Before a battery energy storage system reaches site, buyers want evidence that the delivered package matches the approved design. For a BESS container supplied as an empty enclosure, inspection can verify the structure, finish, doors and specified interface provisions. It cannot verify battery operation, electrical protection, cooling performance or control logic when those systems are outside the supply scope.

Recent TLS content discusses factory acceptance testing (FAT) for integrated BESS. The same quality-planning principle applies to enclosure-only orders: define the checks and acceptance criteria before production, and make sure the inspection plan reflects what is being purchased.

Separate enclosure inspection from system FAT

FAT is often used to describe checks performed at the factory before shipment. Its scope varies by contract. An integrated BESS FAT may include mechanical, electrical, thermal, control, communication and safety tests when those systems are supplied and available for testing.

An enclosure-only order has a narrower boundary. The inspection can confirm the physical product against its drawings and specification. It should not be described as a complete BESS FAT if the container ships without batteries, PCS, BMS, cooling equipment, fire systems and controls. The buyer, enclosure manufacturer and system integrator should assign each test to the party that supplies or installs the relevant equipment.

Build an inspection plan from the approved drawings

The approved drawing set should identify dimensions, openings, doors, structural interfaces, lifting points, finish requirements and any project-specific accessories within scope. A practical inspection plan then turns those requirements into observable checks, with an agreed method and acceptance criterion for each one.

For example, the plan may specify which overall dimensions are measured, how door operation is checked, what finish documentation is required and how cable openings are compared with the approved interface drawing. Inspection points should be selected to suit the order and any applicable standards or customer specifications. There is no single universal checklist for all container projects.

Typical checks for an enclosure-only package

 Dimensions and configuration

Confirm the external dimensions, door locations, equipment openings and overall configuration against the latest approved drawings. If the buyer has specified internal clearances or mounting interfaces, record how these will be checked and which drawing revision governs acceptance.

 Structure and lifting provisions

Review the structural features and lifting points included in the design. The project documents should state the applicable design basis and any required inspection or test evidence. Do not assume a lifting certification, offshore classification or a particular load rating unless it is expressly included and documented for that unit.

 Doors, access and sealing details

Operate doors and access panels to confirm that they open and close as intended. Check the installed hardware and sealing details against the approved scope. If the project requires a water-ingress or other performance test, define the method and acceptance level in the specification; a visual inspection alone does not prove a particular ingress-protection rating.

 Cable openings and customer interfaces

Compare the number, location and size of the agreed cable openings with the interface schedule. Verify frames, blanking arrangements or sealing components only when these are part of the order. Cable glands, cable trays and electrical terminations should not be presumed included.

 Coating and corrosion protection

Where specified, review coating records and carry out agreed visual or thickness checks. The inspection standard, sampling plan, measurement locations and acceptance limits should be agreed in advance. Required performance depends on the site environment and the selected coating system.

 Documentation to request at handover

The purchase order can list the records required for release. Depending on the project, these may include approved as-built drawings, material or weld documentation, coating records, dimensional inspection results, non-conformance closeout and a final inspection report. Only request records relevant to the supplied scope and applicable specification.

The handover package should make clear what the buyer or integrator must complete after delivery. Site installation, final grounding, customer cabling, equipment installation and integrated system commissioning may sit outside the enclosure supplier’s work.

 Plan tests that require integrated equipment separately

If the project expects checks of BMS communication, PCS functions, battery alarms, thermal controls or fire-system responses, identify which supplier provides the equipment and who leads the test. Those functions require an agreed system configuration, test procedure, inputs, expected responses and acceptance criteria. An enclosure supplier cannot demonstrate functions of equipment it does not provide.

For a multi-party project, a responsibility matrix can help connect enclosure inspection, equipment FAT, site acceptance testing and commissioning. The goal is to avoid both gaps and duplicate tests while keeping each result traceable to the responsible party.

 FAQ

 1.Is enclosure inspection the same as BESS FAT?

 No. Enclosure inspection covers the contracted container structure and interfaces. A system FAT may cover electrical, battery, thermal, controls and safety functions if those systems are included and available for testing.

 2.Can an empty container be certified as IP55 through a visual check?

