy exfoliace grafitů

Sdružení požárního a bezpečnostního inženýrství, 2017

Research paper thumbnail of The Resistance of Surface Coatings Exposed to Thermal Load

Proceedings of the 29th European Safety and Reliability Conference (ESREL), 2019

Research paper thumbnail of Inert Substances and Explosion Limits of Hybrid Mixtures

Chemical Engineering Transactions, 2013

Problems of formation of hybrid mixtures are a rather neglected hazard to the manufacturing proce... more Problems of formation of hybrid mixtures are a rather neglected hazard to the manufacturing process. With the origin of such mixtures a necessity of minimizing possible risks that may accompany the formation of hybrid mixtures is connected as well. The article focuses especially on problems of possible inerting of hybrid mixtures.

Research paper thumbnail of Study of Influence of Combustible Gas on Explosion Parameters of Black Coal Dust

Chemical Engineering Transactions, 2012

The article focuses on the matters of explosion parameters of coal dusts and the effect of the ad... more The article focuses on the matters of explosion parameters of coal dusts and the effect of the addition of small amount of combustible gas methane on them. This work presents laboratory tests of the influence of the addition of various amount of methane to the mixture of coal dust with air and its effect on maximum pressure and maximum rate of pressure rise.

Research paper thumbnail of Development of Special Explosive Charges for the Reconstruction of Unstable Damaged Buildings

WIT Transactions on The Built Environment, 2017

Buildings or properties seriously damaged due to detonation of explosives, gas explosions, techno... more Buildings or properties seriously damaged due to detonation of explosives, gas explosions, technological accidents, and other emergency's threaten their surroundings with their instability. Their damage is usually so significant that no repair or reconstruction is ever considered, demolition is inevitable. In such hazardous situations, use of special charges could be the possible solution for a safe disposal of damaged and statically unstable structures. Use of this emergency pyrotechnic instrument could eliminate or considerably reduce the possibility of health hazards of intervening people, rescue equipment and surrounding properties during the disposal process of extremely damaged buildings in a very short time, mainly in neighbourhoods. A System of special sequentially timed charges use the increase of efficiency of external charges and cover with water-bags together with the increase of efficiency of the whole system due to their timing. Developed charges increase the operability and safety of rescue units of IRS (Integrated Rescue System).

Research paper thumbnail of Vliv počáteční teploty a tlaku na výbuchové parametry prachovzdušných směsí

Disertacni prace se zabýva problematikou stanoveni výbuchových parametrů (dolni meze výbusnosti, ... more Disertacni prace se zabýva problematikou stanoveni výbuchových parametrů (dolni meze výbusnosti, maximalniho výbuchoveho tlaku a maximalni rychlosti narůstu výbuchoveho tlaku) prachovzdusných směsi při nestandardnich pocatecnich podminkach, kterými jsou v ramci teto prace mysleny zvýsena pocatecni teplota a změněný pocatecni tlak (podtlak a přetlak). Problematiku stanoveni výbuchových parametrů řesi řada norem CSN EN 14 034 – Stanoveni výbuchových charakteristik rozviřeneho prachu. Postupy vychazejici z těchto norem definuji proceduru, jak postupovat při stanoveni výbuchových charakteristik rozviřeneho prachu při standardnich laboratornich podminkach (pocatecni teplota ti = 20°C a pocatecni tlak pi = 1 bar). V praxi se vsak hořlavý prach může vyskytovat v prostředi, ktere neodpovida standardnim laboratornim podminkam. Může se jednat o zvýsenou teplotu např. při susicich ci jiných technologických procesech nebo při změněných tlakových podminkach, ať už se jedna a snižený tlak (podtla...

Research paper thumbnail of Vliv turbulence na výbuchové parametry

Diplomova prace se zabýva vlivem turbulence na maximalni výbuchove parametry vybraných hořlavých ... more Diplomova prace se zabýva vlivem turbulence na maximalni výbuchove parametry vybraných hořlavých prachů. Prvni kapitola obsahuje použite terminy a definice. Druha kapitola podava přehled o statistice výbuchů v CR a výbusich prachu v minulosti. Třeti kapitola představuje zakladni informace o teorii výbuchu. Ctvrta kapitola se věnuje turbulenci. Pata kapitola je zaměřena na připravu vzorků. V seste kapitole jsou uvedeny výsledky měřeni sitových analýz, sypných hustot, optimalnich koncentraci zvolených prachových vzorků a dale se věnuje urceni turbulence a vlivu turbulence na maximalni výbuchove parametry.

Research paper thumbnail of Porovnání právních předpisů z oblasti stavebního práva a požární ochrany

LEPIK, P.: Porovnani pravnich předpisů z oblasti stavebniho prava a požarni ochrany. Bakalařska p... more LEPIK, P.: Porovnani pravnich předpisů z oblasti stavebniho prava a požarni ochrany. Bakalařska prace. Ostrava: VSB – TU Ostrava, Fakulta bezpecnostniho inženýrstvi. 2009. 42 s.Bakalařska prace se zabýva porovnanim pravnich předpisů z oblasti stavebniho prava a požarni ochrany a vytipovani rozdilných přistupů. Hlavni cast prace je věnovana výkonu statniho požarniho dozoru a s tim souvisejicim povinnostem. Dale jsou uvedeny možnosti projektanta postupovat odlisně od postupu stanoveneho ceskou statni normou.

