Hazardous Area Classification Research Articles

Applying Hazardous Area Classification in Laboratories

Applying Hazardous Area Classification in Laboratories

Hazardous area classification for in flammable liquid storage tanks

Many chemical plants use flammable liquids as raw materials or produce flammable liquids. In both cases, the flammable medium will most likely need to be stored. One option is to use storage tanks. Currently, in Hungary, the fire and explosion protection requirements for upright cylindrical steeltanks are laid down in MSZ 9910-2:1993 and for horizontal cylindrical steeltanks in MSZ 9909-3:1998, supplemented by the MSZ 15633 series of standards. These standards have not changed in the last 30 years and have not followed the innovations in the field, unlike NFPA 497:2021; NFPA 59A:2023; API RP 505:2018; Area Classification Code for Installations Handling Flammable Fluids Part 15:2005 (IP 15); Health and Safety Executive (HSE) HSG 176 Storage of flammable liquid in tanks, 2nd edition:2015 and EIC 60079-10-1:2008. The aim of this study is to compare the conclusions of these standards and to propose a new standard that could be applied in Hungary.

Hazardous Area Classification in Simultaneous Production and Drilling at Oil and Gas Platform

Hazardous area, three-dimensional space, in which a flammable/explosive atmosphere is or may be expected to be present in quantity, requiring ignition source controls to manage safety risks, such as fires and explosions. Fire and explosion can result in catastrophic consequences for people and property, causing loss of life or severe injury and possible loss of business. Hazardous Area Classification is a method of analyzing and classifying the environment where explosive gas atmospheres may occur. The primary purpose of this classification is to facilitate the proper selection and installation of the apparatus to be used safely in that environment, considering the properties of the flammable materials that will be present. The method used is the point source approach, where equipment with variabilities of temperature, pressure, equipment, and the degree and type of ventilation that would take place on release may vary significantly, making individual assessment necessary. This study discusses the extent of the hazardous area due to an explosive atmosphere in Simultaneous Production and Drilling mode. It classifies the identified hazardous area based on frequency and likelihood of flammable release or ignitable cloud expected to be present. Using this information, ignition of flammable release or explosive gas cloud suspension in the air, which inevitably occurs in a Simultaneous Production and Drilling area handling flammable components, can be avoided.

Hazardous Area Classification Assessment at a Pharmaceutical Industry in East Jakarta

Introduction: Fire is a common risk in any industrial facility that uses combustible and flammable raw materials, products, or supporting materials. Among others, the pharmaceutical industry is exposed to such risk due to the application of flammable liquids including ethanol as a volatile solvent in production areas, which has the potential to form explosive atmospheres through evaporation from pools created by accidental releases. Therefore, this study aims to analyze the hazardous area classification (HAC) in ethanol storage areas to facilitate the execution of risk mitigation efforts for reducing the role of ignition sources that cause fire and explosion. Methods: The HAC assessment was carried out in December 2021 - January 2022 using the quantitative method outlined in the International Electrotechnical Commission (IEC) standard: IEC/EN 60079-10-1 for zone determination. During flash point analysis, the ASTM D-93 method was employed to define the class of ethanol as a flammable liquid. Results: The ethanol storage areas fell into the zone 2 category based on the secondary grade of release, as well as the areas’ ventilation effectiveness with a medium dilution, and fair ventilation availability. The extent of zone 2 is up to 3 m from the release source. Conclusion: Ignition sources capable of leading to fire and explosion incidents in ethanol storage areas should be controlled.

Finding a way through the “misty” evaluation of the flammability and explosivity of kerosene aerosols

