Meisterprüfung Hafner Practice Questions - Meisterprüfung Hafner (Austria) Exam

Moisture content u relates water mass to dry wood mass (u = m_w / m_dry), whereas water content w relates water mass to total wet mass (w = m_w / m_total); air-dried wood with u = 20% (w ≈ 16.7%) has a lower heating value H_u ≈ 4.0 kWh/kg (approx. 14.4–14.7 MJ/kg). Moisture content u relates water mass to total wet mass, whereas water content w relates water mass to ash-free organic mass; air-dried wood with u = 20% has H_u ≈ 6.5 kWh/kg. Moisture content u and water content w are identical interchangeable percentages in Austrian stove standards; seasoned beech wood always provides exactly H_u = 2.5 kWh/kg. Moisture content u measures surface moisture while water content w measures chemically bound crystalline water; seasoned wood with u = 20% has H_u ≈ 8.0 kWh/kg.