What is MVER testing?
What is MVER testing?
Moisture Vapor Emissions Rate (MVER) Commonly called the calcium chloride test, MVER is a traditional measure of concrete moisture content. Due to its longevity, building contractors still use it.
How do you measure calcium chloride?
Calcium chloride testing involves sealing a small dish of calcium chloride on a clean section of concrete under a plastic dome. The salt absorbs moisture in that environment (and presumably coming from the concrete slab) and the weight gain after three days is used to calculate the MVER.
What is ASTM F2170?
ASTM F2170 formally recognizes the use of in situ (“in-position”) probes as a means of conducting relative humidity testing. The ASTM F2170 standard represents a fundamental change in how moisture is measured and to what degree of accuracy is to be obtained.
What is MVER in flooring?
MVER is the Moisture Vapor Emission Rate, or the amount of moisture vapor that under the right conditions (differential of temperature & pressure within the slab) rises up through the capillaries of the concrete, with the potential of the water vapor condensing back into a liquid under the floor covering.
How do you test moisture in a concrete slab?
Concrete moisture testing methods This test involves taping an 18” x 18” polyethylene sheet to a concrete surface and then waiting at least 16 hours. Visible condensation on the sheet or darkening of the concrete indicates excessive moisture. Any coating applied to the surface may be at risk of failure.
What is ASTM F1869?
ASTM F1869-11 – Standard Test Method for Measuring Moisture Vapor Emission Rate of Concrete Subfloor Using Anhydrous Calcium Chloride.
How do you measure relative humidity in concrete?
Relative Humidity Test This method requires holes to be drilled into the concrete and a humidity probe inserted at 40 percent of its total depth. The quantitative result and the measurement within the middle of the slab make this test a more accurate and reliable way to measure MVT.
How do you make a 1% calcium chloride solution?
A 1 M calcium chloride solution can be prepared by dissolving 147.02 g of CaCl2. 2H2O in water to a final volume of 1000 ml.
How much water can calcium chloride absorb?
Calcium chloride can absorb up to 300% of its own weight in moisture, compared to 30-40% for clay. Surely the ability to absorb 10X more moisture makes calcium chloride a far superior desiccant?
How do you calculate relative humidity in concrete?
The new industry standard for measuring concrete RH is the in situ concrete relative humidity test as described in the ASTM F2170 standard test method. It involves drilling a hole into the concrete and using an electronic relative humidity probe to directly measure the moisture in the slab.
How do you calculate moisture percentage?
The amount of water is determined by subtracting the dry weight from the initial weight, and the moisture content is then calculated as the amount of water divided by the dry weight or total weight, depending on the reporting method.
What level of moisture is acceptable?
You should be aware that a moisture reading of 0-15% is quite normal and gives no cause for concern. However, moisture readings in excess of 15% indicate the need for further inspection. Levels between 25-30% indicate that there may be water ingress, meaning that remedial work could be required.
What is ASTM F710?
For newly poured slabs, the ASTM F710 standard recommends a water-cement ratio of between 0.40 and 0.45 and a minimum of 7 days wet curing time. It also recommends installation of a moisture retarder under all on- or below-grade concrete floors.
How do you test relative humidity?
Place two or three ice cubes into a glass, add water and stir. Wait three to four minutes. If moisture does not form on the outside of the glass, the air is too dry; you may need a humidifier. If water has condensed on the outside of the glass, the level of relative humidity is high.
What is acceptable moisture level in concrete?
75%
1. What are the acceptable moisture levels in concrete? Acceptable moisture levels in concrete according to ASTM standard, when testing via ASTM F2170, the RH level of a concrete slab needs to be at or below 75% — unless the flooring system manufacturer provides alternate guidelines.
How do you make a 2% CaCl2 solution?
CaCl2 stock solution To prepare a 2.5 M stock solution of CaCl2, dissolve 11 g of CaCl2•6H2O in a final volume of 20 mL of H2O. Sterilize the solution by passing it through a 0.22-μm filter. Store in 1-mL aliquots at 4°C.
How do you make a 4% CaCl2 solution?
Calcium Chloride Stock Solution Preparation and Recipe
- Prepare 800 mL of distilled water in a suitable container.
- Add 58 g of Calcium Chloride to the solution.
- Add distilled water until the volume is 1 L.
- Measure the osmolarity using an osmometer: if below 1000 mmol/kg, add more CaCl2; if above 1000, add H2O.
Does calcium chloride reduce humidity?
Absorption capacity Calcium chloride desiccant absorbs more moisture when the relative humidity (RH) of the surrounding air is higher. And its absorption increases exponentially as RH rises, which is a remarkable result compared to other desiccants like silica gel and clay.
