# Honeywell — Hazardous Materials Safety Interpretation

- **operation:** document
- **citation:** 09-0046
- **title:** Honeywell — Hazardous Materials Safety Interpretation
- **source type:** guidance
- **agency:** Pipeline and Hazardous Materials Safety Administration
- **status:** guidance
- **official:** true
- **published on:** 2009-09-21
- **effective on:** Not available
- **summary:** 09-0046 response to Honeywell concerning 172.102, 173.243, 180.509.
- **machine formats:** - **json:** https://regulus.evalyn.ai/document/phmsa-interpretation-09-0046.json
- **markdown:** https://regulus.evalyn.ai/document/phmsa-interpretation-09-0046.md
- **app url:** https://regulus.evalyn.ai/document/phmsa-interpretation-09-0046
- **source url:** https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretations/2009/090046.pdf
**body:**

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of Transportation
U.S. Department
Washington, DC 20590
1200 New Jersey Ave., SE
Pipeline and Hazardous Materials
Safety Administration
SEP 2 1 2009
Ms. Claire Matlon
Leader, Transportation Regulatory Compliance
Honeywell
101 Columbia Road
Morristown, NJ 07962-1057
Ref. No.: 09-0046
Dear Ms. Matlon:
This responds to your February 12, 2009 letter requesting clarification of the packaging
requirements for a shipment of UN 1790, Hydrofluoric acid with more than 60% strength in
an unlined class DOT 111 tank car in accordance with 49 CFR 173.243, and Special
provisions B15 and B23 in $172.102. Your questions are paraphrased and answered below:
Q1. If a pressure DOT 112S340W tank car tank is re-rated to a non-pressure DOT
111A100W2 tank car, may the tank car be used to transport Hydrofluoric acid with more than
60% strength?
A1. Yes. Section 173.243(a) authorizes class DOT 111 tanks for Hydrofluoric acid with
more than 60% strength. Special provision B15 requires an unlined tank used to transport this
material to have a suitable corrosion allowance. The determination of whether the DOT
112S340W tank will provide suitable corrosion allowance must be made using the
requirements of § 180.509.
Q2. May a 70% concentration by weight of hydrofluoric acid that does not exceed the
corrosion rate of hydrofluoric acid of 65% concentration, be shipped in the described class
DOT 111 tank?
A2. Yes, as stated above. Special provision B23 requires the lading in an unlined tank to be
inhibited so that the corrosive effect on steel is not greater than that of a 65 percent
concentration of hydrofluoric acid. Therefore, if, as you state, the corrosive effect on steel of
your 70% concentration of hydrofluoric acid is not greater than that of a 65% concentration of

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hydrofluoric acid, the lading may be transported in the unlined class DOT 111 tank. Note
that Special provision B23 requires an unlined tank to be passivated before being placed in
service and re-passivated each time after being washed out with water.
I hope this information is helpful. If you have further questions, please do not hesitate to
contact this office.
Sincerely,
Hobo
Hattie L. Mitchell
Chief, Regulatory Review and Reinvention
Office of Hazardous Materials Standards

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Honeywell
P.O. Box 1057
Honeywell International Inc.
Andrews
Morristown, NJ 07962-1057
§/72.101
Date: February 12, 2009
§ 172.102
U.S. DOT
$173.243
Attn: PHH-10
PHMSA Office of Hazardous Materials Standards
Packaging
East Building
1200 New Jersey Avenue, SE.
09-0046
Washington, DC 20590-0001
Subject: Request for interpretation of Special Provisions B15 and B23
Dear Sir or Madam,
Honeywell International requests clarification of the HMR packaging requirements for shipping UN 1790,
Hydrofluoric acid with more than 60% strength (specifically minimum 70% HF by weight) in unlined tank
cars. As specified in 49CFR173.243, DOT class 111 and DOT class 112 cars are acceptable for use
provided they meet the special provision requirements B15 and B23.
Special provision B15 requires that unlined cars have a "suitable corrosion allowance". In order to
achieve this, Honeywell intends to re-rate current DOT112S340W pressure cars to non-pressure
DOT111A100W2 cars. The extra steel in the former DOT112S340W pressure car would accomplish this.
suitable corrosion allowance. The cars will be removed from service once they reach the minimum 7/16"
Honeywell will monitor the re-rated cars through visual and ultrasonic testing on a regular basis to ensure
wall thickness allowed for DOT 111 tank cars as specified in 49CFR 170.201-1.
Special provision B23 states "lading in unlined tanks must be inhibited so that the corrsive effect on steel
is not greater than that of the corrosion rate of hydrofluoric acid of 65% concentration. Published
less for 70% solutions than it is for 65% solutions. Based on this data, is it correct to state that 70% HF
corrosion data found in the attached document (Section 3.2.1) indicates that the corrosion rate on steel is
use of DOT111A100W2 tank cars for use in this service?
solution does not exceed the corrosion rate of hydrofluoric acid of 65% concentration thereby allowing
Should you have any questions on the above information, please contact the applicant at the email
address of phone number listed below.
Sincerely,
Clave Matton
Claire Matlon
Leader, Transportation Regulatory Compliance
973-455-3879
Claire.MatIon @Honeywell.com
Enclosure: Materials of Construction Guideline for Hydrofluoric Acid Solution (Aqueous)
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