A visual check alone does not establish an IP rating. Any required ingress-protection rating and verification method must be specified and assessed for the completed design under the applicable test or certification process.

 3.Should lifting tests be included in every container order?

The required lifting design basis and verification depend on the application, governing requirements and contract. The buyer should state the intended transport and lifting conditions and request the applicable evidence in the specification.

 4.Who tests the BMS, PCS and cooling system?

The suppliers or integrator responsible for those systems should define and perform the relevant tests. The project should document responsibilities and interfaces before the factory test stage.

Conclusion

TLS conducts Factory Acceptance Testing according to its established FAT standards and the requirements applicable to the supplied package. For an enclosure-only order, FAT focuses on the container structure, dimensions, doors, finish and specified interfaces. When batteries, PCS, BMS or other systems are included in TLS’s supply, the applicable tests can also cover those integrated systems.

The FAT scope follows what is included in the project delivery. This gives the customer a clear record of what TLS has inspected and tested before shipment, while identifying any equipment or site checks handled by other suppliers or the system integrator.

A positive-pressure container keeps its inside air pressure slightly higher than the surrounding area by supplying fresh air. When properly designed for the site, this airflow helps reduce the chance of outside contaminants entering through small gaps. It allows selected equipment or work activities to be placed inside a controlled enclosure in locations where the surrounding atmosphere may present a hazard.

Positive pressure is one part of a complete safety design. It does not make every container suitable for every hazardous area. The project must define the area classification, hazards, operating requirements and applicable standards before the enclosure and its systems are specified.

How the basic principle works

Air is drawn from a suitable location, as required and supplied into the container. The supply system maintains internal pressure above the surrounding pressure. Air then leaves through designed outlets or controlled leakage paths.

The actual arrangement may include air intakes, fans or blowers, pressure monitoring, alarms and automatic responses. The selected design depends on the enclosure size, number of occupants, equipment heat, site conditions and project safety requirements.

Why the equipment and room layout matter

The air supply has to reach the areas where people and equipment are located. Large cabinets, partitions or poorly placed openings can affect airflow. The design team should consider where equipment will sit, where operators work, how doors are used and where air enters and exits.

This is why the customer’s equipment layout is useful early in the project. It helps the engineers coordinate the enclosure, air path, access doors and service areas rather than treating ventilation as an afterthought.

Understand monitoring and alarms

Pressure monitoring can indicate whether the system is maintaining its intended condition. Depending on the project, the system may also monitor gas or other conditions and trigger alarms or defined actions if limits are reached.

The alarm thresholds and automatic responses must be set by the project design and applicable requirements. Operators need clear procedures for responding to alarms, and the system needs inspection and maintenance according to its approved documentation.

Positive pressure is not the same as an explosion-proof enclosure

Positive pressure and explosion protection are related to hazardous-area design, but they are not interchangeable terms. A positive-pressure system is one method that may be used to create a protected interior for specified equipment or personnel. The complete design must address the enclosure, ventilation system, electrical equipment, monitoring, shutdown actions and the site’s hazardous-area classification.

Do not select a container based on the phrase “positive pressure” alone. Confirm the project classification, equipment type, applicable standards and required certificates with the responsible engineering team.

Information needed for a project design

Before requesting a proposal, provide the site area classification, expected hazards, intended use, number of occupants, equipment layout, heat loads, utility availability, operating conditions and required standards. The project should also define alarm interfaces, emergency actions, inspection and documentation requirements.

These inputs allow the supplier and project engineers to review a configuration suited to the actual application. Performance claims and certifications should be confirmed for the specific design and contract.

FAQ

1.Does positive pressure stop all hazardous gases from entering?

It is designed to help prevent ingress under the conditions defined for the system. Performance depends on the approved design, correct operation, maintained seals and required maintenance; it should not be treated as a blanket guarantee.

2.Can any equipment be installed inside a positive-pressure container?

No. Equipment suitability depends on the area classification, system design and project requirements. The equipment list should be reviewed by the responsible engineering team.

 3.What happens if the pressure falls?

The monitoring and alarm response should be defined in the project design. Depending on the system, alarms or automatic actions may be required. Operators must follow the approved response procedure.

