- The Rodent Trapping Tip Sheet provides general information on the use of snap traps to address a mouse or rat infestation.IPM’s emphasis is on prevention and avoidance of infestations, so the information provided should not be interpreted as a permanent and/or ongoing response to rodent infestations.
- The Freezer Fact Sheet provides freezer specs from various
institutions. It is unlikely that institutions looking now to purchase a freezer for low-temperature treatments will be able to find the exact brands and models listed in this document. The information is provided to show the range of products that can adequately meet the technical specifications for this type of treatment.
- Freezer Modifications for Museum Pest Control contains an excerpt the Society for the Preservation of Natural History Collections (SPNHC) Newsletter and the Western Association for Art Conservation Newsletter (WAAC) on how to modify home and chest freezers for museum pest control.
- Mechanical Behavior of Animal Hides at Low Temperatures summarizes results from a 2009 Smithsonian Institution Museum Conservation Institute / National Museum of the American Indian research project investigating the effects of low temperature treatment on stretched/constrained animal hides. The project was undertaken to inform treatment decisions for drums and other composite items with stretched animal skins.
Heat Treatment Information
- Download the poster Materials Testing: The Use of Heat and Humidity Chambers for Pest Eradication, by Dr. Marieanne Davy Ball ACR, Department of Conservation, Cultural History Museum, University of Oslo, Oslo, Norway; and Christina Bisulca and Dr. Nancy Odegaard, Preservation Division, Arizona State Museum, University of Arizona presented at the American Institute for Conservation’s 39th Annual Meeting in 2011 for information on what materials may or may not be considered appropriate for the Thermo-Lignum heat treatment. See abstract below.
Dr. Marieanne Davy Ball ACR, Department of Conservation, Cultural History Museum, University of Oslo, Oslo, Norway; and Christina Bisulca and Dr. Nancy Odegaard, Preservation Division, Arizona State Museum, University of Arizona
Heat has long been used in conservation for the artificial aging of materials, but now it is also being used as a pest eradication treatment. The heat chamber heats objects to a temperature where insects cannot sustain life (~54–60°C) at a chosen, set relative humidity. The chamber is being marketed to museums as a less time-consuming pest eradication treatment because the process can be completed in approximately 16 hours, as opposed to days or weeks needed for freezing or carbon dioxide treatments.
Museum objects are often complex composites with adhesives, coatings, or natural oils and resins within the materials themselves. Many of these materials have low melting or glass transition (Tg) points, or are prone to thermally induced dimensional or chemical changes. Mechanical properties of certain materials are dependent on relative humdity: of particular concern is Tg, which decreases with increasing relative humdity for many polymers. The migration of waxes and distortion of some objects after treatment in the heating chamber has already been observed. Due to such unknowns, it was deemed important to identify potential problems that can arise from heat treatment.
To assess the potential effects of the heat treatment, samples of 21 common adhesives, resins, and waxes were tested. For each material, four separate sample preparations were assessed using the material as an adhesive on wood and glass joins, as a film on filter paper, and as a film on glass. These samples were weighed, measured, and photographed prior to and after treatment. Glass film sample preparations were additionally analyzed with Fourier transform infrared spectroscopy (FTIR) to assess any chemical change before and after aging. Due to the probability of an object passing through this eradication process several times within its life, cumulative effects were also recorded from a series of five test runs, recording the core and ambient temperature and relative humidity within the chamber.
Results show that certain classes of materials were susceptible to specific types of deterioration from heat treatment. Even with fresh materials, the epoxies yellowed and the hide glues and natural resins were prone to yellowing, crazing, slippage in joints, and/or weight loss. Many waxes and some synthetic adhesives melted or slumped during heat treatment. Several natural resins and oils showed chemical change (oxidation, loss of water) based on FTIR results. With further testing on other materials (horn, skin/leather, bone, etc.), we should be able to make informed decisions about which materials can be treated safely using heat for pest eradication.
Working with Pest Management Professionals
- Tips For Hiring A Museum Pest Contractor – This document, developed by the IPM Working Group, provides guidance on things to consider and ask when interviewing pest control operators for use in cultural heritage institutions.