PHMSA finalises air packaging rule

The US Pipeline & Hazardous Materials Safety Administration (PHMSA) issued its final rule under docket HM-231A this past April 16. The rulemaking adopts requirements for the closure of inner packagings in combination packagings carrying liquids by air; the requirements are consistent with those in the 2011-2012 edition of the International Civil Aviation Organisation’s (ICAO) Technical Instructions. The rule is effective as of July 1 but voluntary compliance is authorised as from May 16.

PHMSA and the Federal Aviation Administration (FAA) had considered a number of alternative means of reducing the number of leaks and spills involving combination packaging in air transport. At present, stoppers, corks and other closures must be held securely in place by “positive means” in order to prevent the closure from loosening due to vibration or a substantial change in temperature. PHMSA has interpreted this as meaning that a secondary means of maintaining a seal, such as a shrink- wrap band or heat-sealed liner, is required; additionally, research has shown that the simple application of tape on a screw-type closure provides effective prevention against “back-off” of the closure, even under extreme conditions.

PHMSA issued a notice of proposed rulemaking in May 2010 (HCB June 2010, page 14) and received a number of comments, mostly supportive in general. Some industry representatives did, however, point out that the option to tape screw-tops is in most cases impractical. In their view, the use of a leakproof liner is the only feasible means of achieving a secondary seal.

PHMSA accepts this argument, but only for liquids of Packing Groups II and III. For liquids of Packing Group I, a secondary means of closure will be required, along with absorbent material and a rigid, leakproof receptacle or intermediate packaging. The revised text of the requirements can be found in the Hazardous Materials Regulations, §173.27(a), (d) and (e).