1H1 / 1H2 drum

An HDPE Drum is a blow-moulded high-density polyethylene drum, typically 200 to 220 litres capacity, used for the transport of corrosive and aqueous chemical liquids. UN-coded 1H1 for closed-head (non-removable lid) liquid service and 1H2 for open-head (removable lid) solids and viscous-liquid service, the HDPE drum is the default packaging for caustic soda solutions, hydrochloric acid at most concentrations, sodium hypochlorite, and the broad family of aqueous corrosive chemicals that would attack a steel drum within months. HDPE is chemically inert toward most aqueous chemistry up to about 80°C and offers a 5-7 year service life under good handling.

1H1 vs 1H2 construction

For routine chemical sourcing the 1H1 closed-head is the dominant format. Aqueous corrosives, dilute acids, and most aqueous bases ship in 1H1. The 1H2 open-head is used for higher-viscosity products (some polyols, some viscous polymers) and for solid cargoes that would benefit from the corrosion-resistant body but need full-aperture access.

Standard HDPE drum dimensions

For caustic soda 50% solution at SG 1.52, a 200-L drum holds 304 kg net. The fill is governed by the drum’s mass-rated UN code (the test mass on the marking) and the cargo SG. Most factory practice is to fill 200-L drums to a maximum 200 kg net or 304 kg gross, whichever is lower.

Cargo-compatibility envelope

HDPE is chemically inert toward:

• Aqueous bases (caustic soda, KOH, sodium carbonate solutions)
• Aqueous mineral acids (HCl up to 37%, sulphuric acid up to ~70%)
• Aqueous oxidisers at moderate concentration (sodium hypochlorite up to 15%, hydrogen peroxide up to 35%)
• Aqueous salt solutions (most chlorides, sulphates, nitrates)
• Most alcohols, glycols, simple aldehydes
• Water-based polymer dispersions, latexes

HDPE is incompatible with:

• Aromatic solvents (toluene, xylene, benzene). HDPE swells, the drum body bulges and may fail
• Chlorinated solvents (DCM, perchloroethylene). HDPE swells and the bung threads can fail
• High-temperature cargoes above ~80°C. HDPE softens; the drum may deform under stacking pressure or cargo weight
• Concentrated nitric acid (>40%). HDPE oxidises and embrittles
• Concentrated sulphuric acid (>96%), slow attack on the inner surface; for fuming sulphuric (oleum) HDPE is unsuitable
• Highly oxidising cargoes (concentrated hypochlorite, concentrated peroxide solutions) at elevated temperatures

For cargoes outside the HDPE envelope, steel drums (1A1) or lined drums (steel with internal corrosion-resistant coating) are the alternatives.

Container loading economics

For 200-kg HDPE drums on standard Euro pallets (4 drums per pallet, 5 pallets long × 4 wide):

For HDPE drum cargo, 20-foot containers usually weigh out before they cube out. The 40-foot container is rarely the right format unless cargo SG is below 1.0 (light specialty solvents, dilute solutions).

When HDPE drum is the right packaging

HDPE drum is the right choice for:

1. Aqueous corrosive liquids at parcel scale (1-20 MT). Caustic soda solutions, HCl 37%, sodium hypochlorite, all default-ship in HDPE 1H1.
2. Multi-drum split shipments where the buyer dispenses by the drum. A buyer running 200-kg test batches gets cargo, drum, and traceability in one package.
3. Routes with limited IBC handling. Smaller buyers in markets without IBC dispensing infrastructure prefer drums.

HDPE drum is wrong for:

1. Volume bulk shipments. Above ~25 MT per cargo, IBCs (1,000-kg HDPE composite or rigid HDPE) are more economical.
2. Cargoes outside the HDPE envelope, chlorinated solvents, concentrated nitric, fuming sulphuric, high-temperature cargo.
3. Buyers who need long-term storage above 12 months. HDPE allows slow oxygen and CO₂ permeation; cargoes sensitive to atmospheric exposure (some polymerisable monomers, some pharmaceutical intermediates) lose specification over long storage.

The bung-thread leak failure mode

The single most common HDPE drum failure on long sea routes is bung-thread leakage. Three causes:

1. Bung not torqued correctly at the factory. The 2-inch buttress thread needs hand-tightening with a bung wrench to a specific torque. A loose bung leaks slowly through the voyage and arrives partially empty.
2. Differential pressure during voyage. Day-night thermal cycling produces internal pressure swings of ±0.05 bar. Cargoes with significant headspace breathe through any gap; tight cargoes do not.
3. Drum body crush from over-stacking. Many HDPE drums are rated for 4-drum or 5-drum stacks; loaders sometimes stack 6-7 drums during port handling. The bottom drum’s bung face deforms and the seal fails.

The mitigation: specify factory bung torque-check on the loading plan, double-bung the cargo (a flat plastic gasket plus the threaded plug), and limit stacking to the rated tier height.

HDPE drum reuse and disposal

Reconditioned HDPE drums clean to a reusable standard for non-DG cargo, but UN-certified reuse for DG cargo requires recertification by a licensed reconditioner, typically every 2 years. After their useful life, HDPE drums are either:

• Granulated and recycled into low-grade HDPE products (drainage pipe, fence posts, plastic lumber)
• Disposed at industrial waste sites at USD 10-30 per drum, depending on residual contamination

For volume importers, an arrangement with a local drum-reconditioning service can recover USD 15-40 per drum on resale, partially offsetting the per-shipment drum cost.

Related terms

Drum is the parent reference covering all UN-coded drum types. Fibre drum is the paperboard alternative for solids. Lined drum is the steel-with-internal-coating alternative for cargoes outside the HDPE envelope. IBC is the next size up (1,000 kg). IMDG Class 8 corrosives and Class 3 flammable liquids are common 1H1 cargoes. 20-foot container is the standard freight format.