1. What is UN 38.3
UN 38.3 refers to Section 38.3 of the UN Manual of Tests and Criteria. It is the globally recognized safety testing standard for all lithium metal and lithium-ion batteries and cells before they can be transported by air, sea, rail, or road.
No airline, shipping line, or carrier will accept lithium battery cargo without a valid UN 38.3 test report.
The latest version is Rev.8 (2023 edition), which becomes mandatory from January 1, 2026. Reports based on Rev.6 or Rev.7 will no longer be accepted by the Lithium-ion Battery Test Chamber.
2. Why It Is Mandatory
Lithium batteries pose risks of fire, explosion, and toxic fume release if they are damaged, short-circuited, overheated, or mishandled during transport. UN 38.3 verifies that batteries can withstand the extreme conditions of global logistics without leaking, catching fire, exploding, or rupturing.
3. The Eight Core Tests
All tests must be performed in sequence. Tests T.1 through T.5 use the same set of samples. Tests T.6 and T.8 use fresh samples. Test T.7 can reuse undamaged samples from T.1 through T.5.
T.1 Altitude Simulation
Simulates the low-pressure environment inside an aircraft cargo hold at approximately 15,000 meters. Pressure is reduced to 11.6 kPa or below for at least 6 hours. Pass criteria: no leakage, no fire, no rupture, and open circuit voltage must remain at or above 90 percent of the pre-test voltage.
T.2 Thermal Cycling
Evaluates seal integrity and internal electrical connections under extreme temperature swings. High temperature is 72 degrees Celsius, low temperature is minus 40 degrees Celsius, for 10 cycles. Each extreme is held for at least 6 hours with a transition time of no more than 30 minutes. After cycling, the samples rest for 24 hours at 20 degrees Celsius. Pass criteria are the same as T.1.
T.3 Vibration
Simulates transport vibration using a sinusoidal sweep from 7 Hz to 200 Hz and back to 7 Hz. Each sweep cycle takes 15 minutes. There are 12 cycles per axis across three mutually perpendicular mounting positions, totaling 36 cycles over 3 hours. Small batteries under 12 kg use 1 gn to 8 gn acceleration. Large batteries of 12 kg or more use 1 gn to 2 gn. Pass criteria are the same as T.1.
T.4 Shock
Evaluates resistance to cumulative shock impacts using a half-sine pulse. Small batteries under 12 kg are tested at 150 gn for 6 milliseconds. Large batteries of 12 kg or more are tested at 50 gn for 11 milliseconds. Three shocks per axis in three axes, in both directions, totaling 18 shocks. Pass criteria are the same as T.1.
T.5 External Short Circuit
Simulates an accidental external short. The battery is shorted through an external resistance of less than 0.1 ohm at 57 degrees Celsius. The test continues until the case temperature returns to 57 degrees Celsius plus one additional hour. Pass criteria: case temperature must not exceed 170 degrees Celsius, and there must be no fire or rupture within 6 hours after the test.
T.6 Impact and Crush
Simulates mechanical abuse that could cause an internal short circuit.
For cylindrical cells with a diameter of 18 mm or more, a 9.1 kg steel bar is dropped from 61 cm onto the cell.
For prismatic, pouch, coin cells, and other formats, a crush force of 13 kN is applied.
Pass criteria: no fire, no explosion, surface temperature not exceeding 170 degrees Celsius, observed for 6 hours.
T.7 Overcharge (Rechargeable Batteries Only)
Simulates a charger failure scenario. The battery is charged at 2 times the maximum continuous charge current. The voltage limit is 2 times the maximum voltage or 22 volts, whichever is lower, for batteries under 18 volts. For batteries above 18 volts, the limit is 1.2 times the maximum voltage. Duration is 24 hours. Pass criteria: no fire or explosion within 7 days after the test.
T.8 Forced Discharge (Primary Batteries Only)
Simulates a reverse charge scenario. The cell is connected in series with a 12-volt DC power supply and discharged at the maximum discharge current. Pass criteria: no fire or explosion within 7 days after the test.
4. 1.2 Meter Free Fall Drop Test
If batteries are shipped alone (not packed with equipment) and the package contains more than 24 cells or more than 12 batteries, a 1.2 meter free fall test is also required. The package is dropped once on each of six faces: top, bottom, left, right, front, and back.
5. Applicable Products and UN Numbers
Lithium-ion cells are classified as UN3480. Lithium-ion batteries are UN3481. Lithium metal cells are UN3090. Lithium metal batteries are UN3091. Starting from 2025, sodium-ion batteries are classified as UN3551 and must also pass UN 38.3. Equipment containing only lithium button cells with a circuit board is exempt from the test summary requirement during the 2026 transition period.
6. Key Compliance Updates for 2026
First, Rev.8 becomes mandatory on January 1, 2026, and all older reports are invalid. Second, lithium-ion batteries shipped alone by air must be at 30 percent state of charge or below. Third, a test summary must accompany every shipment, including manufacturer details, laboratory information, test report number, and battery description. Fourth, packing instructions PI 965 and PI 968 Part II have been deleted, and PI 966 and PI 969 Part I have been revised. Fifth, the requirement for a phone number on labels will be phased out by December 31, 2026.
7. Test Process and Sample Requirements
Approximately 40 cell samples are needed (15 for testing plus 25 spares). Approximately 37 battery samples are needed (12 for testing plus 25 spares). A UN 38.3 report alone takes about 2 weeks. A complete package including the report, test summary, safety data sheet, and transport certificate takes 3 to 4 weeks. The report has no fixed expiry date, but any change in design, materials, or process will invalidate it. The laboratory must hold CNAS or ILAC accreditation.
8. Mode-Specific Transport Rules
For air transport under IATA DGR, standalone lithium-ion batteries must not exceed 30 percent state of charge and must use the cargo aircraft only label. For sea transport under the IMDG Code, packing group assignment is based on watt-hour rating. For rail and road transport under ADR, a Class 9 hazard label is required, along with UN-approved packaging and a safety data sheet.
9. Packing Groups by Watt-Hour Rating
For lithium-ion cells: above 20 Wh is Packing Group II, above 100 Wh is Packing Group I. For lithium-ion batteries: above 100 Wh is Packing Group II, above 400 Wh is Packing Group I. For lithium metal cells: above 1 gram of lithium is Packing Group II, above 5 grams is Packing Group I. For lithium metal batteries: above 2 grams of lithium is Packing Group II, above 25 grams is Packing Group I. Batteries below these thresholds are not restricted as dangerous goods for transport but still require UN 38.3 testing.
10. Key Takeaways
Always use a CNAS-accredited laboratory. Always use the Rev.8 standard mandatory from 2026. Keep state of charge at or below 30 percent for standalone lithium-ion batteries shipped by air. Update the report whenever there is any design change. Attach the test summary to every shipment. UN 38.3 is not optional. It is the global passport that allows lithium batteries to enter the worldwide logistics system.
Further Reading: UN 38.3 Lithium Battery Transport Safety Test Standard Guide
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