Usage of Raman DTS for wooden material analysis

The contribution deals with a usage of Raman DTS for thermal transmittance monitoring and moisture monitoring in wooden buildings and constructions. Temperature measurement and thermal transmittance is notable for an analysis of moisture distribution inside of wooden girders that are the basic construction parts of wooden buildings during their seasoning and sanitation. In this contribution the results from measurements within real wooden objects will be presented and these results will be compared with laboratory experiments under controlled conditions. For wood sanitation two types of heating are used – flow of hot air and microwave heating. A multimode fiber 62,5/125 in primary coating is applied for measurements, this fiber is putted on the inside and outside surface of wooden construction. Here the fiber meanders are created inside of wooden girders with spacing of 1 cm. Optical fibers are laid in two mutual perpendicular cuts with usage of temperature resolution better than 0,05°C. The measured length of wooden girder is 1,4 m for unambiguously temperature specification inside the girder and its thermal transmittance. The temperature maps of various types of wooden girders are the results of analysis. Different multimode fibers with particular fiber coatings are included in the analysis. These measurements have been provided with Sentinel DTS and they are parts of a wide set DTS application for building industry. We are trying to specify the influence of fiber bending on temperature sensitivity, how to join measuring fiber to transporting fiber, critical length of both fibers and many others. Raman DTS can replace large number of thermometers and provide continuous information about temperature distribution.