Data Loggers Test Air Shipments of Oxygen Containers

Perry Hock is employed by gh Package & Product Testing and Consulting, Inc. in Fairfield, OH. gh Testing is a third party test lab and certification agency for US DOT Hazardous materials package testing, and they are also a certified test lab to perform package/product testing and evaluation. One of the recent tests they performed was a fire test mandated by the Boeing Company and now a test mandated by IATA (International Air Transport Association) for the shipment of oxygen generators.

Oxygen generators are used on passenger aircraft in the event the plane's cabin depressurizes, at which point oxygen masks drop down and the generators themselves are ignited to provide the needed oxygen to the passengers and crew. Many of us recall that terrible ValuJet plane crash in the Florida Everglades a few years ago where nearly 200 passengers and crew lost their lives due to the improper shipment and handling of oxygen containers. These spare oxygen containers caught fire, causing the plane to go down. This accident should have been avoided, and since this accident took place, oxygen generators are now forbidden to be shipped on passenger aircraft, only cargo aircraft. The cargo aircraft will then carry the spare oxygen generators to the passenger aircraft who may be in need on them. gh Testing is assisting in the research so this mishap never happens again.

The reason for the testing is to verify that, even if one of the oxygen generators ignites and starts its exothermic chemical reaction to produce oxygen, the interior of the corrugated box (where the oxygen generators are stored) will not catch fire and the exterior of the package will not emit temperatures above the mandated limit. Onset loggers came in handy, as it is extremely important to the test lab to place logging devices around the package to monitor the temperature levels both inside and outside the package. It is of the utmost importance that the package passes this strict test so when these oxygen generators are shipped by air, there is not another unfortunate incident on a Federal Express, DHL or other cargo-type aircraft.

Since they needed to monitor internal and external temperatures of the package, Perry used 7 HOBO Temp/RH data loggers, and placed them on all 6 faces of the package as well as inside with the oxygen generators. The first version of the package failed miserably by catching fire (see picture). The logger that was placed inside the package had extensive damage with about 75% of its cover melted away. The board within the logger was still intact, however, and they were able to retrieve all the data collected. Two other loggers had the outside cover charred from the fire. Even though the test failed by catching fire and the loggers were damaged as a result, no logger actually failed during the test.

The test time lasts as long as the oxygen generator burns - anywhere from 10 to 15 minutes. The test sequence comprised of igniting an oxygen generator inside the package to simulate one accidentally being ignited, closing the package, and monitoring the package. The exterior of the package cannot have temperatures which exceed a specified temperature mandated by the ICAO (International Civil Air Organization) and IATA regulations.

The data collected by these series of tests proved to be crucial in the shipping of oxygen generators by air and their overall safety factor. Perry and gh Testing determined that fireretardant doatings should be sprayed on the corrugated box, and better poly bags to wrap the generators were necessary to contain any possible fires.