1.1 These test methods apply to the measurement of the free water moisture content of gypsum boards and panels by means of portable electrical conductance and dielectric meters. 1.2 Electrical conductance and dielectric meters are not necessarily equivalent in their readings under the same conditions. When this practice referenced, it is assumed that either type of meter is being used and reported with the relevant ranges for precision and bias as specified in this standard. 1.3 Both types of meters are to be calibrated with respect to free water on an oven-dry mass basis as described in this standard.
Hand held moisture meters are commonly used for collecting data in field investigations of building moisture problems as well as in gypsum plants. Their application to gypsum boards is imprecise and often generates erroneous and misleading data. The absence of guidance on such factors as pin penetration depth, pin size & pin type, etc. for application on gypsum boards needs to be rectified. This standard will specify how these instruments are to be used on gypsum boards and establish the limits of accuracy for their application by means of interlaboratory round robin studies to establish the precision & bias of the test methods.
Keywordsmoisture probe; moisture meter; free water; moisture content; gypsum board; gypsum panel; glass mat gypsum panel; fiber-reinforced gypsum panel; equilibrium relative humidity; equilibrium moisture content; water activity; humidity ratio; relative humidity
The title and scope are in draft form and are under development within this ASTM Committee.Back to Top
Draft Under Development