In high-risk industries such as oil & gas, chemical processing, and offshore platforms, explosive gas atmospheres pose significant safety challenges. According to the IEC 60079-10-1 standard, industrial sites are classified into Zone 0, Zone 1, and Zone 2 based on the frequency and duration of the presence of explosive gases. Each zone comes with distinct requirements for the design and construction of functional enclosures, and understanding these differences is critical for safety and regulatory compliance.
Zone 0: Continuous Explosive Atmospheres
Zone 0 is the most dangerous explosive atmosphere and usually refers to internal spaces such as fuel tanks or chemical reactors where explosive gas mixtures are present continuously or for long periods of time.
As a rule, the installation of any non-essential enclosures or electrical equipment in Zone 0 should be avoided.If necessary, only intrinsically safe (Ex ia) or encapsulated (Ex ma) equipment according to IEC 60079-11 is permitted.The system should have continuous gas monitoring capability and be able to trigger an automatic power-off or alarm mechanism when a set threshold is reached.This ensures reliable operation in extreme Zone 0 environments with complete protection against dust and prolonged submersion in water.
Zone 1: Occasional Explosive Atmospheres
Zone 1 is an area where an explosive atmosphere may occur during normal operation, such as an offshore drilling rig work area or an oil refinery pump room.The enclosure must be protected by one or more of the following methods: explosion-proof (Ex d), pressurised (Ex p) or combined (Ex db + Ex pb).The pressurised system must ensure that the pre-blowing volume is at least 5 times the internal volume of a typical gas (according to IEC 60079-2) or 10 times the internal volume of hydrogen.A pressure monitoring interlock must be installed to automatically shut down the system if the pressure falls below 50 Pa (typical threshold; actual values may depend on product specifications or project requirements).Depending on the environment in which the equipment is installed, the enclosure should have a protection rating of not less than IP54 (indoor) or IP65 (outdoor) to ensure that the dust and water resistance meets the requirements for use.A two-channel gas detector should be installed with an alarm threshold set between 10% and 25% of the LEL (lower explosive limit).Materials must be explosion-proof, anti-static and corrosion-resistant.
Zone 2: Rare and Abnormal Explosive Atmospheres
Zone 2 areas experience explosive gas atmospheres only in abnormal conditions and for short durations, such as gas station ventilation zones or transition areas adjacent to Zone 1. Allowed equipment types include increased safety (Ex e), non-sparking (Ex nA), restricted breathing (Ex nR), and simplified pressurized enclosures (Ex pz). Even simplified systems must ensure a 5x air volume purge before energization. For outdoor enclosures, materials such as 316L stainless steel is recommended, with steel containers having a minimum thickness of 3 mm and GRP containers a minimum thickness of 8 mm（These thicknesses are based on industry best practices or product-specific standards, not on IEC mandates.）.
Conclusion
All explosion-proof container designs must strictly follow relevant standards, including IEC 60079, ATEX, and GB 3836. A few critical points to note: The commonly used designation “Ex de” is non-standard. The correct classification is “Ex db eb,” indicating a compound flameproof and increased safety solution. Pressurized containers (Ex p) are not permitted in Zone 0 and are only applicable in Zone 1 and Zone 2.
Each hazardous zone imposes increasing or decreasing demands on functional container design. Zone 0 allows only intrinsically safe or encapsulated equipment, Zone 1 requires multi-layered explosion protection strategies, and Zone 2 allows simplified protections but still requires adherence to core safety standards. By aligning design and manufacturing with the appropriate zone classification and international standards, equipment safety and operational integrity can be fully assured in explosive gas environments.
TLS Offshore Containers / TLS Special Containers is a global supplier of standard and customised containerised solutions.
Wherever you are in the world TLS can help you, please contact us.
Product brochures:
Offshore pressurised mud logging cabin brochure
MCC | Switchgear | VFD | VSD pressurised shelter
Keywords:#Hazardous Zones,#IEC 60079-10-1,#Zone 0,#Zone 1,#Zone 2,#Explosion-proof Enclosures,#Intrinsically Safe (Ex ia),#Encapsulation (Ex ma),#Flameproof (Ex d),#Pressurized (Ex p),#Compound Protection (Ex db + Ex pb),#Purge Systems,#Pre-purging Volume,#Gas Detection,#Automatic Shutdown,#IP68 Protection,#Non-sparking (Ex nA),#Increased Safety (Ex e),#Restricted Breathing (Ex nR),#Corrosion Resistance
Zone 0: Continuous Explosive Atmospheres
Zone 0 is the most dangerous explosive atmosphere and usually refers to internal spaces such as fuel tanks or chemical reactors where explosive gas mixtures are present continuously or for long periods of time.
