In the dynamic system, once an oxygen concentration of 0.1%
is reached, the nitrogen flow is decreased to a very low rate to maintain
the low oxygen concentration. In contrast, in the dynamic-static system,
while the nitrogen flow is still running at a high rate, the calculated num-
ber of Ageless oxygen-scavenger packets is placed inside the bag, the
opening is heat-sealed, and the nitrogen flow is turned off. The Ageless
maintains the low oxygen concentration by scavenging any oxygen that
may leak into the bag.Many museums own fumigation chambers purchased many years ago,
designed for the use of toxic fumigants such as methyl bromide and ethyl-
ene oxide fluoride. In many cases these chambers can no longer be used
because ofenvironmental regulations against the use of these fumigants.
Recently the Getty Conservation Institute converted the Los Angeles
County Museum of Art’s Vacudyne 36-ft^3 (approx. 1000 l) fumigation
chamber (designed for ethylene oxide fumigation) to the dynamic nitrogen
system described above. Several modifications were made to the existing
mechanical and electrical controls to allow oxygen, temperature, and RH
sensors to be installed inside the chamber. To operate the chamber, it is
flushed with humidified nitrogen. Once the oxygen concentration drops to
0.1%, the inlet valve and the nitrogen flow areclosed, and the oxygen con-
centration inside the chamber is monitored. With this particular chamber
the leak rate was determined to be 50 ppm per day (0.005%). The chamber
needs to be refreshed every eight to ten days to maintain the oxygen con-
centration below 0.1%.The Getty Conservation Institute has sponsored an extended mortality
study at higher oxygen concentrations (0.3%, 0.6%, and 1.0%) which is
being conducted by Michael Rust at the University of California, Riverside.
Results from this study so far suggest that an oxygen concentration of
0.3% is also effective in producing 100% mortality for the cigarette beetle
(Lasioderma serricorne) and furniture carpet beetle (Anthrenus flavipes). This
new research promises much easier implementation of low-oxygen atmos-
phere fumigation for insect eradication in the future.
The use of low-oxygen atmospheres for eradicating insect infesta-
tion is a viable alternative to toxic gas and chemical treatments. All com-
monly found museum pests can be eradicated by using a 0.1% oxygen
atmosphere. The methods described in this article produce and maintain
the RH and oxygen concentration at the required level. These methods are
advantageous because they are nontoxic and low in cost and can be used
in a variety of settings, such as galleries, storerooms, or conservation
laboratories.The authors would like to thank Brian Considine, Montserrat Le Mense,
and Gillian Wilson of the J. Paul Getty Museum; Shin Maekawa of the
Getty Conservation Institute; and Frank Preusser, formerly of the Getty
Conservation Institute, for their support and advice throughout this project.Acknowledgments
Conclusion
Alternative Encapsulation
Systems76 Hanlon and Daniel