Calcium chloride test (MVER)
A moisture vapor emission test in which a dish of dry salt is sealed to a slab and weighed after a set period to measure how much moisture the surface releases.
What does calcium chloride test (mver) mean?
The result is reported as pounds of moisture emitted per thousand square feet per day. It measures only the top layer of the slab, which is why it can pass on a slab that will later fail once a floor covering traps deeper moisture. Much of the industry has shifted toward in-situ relative humidity testing for this reason, though many specifications still name this test.
In practice
You will still see the little domed test kits taped to warehouse and retail slabs before flooring installation.