UN3536 Packaging and Container Requirements: CSC, Fire Suppression, Labeling

Back to UN3536 Complete Guide

1. Container types for UN3536: standard vs non-standard

UN3536 BESS systems come in various physical configurations. The container type must match the cargo dimensions, weight, and handling requirements. Choosing the wrong container type leads to loading difficulties at best and cargo damage or port rejection at worst.

Container Type	Max Payload	Internal Dimensions (L x W x H)	Best For	Notes
20ft Standard	Up to 28 tons	5.90m x 2.35m x 2.39m	Compact BESS units, single-rack systems	Most common for smaller BESS. Easy to handle. Widely available.
40ft Standard	Up to 28 tons	12.03m x 2.35m x 2.39m	Multi-rack BESS, standard containerized systems	Most BESS units are built into 40ft frames. Good availability.
40ft High Cube	Up to 28 tons	12.03m x 2.35m x 2.69m	Tall BESS units, extra cooling space	30cm extra height vs standard 40ft. Good for liquid-cooled BESS.
40ft Open Top	Up to 35 tons	12.03m x 2.35m x (variable)	Tall units requiring top loading, units with protruding components	Top loading via crane. Tarpaulin cover required. Less weather protection.
40ft Flat Rack	Up to 45 tons	12.03m x 2.40m (platform)	Oversized BESS, heavy units, units wider than standard container	No side walls or roof. Requires professional lashing plan. End walls collapsible.

Non-standard container designs

Some BESS manufacturers build systems into custom-designed container frames that deviate from ISO 668 standard dimensions. These are classified as "non-standard containers" under Chinese regulations and are subject to additional structural testing requirements (see section 7 below). At Qingdao, non-standard UN3536 containers must be registered with the port authority at least 14 days before the planned vessel departure to allow time for the additional approval process.

2. CSC Safety Approval Plate: what it is and why it matters

The CSC Safety Approval Plate is a permanent metal plate affixed to every ISO shipping container. According to the International Maritime Organization (IMO), the International Convention for Safe Containers (CSC) has been adopted by over 80 contracting states, making the CSC plate a universally recognized safety certification. It is mandated by the International Convention for Safe Containers (CSC, 1972) and certifies that the container has been inspected and meets international structural safety standards.

For UN3536, the CSC plate has additional significance beyond standard container operations: it serves as the packaging certification for the dangerous goods. The International Maritime Organization (IMO) clarified through IMDG Code SP389 that for UN3536 cargo transport units, the container safety certification fulfills the packaging compliance requirement. Under IMDG Code SP389, the cargo transport unit itself is the packaging. The CSC plate, combined with the Performance Certificate and DG Packaging Certificate, forms the evidence chain that the packaging is safe and compliant.

What the CSC plate must show

• CSC Safety Approval text and reference to the convention
• Country of approval and approval reference number
• Date of manufacture (month and year)
• Manufacturer's identification number
• Maximum gross weight (in kg and lbs)
• Allowable stacking weight for 1.8G (in kg and lbs), the load the container can bear when stacked
• Transverse racking test load value (in kg and lbs)
• First maintenance examination date (ACEP, Approved Continuous Examination Program) or next examination date

3. 2025 revised container inspection rules: what changed

China's Container Statutory Inspection Technical Rules were revised effective October 1, 2025. For UN3536 containers, the key changes are:

1. Classification society certificate now mandatory: In addition to the CSC Safety Approval Plate, containers used as UN3536 cargo transport units must hold a valid inspection certificate from a recognized classification society: CCS (China Classification Society), DNV (Det Norske Veritas), BV (Bureau Veritas), Lloyd's Register, or ABS (American Bureau of Shipping). This certificate is separate from the CSC plate and must be presented as part of the port filing documentation.
2. Non-standard container testing: Any container that deviates from ISO 668 dimensions (standard 20ft, 40ft) must pass additional structural tests before first use and every 30 months thereafter. These tests are defined in JT/T 1543-2025 Appendix F (see section 7).
3. Periodic inspection interval reduced: For UN3536 containers, the periodic inspection interval was reduced from 30 months to 24 months under the 2025 rules. This means the CSC plate's next examination date cycle is 2 years, not 2.5 years.
4. ACE program documentation: If the container is maintained under an Approved Continuous Examination Program (ACEP), the ACEP certificate must be on file with the port authority. At Qingdao, we maintain ACEP documentation for all regularly used UN3536 containers.

4. Fire suppression system requirements

JT/T 1543-2025 specifies fire suppression requirements for UN3536 containers based on total battery capacity. According to the China Ministry of Transport (MOT), these requirements align with international best practices and were developed in consultation with classification societies including CCS and DNV. These requirements represent the first dedicated fire safety standard for BESS containers in transport in any jurisdiction.

