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Field Test Best Practices: A Resource for Practical Residential Building Science

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Humidity control and measurement is a tricky thing to do accurately in a field test setting. There are different types of humidity sensors and hygrometers. A number of things to keep in mind to ensure accurate measurement of humidity in a field test setting include: knowing what parameters you will be measuring, choosing the correct instrument, avoiding external factors that will affect the measurement and keeping good records of calibration, adjustment and repairs.

Temperature and Relative Humidity Sensor

A temperature and relative humidity (T&RH) sensor is a simple, durable and low-cost type of electronic hygrometer used in building science. Commonly available models use thin-film polymer technology. The dielectric properties of the polymer film changes with the change with ambient air relative humidity, and the capacitance of the sensor changes correspondingly.

Moisture Content Sensor

For long term monitoring of moisture content in wood frames to detect mold or decay, it is common to measure the resistance of wood and convert that to a moisture content reading.