In hazardous chemical environments where flammable gases and vapors are frequently present, the safe operation of electrical systems is not only essential for maintaining production efficiency—it is also critical for protecting personnel and assets.
Traditional flameproof (Ex d) solutions are increasingly challenged by their limitations in flexibility, maintenance, and installation costs. TLS, as a specialized manufacturer of functional containerized systems, provides high-safety, easy-to-integrate, and field-deployable pressurized explosion-proof (Ex p) solutions to support safety transformation and intelligent upgrades across the chemical, pharmaceutical, and energy sectors.
1. Why Pressurized Protection is Essential in Hazardous Chemical Zones
Chemical facilities typically include Zone 1 and Zone 2 areas, where explosive gas atmospheres may occur under normal or abnormal conditions. Electrical equipment operating in these areas—such as DCS units, PLC panels, communication devices, VFDs, and gas analyzers—can pose a serious ignition risk due to electrical arcs, sparks, or temperature rise.
With increasing automation and the centralization of equipment, conventional explosion-proof designs struggle to meet modern requirements, including:
2. TLS Pressurized Enclosure Systems: Creating a Safe Space for Electrical Equipment
TLS offers integrated Ex p pressurization systems based on modular container platforms. By maintaining a stable positive pressure within the sealed enclosure, the system prevents flammable gases from entering and coming into contact with potential ignition sources. This approach provides a safe, cost-effective, and scalable solution for explosion protection.
All TLS systems are designed in compliance with GB/T 3836.5-2017 and meet the following classification levels:
3. Core Features of TLS Pressurized Containers
4. Why Choose TLS?
Conclusion
As a key component in electrical safety infrastructure, pressurized explosion-proof containers are becoming indispensable for achieving intrinsic safety and system reliability in hazardous industries. TLS remains committed to advancing the development and deployment of Ex p systems, helping our clients achieve safer, smarter, and more efficient operations.
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:#Pressurized explosion-proof enclosure,#Hazardous area electrical equipment,#Zone 1 and Zone 2 safety,#Explosion-proof container module,#Positive pressure ventilation,#Chemical plant explosion protection,#ATEX and IECEx certified enclosures,#Custom explosion-proof solutions,#Electrical enclosure for flammable gas,#Modular Ex p container systems,#Industrial automation safety,#Explosion-proof electrical housing,#Gas detection and pressure monitoring,#Smart control enclosure system,#Corrosion-resistant electrical cabinet,#Skid-mounted pressurized units,#Offshore and onshore hazardous zones,#Explosion-proof integration solutions
Traditional flameproof (Ex d) solutions are increasingly challenged by their limitations in flexibility, maintenance, and installation costs. TLS, as a specialized manufacturer of functional containerized systems, provides high-safety, easy-to-integrate, and field-deployable pressurized explosion-proof (Ex p) solutions to support safety transformation and intelligent upgrades across the chemical, pharmaceutical, and energy sectors.
1. Why Pressurized Protection is Essential in Hazardous Chemical Zones
Chemical facilities typically include Zone 1 and Zone 2 areas, where explosive gas atmospheres may occur under normal or abnormal conditions. Electrical equipment operating in these areas—such as DCS units, PLC panels, communication devices, VFDs, and gas analyzers—can pose a serious ignition risk due to electrical arcs, sparks, or temperature rise.
With increasing automation and the centralization of equipment, conventional explosion-proof designs struggle to meet modern requirements, including:
- Centralized wiring and safe isolation for multiple devices
- Effective ventilation and heat dissipation in confined spaces
- Rapid equipment access and reliability during frequent maintenance
2. TLS Pressurized Enclosure Systems: Creating a Safe Space for Electrical Equipment
TLS offers integrated Ex p pressurization systems based on modular container platforms. By maintaining a stable positive pressure within the sealed enclosure, the system prevents flammable gases from entering and coming into contact with potential ignition sources. This approach provides a safe, cost-effective, and scalable solution for explosion protection.
All TLS systems are designed in compliance with GB/T 3836.5-2017 and meet the following classification levels:
- Ex px: Downgrades Zone 1 to a non-hazardous area
- Ex py: Downgrades Zone 1 to Zone 2
- Ex pz: Downgrades Zone 2 to a non-hazardous area
3. Core Features of TLS Pressurized Containers
- High Integration & Compatibility: Supports centralized installation of critical components such as control modules, power supplies, VFDs, analyzers, and communication units—saving valuable space while ensuring functional safety.
- Intelligent Control System: Equipped with internal pressure monitoring, gas detection, and auto interlock modules. Local alarms and remote signal outputs ensure safe, real-time operation。
- Ventilation Mode Adaptable: TLS positive pressure container adopts positive pressure ventilation type structure, maintains the positive pressure state inside the box through continuous air supply, applicable to the site conditions with stable gas source (such as compressed air or purified gas system), can effectively respond to the operation needs of petrochemical, offshore and other typical explosion-proof places.
- Easy Deployment & Customization: Fully customizable in terms of dimensions, cut-outs, and internal bracket layouts. Compatible with wall-mounted, skid-mounted, containerized, and freestanding installations. Material options include weathering steel and powder-coated carbon steel for corrosive environments.
4. Why Choose TLS?
- Over a decade of expertise in pressurized enclosure system design and manufacturing
- Products certified to IECEx, ATEX, and GB explosion protection standards
- Fast customization, bulk delivery, and on-site technical support
- Proven project experience across Asia, the Middle East, and North America, with solutions widely adopted in chemical, energy, and offshore sectors—especially in environments with complex installation conditions and high-density electrical integration
Conclusion
As a key component in electrical safety infrastructure, pressurized explosion-proof containers are becoming indispensable for achieving intrinsic safety and system reliability in hazardous industries. TLS remains committed to advancing the development and deployment of Ex p systems, helping our clients achieve safer, smarter, and more efficient operations.
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:#Pressurized explosion-proof enclosure,#Hazardous area electrical equipment,#Zone 1 and Zone 2 safety,#Explosion-proof container module,#Positive pressure ventilation,#Chemical plant explosion protection,#ATEX and IECEx certified enclosures,#Custom explosion-proof solutions,#Electrical enclosure for flammable gas,#Modular Ex p container systems,#Industrial automation safety,#Explosion-proof electrical housing,#Gas detection and pressure monitoring,#Smart control enclosure system,#Corrosion-resistant electrical cabinet,#Skid-mounted pressurized units,#Offshore and onshore hazardous zones,#Explosion-proof integration solutions
Written by Snowy
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
