HOBO data logger to control the indoor environment at JFK
Located on the sixth floor above historic Dealey Plaza in Dallas, where President John Fitzgerald Kennedy was shot, the Sixth Floor Museum in Dealey Plaza serves as a repository for a variety of documentary materials surrounding the assassination on November 22, 1963. More than half a million people visit the Sixth Floor Museum each year to learn more about the fateful day through original photographs, newspaper clippings, letters, films and FBI reports.
While the museum's first priority is to make these artifacts accessible to the public, it must also ensure that each object is protected and preserved from damaging environmental conditions. These include fluctuating temperatures, relative humidity (RH) and excessive light intensity.
"Our collection includes artifacts made from a variety of materials," explains Lacie Ballinger, collections coordinator at the Sixth Floor Museum. "We have a ten-by-ten-foot FBI model of Dealey Plaza that was on loan from the National Archives and was used by the Warren Commission to analyze the trajectory of bullets. The model has glass walls, a plexiglass roof and construction paper was used to simulate the environment, so it is extremely sensitive to light. We also have wooden objects like Caroline Kennedy's footstool and textiles like the flag that flew at half-mast over the Capitol after the assassination. With so many different materials, it can be a challenge to maintain the right environment for our collections."
As part of its strategy to control the indoor environment, the Sixth Floor Museum relies on HOBO® data loggers to continuously monitor temperature, RH and light intensity. HOBO loggers are battery-powered stand-alone devices equipped with an integrated microprocessor, memory for data storage, accurate temperature, RH and light intensity sensors, and a user-replaceable battery. The loggers communicate with a computer and use a software program that activates the logger and allows the user to view and analyze the collected data.
At the Sixth Floor Museum, HOBO data loggers are magnetically attached to various 10-foot-high metal ceiling beams throughout the facility. The beams, Ballinger explains, contribute to the warehouse look of the former Texas Schoolbook Depository, from which the museum was converted in 1989. Each logger is required to record temperature, RH and light every 12 minutes. "In general, we try to keep the temperature in most areas between 67 and 73 degrees Fahrenheit, the humidity between 50 and 55 percent, and the light intensity between 5 and 0 footcandles, depending on the specific objects in the area being measured."
After two weeks of collecting data, Ballinger retrieves the data using a data shuttle. This pocket-sized device can read and store the data from each logger, which Ballinger then transfers to a computer to graph and analyze the data using HOBO BoxCar® Pro software. The software instantly translates the collected data into easy-to-read graphs that clearly display the temperature, humidity and light levels for the two-week period. Ballinger can create customized charts for documentation purposes and print them out for meetings. Since purchasing the data loggers in 2001, they have been working around the clock without any problems. By continuously monitoring environmental conditions at the Sixth Floor Museum, the loggers are helping to preserve artifacts associated with one of the most important and controversial events in American history.
Ballinger concludes, "The most important feature we like about the HOBOs is that they pinpoint when events occur, for example when an air handling system is turned off, and from that we can deduce cause and effect. This is much more difficult with chart recorders. We also like the fact that the loggers can be hidden very easily in exhibition areas and visitors don't notice them."