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
The full lifecycle cost of a battery energy storage system (BESS) includes more than the initial equipment purchase. It covers project development, the DC battery system, power conversion, AC equipment, cabling, energy management, construction, grid connection, operation, battery augmentation and final decommissioning.
For an accurate BESS investment analysis, every cost should be assessed over the project’s intended operating life—not simply compared as an upfront cost per kWh.
What Are the Main Cost Components of a BESS Project?
1. DC Battery System
The DC side normally includes battery cells, modules, racks, battery containers, battery management systems and DC protection equipment. Its cost is primarily driven by the required energy capacity in MWh, battery chemistry, discharge duration, cycle life and usable state-of-charge range.
For longer-duration projects, the DC battery system is often one of the largest capital cost components.
2. Power Conversion System
The power conversion system, or PCS, converts DC electricity into AC electricity during discharge and AC into DC during charging. PCS cost is mainly related to the project’s rated power in MW.
Efficiency, overload capability, grid-forming functions and reactive power requirements can all affect PCS selection and cost.
3. AC Electrical System
The AC system includes step-up transformers, switchgear, protection, metering and, where required, a main transformer and high-voltage equipment. Costs depend on project power, collection voltage and the voltage at the grid connection point.
4. Cables
A BESS project requires DC cables, low- and medium-voltage AC cables, control cables and communication cables. Cable costs are influenced by system layout, equipment spacing, current rating and the distance between the battery system and the point of interconnection.
5. EMS and Control Systems
The energy management system controls charging, discharging, state of charge and operating schedules. The broader control scope may also include the plant power controller, SCADA, remote monitoring, dispatch interfaces and cybersecurity equipment.
EMS cost depends less on battery capacity and more on the required operating functions, market participation and grid-code compliance.
6. Thermal Management, Fire Safety and Auxiliary Systems
Battery cooling, fire detection, fire suppression, ventilation, auxiliary power, UPS, lighting, security and grounding are essential supporting systems. Their design affects safety, availability, energy consumption and long-term maintenance costs.
7. Land and Civil Works
Land costs may include purchase, lease payments, taxes and permitting. Civil works can include site preparation, equipment foundations, roads, drainage, fencing, cable trenches and control buildings.
These costs vary significantly by location and site condition.
8. Grid Connection and Project Delivery
Grid connection costs may include interconnection studies, transmission lines, substations, utility upgrades and grid-side equipment. Engineering, procurement and construction costs cover design, installation, commissioning, project management and testing.
Development fees, insurance, financing costs, taxes and contingency allowances should also be included in the initial investment.
What Costs Occur During BESS Operation?
Operating costs include preventive maintenance, spare parts, system monitoring, software support, insurance, land rent and auxiliary electricity consumption.
Battery degradation is another major lifecycle consideration. Depending on operating conditions and performance guarantees, additional battery capacity may be installed during the project life. PCS units, cooling equipment, sensors and control hardware may also require repair or replacement.
Charging energy and efficiency losses should not be ignored. The project must purchase or generate more electricity than it ultimately delivers because some energy is lost in the batteries, PCS, transformers, cables and cooling systems.
At the end of the project, costs may include equipment removal, battery transport, recycling and site restoration. Recoverable materials and equipment residual value can partially offset these expenses.
How Should BESS Lifecycle Cost Be Evaluated?
Projects should be compared using total cost of ownership and levelized cost of storage, not equipment price alone. The comparison should use the same MW rating, usable MWh capacity, operating life, annual cycling profile, efficiency, availability and end-of-life capacity requirement.
A lower initial price does not always produce the lowest lifecycle cost. System efficiency, degradation, maintenance requirements and integration quality often determine the project’s real long-term economics.
Frequently Asked Questions
What is usually the largest BESS cost component?
For many projects, it is the DC battery system. However, grid connection, civil works and high-voltage equipment can be substantial for complex sites.
Should battery replacement be included?
Yes. Battery augmentation or replacement should be modelled according to expected degradation and the contracted capacity guarantee.
Why is cost per kWh alone insufficient?
It excludes power equipment, grid connection, operating costs, efficiency losses, financing and end-of-life obligations.
