Air Date: 7-29-2011| Episode: 215
One of the most important tools in the toolbox of any IAQ, disaster restoration or building science consultant or contractor is their moisture meters...
One of the most important tools in the toolbox of any IAQ, disaster restoration or building science consultant or contractor is their moisture meters. As important as they are we find that there is a great deal of confusion about how they work, what types work best under different circumstances, how values should be reported, when and how to calibrate and more. Join us with guest Paul Laurenzi, Vice President of Marketing and Sales for Delmhorst Instruments Co.
Delmhorst Instrument Company
Paul Laurenzi, VP Sales and marketing Delmhorst Instrument Company was our guest on last week’s episode of IAQradio. I apologize for the delay in posting the blog. I was a customer of Delmhorst long before I met Paul. Among the earliest customers of Delmhorst Instrument Company were building superintendants in NYC who used the moisture measurement devices to track moisture leaks in plaster ceilings, walls and roofs. The company founder the late Bill Delmhorst was a lover of wood who worked with universities and the USDA to develop credible moisture measurement criteria. The firm currently manufactures specialty moisture meters and a wide range of accessories for use in measuring moisture contents of hay, cotton, leather, paper pulp, etc. the firm also manufactures thermo hygrometers for measuring temperature and relative humidity.
The technology: two primary technologies are used to measure moisture within materials: pin type which works on resistance and non-invasive which works on capacitance. Capacitance type sends a signal ¾” into materials. The signal bounces back with a reading on a comparative numeric scale.
•Moisture content of concrete is difficult to measure accurately due to variables in the material, densities, additives, etc. ASTM Standard F-2170 uses a thermo-hygrometer to quantitatively measure moisture content of cement. The process involves drilling small holes into the cement, special probes and takes 72 hours.
•Sensors used within thermo-hygrometers have a tolerance, as such 6 brand new meters set side by side may have slightly different readings.
•Calibration: For thermo-hygrometers with removable sensors. He advises a sensible approach of purchasing an extra sensor, storing the spare sensor in a stable environment and periodically verifying the sensors in the field meters by swapping out and comparing readings. Two saturated salt solution are offered for use in verifying calibration.
•Delmhorst has developed a Moisture Content Standard, a cube with imbedded resistance values which is used to check the accuracy of pin-type moisture meters.
•For firms interested in ISO confirmation a Letter of Certification for some Delmhorst instruments is available.
•For accuracy and long life, be sure to change batteries frequently and store devices in protective cases when not being used.
•On reports, reading on a relative scale of 0-100 was 60 and my unaffected reference point reading was 10 .
The Delmhorst Company manufactures quality products, listens and is responsive to customer suggestions and needs. Paul Laurenzi is a knowledgeable and all around good guy.
Today’s Music: Weather Song by Tom Glazer