UN 3156

COMPRESSED GAS, OXIDIZING, N.O.S.

UN 3156 — ADR 2025 Table A: class 2, classification code 1O, packing group —, labels 2.2 +5.1, special provisions 274 655 662, limited quantity 0, excepted quantity E0, packing instructions P200, transport category 3, tunnel restriction code (E), hazard identification number 25.

UNECE ADR 2025, ECE/TRANS/352 · checked 2026-10-28

Table A — ADR 2025 (ECE/TRANS/352), UN 3156
(1) UN No.3156
(2) Name and descriptionCOMPRESSED GAS, OXIDIZING, N.O.S.
(3a) Class2
(3b) Classification code1O
(4) Packing group—
(5) Labels2.2 +5.1
(6) Special provisions274 655 662
(7a) Limited quantities0
(7b) Excepted quantitiesE0
(8) Packaging: packing instructionsP200
(9a) Packaging: special packing provisions—
(9b) Packaging: mixed packing provisionsMP9
(10) Portable tanks and bulk containers: instructions(M)
(11) Portable tanks and bulk containers: special provisions—
(12) ADR tank: tank codeCxBN(M)
(13) ADR tank: special provisionsTA4 TT9
(14) Vehicle for tank carriageAT
(15) Transport category (Tunnel restriction code)3 (E)
(16) Special provisions for carriage: packages—
(17) Special provisions for carriage: bulk—
(18) Special provisions for carriage: loading, unloading and handlingCV9 CV10 CV36
(19) Special provisions for carriage: operation—
(20) Hazard identification No.25

ADR 2027 (accepted) — no change for UN 3156

ADR 2027 was accepted: depositary notification C.N.395.2026 (9 October 2026) records no objection to the amendments proposed by C.N.252.2026. It applies from 1 January 2027, and ADR 2025 may still be applied until 30 June 2027 (1.6.1.1). (C.N.395.2026)

ADR 2027: no Table A change for this entry (checked against ECE/TRANS/WP.15/274, Add.1 and Corr.1). Other parts of ADR 2027 may still affect its carriage.

This entry under ADR 2027 on the API: /api/adr?un=3156&edition=2027 (editions and as_of).

ADR 2025 is the edition that applies until ADR 2027 takes effect on 1 January 2027, and FreightUtils answers on it by default until then; the API answers on ADR 2027 now with edition=2027. After that date, ADR 2025 may still be applied until 30 June 2027 (1.6.1.1).

All ADR 2027 Table A changes →Check a list of UN numbers →

In plain words

Tunnels
Tunnel code (E): in tanks, Prohibited in E; in other carriage, Prohibited in E. Every category except E. (ADR 8.6.4; from the ADR table itself)
Small-load exemption
Transport category 3: at most 1000 per transport unit under 1.1.3.6, counted ×1 toward the 1,000-point limit (ADR 1.1.3.6.3; from the ADR table itself)
Labels
Labels: model 2.2 (Gases: non-flammable, non-toxic gases), model 5.1 (Oxidizing substances) (ADR 5.2.2.2.2, label model No. 2.2, 5.2.2.2.2, label model No. 5.1; paraphrase, not yet reviewed)
Packing
Packing instruction P200: Gases in cylinders, tubes, pressure drums and bundles: closure, test pressure, filling limits, periodic inspection and per-gas provisions. Mixed packing provision MP9: May share a combination outer packaging with other Class 2 goods, with other classes that permit it, or with non-ADR goods. (ADR 4.1.4.1, P200, 4.1.10.4, MP9; paraphrase, not yet reviewed)
Tanks
Portable tank instruction (M): Marker in column (10): the substance may also be carried in UN MEGCs (multiple-element gas containers). Tank code CxBN(M): ADR tank code for Class 2 gases: compressed gas tank, X (test pressure from 4.3.3.2.5), openings B, valves/devices N, suffix (M). — C: tank, battery-vehicle or MEGC for compressed gases; X: the minimum relevant test pressure taken from the table in 4.3.3.2.5 for the gas; B: tank filled or discharged from the bottom through openings having 3 closures; or a battery-vehicle/MEGC with openings below the liquid surface or for compressed gases; N: safety valve conforming to 6.8.3.2.9 / 6.8.3.2.10 that is not hermetically closed; (M): the substance may also be carried in battery-vehicles or MEGCs (3.2.1, column (12)) Tank provision TA4: Conformity assessment under 1.8.7 by the competent authority or an inspection body to 1.8.6.3 accredited to EN ISO/IEC 17020:2012 type A. Tank provision TT9: Inspections and tests, including supervision of manufacture, under 1.8.7 by the competent authority or a type A accredited inspection body. Vehicle for tank carriage: AT — Tank vehicle for dangerous goods that is not EX/III, FL or a MEMU: tanks over 1 m³ / 3 m³, or battery-vehicle over 1 m³. (ADR 3.2.1, explanation of Column (10), 4.3.3.1.1, tank code CxBN(M), 6.8.4 (c), TA4, 6.8.4 (d), TT9, 9.1.1.2, AT vehicle; paraphrase, not yet reviewed)
Carriage
Loading provision CV9: Do not throw packages or subject them to impact; stow receptacles so they cannot tip over or fall. Loading provision CV10: Cylinders lie along or across the vehicle axis (across at the front wall); stable or secured ones may stand; flat ones must be wedged. Loading provision CV36: Prefer open or ventilated units; if closed, isolate the cab from the load and mark doors "WARNING NO VENTILATION OPEN WITH CAUTION" (≥ 25 mm). (ADR 7.5.11, CV9, 7.5.11, CV10, 7.5.11, CV36; paraphrase, not yet reviewed)

