Interpretation Response #09-0229 ([Baker Petrolite Corporation] [Mr. Aubrey R. Campbell])
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
Response Publish Date:
Company Name: Baker Petrolite Corporation
Individual Name: Mr. Aubrey R. Campbell
Location State: TX Country: US
View the Interpretation Document
Response text:
November 6, 2009
Mr. Aubrey R. Campbell
Baker Petrolite Corporation
12645 West Airport Blvd.
P.O. Box 5050
Sugarland, TX 77478-5050
Ref. No. 09-0229
Dear Mr. Campbell:
This responds to your October 2, 2009 letter requesting clarification of the requirements under the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) for the transportation of cryogenic liquids in tank cars. Specifically, you request clarification concerning whether the pressure test requirements for class DOT 113 tank cars under
§ 173.319(e) apply to tank cars containing the residue of a cryogenic liquid.
According to your letter, your company offloads refrigerated liquid ethylene from DOT 113 tank cars to a minimal amount considered to be empty by industry standards. The empty tank cars containing a residue of refrigerated liquid ethylene are then returned to the supplier. Based on its understanding of the requirements for empty packagings in § 173.29, which requires an empty packaging containing only the residue of a hazardous material to be transported in the same manner as when it previously contained a greater quantity of hazardous material, the supplier, in accordance with § 173.319(e), monitors the average daily pressure rise in the empty tank cars and conducts follow-up thermal integrity testing on the empty tank cars if the average daily pressure rise exceeds 3 psig (0.2 Bar). You ask if the requirements in § 173.319(e) apply to a tank car that is empty except for a residue of the hazardous material it previously contained.
The answer is no. DOT 113 tank cars containing the residue of a cryogenic liquid are not subject to the requirements of § 173.319(e). Monitoring of the average daily pressure is used to gauge whether energy is being transferred to the lading through the insulation of the tank car, thus indicating a potential problem with the insulation and the need for follow-up thermal integrity testing. Monitoring of DOT 113 tank cars containing residue amounts is not effective for this purpose because the same amount of energy input will cause a greater increase in temperature and vaporization of a small amount of liquid than a large amount of
liquid. The resulting increase in pressure in a tank car containing a residue does not provide an accurate indication of potential insulation problems.
I hope this information is helpful. If you have further questions, please contact this office.
Sincerely,
Charles E. Betts
Chief, Standards Development
Office of Hazardous Materials Standards
173.319(e) 173.29
Regulation Sections
| Section | Subject |
|---|---|
| 173.29 | Empty packagings |
| 173.319 | Cryogenic liquids in tank cars |