• JetA1 mist flammability and explosivity are assessed in a confined explosion vessel. • Influence of initial conditions on explosion sensitivity and severity is studied. • JetA1 mists with a small droplet size have a higher rate of pressure rise. • The MIE of JetA1 mist may be lower than that of vapors at low temperatures. • The vapor/liquid ratio of a mist is a key parameter of its explosion severity. In the context of assessing hydrocarbon mist ignition sensitivity and explosion severity, an original test method is proposed, focusing on kerosene JetA1 mists but is applicable to other hydrocarbons. Experiments were carried out in a modified apparatus based on the 20L explosion sphere. Fine control of the gas/liquid ratio and flow rates, the mist concentration, and the ignition energy and duration, was ensured by a specifically customized control system guaranteeing the flexibility and compliance of the test apparatus. The droplet size distribution (DSD) and the level of turbulence of the JetA1 mist cloud were first determined by an in-situ laser diffraction sensor and by Particle Image Velocimetry, respectively. The lower explosive limit (LEL), the minimum ignition energy (MIE), the limiting oxygen concentration (LOC), the maximum explosion overpressure (P max ), and the maximum rate of pressure rise (dP/dt max ) were then determined for different mist concentrations, ambient temperatures, initial turbulence levels, energies, and DSD. Tests showed that the LEL mist of JetA1 mists of an average diameter of 8 µm is around 94 g/m 3 , a value which increases to 220 g/m 3 with increasing DSD. This value also tends to decrease considerably with increasing temperatures. Moreover, at a JetA1 concentration of 125 g/m 3 , P max and dP/dt max as high as 6 bar and 192 bar/s respectively were reached, the latter increasing to about 480 bar/s at T = 60 °C. These mists were shown to be ignitable using energies as low as 200 mJ, which is lower than that of vapors at low temperatures, and a limiting concentration of oxygen of 15.8 % v/v . The potential presence of hydrocarbon mist should therefore be an element that requires reconsidering the classification of hazardous areas. Finally, to stress the influence of the vapor-liquid ratio present in the cloud before ignition on the combustion kinetics, an evaporation model based on the d 2 -law was developed estimating the evaporation time and the vapor quantity at different initial temperatures or droplet diameters. Findings were shown to be well coherent allowing the proposition of a new technique for determining hydrocarbon mist safety criteria. Finally, results have shown that JetA1 mists can ignite at temperatures below the liquid’s flashpoint under varying turbulence levels and droplet size distributions.

Potential Ignition Sources and Protections in Electric Rotating Machines Operating in Explosive Gas Atmospheres

Electric rotating machines are the main prime movers to drive the necessary process equipment in the petroleum and chemical industries. Safety is a prime concern for personnel and processes. A breakdown can cause a loss of personnel and or revenue. As technology evolves, engineers continue to improve the design of these machines to be as safe as possible for the area in which they are selected for installation while also considering process criticality. This article will discuss the different potential ignition sources in electric rotating machines and how they are designed, manufactured and protected to mitigate the risk of fire/explosion. The applicable regulations/standards are discussed for the various protection techniques adopted for each hazardous area classification. A brief overview of installation practices is also discussed.

Hazardous area classification for wheat flour processing plant

Dust explosion possibly occurs in common unit operations such as mills, grinders, dryers, and other modes of transport. The basic element for the setting of hazardous zone types consist of identifies release sources, determination of classification region of hazardous area, overviewing the basic operation in wheat flour processing plant with their specification requirement and use of a suitable code or calculations to determine area scope. Therefore, this analysis can be more elaborate by classifying the hazardous area into several areas using the International Electro Technical Commission System for Certification to Standards Relating to Equipment for Use in Explosive Atmospheres standard. Thus, wheat flour processing plant area classification can be categorized according to three zones based on the quantity of an explosion into atmosphere and its release frequencies which are zones 20, zones 21, and zones 22. From the results, it can be summarized that zone 20 is almost inside or closer one with the main equipment located near the ignition source which could lead to dust explosion, whereas zone 21 and zone 22 comes after zone 20 which is a less hazardous area as compared to zone 20 areas.

Specific Process Conditions for Non-Hazardous Classification of Hydrogen Handling Facilities.

