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some specified MC
ρwater = density of water (1000 kg/m3 , 1 g/ml, 62.4 lb/ft3)
Specific Gravity of wood may be calculated in different ways.
- always oven-dry weight
- volume can be at any MC; commonly calculated at green, oven dry (OD), or air dry
(AD) conditions. - most commonly used is OD weight and green volume
- called the Basic Specific Gravity (SGBasic)
- it is always important to know the volume MC basis on which the SG is measured
- dimensionless number
- equations and tables are available to interconvert SGs at different MCs, and correlate
SGBasic to wood density at any MC (see the Wood Handbook).
Procedure for measurement of wood Basic Specific Gravity
Oven-dry weight of a wood sample is easy to determine. Volume is the problem.
Green MC – immersing in water introduces minimal problem with absorption.
Dry MC – coat with wax or something like polyurethane.
1. Determine wood sample volume
a. Submerge sample in a graduated cylinder. Measure volume change. Or,
b. Submerge sample in a container of water on a s...
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This note was uploaded on 04/05/2014 for the course FW 1035 taught by Professor Robinson during the Spring '08 term at Michigan Technological University.
- Spring '08