Segregation and separation

Scope

For highway transportation of hazardous materials, the segregation requirements apply to materials that are in:

Regulatory citations

• 49 CFR Part 172 — Hazardous materials table, special provisions, hazardous materials communications, emergency response information, training requirements, and security plans
• 49 CFR 173.33 — Hazardous materials in cargo tank motor vehicles
• 49 CFR 176.83 — Segregation
• 49 CFR 177.848 — Segregation of hazardous materials

Key definitions

• Package: A packaging plus its contents.
• Packaging: A receptacle and any other components or materials necessary for the receptacle to perform its containment function in conformance with the minimum packing requirements.
• Portable tank: A bulk packaging (except a cylinder having a water capacity of 1000 pounds or less) designed primarily to be loaded onto, or on, or temporarily attached to a transport vehicle or ship and equipped with skids, mountings, or accessories to facilitate handling of the tank by mechanical means. It does not include a cargo tank, tank car, multi-unit tank car tank, or trailer carrying 3AX, 3AAX, or 3T cylinders.

Summary of requirements

The following segregation table specifies the restrictions on loading, transporting and storing hazardous materials when offered for or transported by highway.

Note: Cyanides and cyanide mixtures or solutions may not be stored, loaded and transported with acids. Division 4.2 materials may not be stored, loaded and transported with Class 8 liquids.

How to use the table 177.848(e)

To use the Segregation Table:

1. Locate the hazard classes or divisions of the materials in question — one in the vertical column, the other in the horizontal row.
2. Follow each to the location where they intersect.
3. The codes at the intersection are defined as follows:
   • “Blank” means there are no restrictions.
   • “X” means the materials may not be loaded, transported or stored together.
   • “O” means the materials may not be loaded, transported or stored unless separated in a manner that, in the event of leakage, there would be no commingling of the materials under circumstances normal to transportation.
   • “*” means that segregation of different Class 1 materials is governed by the compatibility table in 177.848(f) .
   • “A” means ammonium nitrate fertilizer may be loaded or stored with Division 1.1 or Division 1.5 materials, regardless of the “X.”

The absence of any hazard class or division in the table indicates that no restrictions apply.

Transport vehicle onboard a vessel 176.83(b). When a transport vehicle is to be transported by vessel, other than a ferry vessel, hazardous materials on or within that vehicle must be stowed and segregated in accordance with 176.83(b).

Subsidiary hazards 177.848(e)(6). When the segregation requirements for packages bearing subsidiary hazard labels are more restrictive than those of the primary hazard, the subsidiary segregation requirements must be followed.

However, hazardous materials of the same class may be stowed together without regard to the subsidiary segregation requirements if the materials are incapable of reacting so as to cause:

• Combustion or dangerous evolution of heat;
• Evolution of flammable, poisonous, or asphyxiant gases; or
• Formation of corrosive or unstable materials.

Compatibility Table for Class 1.