Research paper thumbnail of Experimental investigation of deflagration characteristics for venting of gas explosion and their verification of CFD analysis

Α set of 44 experiments on vented methane-air mixture explosions with various concentration value... more Α set of 44 experiments on vented methane-air mixture explosions with various concentration values was executed. In terms of experiments, concentration of explosive mixture was changed in the range from lower explosive limit (LEL) to upper explosive limit (UEL). Measurements were carried out in the compact enclosure with a volume of 250 dm 3 at ambient conditions. Together with experiments, modelling of these processes was carried out by the codes based on computer fluid dynamic (CFD) using numerical tool FLACS (Flame Acceleration Simulator). Results of experiments and CFD models are analysed and compared to each other putting the accent on the compliance of calculated pressure-time curves and experimental pressure traces.

Research paper thumbnail of Influence of the Pyrotechnic Igniter Composition Aging on Explosion Parameters of Dispersed Dusts

Applied Sciences, 2021

A commercially available pyrotechnic igniter was used according to the EN 14034 and ASTM E1226a S... more A commercially available pyrotechnic igniter was used according to the EN 14034 and ASTM E1226a Standards to study the explosiveness of dispersed dusts. Its pyrotechnic composition consists of 1.2 g of zirconium (40% wt.), barium peroxide (30% wt.) and barium nitrate (30% wt.). The energy released during the combustion of that amount of composition is 5 kJ. The article investigates the influence of aging of the pyrotechnic composition in the igniter on its initiation parameters. In the study, igniters of different years from date of manufacture were used: Igniter 1, manufactured in 2021 (less than 1 year from date of manufacture), and Igniter 2 (more than 2 years from date of manufacture). The study was performed in the KV 150M2 explosion chamber with a volume of 365 L and the 20 L sphere chamber with a volume of 20 L. A standard sample of Lycopodium clavatum was used in the KV 150M2 explosion chamber. Magnesium and benzoic acid were used as the samples in the 20 L sphere explosion ...

Research paper thumbnail of Phytotoxicological Tests - Applications of Foils Based on Graphene (Graphene Oxide)

TRANSACTIONS of the VŠB – Technical University of Ostrava, Safety Engineering Series, 2016

This paper discusses the problematics of phytotoxicity of chemicals. It mainly focuses on the phy... more This paper discusses the problematics of phytotoxicity of chemicals. It mainly focuses on the phytotoxicity of nanomaterials made of graphene. It describes phytotoxicological tests performed with foils from materials belonging to the graphene family. It also describes testing the influence of plants on these films. Furthermore, the paper discusses the issues of mutual influence between plants and tested nanomaterials.

Research paper thumbnail of Determination Of The Minimum Ignition Energy On Different Devices

TRANSACTIONS of the VŠB – Technical University of Ostrava, Safety Engineering Series, 2015

This article focuses on determination of the minimum ignition energy of dust. For the measurement... more This article focuses on determination of the minimum ignition energy of dust. For the measurement of the minimum ignition energy of dust are available device from different manufacturers. In this article, the comparison device from three manufacturers - Chilworth, Kühner and Anko are executed. For the experimental measurement of the minimum minimum ignition energy was chosen 5 dust samples so that they are represented sample of organic dust, synthetic organic dust and coal dust. The article briefly introduces each apparatus for determining the minimum ignition energy and there is a comparison of the results obtained with individual devices. Finally, it is an assessment the results obtained and used test equipment.

Research paper thumbnail of Experimental determination of deflagration explosion characteristics of methane–air mixture and their verification by advanced numerical simulation

WIT Transactions on The Built Environment, 2012

Venting is a widely applied method to protect buildings and technological equipment from effects ... more Venting is a widely applied method to protect buildings and technological equipment from effects of internal explosion. The key problem in venting is the adequate design of vent area and an effective material of venting element. Α set of 76 experiments on partly confined methane-air mixture explosions with various parameters was processed. In terms of experiments, vent areas and venting elements with variable values of static activation pressure were changed. During measurements, certain items were determined at steady stoichiometric mixture concentration and atmospheric conditions: reduced explosion pressures, rates of reduced explosion pressures rise, temperatures, flame lengths and deformations of experimental equipment enclosure. Together with experiments, modelling of these processes was carried out by the codes based on computer fluid dynamic (CFD) using numerical tool FLACS (Flame Acceleration Simulator). Results of experiments and CFD models are analysed and compared to each other.

Research paper thumbnail of Effect of temperature on the concentration explosion limits of combustible liquids

Safety and Security Engineering V, 2013

The contribution is focused on the theoretical calculations of the influence of the temperature o... more The contribution is focused on the theoretical calculations of the influence of the temperature on the concentration explosive limits of flammable liquids using empirical formulas. The first part of the paper is concerned with the theoretical basis of computation according to empirical formulas. The other part deals with experimental verification of the theoretical assumption of the calculation of the influence of the temperature on the concentration explosive limits of flammable liquids.

Research paper thumbnail of Explosion limits of industrial spirit and their affecting by temperature

Process Safety Progress, 2014

The article deals with the determination of industrial spirit's explosion limits and their af... more The article deals with the determination of industrial spirit's explosion limits and their affecting by temperature. It describes the determination of explosion limits and the influence of temperature by correlation equations available in professional literature, as well as the validation of these data by means of experiments in explosion autoclave and explosion chamber. © 2014 American Institute of Chemical Engineers Process Saf Prog 33: 380–384, 2014