Explosion protection - basics and terms
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ATEX
ATEX is an acronym for "Atmosphères Explosibles" and refers to two European directives that set the safety requirements for work environments where explosive atmospheres can occur. The ATEX directives are Directive 2014/34/EU (ATEX 114) for equipment and protective systems for use in potentially explosive atmospheres and Directive 1999/92/EC (ATEX 137) for occupational safety in potentially explosive atmospheres.
Potentially explosive areas arise when a mixture of combustible substances (e.g. gases, vapours, mists or dusts) is present in the air and under certain conditions can come into contact with an ignition source. In such environments there is a risk of explosion or fire.
The ATEX directives specify requirements for the design, production and labeling of equipment, protective systems and workplaces used in potentially explosive atmospheres. They are designed to ensure that these products and work environments meet strict safety standards to minimize the risk of explosion and fire and to ensure the safety of people, equipment and the environment.
The ATEX directives cover various aspects, including:
Devices and protective systems: The ATEX 114 directive regulates the design and certification of devices and protective systems used in potentially explosive atmospheres, such as electrical devices, switches, sensors, lighting devices, etc.
Occupational safety: The ATEX 137 guideline deals with the organization and occupational safety in potentially explosive atmospheres. It specifies requirements for risk assessments, explosion protection documents, training, labeling and other measures to ensure worker safety.
Compliance with the ATEX guidelines is mandatory for manufacturers, employers and operators in potentially explosive areas. You must ensure that the equipment and systems used comply with the appropriate ATEX requirements and that adequate safeguards are in place to ensure safety.
The certification of devices and systems according to ATEX is carried out by a Notified Body, which checks conformity with the requirements and issues the corresponding ATEX mark.
The ATEX directives apply in most European countries and help to create uniform safety standards for potentially explosive areas and to minimize the risks of explosions and fires.
Electrostatic charge
Electrostatic buildup refers to the accumulation of electrical charge on a surface or in a material due to the imbalance of electrons. It occurs when two materials come into contact or separate, and electrons are transferred in the process.
When two materials touch and are separated from each other, electron flow can occur between the materials. One material can lose electrons and become positively charged while the other material gains electrons and become negatively charged. This leads to an imbalance of electrical charges on the surfaces of the materials.
The electrostatic charge can also arise from friction between materials. When two materials are rubbed together, electrons can transfer from one material to the other, causing the surfaces to become charged.
Electrostatic charging can occur on both conductive and non-conductive materials. Conductive materials such as metals can easily spread electric charges across their surface, resulting in rapid discharge. On the other hand, non-conductive materials, such as plastics or textiles, can accumulate electrical charges on their surface and hold them for a longer period of time.
Electrostatic charge can have various effects. One of the best known is electrostatic discharge (ESD), in which charges are discharged in the form of a sudden flow of electricity. ESD can damage electronic components, especially in sensitive electronic devices.
Measures are taken in many areas to minimize the negative effects of electrostatic charging. This includes using dissipative materials, grounding equipment and equipment, using anti-static packaging materials, and training employees to deal with electrostatic hazards.
It is important to control static electricity in certain areas, such as electronics production or in explosive atmospheres, to avoid potential damage and ensure safety.
EX-proof lights
EX lights, also known as explosion-proof lights or ATEX lights, are specially designed lighting devices that have been developed for use in potentially explosive areas. They meet certain safety standards to minimize the risk of explosion or fire in environments where flammable gases, vapours, mists or dusts may be present.
The designation "EX" stands for "explosion protection" and refers to compliance with the ATEX directives (Atmosphères Explosibles) in Europe. These directives specify the requirements for equipment and protective systems used in potentially explosive atmospheres.
EX luminaires are divided into different categories according to the ATEX directives, depending on the type of explosion hazard and the zone in which they are to be used. These categories range from "Zone 0" (highest risk of explosion) to "Zone 2" (lower risk of explosion) for gaseous environments and from "Zone 20" (highest risk of explosion) to "Zone 22" (lower risk of explosion) for dusty environments.
