Question: Can I ship solids in a drum rated for liquids?
Answer: Yes, but the reverse is not true. You cannot ship liquids in a drum that is rated only to ship solids. Many open-head drums that are UN rated for shipping liquids have a dual rating. This means that there are actually two UN markings on the container–one for liquids, the other for solids.
If that’s not the case, the Department of Transportation (DOT) has a provision that allows the shipper to use the liquids rating to calculate the maximum allowable weight of solids that can be shipped in the container. [49 CFR 173.24a(b)(3)]. The calculation is not hard, but you still might want to grab a calculator.
Take the capacity of the drum in liters and multiply it by the specific gravity listed in the UN rating. This will give you the permissible maximum gross mass of the filled container in kilograms.
Example: If you have a 55-gallon drum with a UN rating UN 1A2/X1.8/150, the calculation would be:
| 208 |
x |
1.8 |
= |
374.4 kg |
| (volume in liters) |
|
(specific gravity) |
|
(gross allowable weight of filled drum) |
There are two additional allowances that are helpful when a Packing Group liquids-rated container is used for Packing Group II or III solids:
- If the container has a Packing Group I liquids rating, it can be used to ship a Packing Group II solid by multiplying the container’s capacity (in liters) by the specific gravity, multiplied by 1.5 to get the allowable gross weight. Using the same 55-gallon drum from the scenario above, that calculates to:
| 208 |
x |
1.8 |
x |
1.5 |
= |
561.6 kg |
- If the container has a Packing Group I liquids rating, it can be used to ship Packing Group III solids by multiplying the container’s capacity (in liters) by the specific gravity, multiplied by 2.25 to get the allowable gross weight. Using the same 55-gallon drum from the scenario above, that calculates to:
| 208 |
x |
1.8 |
x |
2.25 |
= |
842.4 kg |
Of course, it is nice to have a dual-rated container to give you the reassurance that the supplier has actually tested the drum for both conditions, but if you’re in a pinch and only have containers rated for liquids, it’s good to be aware of this provision.
1 Comment
Dan McDonaldsays:
08/22/2019 at 12:22 pmThanks Karen, this was helpful!
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