Isolation scheme may counter bioterrorists
03/01/2004
By Hank Hogan
GLENN DALE, Md.—Steve Wood, chief of emergency preparedness for San Diego County in southern California, is doing what he can to be ready for a bioterrorist attack—or, a plane load of unlucky passengers.
And he's doing so by putting contamination-control technology, with its roots in the military, to work.
The County recently took delivery of six AEGIS ChemBio systems from TVI Corp. Just announced, the systems provide highly portable isolation chambers. Thanks to pleated carbon filtration technology, pressure control, and variable speed fans, the systems can help control the spread of diseases like SARS or avian flu. Such ailments can come in on any plane—a possibility that has Wood and others concerned.
"A disease can spread around the world in 24 hours because of air travel," he says. "So, somebody can get on an airplane with an exotic disease on another continent, say Australia, and be in San Diego in 15 hours and potentially be infectious and spread that disease. We're just getting better prepared to address those issues."
San Diego County did so by working with TVI during the design and development of the AEGIS. Wood notes that other agencies, hospitals, and first responders around the country have expressed interest. The groups are looking to add to or improve upon their own rapid deployment isolation capability. In the case of San Diego, the systems are in place for surges in demand—times when hospitals within the area find their own isolation chambers aren't enough.
According to TVI executive vice president Chad Sample, the pleated carbon filters in the AEGIS system are lighter and smaller than carbon beds of equivalent filtration capacity. The filters' performance has been verified by testing at United States Army Soldier and Biological Chemical Command (SBCCOM) in Aberdeen, Md. where the filters displayed 15 minutes of life at 99.9992 percent efficiency when challenged with 5,000 milligrams per cubic meter of dimethylphosphonate (DMMP).
This is a standard test for military applications of chemical and biological filtration. Sample says that these were one of the first if not only pleated carbon matrix products to meet and survive such a challenge.
The AEGIS units have a pre-filter and a HEPA filter before the carbon adsorbers. The filtration control system incorporates chamber pressure indicators, audio and visual alarms, automatic adjustment of fan speed, an integrated air lock, and can maintain either positive or negative pressure. The systems come in two sizes— one for three gurneys that measures 20 feet by 9 feet, and another for five gurneys that measures 20 feet by 11 feet. Despite their size, the units are portable as well as easy to set up and take down.