EX lights must have specific safety features to ensure the explosion-proof property. This includes:
Housing: The housing of the EX lights is robust and resistant to external influences. It is designed to contain potential sparks or high temperatures inside the light.
Sealing: The EX luminaires are carefully sealed to prevent the ingress of explosive gases or dust.
Electrical components: The electrical components in the EX lights are designed in such a way that they do not generate any sparks and do not reach surface temperatures that could lead to the ignition of explosive atmospheres.
Marking: Each EX luminaire must be provided with the appropriate markings and certifications confirming its conformity with the applicable standards and directives.
EX luminaires are used in various industries where potentially explosive atmospheres can occur, such as in the chemical industry, in refineries, in the oil and gas industry, in mines, in paint shops and in many other areas. They play a crucial role in ensuring safety and lighting in these environments by minimizing the risk of explosions and fires.
Group classification
The ATEX group classification refers to the classification of potentially explosive substances into two main groups according to the ATEX directive. ATEX stands for "Atmosphères Explosibles", which indicates explosive atmospheres or explosive environments.
The two main groups of ATEX classification are:
Group I: This group relates to underground mining where pit working takes place. These are environments in which methane or other combustible dusts or gases can occur in quantities that can form an explosive atmosphere.
Group I contains the subcategories Ia, Ib and Ic, where Ia denotes the highest explosion hazard and Ic the lowest explosion hazard.
Group II: This group refers to all other industries except mining. It includes environments where flammable gases, vapours, mists or dusts may be present.
Group II is further subdivided into three categories: IIa, IIb and IIc, with IIa denoting the highest explosion hazard and IIc the lowest explosion hazard.
The classification into groups and categories is based on the likelihood of the presence of explosive atmospheres and the potential risk of ignition sources. It is important that equipment and protective systems used in these environments are certified and approved according to their classification to ensure safety.
The ATEX group classification is part of the European Union's ATEX directive, which specifies the requirements for equipment and protective systems used in potentially explosive atmospheres. This directive aims to minimize the risk of explosions and to ensure the safety of workers working in such environments.
Ignition point
The term "flash point" refers to the temperature at which a combustible substance can ignite. It is the lowest temperature at which there is sufficient vapor or gas of a substance to cause combustion or an explosion when combined with an ignition source.
Every combustible substance has a specific ignition point that depends on various factors including its chemical properties, composition, concentration and physical state (solid, liquid, gas). The ignition source can be an open flame, sparks, hot surfaces, electrical discharges or other heat sources.
There are different types of ignition points relevant to different applications and environments:
Flash Point: The temperature at which a flammable liquid produces sufficient vapor to form a flammable mixture with air. Upon reaching the flash point, vapors above the liquid can be ignited, but the liquid itself will not necessarily burn.
Ignition Temperature: The temperature at which a combustible substance in the gas phase is sufficiently heated to cause spontaneous self-ignition when an ignition source is present.
Flammable Limits: The concentration range of a combustible substance in air within which ignition is possible. Below the Lower Explosive Limit (LEL) the concentration is too low to support combustion and above the Upper Explosive Limit (UEL) the concentration is too high to sustain combustion.
Knowing the ignition point of a substance is critical to the safe handling of combustible materials. In potentially explosive atmospheres it is important to take measures to avoid or control sources of ignition and to keep the concentration of flammable substances within safe limits. This may include the use of explosion protection equipment, proper ventilation systems, wearing anti-static clothing, or the use of explosion-proof equipment.
Ignition source
An ignition source is a cause or event that can cause a combustible material to ignite or explode. It provides the energy or conditions to initiate the necessary reaction between the combustible material and an oxidizer (usually oxygen).
There are different types of ignition sources, which can vary depending on the environment and the specific properties of the combustible materials. Here are some examples of ignition sources:
Open Flames: An open flame, such as a candle, lighter, or welding torch, can be an ignition source if it comes in contact with a combustible material.
