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Interpretation Response #21-0065

Below is the interpretation response detail and a list of regulations sections applicable to this response.

Interpretation Response Details

Response Publish Date:

Company Name: Smarter Sorting

Individual Name: AJ Kenny

Location State: TX Country: US

View the Interpretation Document

Response text:

September 23, 2021

Mr. AJ Kenny
Director of Regulations
Smarter Sorting
4901 East Cesar Chavez Street
Austin, TX  78702

Reference No. 21-0065

Dear Mr. Kenny:

This letter is in response to your June 15, 2021, letter requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to exceptions for aqueous solutions of alcohol. Specifically, you ask whether the condition of 24 percent or less alcohol by volume in the § 173.150(e)(1) exception applies to all alcohols in the aqueous solution or just to the flammable alcohol(s) in the aqueous solution.  Furthermore, you provide the following example of an aqueous solution and ask whether the solution is eligible for the § 173.150(e)(1) exception:

  • Aqueous solution has a flashpoint of 54 °C and meets the definition of a flammable liquid (Class 3) (as specified in § 173.120(a));
  • 20 percent of the solution is isopropanol, which is an alcohol and has a flashpoint of 12 °C (i.e., a flammable alcohol);
  • 20 percent of the solution is glycerol, which is an alcohol and has a flashpoint of 175 °C (i.e., a non-flammable alcohol); and
  • The remaining components in the solution do not meet the definition of a hazardous material.

The 24 percent or less alcohol by volume condition in the § 173.150(e)(1) exception applies to flammable alcohols. Thus, the example of the aqueous solution you outlined above would be eligible for the exception in § 173.150(e)(1). As detailed in § 173.150(e)(1), "an aqueous solution containing 24 percent or less alcohol by volume and no other hazardous materials may be reclassed as a combustible liquid." The original intent of this exception was to provide relief for aqueous solution of alcohols that do not meet the definition of a hazard class other than a flammable liquid (Class 3).

Therefore, while the solution itself contains 40 percent alcohol, the criteria for the § 173.150(e)(1) exception should be based on the alcohol(s) that meets the definition of a flammable liquid (Class 3).

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

173.150(e)(1), 173.120(a)

Regulation Sections

Section Subject
173.120 Class 3-Definitions
173.150 Exceptions for Class 3 (flammable and combustible liquids)