ASTM D4442: Standard Test Methods for Direct Moisture Content Measurement of Wood and Wood-Based Materials
Standard: ASTM D4442 – Standard Test Methods for Direct Moisture Content Measurement of Wood and Wood-Based Materials
Certification Required: N/A
Scope: Per ASTM D4442: "These test methods cover the determination of the moisture content (MC) of wood, veneer, and other wood-based materials, including those that contain adhesives and chemical additives."
Applicable Products: Wood and wood-based materials
Test Procedure: The following test procedures are defined within ASTM D4442:
- Method A -Oven-Drying (Primary): Specimens are weighed on a balance and then placed into an oven set to a temperature of 103 ̊C. The specimens are considered to be oven dry when the mass loss in a 3 hour interval is less than or equal to twice the sensitivity of the balance. At this point the oven-dry mass is recorded and the moisture content is calculated.
- Method B -Oven-Drying (Secondary): Specimens are weighed on a balance and then placed into an oven set to a temperature of 103 ̊C. The specimens are considered to be oven dry when no appreciable change is observed in the mass readings at 4 hour intervals. At this point the oven-dry mass is recorded and the moisture content is calculated.
- Method C -Distillation: The wire extraction basket or Wiley siphon is weighed and placed in a weighing bottle. 20 borings are taken from the wood sample and each boring is measured and placed in to the extraction basket or Wiley siphon. The bottle, container, and contents are weighed and transferred to the extraction section of the apparatus. Heat is applied to the apparatus and the toluene is refluxed at a rate of at least 1 drop/s. After the reflux period, the trap is allowed to cool to room temperature and any extra water is transferred to the water layer in the trap. The volume of water collected in the trap is recorded. The extraction container is removed and placed under a hood for 15 min then placed in an oven set to 125 ̊C for 2 hours. The container and borings are transferred to the weighing bottle and the weight is recorded. The weight of the dry extracted wood is then recorded and used to calculate the moisture content.
- Method D -Other Secondary: Other methods can be used to measure the moisture content of wood-based materials. These include Karl Fischer titration, infrared, microwave, nuclear magnetic resonance, vacuum oven drying, etc.
End Result: These tests result in a moisture content value.
Special Notes: N/A
Intertek Testing Locations: York, PA
