USA Banner

Official US Government Icon

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure Site Icon

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Interpretation Response #14-0169 ([A.S. Trust & Holdings, Inc.] [Mr. Richard Maruya])

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

Interpretation Response Details

Response Publish Date:

Company Name: A.S. Trust & Holdings, Inc.

Individual Name: Mr. Richard Maruya

Location State: HI Country: US

View the Interpretation Document

Response text:

March 13, 2015

Mr. Richard Maruya
A.S. Trust & Holdings, Inc.
44129 Mikiola Drive
Kaneohe, HI 96744

Ref. No.: 14-0169

Dear Mr. Maruya:

This is in response to your email dated September 11, 2014 requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) regarding transportation requirements for flammable refrigerants in DOT 39 cylinders. Your questions are paraphrased and answered as follows:

Q1. Is Hydrocarbon gas mixture, liquefied, n.o.s, UN 1965, an appropriate and acceptable classification for R441a and R443a to be used for marking and labeling of packages?

A1. In accordance with § 173.22, it is the shipper's responsibility to properly classify a hazardous material. This Office generally does not perform this function. However, based on the information you have provided the proper shipping name Hydrocarbon gas mixture, liquefied, n.o.s. appears to be an acceptable proper shipping name for R441a and R443a.

Q2. Is a DOT 39 disposable cylinder acceptable to be used for the storage and transport of UN 1965?

A2. The answer is yes. The Column 8B entry for "UN 1965, Hydrocarbon gas mixture, liquefied, n.o.s." under the Hazardous Materials Table (HMT; § 172.101) permits "Hydrocarbon gas mixture, liquefied, n.o.s" Division 2.1 gas to be placed in a non-bulk cylinder prescribed in § 173.304. Section 173.304a(a)(1) permits liquefied gases, except gas in solution, to be placed in a DOT 39 steel cylinder provided the cylinders are not filled and shipped with a mixture that contains a pyrophoric liquid, carbon bisulfide (disulfide), ethyl chloride, ethylene oxide, nickel carbonyl, spirits of nitroglycerin, or toxic material (Division 2.3 (gas poisonous by inhalation) or Division 6.1 (poisonous materials)), unless specifically authorized in 49 CFR Part 173. Based on the information provided in your letter, the gas you described does not contain these materials.

Q3. Is the maximum quantity of either R441a or R443a contained in a DOT 39 cylinder a function of the volume of the cylinder and the pressure of the fluid, which is a function of the temperature of the fluid?

A3. Section 173.304(b) states the liquid portion of a liquefied gas may not completely fill the packaging at any temperature up to and including 55 °C (131 °F). In addition, the filling density can be determined using the formula provided in "Note 1" to the Table in § 173.304a(a)(2). The filling density for any cylinder containing your material, including a DOT specification 39 cylinder, can be determined by calculating the percent ratio of the weight of the gas in the cylinder to the weight of the water the cylinder will hold at 16 ºC (60 ºF).

Q4. Is the maximum volume of a DOT 39 cylinder 1,526 cubic inches for service pressures less than 500 psi?

A4. In accordance with § 178.65, cylinders built to meet a DOT 39 specification may not have a maximum water capacity that exceeds 55 pounds (1,526 cubic inches) for cylinders with service pressure of 500 p.s.i.g. or less, and 10 pounds (277 cubic inches) for cylinders with service pressure in excess of 500 p.s.i.g

Q5. Is the maximum volume of a DOT 39 cylinder containing UN 1965 1.25 liters?

A5. In accordance with § 173.302a, for "a DOT 39 cylinder filled with a Division 2.1 material, the internal volume of the cylinder may not exceed 1.23 L (75 cubic inches)." This internal volume limitation only applies to Division 2.1 non-liquefied materials. As the information you provided indicates your material will be offered in a liquefied state, this 1.23 L limitation does not apply. It is important to note that PHMSA has accepted a petition for rulemaking (P-1622) to consider adopting a limit of 1.23 L (75 cubic inches) for DOT 39 cylinders containing Division 2.1 liquefied compressed gas.

I trust this information is helpful. If you have further questions, please do not hesitate to contact this office.



Duane A. Pfund
International Standards Coordinator
Standards and Rulemaking Division

173.22, 172.101, 173.304, 173.304a(a)(1), 173.304(b), 173.304a(a)(2), 178.65, 173.302a

Regulation Sections

Section Subject
172.101 Purpose and use of hazardous materials table
173.22 Shipper's responsibility
173.302 Filling of cylinders with nonliquefied (permanent) compressed gases or adsorbed gases
173.304 Filling of cylinders with liquefied compressed gases
178.65 Specification 39 non-reusable (non-refillable) cylinders