# Solvay Interox, Inc. — Hazardous Materials Safety Interpretation

- **operation:** document
- **citation:** 99-0196
- **title:** Solvay Interox, Inc. — Hazardous Materials Safety Interpretation
- **source type:** guidance
- **agency:** Pipeline and Hazardous Materials Safety Administration
- **status:** guidance
- **official:** true
- **published on:** 2000-08-25
- **effective on:** Not available
- **summary:** 99-0196 response to Solvay Interox, Inc. concerning 173.31.
- **machine formats:** - **json:** https://regulus.evalyn.ai/document/phmsa-interpretation-99-0196.json
- **markdown:** https://regulus.evalyn.ai/document/phmsa-interpretation-99-0196.md
- **app url:** https://regulus.evalyn.ai/document/phmsa-interpretation-99-0196
- **source url:** https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/1999/990196.pdf
**body:**

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U.S.Department
of Transportation
400 Seventh Street, S.W.
Washington, D.C. 20590
Special Programs
Research and
Administration
AUG 25 2000
Mark A. Feldman, Ph.D., CQMgr
Ref. Nos. 99-0196 & 00-0033
Regulatory Affairs Manager
Solvay Interox, Inc.
P.O. Box 27328
Houston, TX 77227-7328
Dear Dr. Feldman:
I apologize for the delay in responding to your letters concerning the requirement in 49 CFR
173.31(d)(1)(vi) to carefully inspect a frangible (rupture) disc in a pressure relief device prior to
each hazardous material shipment. This requirement has its origins in regulations of the Interstate
Commerce Commission issued in 1921. The wording of this requirement was most recently
revised in a final rule published on September 21, 1995, under RSPA's Docket Nos. HM-175A
and 201 (60 Fed. Reg. 49098).
As the language of § 173.31(d)(1)(vi) states, the purpose of this type of inspection is to check "for
corrosion or damage that may alter the intended operation of the device." For that reason, in
response to a comment submitted in a separate rulemaking proceeding under Docket No. HM-216
(61 Fed. Reg. 28666, 28671; June 5, 1996), we stated in the preamble that RSPA and FRA
believe in order to fully inspect a rupture disc (both top and bottom), the disc must be removed
from the safety vent device. It has been FRA's experience that a rupture disc may appear normal
on the top side, but be severely damaged or corroded on the bottom side.
You and others have raised concerns about the language of the present rule and its application to
persons that forward a loaded tank car received from another location or return a tank car with
residue. We anticipate initiating a rulemaking in the near future to address these concerns.
Sincerely,
Th
Director, Office of Hazardous
Materials Standards
990196
000033
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$
SOLVAY
Mack
SOLVAY
INTEROX
$173.31
00 - 0033
January 25, 2000
Mr. Edward T. Mazzullo
Research & Special Programs Administration
Office of Hazardous Materials Section
Department of Transportation
Washington, D.C. 20590
Re: Interpretation of 49 CFR 173.31(d)(1)(vi), (Pressure Relief Device examination)
Dear Mr. Mazullo:
We recently became aware of a letter sent by the Chemical Manufacturers Association
to the Department of Transportation ("DOT") concerning the interpretation by the
Federal Railroad Administration ("FRA") of 49 CFR 173.31(d)(1)(vi) dated November 5,
1999.
As members of the Chemical Manufacturers Association, we fully support and endorse
we feel that by confining its discussion to residue tank cars, the CMA letter
its efforts to improve the safe handling of hazardous materials in all aspects. However,
unnecessarily limits the scope of discussion. The same points being made by the CMA
with regard to empty cars apply to full railcars as well.
In addition to the points made by the CMA in their letter, requiring the rupture disk to be
removed from the safety device to fully inspect the disk in a loaded tank car presents
further hazards and difficulties for many products due to the inherent nature of the
material.
Many products are dangerous and require appropriate personal protective equipment
before any work may be performed. Some of the personal protective equipment will
decrease the mobility and/or field of vision of an operator climbing a railcar and
inspecting the rupture disk assembly as presently required / interpreted. This will
significantly increase the operational hazards involved in rupture disk verification.
Some materials may react adversely to even minute amounts of contamination resulting
from opening the car. This situation would therefore require cleaning of the car before
and/or after the disk inspection to prevent any such contamination unless the work were
performed under 'clean' conditions.
Solvay Interox, Inc
3333 Richmond Avenue, Houston, Texas 77098-3099 Mailing Address: P.O. Box 27328, Houston, Texas 77227-7328
Solvay Companies Website: http://www.solvay.com
1-800-INTEROX
Fax: 713/524-9032
Responsble Care
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<<<PAGE 3>>>

