# Linde Gas North America — Hazardous Materials Safety Interpretation

- **operation:** document
- **citation:** 19-0049
- **title:** Linde Gas North America — Hazardous Materials Safety Interpretation
- **source type:** guidance
- **agency:** Pipeline and Hazardous Materials Safety Administration
- **status:** guidance
- **official:** true
- **published on:** 2019-08-14
- **effective on:** Not available
- **summary:** 19-0049 response to Linde Gas North America concerning 173.302a.
- **machine formats:** - **json:** https://regulus.evalyn.ai/document/phmsa-interpretation-19-0049.json
- **markdown:** https://regulus.evalyn.ai/document/phmsa-interpretation-19-0049.md
- **app url:** https://regulus.evalyn.ai/document/phmsa-interpretation-19-0049
- **source url:** https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/docs/standards-rulemaking/hazmat/interpretations/72061/190049.pdf
**body:**

<<<PAGE 1>>>

U.S. Department
of Transportation
Pipeline and Hazardous
Materials Safety
Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
AUG 1 4 2019
Mr. Billy Stover
HSE Transport Safety and Compliance Manager
Linde Gas North America
200 Somerset Blvd.
Suite 6000
Bridgewater, NJ 08807
Reference No. 19-0049
Dear Mr. Stover:
This letter is in response to your April 10, 2019, letter requesting clarification of the Hazardous
Materials Regulations (HMR; 49 CFR Parts 1 71-180) applicable to filling limits for cylinders.
Specifically, you request clarification regarding the use of Department of Transportation (DOT)
3A and 3AA cylinders for the transport of Deuterium. In your letter, you state that on January
21, 2016, a final rule was published in the Federal Register (HM-233F; 81 FR 3636) that
incorporated DOT Special Permit 6530 (SP 6530) which allowed certain 3-series cylinders of
hydrogen and hydrogen mixtures to be filled to 110 percent of their marked service pressure.
This incorporation was added as a new paragraph, § 173 .302a( c ). You also state that because of
this revision to the HMR, you believe that it is not necessary to be a party to this SP, mark the SP
number on your trailers, or maintain a copy of the SP on board the trailers and at the fill site.
We have paraphrased and answered your questions as follows:
Q 1. You ask whether the HMR currently allow Deuterium and Deuterium gas mixtures to be
transported in DOT 3A and 3AA cylinders and filled to 110 percent of their marked
service pressure.
Al. The answer is no. Deuterium and Deuterium gas mixtures were not included in SP 6530
until December 2, 2015. The HM-233F Notice of Proposed Rulemaking (NPRM) [80 FR
5340], Section I., Executive Summary, stated that the proposal was based on a review of
all active special permits as of January 1, 2013. Deuterium and Deuterium gas mixtures
were not authorized in SP 6530 as of January 1, 2013, and thus were not considered in
the adoption of the SP in the rulemaking. As currently written,§ 173.302a(c) does not
allow cylinders containing Deuterium or Deuterium gas mixtures to be filled to 110
percent of their marked service pressure.
Q2. You ask why Deuterium and Deuterium gas mixtures are included in SP 6530 but not
included in the current HMR.
A2. Please see answer Al.

<<<PAGE 2>>>

Q3. A3. Provided the HMR do not authorize Deuterium and Deuterium gas mixtures to be filled
to 110 percent of their marked service pressure, you ask whether you may utilize the 10
percent overfill allowance.
As currently written,§ 173.302a(c) does not authorize cylinders of Deuterium and
Deuterium gas mixtures to be filled to 110 percent of their marked service pressure.
However, SP 6530, to which your company appears to be a party, continues to be active
and allows this overfill. Therefore, provided you continue to comply with the terms and
conditions of the SP, you may overfill the specified cylinders to 110 percent of their
marked service pressure.
I hope this information is helpful. Please contact us if we can be of further assistance.
Sincerely,
~~~~
T. Glenn Foster
Chief, Regulatory Review and Reinvention Branch
Standards and Rulemaking Division

<<<PAGE 3>>>

Making our world more productive
~~
~ /05, 20
I 9 -ooq'f
200 Somerset Blvd.
Suite 6000
Bridgewater, 08807, USA
Phone: 770-367-4465
e-mail: billy.stover@linde .com
April I 0, 2019
Office of Hazardous Materials Standards
Pipeline and Hazardous Materials Safety Administration, Attn: PHH-IO U.S. Department of
Transportation, East Building
1200 New Jersey Avenue, SE.
Washington, DC 20590-0001
IJI IMSAPipelinesa lety@do l. gov
Request for Interpretation
Dear Sir or Madame,
Linde Gas North America (Linde) is requesting interpretation and guidance regarding the use
of DOT 3A and 3AA for the transport of Deuterium.
Background
Deuterium is an isotope of Hydrogen and is filled into 3A and 3AA cylinders with less than
1251 b water capacity as permitted by 49 CFR 173.301.
49 CFR l 80.209(b )(l) permits the requalification of such cylinders for a period of ten years if
the requirements of l 80.209(b )( l )(ii) are met. This subparagraph allows the filling of
hydrogen into such cylinders tested at ten-year intervals.
Regulations incorporated on January 21, 2016, into 49 CFR § 173 .302a( c ), now allow certain,
3-Series cylinders and tubes to be filled with hydrogen to 10% over their marked service
pressure. The new DOT regulations have incorporated into the CFR the same cylinder and
pressure relief device requirements that had been part of long-time DOT special permit, DOT-
SP 6530. Due to this incorporation of safety control measures and special provisions in DOT-
SP 6530, it is no longer necessary to be party to this special permit, mark it on your tube
trailers and maintain a copy of the permit on board the trailer and at your fill site.
A review oflnterpretation No: 13-0092 DOT-SP-6530 permit authorized the transport of
hydrogen and mixtures of hydrogen. Deuterium and mixtures of deuterium were authorized in
the revision prior to incorporating into the CFR. https://www.ph111sa.do1.gov/approvals-and-
per111its/haz111at/fi le-serve/offer/SP6530.pdf/20 I 4 I 20204/SP6530

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Making our world more productive
Question 1
Since Deuterium and Deuterium gas mixes were included in Special Permit 6530, would it be
also allowed by the updated regulations?
Question 2
Why weren't Deuterium and Deuterium mixes included in the updated regulations but
allowed in special permit 6530?
Question 3
If the gas and mixtures were not included due to an oversite, how can we currently apply the
10% overfill to cylinders with these gas mixtures?
A written response at your earliest convenience is appreciated.
Sincerely,
Billy Stover
HSE Transport Safety & Compliance Manager
Linde Gas North America
Mobile: +01 770 367-4465
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