Passive Environmental Control: The Use of Insulated Archival Boxes to Control Fluctuations in Relative Humidity and Temperature

Four archival boxes made from different materials, were tested to see how effective they were at stabilizing fluctuations in temperature (T) and relative humidity (RH) and if this method of passive environmental control could meet the environmental requirements of the Archives New Zealand Storage Standard (ANZSS), instead of using heating, ventilation and air conditioning (HVAC)systems. The boxes were placed in an un-insulated attic space in Auckland, New Zealand, during the winter for twelve weeks from June 7, to August 29, 2009. Twenty-four hour samples of T and RH of each box were taken by a Hobo LCD data-logger placed inside the boxes. Another Hobo LCD data-logger was placed in the ambient environment to determine the difference. The main results were; RH fluctuations inside all the boxes met part of Requirement 28, of the ANZSS, during the twelve weeks of the study, by not fluctuating more than 10% over a twenty-four hour period, even though the ambient RH fluctuated by as much 22%. However, although the T inside the boxes mostly fluctuated less than in the ambient environment it did not consistently reach the 4 degree centigrade or below fluctuation level of requirement, 29 of the ANZSS. The conclusion reached from the study is all the archival boxes used in study are effective in controlling fluctuations in RH and T; however, institutions needing to meet the ANZSS will require other methods to control environmental conditions.