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MMS- Are some unreliable with high RH?

(11-08-2011, 07:27 AM)CC Solutions Wrote:  Stephen,
I am one of those who abhor F1869, but my disgust comes from the misapplication of a viable test seen in the field.

Believing that the MVER calculated under wildly varying conditions and then believing that the MVER of a concrete slab indicates the suitability for moisture sensitive flooring is flawed reasoning. We know better than that now.

I do believe calcium chloride is a desiccant, I do believe it can be used to absorb moisture, and I do believe under laboratory conditions it can be used for determining certain conditions of state. For E96 testing it is fine. But for use by a flooring installer this is physics that looks great on paper being pawned for an improper purpose. There are far too many contributing factors that skew the MVER readings to believe the test results.

Further more, the purpose of E96 is to measure moisture permeance through a barrier. The purpose of F1869 is the same, but most don't use it for that! The results harvested are used for a completely different reason.

CaCl does the same thing in both cases, yes, but in one case we learn the permeance of a product and in the other we learn the long term propensity for a successful floor installation? I don't think so.

Oh but I must agree to disagree, although you did not touch base on the point I was trying to make. If E96 uses it to measure the perm rating of a film, and the F-1869 is supposed to do the same, and both use the same dessicant for the test, why can't it measure the permeance of a film over concrete in the field if the ambient temp and rh are within the labs guidleines? In this I am not talking about the dish being directly over a slab? Therein lies the collusion I'm talking about.

If E96 is only for lab purposes then it should be the same for any topical film over concrete. Being that it is impossible to guarantee your applied film is the same exact thickness and conditions onsite are exactly the same. If so then I should be able to perform a Cacl test over a troweled on vapor retarder or even some six mil plastic that would give me complete attestation the product is performing to spec.

Besides, I don't anywhere in E96 that that is a designated test for films applied to the surface of concrete and or floorcovering in general. So I still do not understand why everyone refers to this standard.

I think someone was wandering through the ASTM library one day and said, oh look...a permeance standard. Lets apply it to floorcovering because it sounds neat and no one would ever question an ASTM standard. Unless of course that standard was not applicable to floorcovering. Ho Ho

And how one ever gets from E96 using the dessicant...[[which BTW I don't recall it ever being used for any test like that prior to the formulation of F 1869]], then the lbs/24hr/1000sf formula and end up with an Rh percentage for the limit of "moisture content" in a slab is beyound me. It all sounds like pure conjecture.

Stephen Perrera dba
Top Floor Installation Co.

Messages In This Thread
RE: MMS- Are some unreliable with high RH? - Ernesto - 11-08-2011, 02:27 PM

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