The measurement of moisture in building fabrics has been of interest for many years due to thepotentially devastating consequences of moisture problems within buildings. A range of potentialtechniques are available with which to measure the moisture content of building fabrics in-situ and thispaper focuses on one particular technique, the thermal dual-probe. Note that this method is distinctfrom the single probe technique. Essentially, a short pulse of electrical energy is applied to a wirewithin the heating needle. A separate temperature sensor needle, which incorporates athermocouple (for example), records the resulting maximum temperature rise in the material at acertain distance from the heating needle from which the moisture content can be deduced. Thisapproach offers the potential for some significant advantages over existing techniques. Whilst thetechnique has been successfully applied to soil measurements, a reliable and appropriate dual-probesystem for in-situ measurements in building fabrics has not previously been established. This study(funded by the UK Government's Engineering and Physical Sciences Research Council) has, for thefirst time, successfully optimised the technique for this particular application via extensive FiniteElement modelling and experimental work. Previous work by the authors has compared moisturemeasurements taken using the thermal dual- probe with those obtained from gravimetric analyses.Close agreement between the two techniques was achieved. This current work extends thedevelopment of the thermal dual-probe via comparisons with moisture distribution measurements madeusing an X-ray absorption system. This paper details the experimental work and the results obtained.Encouraging agreement between the two methods was achieved. This work is significant as it opensup the possibility of using this technique reliably in the field for an application such as monitoring thedrying out of a structure post-flood.
THE USE OF A THERMAL DUAL - PROBE FOR THE MOISTURE MEASUREMENT OF BUILDING FABRICS: THE TESTING OF THE TECHNIQUE VIA COMPARISONS WITH MEASUREMENTS FROM AN X-RAY SYSTEM
The 6th International Conference on Indoor Air Quality, Ventilation & Energy Conservation in Buildings IAQVEC 2007, Oct. 28 - 31 2007, Sendai, Japan