Interpretation Response #00-0117 ([Aerostatic Engineering] [Mr. John Terry])
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
Response Publish Date:
Company Name: Aerostatic Engineering
Individual Name: Mr. John Terry
Location State: CA Country: US
View the Interpretation Document
Response text:
April 24, 2002
Mr. John Terry Reference No. 00-0117
Aerostatic Engineering
495 East Brokaw Road
San Jose, CA 95112
Dear Mr. Terry:
This is in response to your letter concerning the purging of a propane cylinder that will be offered for transportation by aircraft under the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180. You enclosed materials on outline your procedures for purging cylinder to a point where the fuel to air ratio is below 2 percent. You inquired how far under 2 percent is purging required. We apologize for the delay. in responding and regret any inconvenience it may have caused.
As you state, § 173.29(b)(2)(ii) requires that a cylinder be sufficiently cleaned of residue and purged of vapor to remove any potential hazard to be considered as not regulated under the HMR. The methods and limits used for determining what qualifies as a “cleaned and purged” under the HMR are intentionally not defined because they vary greatly depending on the properties of the particular hazardous material and type of packaging. In the case of propane, other variables such as purge medium, temperature conditions and cylinder volume are also factors. We would consider a propane cylinder to be sufficiently cleaned and purged when the vapors in the cylinder are no longer capable of sustaining combustion. Of course, when a cleaned and purged cylinder is offered for transportation by aircraft, the cylinder valve must be left open to preclude internal pressure buildup, as prescribed in packing instruction 200 of the International Civil Aviation Organization's Technical Instructions for the Safe Transport of Dangerous Goods by Air.
I hope this satisfies your request.
Sincerely,
Hattie L. Mitchell, Chief
Regulatory Review and Reinvention
Office of Hazardous Materials Standards
173.29
Regulation Sections
| Section | Subject |
|---|---|
| 173.29 | Empty packagings |