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Convert from lbs.per 24 hours to RH%
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12-06-2009, 03:00 PM #1
CFI Newbie *
Status: Offline Posts:2 Threads:2 Joined:Nov 2009
Is the a chart or a formula that would convert lbs. per 24 hrs to RH%?
It seems that there are still some flooring products that specify lbs/24 hours rather than RH%.



12-08-2009, 02:31 PM #2
ChrisC Newbie *
Status: Offline Posts:3 Threads:1 Joined:Sep 2008
not that i've found. it would make my life a whole lot easier if there was one. i have had to call my adhesive mfg to get their RH specs because they hadn't updated their manuals. good luck.

12-16-2009, 11:51 AM #3
CC Solutions Concrete Moisture Evangelist *******
Status: Offline Posts:1,067 Threads:69 Joined:Dec 2009
There is no correlation between RH and emission.

I can create a slab with a 2lb MVER and 98% RH, and I can create a slab with 8lbs MVER and 50% RH. And believe me, I've seen both of these extremes and repaired both of them!

The MVER is readily affected by external conditions. Think of a drywaller spilling water on the floor of a very dry old slab. MVER will shoot through the roof, while RH will be unaffected.

Now consider a slab with a blotter under it, or no vapor retarder. It may show great MVER, especially if it is unfinished in a dry building, yet the RH could be 90% or more. If you put a moisture sensitive floor over this slab, you will have problems even though you had great CaCl tests.

JD Grafton
Concrete Answers for Flooring Problems

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