Explosion Safety Wiki
What you should know.
- Why do explosions occur?
- Avoiding explosions
- Why is explosion safety so crucial?
- What are hazardous areas?
- EX zones for gas-explosive areas
- EX zones for areas with combustible dusts
- The 3 key features of a modern protection concept
- 3 steps to make your processes safer
- What is preventive explosion protection?
- What is flameless explosion venting?
- What is explosion isolation?
- What is explosion suppression?
The most severe explosion in Germany occurred in 1921 at BASF in Ludwigshafen. At that time 561 people died. The effects of explosions without protective systems therefore represent a significant hazard and appropriate measures and guidelines are required to keep the probability of occurrence and the extent of damage as low as possible.
Why do explosions occur?
When a combustible material, an ignition source and atmospheric oxygen collide in a confined space, the result is an explosion. Preventative explosion safety measures aim to stop this potentially lethal mixture from occurring. However, in practice, the vast number of potential ignition sources alone almost always makes this impossible. Consequently, the most important safety features for industrial companies are protection measures that minimise the damage caused by an explosion. Industrial plants must always be protected against the consequences of explosions to ensure that employees are safe and production can be resumed quickly. After all, every hour of lost production costs money. In most cases, explosion safety can be provided cost-effectively through explosion venting and explosion suppression.
The Explosion Pentagon:
The five requirements for a dust explosion.
The five requirements for a dust explosion.
Avoiding explosions
As part of a comprehensive and company-oriented risk assessment, suitable protective systems and measures that contribute to protection against explosions caused by hazardous substances as an ignition source must therefore be defined and implemented. Preventive explosion protection is about avoiding such a collision. However, due to the large number of possible ignition sources alone, this is almost always impossible in practice. That is why constructive explosion protection, which reduces the effects of an explosion, is the be-all and end-all for industrial companies in terms of safety. Industrial systems must always be protected from the consequences of an explosion in such a way that, even in the event of an incident, the safety of the employees and a rapid continuation of production are guaranteed are. Because: Every hour of lost production costs money. In most cases, explosion pressure relief and explosion suppression enable economical constructive explosion protection.
We would be happy to show you solutions tailored to your process, which limit the effects of an explosion to a harmless level and ensure that production can be resumed quickly after an explosion event.
We would be happy to show you solutions tailored to your process, which limit the effects of an explosion to a harmless level and ensure that production can be resumed quickly after an explosion event.
Why is explosion safety so crucial?
Higher – faster – further: not just the objective in sport but also in the development of industrial plant technology. 21st century machinery has long been optimised and is running at high speeds. However, as plants approach their maximum capacity, the risk of an explosion also increases. Rising levels of fine particles produced by fast-running machines are one of the main reasons that the probability of an explosion has increased – these explosions almost always cost human lives. Even if nobody is harmed, an explosion in an inadequately protected industrial plant can still cause immense structural and financial damage.
History shows that explosions in unprotected plants have driven companies to bankruptcy time and time again. After all, every day of lost production puts the company’s existence at risk. Explosion safety concepts usually enable businesses to eliminate production downtime entirely or at the very least reduce it dramatically – and with REMBE® products it is always more affordable than you think.
History shows that explosions in unprotected plants have driven companies to bankruptcy time and time again. After all, every day of lost production puts the company’s existence at risk. Explosion safety concepts usually enable businesses to eliminate production downtime entirely or at the very least reduce it dramatically – and with REMBE® products it is always more affordable than you think.
What are hazardous areas?
Areas in which there is a dangerous explosive atmosphere, i.e. explosive gas/vapour/mist/air mixtures or dust/air mixtures or hybrid mixtures of air and combustible substances can occur, are referred to as potentially explosive areas. They must be divided into zones. For gas-air mixtures, these are zones 0, 1 and 2, for dust-air mixtures zones 20, 21 and 22. The highest number in each case means that an explosive atmosphere does not normally occur or only occurs for a short time. However, it does not mean that these zones are less dangerous.
EX zones for gas-explosive areas
For gas-explosive areas there is a zone classification which defines 3 zones:
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Zone 0 is classified as an area in which there is a permanent or long-term presence of an explosive atmosphere consisting of a mixture of air and flammable substances in the form of gas, vapor or mist.
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Zone 1 is classified as an area where said reaction is likely to occur during normal operation.
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Zone 2 is classified as an area where said reaction is not expected to occur, and if it does occur, it is infrequent and temporary.
Source: Directive 2014/34/EU(ATEX)
EX zones for gas-explosive areas
Areas with combustible dust are also divided into 3 zones:
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Zone 20 contains areas in which an explosive atmosphere in the form of a cloud of combustible dust in the air is present continuously, for a long time or frequently.
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Zone 21 contains areas where this is only occasionally to be expected during normal operation.
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Zone 22 defines areas in which an explosive atmosphere in the form of a cloud of combustible dust in air is not to be expected during normal operation, but if it does occur, it is only for a short time.
