Interpretation Response #25-0017
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
Response Publish Date:
Company Name: Teledyne Scientific & Imaging
Individual Name: Jennifer Kuo
Location State: CA Country: US
View the Interpretation Document
Response text:
April 8, 2025
Jennifer Kuo
Teledyne Scientific & Imaging
1049 Camino Dos Rios
Thousand Oaks, CA 91360
Reference No. 25-0017
Dear Ms. Kuo:
This letter is in response to your February 11, 2025, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the use of the United Nations (UN) identification number and proper shipping name "UN1396, Aluminum powder, uncoated." Specifically, you ask if there is a particle size limit with respect to the use of this hazardous materials description.
No. While certain hazardous materials descriptions and proper shipping names in the § 172.101 Hazardous Materials Table (HMT) limit use of the entry (e.g., a concentration range, particle size, energy capacity, etc.), the entry for "UN1396, Aluminum powder, uncoated" does not specify limiting criteria for particle size. Furthermore, the test method in the UN Manual of Tests and Criteria does not specify a particle size. Hazardous materials that may be dangerous when wet, such as aluminum powder, uncoated, are classified based on the results of testing (i.e., UN Test N.5, Test method for substances which in contact with water emit flammable gases, see Section 33.5 of the UN Manual of Tests and Criteria) irrespective of particle size.
Ultimately, as provided in § 173.22, it is the shipper's responsibility to properly classify and describe a hazardous material based on the classification criteria provided in the HMR.
I hope this information is helpful. Please contact us if we can be of further assistance.
Sincerely,
Dirk Der Kinderen
Chief, Standards Development Branch
Standards and Rulemaking Division
172.101, 173.22