Sparks: Sparks can be generated by mechanical friction, electrical discharges, welding or static electricity. Sparks can have enough energy to ignite a flammable atmosphere.
Hot Surfaces: Hot surfaces such as heating elements, lightbulbs, or hot metal can provide sufficient thermal energy to cause ignition.
Electrical Discharge: High voltage discharges or electrical arcs can be an ignition source, particularly in environments with flammable gases or vapors.
Mechanical Sparks: Mechanical sparks can be generated by grinding, cutting, hammering, or other work on metal parts. These sparks can cause ignition in an environment with combustible dusts.
Electrostatic Discharges: Electrostatic charges created by friction between materials can cause a discharge and act as an ignition source.
It is important to identify, control and eliminate ignition sources in explosive atmospheres to minimize the risk of fire and explosion. This includes the use of explosion-proof devices and equipment, limiting ignition energy, implementing grounding and discharge systems, minimizing friction and sparking, and complying with safety guidelines and regulations.
IP degrees of protection
IP degrees of protection, also known as IP codes or IP classifications, indicate the extent to which electrical devices or housings are protected against the ingress of foreign objects such as dust, water and touch. The IP code consists of the letters "IP" followed by two digits, each of which indicates a specific protection level.
The first digit of the IP code indicates the degree of protection against ingress of solid objects, while the second digit indicates the degree of protection against ingress of moisture or water. Here are the meanings of the most common digits and their associated degrees of protection:
Protection against solid foreign bodies:
0: No special protection against contact or penetration of solid foreign bodies.
1: Protection against the ingress of solid foreign bodies with a diameter of 50 mm or more.
2: Protection against the ingress of solid foreign objects with a diameter of 12.5 mm or more.
3: Protection against the ingress of solid foreign objects with a diameter of 2.5 mm or more.
4: Protection against the ingress of solid foreign bodies with a diameter of 1 mm or more.
5: Protection against dust deposits in harmful quantities.
6: Dustproof protection.
Protection against moisture or water:
0: No special protection against moisture or water.
1: Protection against vertically falling drops.
2: Protection against falling drops up to 15° from vertical.
3: Protection against spray water up to 60° from the vertical.
4: Protection against splashing water from all directions.
5: Protection against water jets from all directions.
6: Protection against strong jets of water and against temporary immersion.
7: Protection against temporary immersion.
8: Protection against permanent immersion.
The IP protection classes are often used to determine the appropriate area of use for electrical devices indoors and outdoors, in industrial environments, in the field of building services and other applications. Depending on foreign object and moisture protection requirements, devices can be selected according to their IP rating to ensure they provide the protection required.
Pressurized enclosure
Pressurization is a method of explosion protection according to the ATEX (Atmosphères Explosibles) directives for electrical equipment and protective systems used in potentially explosive atmospheres. Its purpose is to create a safe environment around electrical equipment by controlling the potential for explosion within the enclosure.
In pressurization, the electrical equipment to be protected is placed in a housing or enclosure designed to isolate potentially explosive atmospheres from the electrical ignition source. A positive pressure is maintained inside the enclosure, which is higher than the atmospheric pressure outside the device. This prevents flammable gases, vapours, mist or dust from penetrating the housing.
The pressurization creates a barrier between the potential source of explosion inside the device and the explosive environment outside. When the unit is in operation, a controlled positive pressure is maintained to prevent ingress of hazardous materials. In the event of a potential malfunction or failure in the device, positive pressure is still maintained to prevent flammable substances from entering the device and causing an explosion.
The pressurized enclosure can be used in various industrial environments where there is a high risk of explosion, such as in the chemical industry, in refineries, in the oil and gas industry or in mines. The use of pressurized equipment requires careful design, monitoring and regular maintenance to ensure the integrity of the enclosure and ensure it meets applicable safety standards.