Total Battery Capacity	Fire Suppression Required	System Type	Inspection Requirement
Under 100 kWh	Not required by JT/T 1543. Carrier may still require.	N/A	N/A
100 kWh to 500 kWh	Required: clean agent or aerosol system	Automatic activation at 70-80 degrees C detection temperature	Certificate valid within 12 months before loading
500 kWh to 3 MWh	Required: clean agent system with manual backup activation	Automatic + manual external activation point accessible from outside the container	Certificate valid within 12 months. Functional test within 30 days.
Over 3 MWh	Required: clean agent system + gas-based supplementary system	Multi-zone detection and discharge. Remote monitoring connection if BMS telemetry active.	Certificate valid within 6 months. Functional test within 30 days.

Approved fire suppression agents

• FK-5-1-12 (Novec 1230): Most commonly used. Clean agent, zero ozone depletion, electrically non-conductive. Effective on lithium battery electrolyte fires when applied at sufficient concentration (typically 4.2 to 5.3 percent by volume).
• HFC-227ea (FM-200): Widely accepted alternative to Novec 1230. Slightly lower environmental rating but well-established in maritime applications.
• Aerosol-based systems: Permitted for smaller systems (under 500 kWh). Stat-X or FirePro type condensed aerosol generators. Must be positioned to deliver agent directly into the battery compartment.

Water-based systems (sprinklers, water mist) are NOT approved for UN3536 container fire suppression under JT/T 1543-2025. The rationale is that water can cause short circuits in non-faulty battery modules, potentially escalating a localized thermal event into a cascading electrical failure.

5. Class 9 labeling and placarding specifications

IMDG Code Chapter 5.3 specifies the placarding requirements for Class 9 dangerous goods. According to the International Maritime Organization (IMO), the placarding requirements for UN3536 containers apply the standard Class 9 display rules with the additional UN number marking as specified in IMDG Code 5.3.2.1. For UN3536 containers, the following applies:

Class 9 placard specifications

• Size: Minimum 250mm x 250mm (standard IMDG placard size)
• Position: One placard on each of the four sides of the container (both sides, both ends, and the top if visible)
• Design: Seven vertical black stripes in the upper half on a white background, with the number "9" underlined in the bottom corner (standard Class 9 miscellaneous dangerous goods placard design per IMDG Code)
• Material: Weather-resistant vinyl or aluminum. Must remain legible after 30+ days of ocean transit including salt spray, rain, and UV exposure
• Attachment: Permanent adhesive or bolted. Tape or temporary attachment is not acceptable for Class 9 placards

UN3536 number marking

• Size: Minimum 100mm character height for the UN number
• Position: On at least two opposing sides of the container, adjacent to the Class 9 placard
• Format: "UN3536" in black text on an orange rectangular panel (standard IMDG UN number display), or directly on the container body adjacent to the Class 9 placard
• Durability: Same weather-resistance standard as the Class 9 placards

Additional markings

• Marine pollutant mark: Not required for UN3536 (lithium batteries are not classified as marine pollutants under the IMDG Code)
• Orientation arrows: Not required for UN3536 containers (orientation arrows apply to liquid DG packaging, not to large CTUs)
• Overweight marking: Required if the container gross weight exceeds the standard 30.48-ton limit. A yellow and black striped "SUPER HEAVY" marking is recommended for units over 30 tons

At our Qingdao CFS, we verify placarding and marking as part of the pre-loading inspection. Missing, damaged, or incorrectly positioned placards are the fastest issue to fix, but also the most common deficiency found during DG packing inspections.

6. UN3536 marking requirements: size, placement, durability

In addition to standard IMDG placarding, UN3536 has specific marking requirements under IMDG Code 5.3.2 and the Chinese national implementation rules.

UN number marking options

The UN number (UN3536) must be displayed using one of two methods:

1. Orange panel method: An orange rectangular panel (minimum 120mm x 300mm, with 10mm black border) displaying "UN3536" in black letters at least 100mm high. Placed adjacent to the Class 9 placard on at least two opposing sides.
2. Direct marking method: The UN number displayed directly on the container body in black characters at least 100mm high, on a white or contrasting background, adjacent to the Class 9 placard.