As a rule, the installation of any non-essential enclosures or electrical equipment in Zone 0 should be avoided.If necessary, only intrinsically safe (Ex ia) or encapsulated (Ex ma) equipment according to IEC 60079-11 is permitted.The system should have continuous gas monitoring capability and be able to trigger an automatic power-off or alarm mechanism when a set threshold is reached.This ensures reliable operation in extreme Zone 0 environments with complete protection against dust and prolonged submersion in water.
Zone 1: Occasional Explosive Atmospheres
Zone 1 is an area where an explosive atmosphere may occur during normal operation, such as an offshore drilling rig work area or an oil refinery pump room.The enclosure must be protected by one or more of the following methods: explosion-proof (Ex d), pressurised (Ex p) or combined (Ex db + Ex pb).The pressurised system must ensure that the pre-blowing volume is at least 5 times the internal volume of a typical gas (according to IEC 60079-2) or 10 times the internal volume of hydrogen.A pressure monitoring interlock must be installed to automatically shut down the system if the pressure falls below 50 Pa (typical threshold; actual values may depend on product specifications or project requirements).Depending on the environment in which the equipment is installed, the enclosure should have a protection rating of not less than IP54 (indoor) or IP65 (outdoor) to ensure that the dust and water resistance meets the requirements for use.A two-channel gas detector should be installed with an alarm threshold set between 10% and 25% of the LEL (lower explosive limit).Materials must be explosion-proof, anti-static and corrosion-resistant.
Zone 2: Rare and Abnormal Explosive Atmospheres
Zone 2 areas experience explosive gas atmospheres only in abnormal conditions and for short durations, such as gas station ventilation zones or transition areas adjacent to Zone 1. Allowed equipment types include increased safety (Ex e), non-sparking (Ex nA), restricted breathing (Ex nR), and simplified pressurized enclosures (Ex pz). Even simplified systems must ensure a 5x air volume purge before energization. For outdoor enclosures, materials such as 316L stainless steel is recommended, with steel containers having a minimum thickness of 3 mm and GRP containers a minimum thickness of 8 mm（These thicknesses are based on industry best practices or product-specific standards, not on IEC mandates.）.
Conclusion
All explosion-proof container designs must strictly follow relevant standards, including IEC 60079, ATEX, and GB 3836. A few critical points to note: The commonly used designation “Ex de” is non-standard. The correct classification is “Ex db eb,” indicating a compound flameproof and increased safety solution. Pressurized containers (Ex p) are not permitted in Zone 0 and are only applicable in Zone 1 and Zone 2.
Each hazardous zone imposes increasing or decreasing demands on functional container design. Zone 0 allows only intrinsically safe or encapsulated equipment, Zone 1 requires multi-layered explosion protection strategies, and Zone 2 allows simplified protections but still requires adherence to core safety standards. By aligning design and manufacturing with the appropriate zone classification and international standards, equipment safety and operational integrity can be fully assured in explosive gas environments.
TLS Offshore Containers / TLS Special Containers is a global supplier of standard and customised containerised solutions.
Wherever you are in the world TLS can help you, please contact us.
Product brochures:
Offshore pressurised mud logging cabin brochure
MCC | Switchgear | VFD | VSD pressurised shelter
Keywords:#Hazardous Zones,#IEC 60079-10-1,#Zone 0,#Zone 1,#Zone 2,#Explosion-proof Enclosures,#Intrinsically Safe (Ex ia),#Encapsulation (Ex ma),#Flameproof (Ex d),#Pressurized (Ex p),#Compound Protection (Ex db + Ex pb),#Purge Systems,#Pre-purging Volume,#Gas Detection,#Automatic Shutdown,#IP68 Protection,#Non-sparking (Ex nA),#Increased Safety (Ex e),#Restricted Breathing (Ex nR),#Corrosion Resistance
Written by Snowy
Positive Pressure Explosion-Proof is a widely adopted method used in hazardous environments to prevent explosions by maintaining a higher internal pressure within a sealed container. This controlled internal overpressure effectively blocks the ingress of flammable gases or vapors from the surrounding atmosphere, thereby reducing the risk of explosive gas mixtures forming inside the container.
1. Creating a Protective Barrier Through Pressure Differential
At the core of Positive Pressure Explosion-Proof lies the physical principle of gas diffusion—from high-pressure zones to low-pressure zones. By maintaining a slight overpressure inside the container, any external flammable gas is effectively prevented from entering. This isolation ensures that even if explosive gases are present outside, they cannot mix with the air inside, reducing the possibility of ignition.