Source: Directive 2014/34/EU(ATEX)
The 3 key features of a modern protection concept
1. Reliability and productivity
Protection systems must be permanently available and operational. The possibility of false triggers must be excluded as this reduces the productivity of the plant.
2. Compliance
Modern protection systems must satisfy all legal requirements and thus guarantee legal compliance for plant operators.
3. Cost-effectiveness
Protection systems must be as simple as possible to install and require minimum investment of time and financial resources. The running costs of the systems must also be kept as low as possible.
All protection concepts from REMBE® meet these requirements. That's a promise!
Protection systems must be permanently available and operational. The possibility of false triggers must be excluded as this reduces the productivity of the plant.
2. Compliance
Modern protection systems must satisfy all legal requirements and thus guarantee legal compliance for plant operators.
3. Cost-effectiveness
Protection systems must be as simple as possible to install and require minimum investment of time and financial resources. The running costs of the systems must also be kept as low as possible.
All protection concepts from REMBE® meet these requirements. That's a promise!
3 steps to make your processes safer
1. Risk assessment
A risk assessment determines the probability that an explosive mixture of dust and air (divided into zones) will come into contact with an effective ignition source. If there is a danger of an explosion occurring, you must take steps to prevent, or at least reduce the probability of this happening (see Step 2). Alternatively, you must implement a protection system that reduces the damage an explosion would cause to an acceptable level (see Step 3).
2. Prevention and organisational measures
Technical measures
Effective dust extraction systems prevent the build-up of an explosive atmosphere. Inert gas blanketing is also recommended to reduce oxygen levels.
Eliminate effective ignition sources
Only ever use the appropriate equipment (e.g. category 1D) and prevent foreign bodies from entering the product stream. Check that equipment is correctly grounded to avoid electrostatic discharges.
Organisational measures
Employees should always receive comprehensive training. Documented cleaning procedures and permit-to-work systems for hot-work create an additional level of safety.
Effective dust extraction systems prevent the build-up of an explosive atmosphere. Inert gas blanketing is also recommended to reduce oxygen levels.
Eliminate effective ignition sources
Only ever use the appropriate equipment (e.g. category 1D) and prevent foreign bodies from entering the product stream. Check that equipment is correctly grounded to avoid electrostatic discharges.
Organisational measures
Employees should always receive comprehensive training. Documented cleaning procedures and permit-to-work systems for hot-work create an additional level of safety.
3. Protective measures
Explosion pressure resistant or explosion proof vessels
These terms are used to describe vessels, which are strong enough to withstand the maximum explosion pressure.
Conventional explosion venting
Explosion venting is a technique for protecting enclosed vessels that prevents the pressure within the vessel from rising above a permitted level. Breaking points, such as explosion vents, in the walls of the plant, rupture when the pressure reaches a predefined level and thus reduce the pressure in the vessel below its strength.
Flameless explosion venting
This essentially uses the same principle as conventional explosion venting. However, it offers the advantage that the explosion can be vented indoors because the flame and pressure wave of the explosion are contained. This eliminates the risk of injury even when working in close proximity to the equipment.
Explosion suppression
Pressure and/or infrared sensors detect the explosion at a very early stage. Within a few milliseconds, a control system smothers the germ of the explosion using an extinguishing powder that is released into the plant.
Decoupling These explosion protection measures must always be combined with explosion-related decoupling in order to avoid the devastating effects of the explosion spreading and secondary explosions.
These terms are used to describe vessels, which are strong enough to withstand the maximum explosion pressure.
Conventional explosion venting
Explosion venting is a technique for protecting enclosed vessels that prevents the pressure within the vessel from rising above a permitted level. Breaking points, such as explosion vents, in the walls of the plant, rupture when the pressure reaches a predefined level and thus reduce the pressure in the vessel below its strength.
Flameless explosion venting
This essentially uses the same principle as conventional explosion venting. However, it offers the advantage that the explosion can be vented indoors because the flame and pressure wave of the explosion are contained. This eliminates the risk of injury even when working in close proximity to the equipment.
Explosion suppression
Pressure and/or infrared sensors detect the explosion at a very early stage. Within a few milliseconds, a control system smothers the germ of the explosion using an extinguishing powder that is released into the plant.
Decoupling These explosion protection measures must always be combined with explosion-related decoupling in order to avoid the devastating effects of the explosion spreading and secondary explosions.
What is preventive explosion protection?
Preventive explosion protection describes all measures to reduce or even eliminate the probability of an explosion. There are fundamentally different prerequisites for the occurrence of an explosion. Explosive gas or dust mixture - oxygen - source of ignition. To prevent an explosion from occurring, it is sufficient to remove one of the required prerequisites from the action circle. In order to find the right protection against such an event, the various applications/cases must be assessed very carefully. Thus, ignition can be life-threatening not only in a closed but also in an open process.
