Conservation treatment

We have a number of initiatives underway to help us to deliver effective stewardship of The National Archives' collections.  

Mapping our collections

We are mapping the collections held at The National Archives in terms of material, condition and storage requirements. First we are exploiting existing information available from the catalogue and The National Archives' document ordering system, incorporating information from other databases. We are using specially developed CAD software to process this information and to create visual images or maps of the collections.

In a second phase, we will fill gaps with information gathered from cataloguing projects and condition surveys.

Informing conservation treatment

Mapping the collection will provide valuable information to improve storage and prioritise records in need of conservation. Having a comprehensive picture of the collection will help to predict the knowledge and skills we will need in the future.

Conservators and conservation technicians work with preservation specialists and conservation scientists to decide on the most appropriate treatments for records.

Find out more about our conservation projects.


Document surveys are also used to inform the digitisation of our archival collections, from planning stages through to imaging and storage. We select and prepare records for digitisation, choose the equipment, make any necessary repairs to damaged documents and undertake the scanning.

View our online records, and find out more about some of the collections we are currently digitising and improving access to online, with the help of volunteers.

Building Environment Simulation (BES)

To extend the useful life of The National Archives' collections, we store records in environmental conditions which slow down chemical degradation, prevent mould growth and mechanical damage. 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.

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

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)

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