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Arghya Sen, Senior Systems Engineer

Museums house thousands of priceless and delicate artifacts that tell an important story of our history and culture over time. Maintaining optimal internal conditions to protect these collections is paramount, yet incredibly challenging and fraught with risk. Getting it wrong could lead to mould growing on the precious artworks like the Mona Lisa, powdering on marble statues, and ancient scrolls becoming too brittle to examine – a museum director’s worst nightmare! 

Maintaining an equilibrium between visitor comfort and artifact preservation demands a new approach to building operation management, one that can also facilitate lower operational costs and reduced carbon emissions. I had the pleasure of discussing this new way forward with Anthony Caruana in the latest episode of the Building Peak Performance podcast.

 

 A Practical Guide for Sustainable Climate Control and Lighting in Museums and Galleries 2014, Museums & Galleries Queensland in partnership with Museums & Galleries of NSW, pg 29,

A Practical Guide for Sustainable Climate Control and Lighting in Museums and Galleries 2014, Museums & Galleries Queensland in partnership with Museums & Galleries of NSW, pg 29, http://www.magsq.com.au/_dbase_upl/APracticalGuideforSustainableClimateControlandLightinginMuseumsandGalleries.pdf

 

Visitor comfort VS artifact preservation

When thinking about and designing a complex indoor environmental control system for a building such as a museum, a lot of time and thought goes into how to design a system that can balance the thermal comfort of tenants and visitors with the optimum conditions necessary to protect and preserve the artefacts on display.

Humidity levels must be carefully managed otherwise the materials that make up an object or artefact could adversely react. This is because most artworks are generally made from a wide range of organic substances such as wood, cotton, paper, bone, ivory, leather and parchment. These substances are hygroscopic, which means they are affected by the moisture content in the surrounding air. Deterioration is inevitable, however by carefully managing humidity levels, their rate of deterioration can be stabilised. 

And herein lies the issue. Humidity levels are notoriously difficult to maintain as the constant influx of people through a room leads to fluctuations in temperature and humidity. 

From my experience as a building controls engineer, there is generally a dissonance between design intent and operational intent. Often the system designer will focus on maintaining the correct conditions to balance the needs of visitors and artifacts without giving enough thought to the operational requirements of achieving this balance. 

As a result, what we tend to see within a museum for example, are systems pulling and pushing against each other as they attempt to create the right internal conditions. The cooling system competes with the heating system while the humidifier battles with the dehumidification process, leading to variable internal conditions and costly energy bills.

New ways to preserve the old

Accurately measuring the air moisture content is the most effective way of maintaining the right humidity levels in a museum.  

Relative Humidity (RH), expressed as a percentage, is commonly used to measure the amount of moisture in the air relative to the amount the air is capable of holding, however it is variable to zone temperature which impacts its accuracy.

CIM’s PEAK platform measures relative humidity and combines it with temperature data to deliver a more accurate parameter called ‘dew point’. Dew point is a measure of the absolute humidity, regardless of temperature. It is called dew point because it predicts the temperature at which moisture will condense on a surface. 

Unlike relative humidity that varies with temperature, dew point provides an indication of air moisture content and remains constant regardless of temperature. It enables you to control the internal environment to an absolute value and strike the right balance between visitor comfort, artefact preservation and energy use.

For many humid climate conditions and applications, we no longer believe that controlling relative humidity automatically controls moisture, so dewpoint has become a game-changer for our industry.  So why has the industry been slow to implement this change? 

You can’t control what you can’t measure

Until recently, the industry believed the only way to accurately measure and determine dew point was by using very expensive sensors such as chilled mirror hygrometers, or a temperature and humidity measurement formula that required complex computer calculations. 

Building analytics is changing this perception, by shining a spotlight on the power of dew point, calculated using existing building data,  as a more viable method of controlling air moisture.

Initially, there was some pushback at implementing dew point controls as museum stakeholders were understandably wary of altering their internal environment that, as far as they knew, was doing a good job of preserving artifacts and maintaining visitor comfort. 

Data collected across other buildings by CIM’s PEAK platform proved the importance of measuring dew point, leading to trials across several cultural institutions. The data collected by PEAK at these sites quickly painted an accurate picture of indoor air quality and performance at each site, verifying the importance of incorporating dew point into a museum’s control strategy. 

What we began to see were systems cooperating with each other, making them more energy and cost-effective and indoor conditions maintained precisely how they should have been. Humidity control has been the most inefficient and difficult control strategy, so by ruling it out we are able to carry dew point control strategies to assets such as hospitals, where lives depend on precise moisture content control.

Data collected by CIM’s PEAK platform is facilitating a new way of protecting and preserving artifacts in museums and galleries that provides useful insights for all operators of all building types. Get in touch with us to find out more.

To find out more about Arghya, read about his unique journey from Calcutta to Antarctica to joining CIM.