DOT transport classification

Sodium hydroxide solution (caustic soda): DOT classification

Sodium hydroxide solution (caustic soda) does not have a UN number that changes at a stated concentration. Under 49 CFR 172.101 the packing group is assigned by test criteria, not by percentage — see below for what decides it and how Alliance Chemical's own grades are classified.

CAS 1310-73-2 · Source: 49 CFR 172.101 Hazardous Materials Table; packing group per 49 CFR 173.137

Why there is no percentage cutoff

UN1824 is Class 8 throughout; the packing group follows the 49 CFR 173.137 corrosivity criteria rather than a stated percentage. Concentrated solutions (25%, 50%) ship PG II. Solid sodium hydroxide is a different entry, UN1823.

How Alliance Chemical's grades are classified

Each classification below is the verified value for that product, not an inference from its strength.
UN numberClassPacking groupProducts
UN18238IIKomodo Drain Cleaner Technical Grade in a 4-lb white plastic bottle, Alliance ChemicalKomodo Drain CleanerSodium Hydroxide Flakes Technical Grade 4-lb white plastic bottle Alliance ChemicalSodium Hydroxide FlakesSodium Hydroxide Flakes ACS Grade 4-pound plastic bottle, Alliance Chemical for chemical synthesisSodium Hydroxide Flakes ACS Grade
UN18248IISodium Hydroxide 5% ACS GradeSodium Hydroxide 5% ACS GradeSodium Hydroxide 5% Technical GradeSodium Hydroxide 5% Technical GradeSodium Hydroxide 10% ACS GradeSodium Hydroxide 10% ACS GradeSodium Hydroxide 10% Technical GradeSodium Hydroxide 10% Technical GradeSodium Hydroxide 15% ACS GradeSodium Hydroxide 15% ACS GradeSodium Hydroxide 15% Technical GradeSodium Hydroxide 15% Technical GradeSodium Hydroxide 20% ACS GradeSodium Hydroxide 20% ACS GradeSodium Hydroxide 20% Technical GradeSodium Hydroxide 20% Technical GradeSodium Hydroxide 25%Sodium Hydroxide 25%Sodium Hydroxide 25% ACS GradeSodium Hydroxide 25% ACS GradeSodium Hydroxide 30% ACS GradeSodium Hydroxide 30% ACS GradeSodium Hydroxide 30% Technical GradeSodium Hydroxide 30% Technical GradeSodium Hydroxide 50% Membrane Grade solution in a 1-gallon jug, Alliance ChemicalSodium Hydroxide 50% Membrane Grade (Caustic Soda, Lye)Sodium Hydroxide 50% Solution ACS Grade in a 1-gallon plastic jug for pH neutralization, Alliance ChemicalSodium Hydroxide 50% Solution ACS Grade

How to read this

  • Percentages are by mass. 49 CFR 172.101 thresholds are w/w, but product labels often state volume (v/v). Near a cutoff the two can fall on opposite sides, so confirm the basis before classifying a shipment.
  • Products listed are verified individually. A product appears in a band only when its own reviewed classification matches it. Where a product's classification is still under review, we leave it out rather than infer it from the table.
  • This page is a reference, not a shipping paper. Classification for an actual shipment depends on packaging, quantity and mode; consult the current eCFR entry and the product's safety data sheet.

Source

49 CFR 172.101 Hazardous Materials Table; packing group per 49 CFR 173.137. Reference text: “Caustic soda solution. PG by corrosivity (173.137): concentrated solutions (e.g. 50%, 25%) ship PG II; dilute solutions ship PG III. Solid NaOH = UN1823 (PG II).”

All DOT classification references