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Development of an Optical Fiber-Based Moisture Sensor for Building Envelopes



William M. Healy, S Luo, M Evans, A Sucheta, Y Liu


Optical fiber-based moisture sensors have been developed to help detect moisture problems in building envelopes. The sensors are created with a coating on a long period grating that is written onto optical fiber. As the coating absorbs moisture from its surroundings, the refractive index of the coating changes, thereby changing the propagation of light down the fiber. In addition to the humidity sensors, temperature sensors based on Fiber Bragg Grating technology and Fabry-Perot interferometry have been developed to provide temperature compensation. Tests in a humidity chamber show significant sensitivity of the sensors to humidity, with a linear response to temperature. In addition to tests in the environmental chamber, the sensors were also tested as moisture content sensors on samples of gypsum board, oriented strand board, and pine. These tests again showed marked sensitivity to the moisture level. The sensors are very appealing because of their small size, durability, and ease of multiplexing and could potentially serve as a vital tool in detecting moisture issues in buildings.
Air Infiltration and Ventilation Centre


envelope, humidity, instrumentation, moisture, sensor


Healy, W. , Luo, S. , Evans, M. , Sucheta, A. and Liu, Y. (2003), Development of an Optical Fiber-Based Moisture Sensor for Building Envelopes, Air Infiltration and Ventilation Centre, [online], (Accessed June 24, 2024)


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Created October 1, 2003, Updated February 19, 2017