HS Code 73.11 – Containers for compressed or liquefied gas, of iron or steel

HS code 7311 is a 4-digit heading in the Harmonized System that covers: Containers for compressed or liquefied gas, of iron or steel. Heading 7311 is specifically dedicated to containers for compressed or liquefied gas, of iron or steel. This classification encompasses a range of specialized vessels designed to safely hold gases under high pressure or in liquefied form, including industrial gas cylinders, medical gas tanks, propane tanks, and CNG (Compressed Natural Gas) cylinders. The crucial aspects for classification are the material (iron or steel) and the explicit design for containing compressed or liquefied gas. This distinguishes them from general liquid or solid storage tanks (7309, 7310). The scope includes both empty and filled containers, as long as their primary design is for gas. Sub-categories often relate to the specific gas they are designed for, their pressure rating, and construction method (e.g., seamless, welded). This classification is critically important for trade compliance due to the inherent safety risks associated with high-pressure gas. Importers and exporters must adhere to stringent national and international safety standards (e.g., DOT, ISO, ADR), testing requirements, and marking regulations, which significantly impact market access and liability. Historically, the demand for these containers has grown with industrialization, healthcare advancements, and the use of alternative fuels. As part of Chapter 73, it underscores the specialized application of iron and steel in safety-critical containment solutions.

Industrial oxygen cylinders, acetylene gas cylinders, nitrogen gas cylinders, carbon dioxide cylinders, propane tanks (LPG), butane gas cylinders, CNG (Compressed Natural Gas) tanks for vehicles, medical gas cylinders (e.g., for nitrous oxide), diving cylinders (scuba tanks), fire extinguisher cylinders (empty), refrigerant gas cylinders, helium gas cylinders, hydrogen gas cylinders, cryogenic gas cylinders (steel), ammonia gas cylinders, chlorine gas cylinders, specialty gas cylinders, calibration gas cylinders, automotive LPG tanks, small disposable gas cartridges (steel, for lighters/camping stoves), gas storage spheres (steel, for bulk gas), welding gas cylinders, air brake tanks (for vehicles).

The primary misclassification error is confusing these gas containers (7311) with general-purpose liquid or solid storage tanks (7309, 7310). The key is the design for *compressed or liquefied gas* – a steel drum (7310) is not a gas cylinder. Even if empty, if it's designed for gas, it's 7311. Another mistake is classifying gas containers made of other materials, such as aluminum (7613), under this heading. Additionally, pressure vessels that are integral, non-separable parts of machinery (e.g., an air reservoir built into a braking system classified under 8708) might be incorrectly classified as standalone gas containers.

In 2025, the top exporters of HS code 7311 in UN Comtrade data were China ($1.3B, 29% of world exports), the United States ($326M) and Türkiye ($283M). World exports came to about $4.5B, adding countries' reported figures and partner-based estimates for those that did not report (UN Comtrade data). Countries that did not report 2025 data are estimated from partner records, which can understate them.

In 2025, the top importers of HS code 7311 in UN Comtrade data were the United States ($503M, 12% of world imports), Germany ($215M) and South Korea ($213M). World imports came to about $4.1B, adding countries' reported figures and partner-based estimates for those that did not report (UN Comtrade data). Countries that did not report 2025 data are estimated from partner records, which can understate them.

HS code 7311 is a 4-digit heading under Chapter 73 of the Harmonized System. The first 2 digits (73) identify the chapter, and digits 3-4 (11) specify the heading. This code contains multiple 6-digit subheadings for precise product classification.