What it measures
A pre-weighed dish of anhydrous calcium chloride is sealed under a plastic dome on the prepared slab. Over roughly three days it absorbs moisture emitted by the concrete. The weight gain is converted to a moisture vapor emission rate (MVER) in pounds per 1,000 square feet per 24 hours.
How the test works
- Bring the space to service conditions (temperature and humidity) beforehand, as the method requires.
- Clean the test spot to bare concrete, removing coatings, curing compounds and laitance.
- Weigh the dish, place it, seal the dome and record the start time.
- After the exposure period, reweigh and calculate MVER.
Interpreting results
Coating and flooring manufacturers publish maximum MVER limits for their products. A result above the limit calls for more drying time or a moisture-mitigation primer. The test mainly reflects the top layer of the slab and is sensitive to ambient conditions, which is why many specifiers prefer or add in-situ RH testing.
About this summaryThis is an independent, plain-English overview for orientation. It does not reproduce the standard. Always work from the current official edition, available from the publishing organization.