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We're almost at 3lbs MVER, so what if the rH is over 90% ?

#21
Service condition for a hospital in the midwest is temperature between 63 and 78 degrees and RH between 30% and 60%.

If you take the new ASTM at literal meaning, that's where the readings should fall. Nowhere does it say you need an HVAC system.

I have been on job sites that they had an HVAC system running and I couldn't conduct any testing. The RH was too high or the temperature was too high or low. On several jobs the GC baked the buildings and the temperature was over 100 degrees. So HVAC isn't really a consideration.

What you need is the slab and the ambient humidity in the range that the facility will be in during operation, and that is pretty easy to hit.
JD Grafton
Concrete Answers for Flooring Problems
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#22
"Service Conditions" is probably the only grey area of 2170, but it is up to the customer/GC/Project manager to determine that correctly. But you don't necessarily need HVACs running to produce it.

Interesting that the standard for RH via the hood method (F2420) says "service conditions OR (a stated range of RH and temp) if that's not possible".

I presume that is because both the hood, and the MVER method, are more prone to the surface conditions, than RH at-depth is. Bad grammar, sorry.
The problem with socialism is that you soon run out of other people's money.
- Margaret Thatcher

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#23
I believe you are right, as the prior version of 2170 did list an 'or' statement.

What we have found is the temperature will affect the readings, so we try to measure the concrete at the service temperature.
JD Grafton
Concrete Answers for Flooring Problems
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#24
To hit that mark would be very rare out here in the Southwest. Besides that, there's other issues with testing before the HVAC is up and running. Think about it.

And I don't think that they meant to say if the site is in the zone of one or two days. This should be corrected immediately.
Stephen Perrera dba
Top Floor Installation Co.
http://www.tucsonazflooring.com
http://www.floorsavior.com
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#25
(08-17-2012, 07:16 AM)Ernesto Wrote:  To hit that mark would be very rare out here in the Southwest. Besides that, there's other issues with testing before the HVAC is up and running. Think about it.

And I don't think that they meant to say if the site is in the zone of one or two days. This should be corrected immediately.

The ASTM says 48hrs. It's really not rocket science,but people still mess it up.
JD Grafton
Concrete Answers for Flooring Problems
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#26
(08-17-2012, 07:50 AM)CC Solutions Wrote:  The ASTM says 48hrs. It's really not rocket science,but people still mess it up.

And some people try to oversimplify the causes and effects with aire pressue in buildings along with moisture testing. Theres quite a few of these you probably should read. http://www.buildingscience.com/documents/digests/bsd-108-investigating-and-diagnosing-moisture-problems/
Stephen Perrera dba
Top Floor Installation Co.
http://www.tucsonazflooring.com
http://www.floorsavior.com
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#27
It doesn't have to be that hard, especially with in-situ RH testing. That's one of the many reasons RH works and CaCl is dead. Wink

Because you believe in CaCl testing consider this: You may have increased atmospheric pressure in a room, perhaps as much as 5/1000th of an inch of water column. Perhaps that air is more humid than the floor slab. Now you place a test kit and seal the calcium chloride cup on the concrete. You have sealed the dish from the increased pressure and created an artificially elevated dry and arid environment around the cup. How is the test affected by the ambient conditions when it is sealed from them?

The answer is: It doesn't matter. Why? Because the test is meaningless. The results mean nothing, a low reading doesn't mean the floor is dry, a high reading doesn't mean it's wet.

Manufacturers are all finally abandoning MVER testing because it doesn't mean anything. Wagner has made RH testing easy, accurate, dependable and highly repeatable.
JD Grafton
Concrete Answers for Flooring Problems
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#28
Yeppers.

RH "at depth"= less affected by ambient conditions. Once you drill that hole you're not having to worry about a bunch of other factors.

That said, F2170 still needs to be read carefully. I've already clued up some contractors on the requirements, and the colour drains from their faces Smile
The Aussie flooring industry has finally dragged itself up to the USA level of knowledge- our resilient standard now specifies in-situ RH, but unfortunately also allows for surface RH with the hood, which means we'll be doing tests which will take AT LEAST 72 hours....plus a few days... "how long is a piece of string" Confused So these ambient conditions we're discussing here will be more of a factor.

Speaking of the hood, I've got a fuzzy question for Jason on another thread.

Now I'll let you guys go on and have another MVER debate ... Big Grin
The problem with socialism is that you soon run out of other people's money.
- Margaret Thatcher

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