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This study aims to test the performance of MDF over a range of relative humidities. This range of humidities was generated by the use of saturated salt solutions.
It is a intrinsic property of saturated salts that they will induce a certain vapour pressure in accord with their solubility characteristics. This vapour pressure will then induce a stable relative humidity in the local area of the salt. Small PMMA boxes have been constructed specifically for this purpose. Six different salts and water were chosen, so as to ensure a range of humidities from 0 to 100 %.
Table: The salts and their RH's used in this experiment
Figure: The Chambers used in the experiment.
MDF samples were kept in the chambers for six weeks. This is
sufficient time to ensure that the samples achieve a range of EMC. Studies
[Greubel, 1987] using computer-aided testing systems have shown that EMC's
can be achieved in eight hours, conversely it has also been found
[Watkinson, 1990] that it can take twelve weeks to achieve EMC in
particleboard and MDF. See Sections 
and Put
graph of MC versus time from Skaar in theory and cite here
After six weeks in the humidity chambers the samples were removed,
weighed and their dimensions measured.
Figure: The Hydrometer used in this experiment.