It is critical for archive environments to maintain adequate environmental levels in areas where historical records are held. An unsuitable environment, including inappropriate temperature and humidity levels, can adversely impact the condition of precious materials, causing issues such as mould growth and accelerating the rate of material deterioration.

Berkshire Record Office holds the archives of the Royal County of Berkshire. It exists to look after nearly 900 years of the County's history, including that of its major towns such as Reading, Newbury and Windsor. Records under its care include those of public authorities, e.g. councils, hospitals and courts, and also of businesses and individuals.

Sue Hourigan, Senior Conservator for Berkshire Record Office, helped to design the current, purpose-built building in which the Berkshire Record Office runs its services and stores its archives. Responsible for looking after 7 miles of historic records across six strongrooms, Sue is experienced in maintaining the correct environment for effective preservation.

To ensure that suitable levels of temperature and humidity are maintained in the Record Office's six strongrooms, Sue uses Tinytag Ultra 2 TGU-4500 indoor temperature and relative humidity data loggers.

In each of the strongrooms, a Tinytag data logger continuously monitors and records the temperature and humidity levels. Data is downloaded to a PC from the data loggers at least twice a month using Tinytag Explorer software. Sue is particularly pleased with the flexibility of the software's graph customisation features that allow her to adjust how the data is visually presented: "I adjust the graphs to represent water and heat - so, the relative humidity line is blue, and the temperature line is red," she explains.

It is essential for the Record Office to understand daily temperature and relative humidity levels. Mould growth, which happens at a higher humidity, is a particular concern for archive environments; it can cause irreversible physical and chemical damage to many of the irreplaceable items in archival collections and presents a significant health hazard to those who handle affected items. Data from the loggers helps Berkshire Record Office to keep temperature and humidity at the correct levels to prevent such damage to their collections. If the data shows higher humidity than is ideal, Sue is able to ensure that the air conditioning is adjusted in response.

Data from long-term monitoring is also important for helping the Record Office to maintain the archive environment and achieve its aims. Long-term environmental data supported the Record Office's application for Archive Service Accreditation, which it achieved in 2017. The data from the Tinytags showed that the strongrooms were kept within the correct environmental parameters for the required number of days, allowing the Record Office to prove that the archive environment is suitable for effective preservation of the collections.

The Tinytag Ultra 2 data loggers and easy-to-use Tinytag Explorer software have been invaluable for Berkshire Record Office's collections care. Reflecting on her experience using the loggers, Sue comments, "I wish I had bought the Tinytags sooner!"

Images courtesy of The Berkshire Record Office.