SOLVAY
SOLVAY
INTEROX
For very high purity materials, opening the railcar to perform the rupture disk inspection
may also compromise its quality unless the work were, again, performed under
appropriate 'clean' conditions.
This would be the case, for example, for some grades of our product, hydrogen
peroxide. Should it be necessary to clean a car before disk inspection, we would be
required to rinse the car with high purity water. After inspection, we would again rinse
to or superior in purity to that to be loaded in the rail car. This would delay shipment by
the car with high purity water and then again with at least 1000 gallons of product equai
at least one day, and perhaps more.
additional waste will be generated and will require appropriate handling for disposal.
It should be noted, too, that, with each cleaning, as mentioned above, significant
Very few, if any, of the rupture disks we have in service fail due to age or deterioration.
Most fail due to mishandling or hydraulic surge during transit.
History has shown that, at least for our peroxygen products, that a top only inspection is
adequate to provide the necessary safety margins.
We respectfully request that you consider the actions and consequences that will result
should DOT interpretation continue as at present. We ask that DOT issue a revised
interpretation applicable to all offerors of rail tank cars reversing the interpretation DOT
in Federal Register Docket HM-175A & HM-201 preamble (40CFR 173.31) of
has presented in the preamble to HM-216 [61FR 28671] back to its original explanation
September 1995.
Sincerely,
nave Tille
Dr. Marc A. Feldman, CQMgr
Regulatory Affairs Manager
Solvay Interox, Inc.
Cc:
M.E.Nevill
G.W. Rousseau
P.J. Harding
C.R. Escobar

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SOLVAY
SOLVAY
INTEROX
Mack
3173.31
09-0196
July 15, 1999
Mr. Edward T. Mazzullo
Office of Hazardous Materials Section
Research & Special Programs Administration
Department of Transportation
Washington, D.C. 20590
Re: Interpretation of 49 CFR 173.31 (d)(1)(vi)
Dear Mr. Mazullo:
We recently became aware of discussions at the Department of Transportation
("DOT") concerning the interpretation by the Federal Railroad Administration
("FRA") of 49 CFR 173.31(d)(1)(vi). As you know, this section addresses
pressure relief device examination before shipping.
It is our understanding that the FRA now interprets this section to require that the
railcar rupture disk must be removed from the safety device and carefully
inspected, both top and bottom, before the railcar is moved. This new
interpretation apparently applies to all railcars, whether loaded or unloaded but
containing a residue.
We believe this interpretation is contradictory to the original intent of this safety
requirement and that it potentially increases the hazards and difficulty in
transporting railcars.
The Contradiction:
The Federal Register Docket HM-175A & HM-201 rule-making preamble (40
CFR 173.31) of September 21, 1995 states that the removal of the phrase "to the
extent practicable" does not expand the scope of the standard. DOT continues
to say that the purpose of the rule-making was to "clarify the purpose of the
regulations and to make the regulation more realistic and to eliminate from ,
regulations items which were either very difficult to inspect such as a full
inspection of safety relief valves or excess flow valves." DOT has also indicated
that "Irlead literally, the regulation at that time would impose a duty on the
shipper to disassemble and inspect safety valves and excess flow valves prior to
each trip", which implied that this was not the result sought.
Solvav Interox, Inc
3333 Richmond Avenue, Houston, Texas 77098-3099 Mailing Address: P.O. Box 27328, Houston, Texas 77227-7328
Solvay Companies Website: http://www.solvay.com
1-800-INTEROX 713/525-6500 Fax: 713/524-9032
Respons ble Care'
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<<<PAGE 5>>>

July 15, 1999
Mr. Edward T. Mazzullo
Page 2 of 3
Unless a distinction is now being made between these valves and rupture disks,
216 [61 FR 28671], where it interprets 40 CFR 173.31(d) to mean the disk must
which is not our understanding, DOT has reversed itself in the preamble to HM-
be removed from the safety device to fully inspect a rupture disk.
Safety and Operational Consequences:
Requiring customers to open the rupture disk assembly for inspection
prior to returning an "empty" railcar would create significant risk to safety
and potential liability unless extensive training were provided to each
customer and each facility.
2.
Opening the rupture disk assembly may be hazardous in and of itself due
to the nature of the materials being shipped. Many materials are
inherently dangerous and require appropriate personal protective
equipment or thorough car cleaning before any work may be performed.
Some materials may react adversely to any contamination resulting from
opening the car and may require additional cleaning after inspection. This
would be the case, for example, with hydrogen peroxide, which we ship in
railcars. Many customers do not have the resources to complete these
material specific requirements. It should be noted that, with each
cleaning, significant additional waste may generated. In sum, it is likely
that many cars would need to be cleaned before every shipment, and
some may need to be cleaned twice before shipping. These cleanings
would have to be performed by both the supplier and the customer.
Every site that sends a hazardous material shipment or returns an "empty"
railcar containing residue would be required to register with the
Association of American Railroads (AAR) as at least a Class F tank car
facility.
The quality of very high purity materials may be compromised by opening
a railcar to perform the rupture disk inspection.
The Department of Transportation and Research and Special Programs
Administration ('RSPA") have always tried to balance risk and hazard
management with reason and practicality. This departure is a surprise and in our
opinion does not follow those guidelines.
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We respectfully request that you review the actions and consequences that will
result should this interpretation continue in this direction.
Sincerely,
Dr. Marc A. Feldman, CQMgr
Regulatory Affairs Manager
Solvay Interox, Inc.
Cc:
M.E.Nevill
G.W. Rousseau
M. Heimowitz
L.D. Pieper
P.J. Harding
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