Hazardous area classification design is required to reduce the explosion risk in process plants. Among the international design guidelines, only IEC 60079-10-1 proposes a new type of zone, namely zone 2 NE, to prevent explosion hazards. We studied how to meet the zone 2 NE grade for a facility handling hydrogen gas, which is considered as most dangerous among explosive gases. Zone 2 NE can be achieved considering the grade of release, as well as the availability and effectiveness of ventilation, which are factors indicative of the facility condition and its surroundings. In the present study, we demonstrate that zone 2 NE can be achieved when the degree of ventilation is high by accessing temperature, pressure, and size of leak hole. The release characteristic can be derived by substituting the process condition of the hydrogen gas facility. The equations are summarized considering relation of the operating temperature, operating pressure, and size of leak hole. Through this relationship, the non-hazardous condition can be realized from the perspective of inherent safety by the combination of each parameter before the initial design of the hydrogen gas facility.

Risk assessment of workers' exposure to BTEX and hazardous area classification at gasoline stations.

Vaporization of benzene, toluene, ethylbenzene, and xylene (BTEX) compounds pollutes the air and causes health hazards at gasoline stations. This study revealed the risk of BTEX exposure according to the hazardous area classification at gasoline stations. The risk assessment of gasoline workers from a representative group of 47 stations, which followed the United States Environmental Protection Agency-IRIS method of assessing BTEX exposure, was expressed as the hazard index (HI). A result of matrix multipliers of the hazardous exposure index and fire possibility from flammable gas classified hazardous area-I and area-II at the fuel dispensers. BTEX concentrations were actively sampled in ambient air and a flammable gas detector was used to measure the flammability level. Results showed that the BTEX concentrations from ambient air monitoring were in the range of 0.1-136.9, 8.1-406.0, 0.8-24.1 and 0.4-105.5 ppb for benzene, toluene, ethylbenzene, and xylene, respectively, which exceeded the NIOSH exposure limit of 100 ppb of benzene concentration. The risk assessment indicated that five stations reached an unacceptable risk of worker exposure to BTEX (HI>1), which correlated with the numbers of gasoline dispensers and daily gasoline sold. The risk matrix classified hazardous area-I at 4 meters and hazardous area-II at 4-8 meters in radius around the fuel dispensers. This study revealed the hazardous areas at gasoline stations and suggests that entrepreneurs must strictly control the safety operation practice of workers, install vapor recovery systems on dispenser nozzles to control BTEX vaporization and keep the hazardous areas clear of fire ignition sources within an eight-meter radius of the dispensers.

A CFD-based empirical model for hazardous area extent prediction including wind effects

Hazardous extent predictions that ensure process safety while avoiding overestimation have been a challenge for hazardous area classification. Specific leak scenarios can be addressed to build rapid empirical models to accurately determine hazardous extent considering several factors that are not included in general approaches. In view of that, this work aims to propose a novel CFD-based empirical model for gas emissions in open and unobstructed areas. It considers a wide range of variables such as storage temperature and pressure, orifice diameter, molecular weight, gas concentration, and wind velocity. A sensitivity analysis was performed to evaluate each variable's contribution to the gas cloud extent. The linear regression model resulting from the combination of all variables contribution was coupled with Ewan and Moddie's model to minimize the prediction errors due to the non-monotonic wind effects. The suggested algorithm accurately calculates the hazardous extent with a coefficient of determination equals to 0.9842 and a RMSE of 0.0151 for a dataset of 600 cases of generic gases release. The proposed model was also validated for 60 cases of hydrogen releases under different storage conditions, giving a coefficient of determination equal to 0.9829 and a RMSE of 0.0680, indicating a good agreement with the data.

인화점 기반의 KS C IEC 60079-10-1:2015 표준의 인화성 액체 적용에 관한 연구

This paper is written to suggest the guideline for the flash point of flammable liquids when the KS C IEC 60079-10-1:2015 standard is applied for the hazardous area classification. Flammable liquid is defined as “liquid capable of producing a flammable vapour under any foreseeable operating conditions” in the KS C IEC 60079-10-1:2015 standard and an example of the flammable liquid is shown as the liquid that is handled at temperatures close to or above its flash point. Therefore the relationship between flash points and flammable liquids is not clear. Occupational safety and health act in Korea, Ministry of Employment and Labor notification(No. 1993-19), NFPA 497, API RP 505 and EI 15 are reviewed to compare the flash points for the application of the hazardous area classification and the guideline for flash points is suggested.