2. Disrupting the Fire Triangle
The fire triangle consists of three essential elements: fuel, oxygen, and an ignition source. An explosion can only occur when all three are present simultaneously. The positive pressure system ensures that the conditions for the formation of explosive gas mixtures inside the container are not present by preventing combustible gases from entering the container, and that even if an ignition source and oxygen are present, an explosive environment will not be formed, thus effectively avoiding the risk of explosion.
3. Structural Integrity and Material Considerations
For positive pressure systems to function reliably, the container must be structurally sound and well-sealed. High-quality sealing prevents pressure loss, while the materials used must withstand internal overpressure and resist corrosion from external environmental factors. These design elements are critical to maintaining system integrity over long-term operation in harsh or hazardous conditions.
4. Monitoring and Control Systems
Maintaining stable internal pressure is crucial for effective explosion protection. Positive pressure systems typically incorporate pressure sensors, regulators, and control interfaces to monitor and adjust internal pressure levels.
When the internal pressure drops below the preset threshold, the pressurization system—either automatically or manually—can be activated to restore positive pressure. Conversely, if the pressure exceeds safety limits, exhaust or relief valves are engaged to prevent over-pressurization and potential structural damage.
This dual mechanism ensures both safety and reliability, accommodating various operational scenarios where full automation may not be practical or necessary.
Conclusion
Positive Pressure Explosion-Proof provides a practical and effective solution for safeguarding electrical equipment, control systems, and instrumentation in hazardous areas. By maintaining an internal overpressure, it minimizes the risk of explosive atmospheres forming inside enclosures, significantly enhancing operational safety.
With its widespread use in industries such as oil & gas, petrochemicals, offshore operations, and energy storage systems, understanding and properly implementing this technology is essential. Whether in design, commissioning, or maintenance, a deep understanding of positive pressure principles ensures compliance, safety, and long-term system performance.
TLS Offshore Containers / TLS Special Containers is a global supplier of standard and customised containerised solutions.
Wherever you are in the world TLS can help you, please contact us.
Product brochures:
Offshore pressurised mud logging cabin brochure
MCC | Switchgear | VFD | VSD pressurised shelter
Keywords:#Positive pressure,#Explosion protection,#Explosion-proof,#Hazardous areas,#Pressurized enclosure,#Overpressure,#Flammable gases,#Ingress protection,#Gas diffusion,#Fire triangle,#Ignition source,#Fuel isolation,#Combustion prevention,#Sealed enclosure,#Pressure monitoring,#Relief valve,#Pressure sensor,#Manual activation,#Control system,#Industrial safety
1. Creating a Protective Barrier Through Pressure Differential
At the core of Positive Pressure Explosion-Proof lies the physical principle of gas diffusion—from high-pressure zones to low-pressure zones. By maintaining a slight overpressure inside the container, any external flammable gas is effectively prevented from entering. This isolation ensures that even if explosive gases are present outside, they cannot mix with the air inside, reducing the possibility of ignition.
2. Disrupting the Fire Triangle
The fire triangle consists of three essential elements: fuel, oxygen, and an ignition source. An explosion can only occur when all three are present simultaneously. The positive pressure system ensures that the conditions for the formation of explosive gas mixtures inside the container are not present by preventing combustible gases from entering the container, and that even if an ignition source and oxygen are present, an explosive environment will not be formed, thus effectively avoiding the risk of explosion.
3. Structural Integrity and Material Considerations
For positive pressure systems to function reliably, the container must be structurally sound and well-sealed. High-quality sealing prevents pressure loss, while the materials used must withstand internal overpressure and resist corrosion from external environmental factors. These design elements are critical to maintaining system integrity over long-term operation in harsh or hazardous conditions.
4. Monitoring and Control Systems
Maintaining stable internal pressure is crucial for effective explosion protection. Positive pressure systems typically incorporate pressure sensors, regulators, and control interfaces to monitor and adjust internal pressure levels.
When the internal pressure drops below the preset threshold, the pressurization system—either automatically or manually—can be activated to restore positive pressure. Conversely, if the pressure exceeds safety limits, exhaust or relief valves are engaged to prevent over-pressurization and potential structural damage.
This dual mechanism ensures both safety and reliability, accommodating various operational scenarios where full automation may not be practical or necessary.
