This is heritage science…acoustic emission monitoring of gilded furniture at Knole, Kent

In our second post of #BSW2016, we ‘listen’ to furniture as Nigel Blades, Lisa McCullough and Martha Infray of the the National Trust share with us a project that has just started at Knole in Kent to analyse acoustic emission events from decorated furniture.

The work will improve understanding of collections environments at Knole and throughout the National Trust so that they can provide the right conditions to look after fragile objects such as gilded and decorated furniture. The research will be published so that heritage science colleagues from across the world can benefit from the knowledge gained.

Knole in Kent is home to one of the national Trust’s most important collections of furniture, including rare 17th century tables, torchères and chairs. Many of the items have been in the same rooms at Knole for 300 years.

As part of a heritage science research project, commissioned by the National Trust, four of Knole’s most significant pieces of furniture, the Gole Suite table and torchère and Jensen Suite table and torchère are being monitored to quantify their response to changing environmental conditions.

Acoustic emission (AE) is being used to measure wood response to the environment. An acoustic sensor has been attached to each piece of furniture. Using an amplifier and computer any movement and crack development in the wood can be recorded and quantified.

Furniture conservator John Hartley (left) and research Marcin Strojecki (right) discuss AE sensor attachment to the 17th century Gole Torchere

The Jensen Suite is displayed in the Spangled Bedroom, which has no environmental control. These conditions contrast with the Gole Suite located in the Great Store, which is controlled by conservation heating to keep the relative humidity (RH) below 65%.

Furniture conservator John Hartley prepares the sensor attachment for the Jensen Suite table

The monitoring will run for a full year to understand the significance of seasonal variations and the differences between object response in controlled and uncontrolled environments.

The completed AE sensor attachment

The acoustic emission sensors were installed by researchers from the Jerzy Harber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Krakow, Poland who are pioneers in the application of this technique in heritage science.

The acoustic emission events will be analysed together with temperature and RH measurements for the rooms where the objects are displayed. The team will learn how Knole’s decorated furniture responds in an uncontrolled historic house environment in comparison to a space in which the RH is controlled. This knowledge will help them to manage the move from uncontrolled to RH-controlled collections environments that is one of the conservation aims of the Knole project, running 2014-2018.


To find out more about this project contact Dr Nigel Blades, Preventive Conservation Adviser (Environment), National Trust.

Further information on conservation at Knole is available at



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