Heat Panels for Controlling Crawling Insects in Storage Areas
As the museum community becomes increasingly aware of the adverse effects that most pesticides have on human health and specimen integrity, and because of the growing number of government regulations that restrict the availability and use of pesticides, there is growing support for developing techniques that would enhance integrated pest management programs. Integrated pest management strategies that prevent access of pests to storage areas are the most useful. Even superior storage facilities may need protective devices in the vicinity of access areas, such as doors or hallways. A heat panel can be an effective method for preventing access of crawling insects into collection areas.
Stephen L. Williams
Natural Science Research Lab.
Museum of Texas Tech. Univ.
4th Street and Indiana Avenue
Lubbock, Texas 79409 USA
Tel (806) 742-2486
Fax (806) 742-1136
Illustration: Stephen L. Williams
Heat panels to control insects can be designed and constructed for almost any storage situation. A heat panel uses an electric heat controller to regulate the temperature of a flexible heating cord that generates heat along a metal surface (Fig. 1A). Aluminum molding is used to protect the cord and to provide a suitable material for transmitting the heat (Fig. 1B). An acrylic sheet is used to insulate high temperatures from structural surfaces. The heating cord can also be manipulated to locally intensify heat, if needed (Fig. 1C).
Figure 1. The heat panel installed around a doorway (A), showing an enlarged sector of the panel (B), and the arrangement of the heating cord under the floor panel (C). Parts are identified as follows:
- electric heat controller
- extension adapter cord
- electric heating cord
- aluminum molding.
Materials Tools Supplies
- Aluminum molding
- Electric drill and bits
- Electric heat controller
- Extension adapter cord
- Flexible electric heating cord
- Metal file
- Polymethylmethacrylate sheet,1/8in
- Screw driver
- Screws for aluminum molding
- Identify the structural surface (for example, floor, wall, window, or doorway) where a heat panel is to be placed to effectively retard the passage of crawling insects. It should be located near an electrical outlet.
- Obtain a heat cord that has a length that exceeds the length of the proposed panel (extra length can be accommodated under the aluminum molding). For instance, a normal 30in -36in doorway would require a 24ft heat cable. This length operates on 120 volts and uses a maximum of 562 watts. With longer heating cords, there may be a need to use electrical systems that can accommodate more wattage, and possibly more voltage. For such situations, the gauge of electrical wire and ongoing uses of the electrical circuit should be checked for safety.
- Choose an aluminum molding that is broad enough to create a formidable barrier to insects once they are exposed to the heated surface. Generally, the width of the barrier should be at least 11/2 – 2 times the length of the pest to be controlled.
- To enhance the effectiveness of the heat panel, set up a physical barrier to stop the insects before they crawl onto the heat panel. This can be done with acrylic sheet insulation or additional aluminum molding (Fig. 1B). The length of aluminum molding and acrylic sheet should be cut to accommodate the desired dimensions of the heat panel, and to fit existing structural features. Because the acrylic sheet is used to prevent the transfer of heat to structural surfaces, it must have a greater width than the aluminum molding.
- After all aluminum and acrylic parts of the heat panel are cut to size, bore holes into the acrylic and aluminum panels and secure the panels to their intended locations.
- Loosen the aluminum panel, or remove it, to permit placement of the heating cord. In areas where insects may be a greater threat (for example, the floor) the heating cord can be doubled or tripled so that greater amounts of heat can be generated (Fig. 1C). Aluminum foil can be used to hold the cord in place, and to serve as a heat reservoir below the heat panel.
The heat panel described was used on the door of a room housing a dermestid colony and was found to be effective in restricting the passage of dermestids through a metal doorway over a cement floor. Adjusting the temperature controller to maximum levels, it was possible to obtain temperatures of 150º-180ºF, depending on the number of heating cords used. The cost for electrical equipment and building materials was about $250 (1991 prices).
With any heat-generating device, precautions should always be taken to avoid contact between such devices and combustible materials. Although the described system is most appropriate on metal and cement surfaces, there is still a need to avoid heating structural surfaces because of loss in effectiveness of the heat panel itself. Even so, the temperatures can scorch surfaces with time depending on settings used.
When installing heat panels it would be wise to use materials in association with the system that would provide protection in case there is a malfunction in the system.
IPM, Pests, Control, Heat, Dermestid