Before an explosion can occur, three things must come together: an ignition source, a combustible material, and oxygen. Especially in the area of handling flammable liquids or when filling devices with flammable dust, it is often sufficient to take preventive explosion protection measures, with the "avoidance of effective sources of ignition" being a priority.
Electrostatic charges are created on the surface by friction of chargeable materials. This charge remains on the fabric until it either slowly dissipates or discharges by arcing on a conductor. The spark produced by this discharge can lead to ignition if an explosive atmosphere occurs. In order to prevent this electrostatic charge and safely discharge any charges that arise, suitable grounding devices such as grounding clamps must be used on e.g. barrels, systems and pipes. Grounding clamps are particularly useful for mobile objects, since the grounding clamps can be assembled and disassembled quickly.
Before an explosion can occur, three things must come together: an ignition source, a combustible material, and oxygen. Especially in the area of handling flammable liquids or when filling devices with flammable dust, it is often sufficient to take preventive explosion protection measures, with the "avoidance of effective sources of ignition" being a priority.
Electrostatic charges are created on the surface by friction of chargeable materials. This charge remains on the fabric until it either slowly dissipates or discharges by arcing on a conductor. The spark produced by this discharge can lead to ignition if an explosive atmosphere occurs. In order to prevent this electrostatic charge and safely discharge any charges that arise, suitable grounding devices such as grounding clamps must be used on e.g. barrels, systems and pipes. Grounding clamps are particularly useful for mobile objects, since the grounding clamps can be assembled and disassembled quickly.
What is flameless explosion venting?
With flameless pressure relief, the flames in the filter fabric of the flame trap are cooled extremely efficiently and thus nipped in the bud. Neither flames nor pressure escape. The production plant can be set up in a process-optimized manner. Likewise, the increase in pressure and noise pollution in the operating room that are typical of an explosion are reduced to a barely perceptible minimum. The filter design guarantees that no burned or unburned substances escape. In addition to reducing the effects of the explosion, this also ensures the highest level of protection for employees.
Advantages
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Pressure relief without flame and dust propagation.
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process-optimized installation of the system.
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Safest + most economical solution indoors.
The situation: Bursting discs are not sufficient to relieve the pressure on indoor plant components. The escaping dust and flames pose an enormous risk to personnel and the system. Secondary explosions caused by dust being thrown up are just one example. Vent ducts, also known as relief ducts, are often used to vent the pressure and flames of an explosion to the outside.
The problem: This solution prevents a process-optimized system design. The longer the vent duct, the more stable the vent duct and the system itself must be built. This increases the costs significantly. The reason: the further away the explosion is from the source of the explosion, the pressure that the duct and the system have to withstand increases.
The problem: This solution prevents a process-optimized system design. The longer the vent duct, the more stable the vent duct and the system itself must be built. This increases the costs significantly. The reason: the further away the explosion is from the source of the explosion, the pressure that the duct and the system have to withstand increases.
What is explosion isolation?
When it comes to decoupling, a distinction is made between active and passive systems:
Passive decoupling systems react solely to the explosion effect and prevent the spread of flames and pressure due to their structural design.
Active systems perceive an explosion via detectors or sensors that register the pressure or flames and then take countermeasures such as e.g. B. closing a valve.
The aim of decoupling is to protect adjacent parts of the plant from the spread of the explosion in the event of an incident. By sealing pipes and conveying equipment, the explosion does not penetrate into other parts of the plant. Quench valves, non-return flaps or valves are used for explosion decoupling. Extinguishing the explosion flames using a chemical extinguishing agent barrier is also common. Valves and extinguishing barriers are able to decouple in both directions at the same time.
Passive decoupling systems react solely to the explosion effect and prevent the spread of flames and pressure due to their structural design.
Active systems perceive an explosion via detectors or sensors that register the pressure or flames and then take countermeasures such as e.g. B. closing a valve.
The aim of decoupling is to protect adjacent parts of the plant from the spread of the explosion in the event of an incident. By sealing pipes and conveying equipment, the explosion does not penetrate into other parts of the plant. Quench valves, non-return flaps or valves are used for explosion decoupling. Extinguishing the explosion flames using a chemical extinguishing agent barrier is also common. Valves and extinguishing barriers are able to decouple in both directions at the same time.
What is explosion suppression?
Explosion suppression is an explosion protection measure in which the combustion of an explosive atmosphere in a closed or essentially closed volume is detected (recognised) and stopped in the initial phase, thus preventing destructive pressure increases. A controller initiates the sudden release of extinguishing powder from the extinguishing bootle into the volume to be protected in the shortest possible time. An explosion is considered suppressed if the explosion pressure does not exceed the engineered strength of the affected volume, or the degree of flame propagation remains within the specified limits in open spaces.
These explosion protection measures must always be combined with explosion isolation to avoid the devastating effects of explosion propagation and secondary explosions.
Any Questions?
We would be happy to show you solutions tailored to your process that limit the effects of an explosion to a harmless level and ensure that production can be resumed quickly after an explosion event.
