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Abstract:

The paper describes calculations of the humidity in King's College Chapel, Cambridge, based on climatological data, and subsequent measurements of the temperature and humidity in the building for a period of 12 months. The humidities actually experienced in winter were appreciably greater than those predicted, because the structure absorbed moisture exhaled by summertime visitors. A proportion of this moisture was re-emitted to the air in the building during the following winter and helped to keep the humidity higher than was expected. It was concluded that because of this, and because the existing heating system was incapable of maintaining a temperature excess of more than about 10 degrees, there was little chance of the relative humidity falling below about 50 per cent. There should therefore be no danger of damage to a very valuable painting on a wooden panel which was to be placed on exhibition in the Chapel.