Conclusion
Positive Pressure Explosion-Proof provides a practical and effective solution for safeguarding electrical equipment, control systems, and instrumentation in hazardous areas. By maintaining an internal overpressure, it minimizes the risk of explosive atmospheres forming inside enclosures, significantly enhancing operational safety.
With its widespread use in industries such as oil & gas, petrochemicals, offshore operations, and energy storage systems, understanding and properly implementing this technology is essential. Whether in design, commissioning, or maintenance, a deep understanding of positive pressure principles ensures compliance, safety, and long-term system performance.
TLS Offshore Containers / TLS Special Containers is a global supplier of standard and customised containerised solutions.
Wherever you are in the world TLS can help you, please contact us.
Product brochures:
Offshore pressurised mud logging cabin brochure
MCC | Switchgear | VFD | VSD pressurised shelter
Keywords:#Positive pressure,#Explosion protection,#Explosion-proof,#Hazardous areas,#Pressurized enclosure,#Overpressure,#Flammable gases,#Ingress protection,#Gas diffusion,#Fire triangle,#Ignition source,#Fuel isolation,#Combustion prevention,#Sealed enclosure,#Pressure monitoring,#Relief valve,#Pressure sensor,#Manual activation,#Control system,#Industrial safety
Written by Snowy
IEC60079-13:2010 has introduced significant updates and improvements to the pressurized explosion-proof (Ex p) techniques, particularly regarding the types of explosion protection. The standard now categorizes pressurized rooms into four different types of protection: px, py, pz, and pv. Each type has distinct applications, protection levels, monitoring requirements, and device specifications. This blog will delve into the differences between these four pressurized protection types and explore their applications in various industrial environments.
1. px Explosion-Proof (Highest Level of Protection)
The px explosion-proof protection is suitable for Zone 1 and Zone 2 hazardous areas. The primary protective gas used is clean air, although inert gases can be used under special conditions. The critical requirement is that the internal pressure must always be higher than the external environment, ensuring that explosive gases cannot enter the protected area. The equipment protection level (EPL) must meet the Gb classification, offering a higher level of explosion protection.
This type of explosion protection is commonly used in control rooms within petrochemical plants and refineries, as well as electrical cabinets and distribution rooms in areas with high explosive gas risks, such as hydrogen or methane leakage zones.
2. py Explosion-Proof (Medium Level of Protection)
The py explosion-proof protection is also suitable for Zone 1 and Zone 2 environments. Typically, the EPL required is Gb, although it can be relaxed to Gc under specific conditions. Non-explosion-proof electrical equipment may be used with interlocking protection. Compared to px protection, py offers more tolerance for pressure fluctuations.
This protection type is typically used for auxiliary equipment in chemical production workshops, non-core process areas in pharmaceutical plants, or as a supplementary solution to px protection.
3. pz Explosion-Proof (Lowest Level of Protection)
The pz explosion-proof protection is only applicable in Zone 2 environments, where explosive gases are occasionally present. A key requirement for pz protection is that when the intake air is from Zone 2, combustible gas detectors must be installed to ensure the safety of the air entering the room. The EPL for pz protection can be Gc.
pz protection is ideal for lighter industrial settings, food processing, pharmaceutical plants, and other non-high-risk environments. It is typically used in well-ventilated areas, such as the perimeter of factories, as a supplementary measure to px or py protection.
4. pv Explosion-Proof (Formal introduction and regularisation)
Introduced by IEC60079-13:2010, the pv explosion-proof protection is suitable for non-hazardous areas that still have internal sources of release. This protection works by diluting the explosive substances inside the room to below safe concentration levels, thus preventing explosions. The EPL for pv protection may range from Gb to Gc, allowing for the use of non-explosion-proof equipment.
The pv protection method is widely used in environments such as laboratories, electronics manufacturing, and precision instrument production, where volatile chemicals are present. It is also applicable in fuel testing stations and other areas with controlled risks where small amounts of combustible gases might be present.
5. Conclusion
IEC60079-13:2010 has significantly expanded the applicability of pressurized explosion-proof techniques by introducing the pv protection type and refining the px, py, and pz protection methods. These improvements make explosion-proof technology suitable for a wider range of industrial environments. Each protection type varies in terms of hazardous area classification, device selection, and required protective gas. When choosing an explosion-proof type, it is essential to consider factors such as the application environment, combustible substance release conditions, and explosion-proof costs.
As industrial safety standards continue to evolve, pressurized explosion-proof technologies will continue to develop, providing more efficient and safer explosion protection solutions across industries.