Assembled from FreightUtils' meanings of the Table A codes, not the official text. A statement marked “not yet reviewed” has not yet been checked against ADR by a person.

Class 2 — Gases
UN 3156Class 2 — Gases
Packing Group
N/A
Not applicable
Classification Code
1O
Tunnel Code
(E) meaning →
Code governing tunnel passage
Transport Category
3
For the 1,000-point rule (0 = highest restriction)
Hazard ID No.
25
Kemler code
Limited Quantity
0
Max per inner package for LQ relief
Excepted Quantity
E0
EQ code for excepted quantity relief
Thresholds — why, not just the verdict
Transport Category
Category 3
×1 points per kg/L — up to 1,000 kg/L of this substance alone stays under the 1,000-point threshold
Per-substance max
1,000 kg/L
Per-substance maximum for 1.1.3.6 relief (1.1.3.6.3)
Limited Quantity
Not permitted
No limited-quantity relief for this entry (Chapter 3.4)
Excepted Quantity
E0
No excepted-quantity relief for this entry (Chapter 3.5)
Tunnel Code
Governs which tunnel categories the load may pass
Special Provisions
SP 274, SP 655, SP 662
May alter scope or limits — full text in ADR 2025 Chapter 3.3
Hazard Labels Required
Label 2.2Label 5.1

These labels must be displayed on packages and vehicle placards in accordance with ADR 2025.

Special Provisions
SP 274SP 655SP 662

Refer to ADR 2025 Chapter 3.3 for full text of each provision.

Check if UN 3156 qualifies for 1.1.3.6 exemption
Calculate small load points and check exemption thresholds
Open calculator →

Other Gases near UN 3156 (Class 2)

UN 3153
PERFLUORO(METHYL VINYL ETHER)
UN 3154
PERFLUORO(ETHYL VINYL ETHER)
UN 3157
LIQUEFIED GAS, OXIDIZING, N.O.S.
UN 3158
GAS, REFRIGERATED LIQUID, N.O.S.
UN 3159
1,1,1,2-TETRAFLUOROETHANE (REFRI…
All Class 2 UN numbers →
Use this data programmatically
GET /api/adr?un=3156
View API Docs →
📅Data: UNECE ADR 2025 (ECE/TRANS/352), via EU Directive 2008/68/EC. Last verified October 2026

ADR reference data only. Classification is the consignor's legal responsibility. Consult a DGSA for compliance decisions.

Stay updated
ADR 2027 changes, new tools, and freight industry updates. No spam, unsubscribe anytime.
Related Tools
ADR 1.1.3.6 Exemption Calculator→LQ/EQ Checker→ADR Dangerous Goods Lookup→

Found an error? Let us know → contact@freightutils.com

← UN3155↑ Back to searchUN3157 →