Temperature classes
Temperature classes in the context of ATEX refer to the classification of electrical equipment and protective systems in terms of their maximum allowable surface temperature. ATEX stands for "Atmosphères Explosibles" and refers to explosive atmospheres or explosive environments where flammable gases, vapours, mists or dusts may be present.
The temperature classes in ATEX are used in combination with the groups (group II for industrial applications) and the categories (e.g. II 2G for gaseous environments) to determine the suitability of electrical equipment for use in potentially explosive atmospheres.
The temperature classes in ATEX include the following categories:
T1: Maximum allowable surface temperature of 450°C.
T2: Maximum permissible surface temperature of 300°C.
T3: Maximum permissible surface temperature of 200°C.
T4: Maximum allowable surface temperature of 135°C.
T5: Maximum permissible surface temperature of 100°C.
T6: Maximum permissible surface temperature of 85°C.
The temperature classes indicate the temperature up to which the device or protective mechanism in question can be operated without reaching a dangerous temperature that could constitute a source of ignition. The classification of the temperature classes is based on specific tests and evaluations of the devices according to the ATEX standards and directives.
It is important to note that selection of the appropriate temperature rating is critical to minimizing the risk of ignition or explosion in hazardous environments. The devices must be designed and certified to meet the requirements of the relevant temperature class and meet the specified safety standards.
Type examination
The type examination is usually carried out by independent test centers or accredited laboratories. The tests are carried out using specified criteria and test methods, which may vary depending on the type of product and the relevant regulations.
Various aspects of the product are checked during the type examination, including its safety, performance, quality, reliability and conformity to the relevant technical specifications. For example, this may include physical testing, electrical testing, environmental testing, functional testing, safety testing, chemical analysis, or other specific testing.
The aim of type testing is to ensure that the tested sample meets the specified requirements and that these characteristics are transferrable to all manufactured examples of the product. If the sample successfully passes the tests, it is considered representative of the entire product batch and the product is given the appropriate certification or conformity marking.The type examination is particularly important in areas such as electrical engineering, mechanical engineering, medical technology, the automotive industry and many other branches of industry. It serves to ensure the safety, quality and reliability of products and to increase consumer confidence in the compliant and safe use of products.
Zone classification gas/dust
The zoning in terms of gas and dust environments is part of the ATEX (Atmosphères Explosibles) system and is used to classify potentially explosive atmospheres. This classification is based on the presence of flammable gases, vapours, mists or dusts and makes it possible to take appropriate protective measures to minimize the risk of explosion.
The zoning in gaseous environments is defined as follows:
Zone 0: A zone in which an explosive atmosphere consisting of a gas mixture is present continuously, for a long time or frequently. For example in tanks or containers.
Zone 1: A zone in which an explosive atmosphere of gaseous mixture is likely to occasionally exist under normal operating conditions. For example in the vicinity of leaks or during normal operational processes.
Zone 2: A zone in which an explosive atmosphere of gas mixtures does not normally exist under normal operating conditions and, if it does exist, only rarely and for a short time. For example, outside the immediate vicinity of leaks or in unusual operating conditions.
The zone classification in dusty environments is defined as follows:
Zone 20: A zone in which an explosive atmosphere in the form of a combustible dust mixture is present constantly, for long periods of time or frequently. For example in bulk material stores or mills.
Zone 21: A zone in which an explosive atmosphere in the form of a combustible dust mixture is likely to be present occasionally under normal operating conditions. For example in the vicinity of filling plants or lines.
Zone 22: A zone in which an explosive atmosphere in the form of a combustible dust mixture does not normally exist under normal operating conditions and, if it does exist, only rarely and for a short time. For example, outside the immediate vicinity of bottling plants or in unusual operating conditions.The zoning serves as a guide for the selection and installation of electrical devices, protective systems and equipment in hazardous areas. It helps to implement appropriate protective measures such as the use of explosion-proof devices, monitoring systems or isolation techniques to minimize the risk of explosions and ensure the safety of personnel and facilities.