We have a number of initiatives underway designed to provide evidence of the conditions in which our collections are currently stored and enable us to make sustainable improvements in the future.

Building Environment Simulation (BES)

The collection care department is responsible for the long-term preservation of the collections held by The National Archives. Preservation is best secured by storing the collections under environmental conditions which slow down chemical degradation, prevent mould growth and mechanical damage, while still allowing uninterrupted access to the records. The National Archives' repository building in Kew is serviced by vast heating, ventilating and air conditioning (HVAC) systems. These need to maintain appropriate conditions for records in storage throughout the year, and also to provide comfortable working conditions for readers and staff. Given their age and original design, these HVAC systems are complicated and costly to operate and maintain.

It is a priority to ensure that the repository environments are better understood so that they can be managed sustainably. The National Archives, like other UK public bodies, is required to meet Government sustainability targets which reflect global concern for greater environmental responsibility.

A 22-month research project began in December 2008 to investigate the environmental conditions provided for collections housed at Kew. Led by the Centre for Sustainable Heritage at UCL, in collaboration with The National Archives, this project was completed in September 2010.

The aim of the project was to develop a building model that would simulate the environmental conditions (relative humidity and temperature) on three floors of repositories at Kew, and provide The National Archives with the information needed to optimise building performance and achieve a stable preservation environment with reduced energy use.

Building environment simulation project (PDF, 0.05Mb)

Annual environmental review: assessing environmental conditions for The National Archives collections

Environmental data (on relative humidity and temperature) generated by our environmental monitoring system forms the basis for our annual environmental assessment. This assessment defines the standards of preservation for The National Archives' repositories.

Four interdependent factors affecting the quality of the preservation environment are considered:

  • chemical degradation
  • environmental stability
  • probability of mould growth
  • impact of the external environment on conditions achieved inside the repositories

This method of environmental assessment does not rely on or reference any published standards or guidelines for relative humidity or temperature. Each of the four factors is depicted in a map or graph of the repository. We find that presenting the data visually is easier to understand. All four factors form the basis for our conclusions which guide our environmental policies and practices.

Related references

K Ntanos and S VanSnick, Environmental assessment without limits at The National Archives (Choices in conservation: practice versus research, ICOM-CC Graphic Documents Working Group Interim Meeting 6-8 October, Copenhagen, 2010 pp 19-22)

Environmental assessment without limits (PDF, 0.39Mb)

Climate mapping

Relative humidity and temperature variations across three repositories in the building were mapped in 2007 to investigate the degree of environmental stability achieved by the HVAC system.

The results were used to develop The National Archives' environmental monitoring programme and underpin improvements in the building management system and environmental controls.


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