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Interpretation Response #04-0023 ([Haas TCM] [Mr. Larry Holcombe])

Below is the interpretation response detail and a list of regulations sections applicable to this response.

Interpretation Response Details

Response Publish Date:

Company Name: Haas TCM

Individual Name: Mr. Larry Holcombe

Location State: PA Country: US

View the Interpretation Document

Response text:

May 5, 2004

 

Mr. Larry Holcombe                Reference No. 04-0023
Account Manager
Haas TCM
1646 West Chester Pike
West Chester, PA 19382

Dear Mr. Holcombe:

This responds to your letter concerning determination of the vapor pressure to calculate the test pressure for packages intended for air transportation in § 173.27 of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180).  Your questions are paraphrased and answered below:

Q1. Is it correct to obtain the vapor pressure from engineering tables if the liquid consists of a single chemical component?

Al. Yes, obtaining the vapor pressure for a liquid that consists of a single chemical component from engineering tables is acceptable.

Q2.      For liquids with multiple chemical components, you propose to use vapor pressure from engineering tables for the most volatile component at the specified temperature and set a vapor pressure threshold limit equal to 50% of minimum test pressure for the package.  If the vapor pressure of the mixture exceeds the threshold limit, you further propose to measure the vapor pressure by laboratory testing.  You ask if this approach is suitable.

A2.      We are unable to determine the suitability of your approach.  The Hazardous Materials Regulations do not prescribe specific methods for determining the vapor pressure.  The vapor pressure may be determined by testing or empirically.  Any test method that leads to the determination that the package is capable of withstanding the pressure requirements in § 173.27 without leakage may be used.

I hope this determination is helpful.

Sincerely,

 

Hattie L. Mitchell
Chief, Regulatory Review and Reinvention
Office of Hazardous Materials Standards

173.27

Regulation Sections