 4.Is positive pressure the same as an explosion-proof rating?

No. The terms describe different design concepts. Confirm the required hazardous-area protection method and certification for the complete project.

Conclusion

A positive-pressure container is only as effective as the design behind it. The enclosure, air supply, equipment layout, pressure monitoring and alarm response must work together and suit the conditions of the specific site. Positive pressure is one part of that design—not a stand-alone guarantee or a substitute for confirming the required hazardous-area protection. A clear project design basis helps ensure that the container and its interfaces are planned as one coordinated solution.

An offshore accommodation module is more than a set of rooms inside a container. Its layout shapes how people rest between shifts, move through the space, use shared facilities and find a little privacy in a demanding environment. A good plan is not simply the one that fits the most beds. It is the one that supports the way the crew will live onboard.

That makes room arrangement an important part of the project from the start. Decisions about bedrooms, bathrooms, circulation and shared areas are connected: changing one can affect how the others work.

Rest depends on more than the bed

Offshore teams may work different shifts, so people in the same accommodation area may be resting at different times. A bedroom should provide enough space to get in and out comfortably, store personal belongings and use the furniture included in the design. The location of doors and circulation routes also matters, especially when people need to move around while others are sleeping.

Privacy is shaped by the overall plan as well as by the number of beds. A layout with separate rooms may offer more individual space, while shared rooms can accommodate more occupants within a given footprint. Neither arrangement suits every project. The balance depends on crew routines, the expected length of stay and the space available.

Shared facilities need a practical arrangement

Bathrooms and showers are among the spaces used repeatedly throughout the day. Their number and location affect how easily people can use them around shift changes, and they need to work with the module’s water, drainage and ventilation services.

The facilities also take up space that could otherwise be used for bedrooms, storage or a shared area. This is why a room plan should be considered as a whole. Adding a bathroom or increasing the number of sleeping places can affect circulation, privacy and the usable area in other rooms.

Circulation is part of the living space

Corridors, entrances and door swings are sometimes treated as leftover space on a drawing, but they are part of how people experience the accommodation. Narrow routes can make it harder to pass one another or carry personal items. Poorly placed doors can interrupt furniture layouts or reduce privacy.

The module’s internal partitions, fixtures and service routes also occupy space. A scaled floor plan helps reveal these interactions before the room arrangement is finalized. It makes it easier to compare options such as a different room mix, a longer module or a more compact shared area.

When connected modules make sense

If one module cannot provide a comfortable room arrangement, linked modules may create more usable space or allow sleeping and shared facilities to be separated. This can open up different layout possibilities, but it also introduces questions about movement between units and how the connection will be sealed and serviced.

The connection should therefore be considered alongside the floor plan. Structural interfaces, weather sealing, fire separation and electrical or plumbing services may need coordination, depending on the project design. Transport dimensions, lifting and the installation location can also influence whether a multi-module arrangement is practical.

A balanced layout starts with the way people will use it

There is no single room plan that works for every offshore project. Occupant capacity matters, but so do shift patterns, privacy, bathroom use, storage, available footprint and site constraints. Looking at these factors together helps teams understand the trade-offs between a higher bed count and a more comfortable day-to-day arrangement.

At TLS, accommodation layouts can be developed around the project’s intended use and constraints. Comparing layout concepts early can help the project team identify a practical direction before the detailed design is fixed.

FAQ

1.Does a higher bed count always make better use of a module?

Not necessarily. More beds can reduce available space for circulation, storage and privacy. The right balance depends on how the accommodation will be used.

2.Can bedrooms and bathrooms be arranged in one module?

 Often, but the workable combination depends on the module dimensions, room sizes, fixtures, doors and service connections. A floor plan helps show how those elements fit together.

3.What is the benefit of linking accommodation modules? 

Linked modules can provide additional floor area or separate sleeping rooms from shared facilities. Their suitability depends on the site, transport and installation conditions, as well as the design of the connections.

Accommodation designed around offshore routines

The most effective offshore accommodation layout considers how crew members move, rest and use shared facilities throughout their stay. By treating bedrooms, bathrooms, circulation and module connections as parts of one design, project teams can develop spaces that make better use of the available footprint.