# Mr. Robert D. Howerton, Ph.D. — Hazardous Materials Safety Interpretation

- **operation:** document
- **citation:** 06-0200
- **title:** Mr. Robert D. Howerton, Ph.D. — Hazardous Materials Safety Interpretation
- **source type:** guidance
- **agency:** Pipeline and Hazardous Materials Safety Administration
- **status:** guidance
- **official:** true
- **published on:** 2006-09-27
- **effective on:** Not available
- **summary:** 06-0200 concerning 173.306.
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- **markdown:** https://regulus.evalyn.ai/document/phmsa-interpretation-06-0200.md
- **app url:** https://regulus.evalyn.ai/document/phmsa-interpretation-06-0200
- **source url:** https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/2006/060200.pdf
**body:**

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U.S. Department
of Transportation
Wastington, D.C. 20590
400 Sieventh Street, S.W.
Pipeline and
Administratior
Hazardous Materials Safet
SEP 2 7 2006
2582 Wood Trail Lane
Mr. Robert D. Howerton, Ph.D.
Ref. No. 06-0200
Decatur, GA 30033
Dear Dr. Howerton:
This is in response to your electronic transmission requesting clarification of the
rebuilding of accumulators. Specifically, you ask for a procedure whereby you would
Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) as they pertain to the
notify and receive corroboration from the U.S. Department of Transportation DOT) or a
third party that the rebuilt accumulators can withstand at least 5,000 psi, and that the
pressure test apparatus that you are building is capable of testing the accumulators at the
transporting accumulators, and whether any records are required to be maintained for the
required pressure. Additionally, you ask about exceptions under the HMR applicable to
rebuilt accumulators.
Under the HMR, if your rebuilt accumulators meet the requirements in § 173.306(f)(1)
through (f)(4)(iv), you are not required to submit supperting documentation to the DOT.
accumulators meeting the above requirements; however, you may elect to receive
The DOT does not verify test results nor does it approve pressure test apparatus for
substantiation from a third party. As stated in § 173.306(f)(5), if the accumulators do not
approval in accordance with Subpart H of Part 107 before the accumulators may be
meet the requirements in § 173.306(f)(1) through (f)(4)(iv), you must apply for an
meet the requirements in § 173.306(f)(3). Provided the accumulators have a charging
With respect to exceptions applicable to accumulators, you state that the accumulators
pressure exceeding 200 psig at 70° F, the articles are not required to be labeled (except
for transportation by air) and are additionally excepted from specification packaging
requirements provided the articles meet the requirements in § 173.306(f)(2) through
equirements by any mode of transportation
f(3)(ii). These accumulators are not accepted from the HMR's shipping pape
173-306(f)(3)
060200

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Finally, we note that you referenced "Nitrogen, compressed," UN1066 in your letter.
When selecting a proper shipping name, the name that most appropriately describes the
non-liquefied, non-flammable gas, and non-flammable liquids are most appropriately
article or material being transported must be chosen. Hydraulic accumulators containing
described as "Accumulators, pressurized, hydraulic," UN3164. Pneumatic accumulators
described as "Accumulators, pressurized, pneumatic," UN3164.
containing non-liquefied, non-flammable compressed gas are most appropriately
I hope this information is helpful. Please contact this office if you need additional
assistance.
Sincerely,
Hattie L. Mitchell
Office of Hazardous Materials Standards
Chief, Regulatory Review and Reinvention

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M'Intyre
3172.101
Robert D. Howerton
2582 Wood Trail Lane
Decatur, GA 30033
404-343-6307
Cylinders
06-0200
August 23, 2006
Mr. Edward T. Mazzullo
Director, Office of Hazardous Materials Standards
U.S. DOT/PHMSA (PHH-10)
Washington, DC 20590-001
Dear Mr. Mazzullo:
It is my intention to establish in the near future a business that offers the service
of rebuilding Rolls-Royce (and Bentley) hydraulic accumulators. (The accum-
were manufactured in the years from 1970 to 1980 roughly. They have an
ulators in question were installed on the Rolls-Royce Silver Shadow series, which
internal volume of 27 cubic inches and are charged with 1000 psi of nitrogen
gas.)
With this intention in mind, I quickly became aware that the nitrogen charged
recently your Hazardous Materials Transportation Training Modules. I
accumulators constituted a hazardous material and for that reason I completed
conscientiously completed all the quizzes and passed them with an average
score of around 85%, so I feel that I am generally well acquainted with your rules
and regulations.
Applying the knowledge I acquired I looked up Nitrogen, Compressed in the HMT
and noted in column 8A that exceptions were cited in §173.306. Here I noted
that my product came under category (f) (3) and would be exempt from labeling
and general packaging requirements (we have no intention of shipping the
product by air) so long as i) it was shipped as an inside package; ii) it was tested
after being rebuilt at a pressure of 3,000 psi and iii) it was designed with a burst
pressure of not less than 5,000 psi. I also noted that there was no exerption
from your shipping paper requirements when shipped by rail or truck. I trust you
will not disagree with these (paraphrased) requirements.
I am a graduate engineer with both a bachelor's degree from Swarthmore
College and a Ph. D. from Georgia Tech. Until recently I was a licensed
Professional Engineer in the State of Georgia (I let the license lapse) ard I have
practiced as an engineer for over 40 years. I've used this experience to
accomplish two relevant tasks: first of all, I have carefully measured a typical
Rolls-Royce accumulator and carried out metallurgical testing on the device and
in a 44 page report I have established that the accumulator has a burst pressure

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of at least 13,000 psi; and secondly, I have designed and am in the process of
fabricating a pressure testing apparatus capable of testing each accumulator at a
pressure of 3,000 psi after it is rebuilt.
So the two principal questions that I address to you are:
1. How can I establish with the DOT that the accumulator I intend to
rebuild can withstand at least 5,000 psi? Can I submit my report to
your experts for corroboration? Or can I submit the report to a
transmit the conclusions of the third party to the DOT? In sum where
qualified third party and then what are the procedures needed to
do I go from here?
2. How can I establish with the DOT that the pressure test apparatus that
I am building is capable of testing the accumulators at the required
device. (The photographs will show a hydraulic pressure gage.) And
pressure of 3,000 psi? I can submit drawings and photographs of the
what records of each test do I have to keep?
I will have some more questions at a future date but these are the paramount
questions at this time. I will greatly appreciate your giving me the guidance that I
need here.
Best regards,
Robert D. Howerton, Ph.D.
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