If you’re looking for a safe, durable, and certified solution for your offshore operations, TLS Offshore EX-Proof Containers are the perfect choice. With their innovative pressurization system and extensive certifications, TLS ensures the highest levels of safety and performance in some of the most challenging conditions.
TLS Offshore Containers / TLS Special Containers is a global supplier of standard and customised containerised solutions.
Wherever you are in the world TLS can help you, please contact us.
Product brochures:
Offshore pressurised mud logging cabin brochure
MCC | Switchgear | VFD | VSD pressurised shelter
Keywords:#IEC60079-13:2010,#Explosion-proof protection,#Pressurized explosion protection,#px protection,#py protection,#pz protection,#pv protection,#Equipment protection level (EPL),#Hazardous area classification,#Zone 2,#Inert gases,#Combustible gas detectors,#Explosion-proof devices,#Industrial safety standards.
1. px Explosion-Proof (Highest Level of Protection)
The px explosion-proof protection is suitable for Zone 1 and Zone 2 hazardous areas. The primary protective gas used is clean air, although inert gases can be used under special conditions. The critical requirement is that the internal pressure must always be higher than the external environment, ensuring that explosive gases cannot enter the protected area. The equipment protection level (EPL) must meet the Gb classification, offering a higher level of explosion protection.
This type of explosion protection is commonly used in control rooms within petrochemical plants and refineries, as well as electrical cabinets and distribution rooms in areas with high explosive gas risks, such as hydrogen or methane leakage zones.
2. py Explosion-Proof (Medium Level of Protection)
The py explosion-proof protection is also suitable for Zone 1 and Zone 2 environments. Typically, the EPL required is Gb, although it can be relaxed to Gc under specific conditions. Non-explosion-proof electrical equipment may be used with interlocking protection. Compared to px protection, py offers more tolerance for pressure fluctuations.
This protection type is typically used for auxiliary equipment in chemical production workshops, non-core process areas in pharmaceutical plants, or as a supplementary solution to px protection.
3. pz Explosion-Proof (Lowest Level of Protection)
The pz explosion-proof protection is only applicable in Zone 2 environments, where explosive gases are occasionally present. A key requirement for pz protection is that when the intake air is from Zone 2, combustible gas detectors must be installed to ensure the safety of the air entering the room. The EPL for pz protection can be Gc.
pz protection is ideal for lighter industrial settings, food processing, pharmaceutical plants, and other non-high-risk environments. It is typically used in well-ventilated areas, such as the perimeter of factories, as a supplementary measure to px or py protection.
4. pv Explosion-Proof (Formal introduction and regularisation)
Introduced by IEC60079-13:2010, the pv explosion-proof protection is suitable for non-hazardous areas that still have internal sources of release. This protection works by diluting the explosive substances inside the room to below safe concentration levels, thus preventing explosions. The EPL for pv protection may range from Gb to Gc, allowing for the use of non-explosion-proof equipment.
The pv protection method is widely used in environments such as laboratories, electronics manufacturing, and precision instrument production, where volatile chemicals are present. It is also applicable in fuel testing stations and other areas with controlled risks where small amounts of combustible gases might be present.
5. Conclusion
IEC60079-13:2010 has significantly expanded the applicability of pressurized explosion-proof techniques by introducing the pv protection type and refining the px, py, and pz protection methods. These improvements make explosion-proof technology suitable for a wider range of industrial environments. Each protection type varies in terms of hazardous area classification, device selection, and required protective gas. When choosing an explosion-proof type, it is essential to consider factors such as the application environment, combustible substance release conditions, and explosion-proof costs.
As industrial safety standards continue to evolve, pressurized explosion-proof technologies will continue to develop, providing more efficient and safer explosion protection solutions across industries.
If you’re looking for a safe, durable, and certified solution for your offshore operations, TLS Offshore EX-Proof Containers are the perfect choice. With their innovative pressurization system and extensive certifications, TLS ensures the highest levels of safety and performance in some of the most challenging conditions.
TLS Offshore Containers / TLS Special Containers is a global supplier of standard and customised containerised solutions.
Wherever you are in the world TLS can help you, please contact us.
Product brochures:
Offshore pressurised mud logging cabin brochure
MCC | Switchgear | VFD | VSD pressurised shelter
Keywords:#IEC60079-13:2010,#Explosion-proof protection,#Pressurized explosion protection,#px protection,#py protection,#pz protection,#pv protection,#Equipment protection level (EPL),#Hazardous area classification,#Zone 2,#Inert gases,#Combustible gas detectors,#Explosion-proof devices,#Industrial safety standards.