폭발위험장소 설정 시 인화성액체 누출률의 최적 산정방법 연구

In order to determine the extent to which explosion-proof devices should be used in case of leakage in industrial sites handling flammable gases and flammable liquids, the calculation for classification of hazardous area should be carried out. At this time, the Korean Industrial Standard KS C 60079-10-1 citing IEC 60079-10-1, which is an international standard applied, is widely used. However, since the proposed liquid release rate equation does not clearly suggest a method of calculating the amount of vaporized, the calculation process is complicated, or excessive or insufficient results are induced. In order to improve this point, we propose an optimal liquid release rate calculation method, simplify the calculation process, and propose a practical and reasonable method.

On the non-monotonic wind influence on flammable gas cloud from CFD simulations for hazardous area classification

Hazardous areas are defined as a result of a variety of variables as storage temperature, pressure, leak orifice size, physical properties of flammable substance, and wind characteristics. The potential formation of an explosive atmosphere must be accurately assessed to ensure process safety. Therefore, computational fluid dynamics (CFD) arises as an important tool for accurate predictions as recommended by the international standard IEC 60079-10-1 (2015). This study aims to analyze the influence of wind velocity magnitude and direction on the hazardous area classification. The authors evaluated the extent and volume for methane, propane, and hydrogen leakages from a CFD model. For each flammable gas, the wind velocity magnitude and direction were regularly varied. The outcomes show that the behavior of the plume size as the wind varies mainly depends on the gas concentration. Counter-flow wind directions lead to zero relative velocity closer to the release point, which concentrates the gas, and wind in the release direction promotes a higher dilution of the gas cloud increasing the hazardous extent while decreases the volume. As a consequence, the wind also influences the zone type, which was accurately predicted from CFD simulations and significant differences were found when compared to the standard analyses. These differences are, to some extent, related to the consideration of wind velocity effects on the gas jet release.

Using unmanned aerial vehicles and robotics in hazardous locations safely

AbstractConfined space entries and elevated work are two of the most hazardous practices in the chemical industry. As part of its breakthrough Manufacturing 4.0 initiative, The Dow Chemical Company has been employing devices such as unmanned aerial vehicles (UAVs or “drones”) and robots to eliminate the need for employees to enter confined spaces or conduct elevated work, while allowing effective, remote inspections. Since piloting the use of UAVs and robots in 2016 at Dow, over 1000 confined space entries have been avoided. UAVs are being used to inspect distillation columns, flares, transmission towers, and pipelines—avoiding the need for over 2200 elevated work inspections by humans. Robotic miniature submarines are also being used to allow remote sensing for underwater inspections. The role of UAVs and robots in safety is continuing to expand beyond gathering visual data; robots are now equipped with sophisticated tools for gathering samples and nondestructive data, enhancing the ability to monitor environmental performance and ensure mechanical integrity. They are also being used to perform functions such as dismantling and removing internal equipment, cutting/sawing, hydroblasting, vacuuming sludge, and performing vessel wall/pipe thickness, ultraviolet, gauss (magnetic), and infrared scans. The benefits of UAVs and robots in reducing human risk, enhancing data collection, and improving productivity are quite clear; however, the hazards of these technologies need to be carefully evaluated to ensure that the devices can be used safely in specific applications. UAVs can present collision hazards, and a poorly chosen flight path could result in human injury, significant damage to process equipment, or the loss of the UAV. During internal equipment inspections, UAVs and robots can be made of incompatible materials of construction that could contaminate or damage the equipment being inspected or the UAV or robot itself. Also, during internal inspections, UAVs and robots can become disabled or lose power inside of the equipment, requiring emergency extrication. Another key consideration is hazardous area classification (HAC). UAVs and robots are energized devices that could potentially present ignition sources to flammable materials and combustible dusts, so consideration of the HAC of the work area (internal and external to the equipment)—as well as the certification of the robotic equipment for the specific application—is vital when employing these technologies. Manufacturing 4.0 provides a compelling vision of safer production operations. The use of UAVs and robots can significantly reduce human exposure to process and personal hazards. However, to capitalize on this potential, it is critical that organizations employing these technologies perform thorough hazard analyses, supply adequate guidance, and provide tools that can be leveraged at the site level to facilitate the development of safe work plans for specific applications. This article discusses potential hazards that should be considered when evaluating the suitability of a UAV or robot for a particular application and provides guidance on leveraging hazard recognition tools and training to the site level.

