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Interpretation Response #11-0062 ([DuPont Company] [Mr. Randolph Martin])

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

Interpretation Response Details

Response Publish Date:

Company Name: DuPont Company

Individual Name: Mr. Randolph Martin

Location State: DE Country: US

View the Interpretation Document

Response text:

September 14, 2011



Mr. Randolph Martin

Hazardous Materials Distribution Consultant

DuPont Company

4417 Lancaster Pike, BMP22/2222

Wilmington, DE 19375

Reference No. 11-0062

Dear Mr. Martin:

This is in response to your March 4, 2011 e-mail and March 23, 2011 telephone conversation with a member of my staff concerning "UN 3161, Liquefied gas, flammable, n.o.s. (2,3,3,3-Tetrafluoropropene), 2.1 (flammable gas)" and Specification DOT 39 steel cylinders. Specifically, you ask if this refrigerant gas is permitted in a DOT 39 cylinder under the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180).

The answer is yes. The Column 8B entry for "UN 3161, Liquefied gas, flammable, n.o.s." under the Hazardous Materials Table (HMT; § 172.101) permits "2,3,3,3-Tetrafluoropropene" Division 2.1 gas to be placed in a non-bulk cylinder prescribed in § 173.304. Under the HMR, DOT specification cylinders must meet the requirements prescribed in §§ 173.301, 173.301a, 173.304a, and 173.305, as applicable (see § 173.304(a)). 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.

You also ask if § 173.304(d) prohibits "2,3,3,3-Tetrafluoropropene" refrigerant gas from being placed in a DOT 39 steel cylinder because this section states non-toxic and non-flammable gases must be offered for transportation in cylinders prescribed in § 173.304a. The answer is no. Section 173.304(d) does not apply to your material because it prescribes packaging requirements for non-toxic and non-flammable refrigerant or dispersant gases only.

Further, you ask if the maximum permitted filling density limitations for "NA 1954, Refrigerant gases, n.o.s., 2.1 (flammable gas)" prescribed in the § 173.304a(a)(2) Table apply to "2,3,3,3-Tetrafluoropropene" refrigerant gas. If "2,3,3,3-Tetrafluoropropene" is being shipped under the proper shipping name "Liquefied gas, flammable, n.o.s.," the answer is no. If "2,3,3,3-Tetrafluoropropene" is being shipped under the proper shipping description "NA 1954, Refrigerant gases, n.o.s., 2.1," the answer is yes. The filling limits prescribed in § 173.304(b) only apply to refrigerant gases being shipped as "NA 1954, Refrigerant gas, n.o.s." 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).

I hope this satisfies your request.


T. Glenn Foster

Chief, Regulatory Review and Reinvention Branch

Standards and Rulemaking Division

173.304, 173.304a,

Regulation Sections

Section Subject
173.301 General requirements for shipment of compressed gases and other hazardous materials in cylinders, UN pressure receptacles and spherical pressure vessels
173.304 Filling of cylinders with liquefied compressed gases
173.304a Additional requirements for shipment of liquefied compressed gases in specification cylinders