Class 3 highway/rail placarding starting rules

Short answer

Class 3 is a Table 2 material, normally using the FLAMMABLE placard defined in 49 CFR 172.542. For highway or rail non-bulk shipments, the less-than-454 kg (1,001 lb) exception in 49 CFR 172.504(c) uses the aggregate gross weight of all Table 2 hazardous materials—packaging plus contents. At 454 kg or more, that weight exception does not apply.

Check the exceptions

The weight exception does not cover bulk packages or materials subject to 49 CFR 172.505. Bulk Class 3 packages generally require placarding regardless of quantity. Limited-quantity, combustible-liquid, subsidiary-hazard and mixed-load rules can change the result; a DANGEROUS placard is permitted only when its specific conditions are met. A vehicle placard is different from a package label.

To decide a particular load

Provide the proper shipping name/UN number, hazard and packing group, highway/rail mode, bulk or non-bulk packaging, package capacities, aggregate gross weights and any other hazardous materials. A product described only as “flammable liquid” is not enough to clear a shipment.