Document ID: PHMSA-2016-0078-0001
Agency: phmsa
Document Type: Notice
Title: Hazardous Materials: Use of DOT Specification 39 Cylinders for Liquefied Flammable Compressed Gas
Posted Date: 2016-12-13T05:00Z

[Federal Register Volume 81, Number 239 (Tuesday, December 13, 2016)]
[Notices]
[Pages 90061-90062]
From the Federal Register Online via the Government Publishing Office [http://www.gpo.gov/]
[FR Doc No: 2016-29813]

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DEPARTMENT OF TRANSPORTATION

Pipeline and Hazardous Materials Safety Administration

[Docket No. PHMSA-2016-0078; Notice No. 2016-14]

Hazardous Materials: Use of DOT Specification 39 Cylinders for 
Liquefied Flammable Compressed Gas

AGENCY: Pipeline and Hazardous Materials Safety Administration (PHMSA), 
DOT.

ACTION: Safety advisory notice.

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SUMMARY: PHMSA is issuing this safety advisory notice to inform 
offerors and users of DOT Specification 39 (DOT-39) cylinders that DOT-
39 cylinders with an internal volume exceeding 75 cubic inches (in\3\) 
(1.23 L) should not be filled with liquefied flammable compressed gas. 
PHMSA maintains filling or transporting DOT-39 cylinders with an 
internal volume exceeding 75 in\3\ (1.23 L) is not safe.

FOR FURTHER INFORMATION CONTACT: Refaat Shafkey, General Engineer, 
Engineering and Research Division, Office of Hazardous Materials 
Safety, Pipeline and Hazardous Materials Safety Administration, U.S. 
Department of Transportation, 1200 New Jersey Ave. SE., Washington, DC 
20590. Telephone: (202) 366-4545 or, via email: refaat.shafkey@dot.gov.

[[Page 90062]]

SUPPLEMENTARY INFORMATION: 

Public Action Requested

    PHMSA advises offerors of DOT-39 cylinders having an internal 
volume exceeding 75 cubic inches (in\3\) (1.23 L) that such cylinders 
should not be filled with liquefied flammable compressed gas. PHMSA 
further advises the public not to use any DOT-39 cylinder with an 
internal volume greater than 75 in\3\ (1.23 L) containing a liquefied 
flammable compressed gas.

Safety Concern

    The release of a liquefied flammable compressed gas from or rupture 
of such a cylinder having an internal volume exceeding 75 in\3\ (1.23 
L) is a safety concern that could result in extensive property damage, 
serious personal injury, or even death. A liquefied flammable 
compressed gas has a stored energy that is several times greater than 
that of a non-liquefied compressed gas. Further, a DOT-39 cylinder can 
have a volume of up to 1,526 in\3\ (25 L) at a service pressure of 500 
psig or less and, as such, can have up to 22 times the stored energy of 
a DOT-39 cylinder limited to 75 in\3\ (1.23 L). Additionally, because 
of the design specifications that allow for thinner walls when used at 
lower pressure, the cylinders may be at greater risk from corrosion or 
puncture. Given the known risks associated with cylinders that are 
filled with liquefied flammable compressed gases, PHMSA is issuing this 
safety advisory notice to inform offerors and users of DOT-39 cylinders 
that cylinders with an internal volume of 75 in\3\ (1.23 L) or more 
should not be filled with liquefied flammable compressed gas.

Background

    This safety advisory notice is being issued in part because of 
concern over confusion about the regulatory requirements when using 
DOT-39 cylinders for liquefied compressed gases. Historically, the 
Hazardous Materials Regulations (HMR; 49 CFR parts 171-180) limited the 
internal volume of a DOT-39 specification cylinder to 75 in\3\ (1.23 L) 
when used for certain liquefied flammable compressed gases. This size 
limitation applied when DOT-39 cylinders were used for gases that were 
subject to Note 9 following the table at Sec.  173.304(a)(2) or 
liquefied petroleum gas as addressed in Sec.  173.304(d)(3) (The table 
is currently located at Sec.  173.304a).
    In an October 30, 1998 notice of proposed rulemaking (NPRM), the 
Research and Special Programs Administration (RSPA)--the predecessor 
agency to PHMSA--proposed to extend the 75 in\3\ (1.23 L) volume 
limitation of DOT-39 cylinders to all liquefied flammable compressed 
gases by revising Sec.  173.304 to delete Note 9 from the table at 
Sec.  173.304(a)(2) and adding Sec. Sec.  173.304a and 173.304b.\1\ 
RSPA received several comments in opposition to extending the limit to 
all liquefied flammable compressed gases which would have been codified 
in Sec.  173.304a(a)(3). RSPA published a final rule on August 8, 2002 
and, based on the opposing comments, decided not to extend the 75 in\3\ 
(1.23 L) limitation to all liquefied flammable compressed gases in a 
DOT-39 cylinder at that time. However, in the process of publishing the 
final rule, the agency inadvertently omitted the 75 in\3\ (1.23 L) 
limitation for liquefied flammable compressed gas and liquefied 
petroleum gas.\2\
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    \1\ NPRM--Hazardous Materials: Requirements for DOT 
Specification Cylinders (HM-220D) [63 FR 58460].
    \2\ Final Rule--Hazardous Materials: Requirements for 
Maintenance, Requalification, Repair and Use of DOT Specification 
Cylinders (HM-220D) [67 FR 51625]
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    On November 13, 2014, PHMSA accepted a petition for rulemaking (P-
1622) from Worthington Cylinders to address this error in a rulemaking. 
On July 26, 2016, PHMSA published in the Federal Register an NPRM 
titled, ``Hazardous Materials: Miscellaneous Amendments Pertaining to 
DOT Specification Cylinders (RRR),'' [81 FR 48977; Docket No. PHMSA-
2011-0140 (HM-234) \3\] that again proposes to extend the limit on the 
internal volume of DOT-39 cylinders to use with all liquefied flammable 
compressed gases, thus correcting the inadvertently omitted size 
limitation and expanding the applicability to capture those liquefied 
flammable compressed gases (e.g., difluoromethane (Refrigerant gas R 
32)) either not reflected in the Sec.  173.304a(a)(2) table or not 
considered a liquefied petroleum gas.
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    \3\ https://www.gpo.gov/fdsys/pkg/FR-2016-07-26/pdf/2016-16689.pdf.

    Issued in Washington, DC on December 5, 2016.
William S. Schoonover,
Acting Associate Administrator for Hazardous Materials Safety, Pipeline 
and Hazardous Materials Safety Administration.
[FR Doc. 2016-29813 Filed 12-12-16; 8:45 am]
 BILLING CODE 4910-60-P