Thermoglazed glass shields to protect ancient artefacts

Protective shields designed to prevent archaeological discoveries suffering damage through public display and long-term exposure to air are being developed as part of a European project.

Artifacts such as China’s terracotta army are under serious, irreversible threat from a combination of tourists, pollution and exposure to the environment. In the case of the Xi’an army, the terracotta is drying out and the figures are crumbling.

The Eurocare Arch In-situ project, a joint Slovene-Swedish venture led by architect Milan Kovac, is developing technologies to preserve ancient objects and monuments in near-perfect condition at the sites of their discovery. ‘Archaeological remains have survived in some cases for millennia before being discovered, because they are protected by the earth. But as soon as they are removed, the decay starts,’ said Kovac.

The research team, including archaeologists, lighting engineers, materials specialists and microbiologists, has designed protective shields using multilayer thermoglazed glass to cover the sites. The glass contains a membrane or film that, when connected to an electrical supply, gives out enough heat to counteract the potentially damaging effects of condensation, said Kovac.

The shield can also be used to provide structural support for the artifacts, and protect them from vibration. Reflective glass and filters are also used to control ventilation and UV light, to keep the temperature and humidity stable within the preservation chamber. ‘The membrane is developed differently depending on the case. In some instances it is designed purely to eliminate condensation, in others we would also want to filter out light.’

The team has worked on projects in Egypt and China, and the shield has been used to preserve recent discoveries at Crnomelj in Slovenia. Work on a new building uncovered the remains of an iron age settlement, a Roman defence wall and tower and a medieval settlement with two city walls, so the team designed a glazed and sealed floor and wall structure to preserve the artefacts in situ.

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