Interpretation Response #11-0020
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
July 25, 2011
Ms. Robbin L. Miller
Department of the Air Force
5215 Thurlow St. Ste. 5
Wright-Patterson AFB OH 45433-5540
Reference No.: 11-0020
Dear Ms. Miller:
This responds to your letter requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the hydrostatic pressure and leakproofness requirements for a combination package transported via aircraft. Specifically, you describe a scenario and ask several questions regarding that scenario. The scenario and questions are paraphrased and answered as follows:
In your incoming letter, you describe a combination packaging composed of a 30-gallon steel drum lined with a 4-mil plastic bag containing a 1-gallon plastic bottle surrounded by vermiculite. This completed combination package has been tested to the Packing Group (PG) I level. The combination package was subjected to and successfully passed the stack, drop and vibration tests specified in Subpart M of Part 178 of the HMR. The inner packaging of this combination packaging does not meet pressure requirements specified in § 173.27(c). However, the outer packaging successfully passed a hydrostatic pressure test with a test pressure of 95 kPA. You wish to transport via aircraft a PG I liquid with a vapor pressure of 110 kPa at 50o C in this combination packaging.
Q1. It is your understanding of § 173.27(c)(3)(i), and a previously issued Pipeline and Hazardous Materials Safety Administration (PHMSA) Interpretation issued on July 8, 2003 [Ref. No. 03-0163], that a PG I liquid may be transported aboard an aircraft in the tested combination packaging described in the above scenario. Is this corect?
A1. The answer is yes. For transportation by aircraft, § 173.27(c)(2) requires that packagings must be capable of withstanding, without leakage an internal pressure based on the vapor pressure of the material to be transported when its basic function is retention of liquid. Section 173.27(c)(3)(i) allows inner packagings that are not capable of meeting the pressure requirement to be placed in a supplemental outer packaging which does meet the pressure requirement. In accordance with § 173.27(c)(2)(ii)(B), for transportation by aircraft of a liquid with a vapor pressure of 110 kPA at 50o C, the outer packaging of a combination packaging must be capable of meeting a pressure requirement. The pressure requirement is the greater of either 95 kPA or 92.5 kPA if the inner packaging is not capable of meeting the pressure requirement. Based on the requirements in § 173.27(c) the combination packaging you describe in your incoming letter does demonstrate it is capable of meeting pressure requirements and, therefore, can be used to meet this requirement.
Q2. If the above described PG I liquid's vapor pressure was 120 kPA at 50oC, and the inner packaging of the combination packaging does not meet any of the requirements in § 173.27(c), what would the required pressure rating be for the outer packaging?
A2. In accordance with § 173.27(c)(2)(ii)(B), for transportation by aircraft of a liquid with a vapor pressure of 120 kPA at 50oC, the outer packaging of a combination packaging must be capable of meeting a pressure requirement of 110 kPA at 50oC if the inner packaging is not capable of meeting the pressure requirement.
Q3. It is your understanding of § 178.604(a)(2), that there is no leakproofness requirement for either the inner or outer packaging of the packaging mentioned above. Is this understanding correct?
A3. The answer is yes. In accordance with § 178.604(a), the leakproofness test must be performed on all packagings intended to contain liquids, except the test is not required for inner packagings of combination packagings. The outer packaging of the combination packaging you describe in your letter is intended to contain the inner package, not liquids; thus, it is not subject to the leakproofness test specified in § 178.604(a). However, it should be noted that the outer package of this combination package still must meet the requirements specified in § 173.27(c)(3)(i).
I hope this satisfies your inquiry. Please contact us if we can be of further assistance.
T. Glenn Foster
Chief, Regulatory Review and Reinvention Branch
Standards and Rulemaking Division
173.27, 173.27(c), 173.27(c)(2)(ii)(B), 173.27(c)(3)(i), 178.604(a), 178.604(a)(2),
|§ 178.604||Leakproofness test|