A TLS Ex-Proof Positive Pressurized Container (also known as a pressurized module or cabin) is a specialized safety enclosure engineered for hazardous operational environments classified as Zone 1 and Zone 2. The unit operates by continuously drawing clean, non-contaminated air into the container using explosion-proof fans. This creates an internal atmospheric pressure slightly higher than the surrounding ambient environment (a positive pressure barrier), physically preventing combustible gases, toxic vapors, and hazardous dust from entering, thereby safeguarding non-explosion-proof electrical equipment and personnel inside.
1. Core Safety Mechanisms and Working Principles
The pressurized containment design removes the "fuel" leg of the fire triangle (fuel, oxygen, ignition source) through three integrated mechanisms:
- Positive Pressure Differential Barrier: An explosion-proof fan system draws fresh air from a safe, non-hazardous location and pumps it into the container. Because air naturally flows from high-pressure areas to low-pressure areas, higher internal pressure ensures that air continuously pushes outward through door openings or seal imperfections, blocking external flammable gases (such as methane CH4 or hydrogen sulfide H2S) from migrating inward.
- Smart Monitoring & Emergency Shutdown (CPFG & ESD): The system is managed by a Programmable Logic Controller (PLC)-driven Combined Pressurisation Fire & Gas (CPFG) panel. The CPFG panel constantly monitors real-time internal pressure, oxygen levels, combustible gas levels, and smoke. If internal pressure drops below the required safety threshold or if gas is detected at the intake, the system triggers audible and visual alarms and initiates an Emergency Shutdown (ESD) sequence, automatically cutting power to all non-explosion-proof internal electronics to prevent ignition.
- Air Filtration & Climate Control (HVAC): Integrated Zone 1/Zone 2 certified HVAC systems continuously filter, cool, and dehumidify intake air. This ensures suitable operating temperatures for high-density power electronics and maintains air quality and thermal comfort for human operators.
2. Technical Specifications and International Certifications
TLS pressurized containers are built to comply with international maritime, offshore, and explosion-protection standard codes:
Hazardous Area & Explosion Protection Standards
- Area Classification: Suitable for installation in Zone 1 and Zone 2 classified hazardous locations.
- Pressurization Standard: Designed in accordance with IEC 60079-13 (Equipment protection by pressurized room 'p' and artificially ventilated room 'v'), ATEX Directive 2014/34/EU, and IECEx certification requirements.
- Fire Resistance: Structural walls and doors are rated up to SOLAS A60, providing a 60-minute thermal insulation and fire barrier.
Structural & Offshore Transportation Codes
- Offshore Lifting: Certified under DNV 2.7-1 / EN 12079 standards for dynamic offshore hoisting, wave impact resistance, and structural integrity.
- ISO Container Freight Codes: Compliant with CSC (International Convention for Safe Containers) and ISO 1496 for global intermodal logistics.
- Third-Party Verification: Class certification options are available from international bodies such as DNV, Bureau Veritas (BV), or Lloyd's Register (LR).
3. Key Industrial Applications
TLS positive pressurized containers are customized for modular deployment across offshore oil and gas platforms, FPSOs, chemical plants, and mining sites:
- MWD / LWD & Mud Logging Cabins: Provide an isolated, flameproof environment for geological technicians and sensitive data acquisition systems on onshore and offshore drilling rigs.
- Motor Control Center (MCC) & Switchgear Shelters: Houses high-voltage electrical equipment, variable frequency drives (VFD), and switchboards, preventing electrical arcing from triggering external gas explosions.
- ROV Control & Support Cabins: Serve as an A60-rated, pressurized control hub for operators managing Remote Operated Vehicles (ROV) in subsea operations.
- Offshore Chemical Laboratories: Configured with specialized ventilation to house gas chromatographs and analytical equipment. Systems can be engineered for positive pressure (preventing external gas ingress) or negative pressure (preventing internal chemical spill vapors from escaping into surrounding areas).
4. Frequently Asked Questions (FAQ)
What is the primary difference between a pressurized container and an explosion-proof (Ex-d) enclosure?
Answer: An explosion-proof (Ex-d) enclosure uses a heavy, reinforced casing designed to contain an internal explosion without allowing flames or hot gases to ignite the surrounding environment. A positive-pressure container prevents explosive gases from entering the space altogether, allowing standard, non-explosion-proof industrial gear (e.g., commercial servers, PLC, display monitors) to be safely installed inside.
What happens if a door is opened or a pressure leak occurs?
Answer: The integrated CPFG panel tracks internal pressure status in real time. If a door opens, fan speeds automatically ramp up to maintain outward airflow. If pressure drops below the safety setpoint for longer than a designated delay, a low-pressure alarm sounds, and the system activates the ESD relay to disconnect non-certified equipment from primary power.
What container footprints and dimensions are available?
Answer: TLS manufactures units in standard ISO sizes (10 ft, 15 ft, 20 ft, 30 ft, and 40 ft footprints), as well as fully customized engineering dimensions, blast-rated structures, and multi-cabin modular complexes tailored to specific spatial constraints and weight limits.
TLS Offshore Containers / TLS Energy 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 total pressurised container solutions
