Determining whether insulation material contains moisture can be achieved through a combination of methods, including visual observation, tactile testing, professional instrument measurement, and laboratory testing. Moisture content significantly reduces insulation performance, making timely identification crucial.
Simple On-Site Assessment Methods
Appearance Changes: Insulation materials containing moisture often appear darker in color, have a damp surface, or show water stains. For example, rock wool boards change from light yellow to dark brown after absorbing water.
Dampness to the Touch: Touch the surface of the material or cracks. If it feels damp, cold, or sticky, or if water seeps out when squeezed, it indicates water ingress.
Sound Test: Gently tap the insulation layer with a hard object. Dry areas produce a crisp sound, while moist areas produce a dull sound because moisture increases the material's density.
Quick Testing Using Professional Equipment
Portable Moisture Analyzer: This uses a resistance or capacitance principle. Insert the probe into the material surface to directly read the moisture content. Suitable for various types of boards such as EPS, XPS, and rock wool.
Infrared thermal imager: Due to differences in heat capacity, water-containing areas exhibit abnormal temperature differences in infrared images, often appearing as localized low-temperature areas (blue/green patches), allowing for rapid location of water seepage points.
Precise Laboratory Measurement Methods
Drying Method (Arbitration Method): Core samples are sealed and sent for testing, dried in an oven at 105±5℃ to constant weight, and the moisture content is calculated based on the mass difference. This is the national standard method and yields the most accurate results.
Water Absorption Test Standard: Rigid foam plastics are subjected to a 96-hour immersion test according to GB/T 8810-2005, or mineral wool is subjected to vacuum saturation treatment according to GB/T 5480-2017 to quantify the material's resistance to water absorption.
