April 2012 Rapid RH Newsletter – How to Calibrate Digital pH Meter
Understanding How Lightweight Concrete Works
Let’s take a hypothetical. Architects design a building with lightweight concrete composed with a very diverse aggregate mix. The slab is poured and finished. The flooring contractor, after some time, begins CaCl testing and RH testing. The moisture vapor emission rate differs from the RH testing result, painting a much different picture for the flooring installer…
Calcium Chloride (MVER)'s Achilles Heel
Technical evolution has influenced two guidelines practiced by the American Society for Testing and Materials (ASTM). Specifically, ASTM F2170 co-exists with ASTMF1869 as construction moves from one era of moisture content measurement to another.Moisture Vapor Emissions Rate (MVER) Regulation:
ASTM F1869: Use this test method to obtain a quantitative value indicating the rate of moisture vapor emission from the surface of a concrete floor and whether or not that floor is acceptable to receive resilient floor covering. The moisture vapor emission rate only reflects the condition of the concrete floor at the time of the test…
From the Forum: How thick is your floor?
A flooring contractor used Wagners to test a new slab and the GC wanted a second opinion.
I was called in and tested a few locations using the same Rapid RH (is there anything else?) and concurred with the flooring sub that the floor was too wet for the flooring they were installing.
The floor was put in anyway, using a latex sealer and ‘special’ glue. It is failing just a few months later.
I was called in again and asked to evaluate the slab, starting with RH. This is where things get more serious. We have a failure so now we have to ramp it up a bit. Even though I am being told the slab is 4″ thick, I need to verify that it really is. Well guess what?…