Wood and Timber Drying Relative humidity along with time and temperature affect wood drying. Normally these parameters are based on previous drying experience, with the goal being to optimize drying time while minimizing wood cracking. The process parameters are unique to the system used, with different woods and seasonal variations affecting the result. This makes wood drying a demanding process. To achieve the best results, relative humidity needs to be continuously monitored. Wood is a porous material, i.e. it is hygroscopic, absorbing moisture to reach an equilibrium with the ambient environment. The mechanical properties of wood vary with the temperature, pressure and moisture content. In most applications the moisture in the wood cells must be removed to allow further processing and to protect wood from blue stain, fungi and mold, as well as from cracks and checks. The initial moisture content of green wood, i.e. freshly sawn timber, varies from 50 to 100%, depending on the species. When used as a construction material in, for instance, a normal temperate zone climate, the timber is dried to a moisture content of 18%, while for joinery and carpentry a moisture content of 10% to 15% is ideal. READ HOW A SAWMILL MINIMIZED THE DRYING TIME FOR TIMBER GOODS The accuracy of relative humidity measurements really matters. It directly affects the quality of the drying process and indirectly affects facility capacity. Inaccurate measurements can cause the following problems: If relative humidity is inaccurately shown as too moist, wood may crack due to the overly dry conditions. Over-drying wastes energy and ties up expensive facility capacity unnecessarily. If relative humidity is inaccurately shown as too dry, the overly moist conditions will slow the drying process, leading to longer drying times and reduced capacity. Three main factors help to keep measurements accurate: use of the appropriate sensor, ensuring that the measurement device is installed correctly and regular calibration of the measurement device. WATCH WEBINAR: MEASURING HUMIDITY IN CONDENSING ENVIRONMENTS Wood and timber drying related products Relative Humidity and Temperature Probe HMP7 Vaisala HUMICAP® Humidity and Temperature Probe HMP7 is designed for applications which involve constant high humidity or rapid changes in humidity Read more Handheld Humidity and Temperature Meter HM70 Vaisala HUMICAP® HM70 Handheld is designed for demanding humidity measurement in spot-checking applications. It is also ideal for field checking and calibration of Vaisala's fixed humidity instruments. Read more Indigo200 Series Transmitters for Vaisala smart probes Vaisala Indigo200 series transmitters are host devices for displaying measurement values from Vaisala's Smart Humidity, Temperature, Dew Point, Moisture in Oil, CO 2 and H 2 O 2 Probes. Read more Indigo500 Series Transmitters The Vaisala Indigo500 series transmitters are host devices for Vaisala Indigo-compatible, stand-alone smart probes. The Indigo500 series include multi-functional Indigo520 transmitter and Indigo510 transmitter with basic features. Read more Dew Point Transmitters DMT345 and DMT346 Note that the DMT340 series is being discontinued. The Vaisala DRYCAP® Dewpoint Transmitters DMT345 and DMT346 are designed for humidity measurement in industrial drying applications with particularly high temperatures. Read more Related stories Expert article Bringing out the beauty of wood: Veneer drying with humidity control During manufacturing, veneer is dried in a drier circulating hot and humid air. This is a demanding processing step, and accurate dewpoint control is essential in obtaining the best quality veneer for demanding wood products and long-lasting finishes. Learn more Blog Do I need an Indigo transmitter or just an Indigo probe? There are many probe options to choose from measuring several parameters: humidity, temperature, dew point, CO2, moisture in oil, and vaporized hydrogen peroxide. The probes can be attached to Indigo500 or Indigo200 series transmitter. When is a probe sufficient on its own – and when do you need both a probe and a transmitter? Read more Blog Built to survive, even outside: the Vaisala Indigo500 Series Some of our customers have applications that require measurement transmitters to be installed outside, so the Vaisala Indigo500 and its family of smart probes have been designed to be durable enough for these kinds of rough, tough conditions. Learn more Blog Indigo500 series dual-probe support Learn about the benefits of using two probes measuring either the same parameter or two different ones. Read more Blog Measuring humidity in condensing environments Taking measurements in environments with high relative humidity (over 90%) is always a challenge because the environment is so close to saturation. Learn more Blog Humidity and Wood Drying – A Fine Balancing Act As a natural product, wood has a unique set of characteristics that can make drying a challenging and complex process – one where relative humidity (RH) plays a critical role. Learn more Customer case Optimal timber drying conditions at the Korkeakoski Sawmill In order to run efficiently, the Korkeakoski sawmill seeks to minimize the drying time for timber goods. Therefore the drying temperatures must be very high, which creates very specific requirements for the humidity conditions in the chambers. Learn more
Wood and timber drying related products Relative Humidity and Temperature Probe HMP7 Vaisala HUMICAP® Humidity and Temperature Probe HMP7 is designed for applications which involve constant high humidity or rapid changes in humidity Read more Handheld Humidity and Temperature Meter HM70 Vaisala HUMICAP® HM70 Handheld is designed for demanding humidity measurement in spot-checking applications. It is also ideal for field checking and calibration of Vaisala's fixed humidity instruments. Read more Indigo200 Series Transmitters for Vaisala smart probes Vaisala Indigo200 series transmitters are host devices for displaying measurement values from Vaisala's Smart Humidity, Temperature, Dew Point, Moisture in Oil, CO 2 and H 2 O 2 Probes. Read more Indigo500 Series Transmitters The Vaisala Indigo500 series transmitters are host devices for Vaisala Indigo-compatible, stand-alone smart probes. The Indigo500 series include multi-functional Indigo520 transmitter and Indigo510 transmitter with basic features. Read more Dew Point Transmitters DMT345 and DMT346 Note that the DMT340 series is being discontinued. The Vaisala DRYCAP® Dewpoint Transmitters DMT345 and DMT346 are designed for humidity measurement in industrial drying applications with particularly high temperatures. Read more
Relative Humidity and Temperature Probe HMP7 Vaisala HUMICAP® Humidity and Temperature Probe HMP7 is designed for applications which involve constant high humidity or rapid changes in humidity Read more
Handheld Humidity and Temperature Meter HM70 Vaisala HUMICAP® HM70 Handheld is designed for demanding humidity measurement in spot-checking applications. It is also ideal for field checking and calibration of Vaisala's fixed humidity instruments. Read more
Indigo200 Series Transmitters for Vaisala smart probes Vaisala Indigo200 series transmitters are host devices for displaying measurement values from Vaisala's Smart Humidity, Temperature, Dew Point, Moisture in Oil, CO 2 and H 2 O 2 Probes. Read more
Indigo500 Series Transmitters The Vaisala Indigo500 series transmitters are host devices for Vaisala Indigo-compatible, stand-alone smart probes. The Indigo500 series include multi-functional Indigo520 transmitter and Indigo510 transmitter with basic features. Read more
Dew Point Transmitters DMT345 and DMT346 Note that the DMT340 series is being discontinued. The Vaisala DRYCAP® Dewpoint Transmitters DMT345 and DMT346 are designed for humidity measurement in industrial drying applications with particularly high temperatures. Read more