폭발위험장소 선정 시 풍속 변화에 관한 연구

폭발위험장소 선정 시 풍속 변화에 관한 연구

폭발위험장소 선정 시 풍속 변화에 관한 연구

폭발위험장소 선정 시 풍속 변화에 관한 연구

CFD simulation of flashing jet applied to area classification

AbstractIndustrially flammable gases are stored and transported in the form of pressurized liquid. The occurrence of leaks from pressurized flammable liquids in vessels or pipes may cause a two‐phase release, containing a mixture of liquid droplets and vapour of flammable substances. This phenomenon, called flashing, occurs when a superheated liquid comes into a lower pressure environment. The study and understanding of this type of release are of fundamental importance for the hazardous area classification that is addressed by the IEC 60079‐10‐1 standard, which recommends the use of computational fluid dynamics (CFD) for the calculation of a hazardous area. This work uses CFD to predict the hazardous area extent and volume that resulted from the complex two‐phase release, which had not been addressed previously in other literature. The influence of wind and release conditions on the area classification is analyzed. The CFD results agree with the available experimental data. A new parameter as a function of the volume and extent of the jet is proposed for hazardous area classification.

A Methodological Approach for the Characterization of Hazardous Zones due to Potentially Explosive Atmospheres: a Case Study

The biogas role is becoming crucial in the panorama of sustainable development. In fact, Countries of the European Union have agreed on a new 2030 Framework for climate and energy, which includes targets aimed at achieving a more competitive, secure and sustainable energy system. A specific target has established that at least a 27% share of renewable energy consumption must be achieved. Biogas sector is quickly developed in Italy, which is the second biogas producer in Europe, after Germany, and by the end of 2017 about 1,900 plants were operating. One of the main hazards, associated with the biogas production, is the formation of potentially explosive atmospheres (methane is present in biogas composition), deriving from accidental biofuel releases. Indeed, in the industrial plants there are several potential sources, such as valves, flanges, compressors, etc.. The paper illustrates a case study, referred to a biogas production plant. In particular, the paper describes a methodological approach aimed at classifying the places (zone 0 or zone 1 or zone 2 or non-hazardous zone), where potentially explosive atmospheres could occur, and characterizing explosive atmosphere geometry in terms of extent and volume. This topic plays a very important role in order to ensure a safer operation of the plants, because classification of hazardous areas allows to choose equipment and protective systems (according to Atex Directive 2014/34/EU) intended for use in potentially explosive atmospheres. The classification has been carried out in accordance with Atex Directive 99/92/EC, which states the minimum requirements for improving the safety and health protection of workers exposed to potentially explosive mixtures.

국내 폭발위험장소 선정 기준 주요 개정안 분석 및 한계점 보완 대책에 대한 연구

Hazardous area classification must be carried out to prevent explosion in the industry. In Korea, hazardous area classification is regulated as a legal requirement to translate international standard IEC 60079-10-1 edition 2.0. However, this standard had many changes compared to the previous version, IEC edition 1.0. Therefore, this study analyzed major amendments of IEC edition 2.0. IEC edition 2.0 did not provide a clear standard for selecting the type and radius of hazardous area. But this study proposed a conservative solution of the hazardous area classification design in IEC edition 2.0. However, this approach is not a perfect solution because excessive design margin is considered for a certain section. In addition, this study proposed a conversion factor that can convert the explosion radius designed with the existing IEC edition 1.0 into the release characteristic value of IEC edition 2.0. However, in the end, this solution also encountered the problem of interpreting the incomplete plot presented in IEC edition 2.0. Therefore, it is necessary to provide data for supplementing it at the national level and other international standard also should be permitted for reference.

국내 폭발위험장소 선정 기준 주요 개정안 분석 및 한계점 보완 대책에 대한 연구

국내 폭발위험장소 선정 기준 주요 개정안 분석 및 한계점 보완 대책에 대한 연구