Placement verification

During DG packing inspection, the inspector checks:

• UN3536 marking present on at least two opposing sides (both long sides, or both ends, or one long side and one end of each pair)
• Marking clearly visible from ground level when the container is on a chassis or in a stack
• No conflicting UN numbers visible (if a container previously carried different DG cargo, old markings must be removed or completely covered)
• Characters are cleanly legible: no peeling, fading, or obstruction from container doors, locking bars, or CSC plate

7. Non-standard container structural testing

JT/T 1543-2025 Appendix F defines three mandatory structural tests for UN3536 containers that deviate from ISO 668 standard dimensions. These tests are derived from the CSC structural testing regime but with additional requirements specific to battery containment.

Test	Standard	What Is Tested	Pass Criteria
Lifting test	JT/T 1543-2025 Appendix F.1	Container lifted from all four top corner fittings with payload at 2.0 x rated maximum gross weight	No permanent deformation exceeding 5mm at any corner post. No cracking in structural welds. Floor deflection not exceeding L/300.
Vertical impact test	JT/T 1543-2025 Appendix F.2	Container dropped from 150mm height onto a rigid steel platform, landing on all four bottom corner fittings simultaneously, at rated maximum gross weight	No structural damage. Battery modules must remain securely mounted. No displacement of battery racks exceeding 3mm from baseline position.
Longitudinal securing test	JT/T 1543-2025 Appendix F.3	Container subjected to 2.0 x rated maximum gross weight in longitudinal deceleration (simulating emergency braking during road transport or vessel motion in heavy seas)	Battery modules remain within their mounting frames. No contact between adjacent modules. Lashing points and tie-down anchors show no deformation.

These tests must be conducted by a classification society (CCS, DNV, BV, Lloyd's Register, or ABS) or an accredited testing laboratory. The test report is valid for 30 months and must be renewed upon expiry or after any structural modification to the container.

If your BESS manufacturer uses a custom container design, confirm that the structural test reports are available before booking. At Qingdao, we have seen several cases where non-standard containers arrived without valid test reports, causing 2 to 3 week delays while the testing was arranged.

8. Pre-loading inspection checklist (10-point check)

This is the checklist our DG-certified packing inspectors use at the Qingdao CFS before every UN3536 container moves to the terminal. Each item is verified, documented with a photograph, and signed off.

1. CSC Safety Approval Plate: Present, legible, next examination date not expired. Container identification number matches the booking.
2. Classification society certificate: Valid CCS, DNV, BV, LR, or ABS inspection certificate on file. Expiry date confirmed.
3. Container structural condition: No dents exceeding 25mm depth. No holes, cracks, or corrosion in the floor, walls, roof, or corner posts. Door gaskets intact and sealing properly.
4. Battery installation security: Battery modules/racks securely mounted. No loose hardware. All mounting bolts torqued to specification. Visual confirmation that no module has shifted since factory installation.
5. Series/parallel disconnection: Physical disconnection verified at all series and parallel connection points per the electrical schematic. Disconnected cables secured against movement. Photographed.
6. Fire suppression system: If required (capacity over 100 kWh): system present, inspection certificate valid within 12 months, functional test completed within 30 days. Manual activation point accessible and marked.
7. SOC verification: BMS SOC reading compared against carrier limit. SOC certificate signed and dated. If SOC exceeds limit, unit held at CFS for discharge.
8. Class 9 placards: Present on all four sides. Minimum 250mm x 250mm. Weather-resistant. No damage. Correctly positioned.
9. UN3536 marking: Present on at least two opposing sides. Minimum 100mm character height. Legible. No conflicting markings visible.
10. Documentation pack: MSDS and emergency response guide placed in a weatherproof pouch inside the container, accessible from the door. Container Packing Certificate prepared and signed.

9. Frequently asked questions

Sources and references

• IMDG Code Special Provision 389 (SP389): IMO International Maritime Dangerous Goods Code, Amendment 42-24. IMO IMDG Code
• JT/T 1543-2025 《船舶载运锂电池安全技术要求》: 交通运输部, 2025年1月26日发布, 2025年5月1日实施. 交通运输部公告
• UN TDG Rev. 24 (2025): UN Model Regulations, 24th revised edition, splitting UN3536 into three codes. UNECE TDG
• Ningbo Port UN38.3 Mandatory Requirement: ONE (Ocean Network Express) advisory, October 2025. ONE Advisory, Seatrade Maritime
• UN38.3: UN Manual of Tests and Criteria, Part III, Sub-section 38.3. UNECE Manual of Tests
• PHMSA Interpretation 25-0015 (April 2025): Clarification on UN3536 placarding requirements. PHMSA 25-0015
• Container Statutory Inspection Technical Rules (2025版): 中国船级社, effective October 1, 2025. Referenced from CCS technical notices.

All operational data based on Great Hensen's shipping records: 1,000+ TEU of UN3536 cargo shipped since 2022. Last verified: July 2026.