Archive through August 12, 2011

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Author Message David Axt, AIA, CCS, CSI Senior Member Username: david_axt Post Number: 1239 Registered: 03-2002 Posted on Wednesday, August 10, 2011 - 05:32 pm:    What do you guys think of this real world underslab vapor permeance study? http://www.vaporbarrierpermeancestudy.com/ What concerns me is that, if this study is accurate, some manufacturers are lying about their test results. Richard L Matteo, AIA, CSI, CCS Senior Member Username: rlmat Post Number: 437 Registered: 10-2003 Posted on Wednesday, August 10, 2011 - 05:53 pm:    Before I left my last firm, the Stego rep was trying to get me to specify products that were 0.0001 permeance. That's pretty much a vapor barrier and not a vapor retarder. Also, he was referencing an ACI standard that conflicted with the ASTM Standard (I don't have them in front of me) After a quick look at the report, most of the mfgrs that were really out of wack, I don't specify anyway and the ones that I do still meet the requirements for vapor retarders.The next time I do a spec involving vapor retarders,I will probablt revisit this whole issue again. Even though it was a "blind" study, Stego was behind it and I'm not sure of their ulterior motive. Lynn Javoroski CSI CCS LEED® AP SCIP Affiliate Senior Member Username: lynn_javoroski Post Number: 1292 Registered: 07-2002 Posted on Thursday, August 11, 2011 - 09:43 am:    Ulterior motive aside, it seems clear that it was anonymous and blind (unless everyone is lying through their teeth). As to the discrepancy in the values reported by various manufacturers; some test under different standards. That's one thing we have to be very careful about when comparing manufacturer's products. If a manufacturer chooses a test that gives the result they wanted, instead of the test a competitor chose, and we don't notice that difference, the manufacturer has successfully fooled us all. anon (Unregistered Guest) Unregistered guest Posted on Thursday, August 11, 2011 - 02:23 pm:    I called BS on this when it was sent to me by the Stego rep. After a lot of evasiveness on the part of the rep, and third party testing I asked for from one of the product manufacturer's in the study showing that their products did INDEED pass the tests (in contrast to the study), I am satisfied that the study is worthless. I have removed Stego from my specs because the only thing I hate more than negative selling is outright lying.... Ellis C. Whitby, PE, CSI, AIA, LEED® AP Senior Member Username: ecwhitby Post Number: 115 Registered: 03-2003 Posted on Friday, August 12, 2011 - 08:37 am:    RE: “anon (Unregistered Guest)” “Posted on Thursday, August 11, 2011 - 02:23 pm”: I am curious: did you contact the professor who authored the study? anon (Unregistered Guest) Unregistered guest Posted on Friday, August 12, 2011 - 11:47 am:    Ellis, No, I did not. I didn't feel the need to do so once I had the thrid party testing from one of the manufacturers that was thrown under the bus in the study. I shared this third party testing with the Stego rep and pointed out that his "study" did not contain the same information as the third party testing provided by one of the manufacturers and that it would be impossible to evaluate the two side-by-side because of this. Look closely at the way the "study" reports the results against the test methods stated - not what one expects to find in a true third party test conducted by a certified testing laboratory. At this point in the dialogue, the Stego rep basically cried Uncle and had nothing more to argue. Don't trust this study, it's not legit. Ellis C. Whitby, PE, CSI, AIA, LEED® AP Senior Member Username: ecwhitby Post Number: 116 Registered: 03-2003 Posted on Friday, August 12, 2011 - 12:06 pm:    It appears that you trust the “third party” testing for one manufacture over the “third party” testing by Stego. If the Stego study was that bad I would expect one or more of the major manufacturers to fund their own study comparing Stego’s and their other competitors products to their own. I wonder if one has been done? Maybe I am over looking something but the Stego study does not look all the bad. Then again, I am not a material researcher or PhD. anon (Unregistered Guest) Unregistered guest Posted on Friday, August 12, 2011 - 02:58 pm:    Um, yeah, I tend to favor third party testing conducted by certified laboratories that are in the business of third party testing of building materials over someone with a phd in food and nutrition. http://workgroups.clemson.edu/CAFLS0320_PKGSC_INSIGHTS/faculty/cooksey.php Are you kidding? Ellis C. Whitby, PE, CSI, AIA, LEED® AP Senior Member Username: ecwhitby Post Number: 117 Registered: 03-2003 Posted on Friday, August 12, 2011 - 03:19 pm:    Actually, vapor transmission is tested in food services. You know: to separate the bad from the good. All that shrink wrap you see in the supermarket has been developed to limit vapor transmission. It is not a stretch to imagine the same techniques being used successfully study water vapor transmission in vapor barriers. I still do not know if the study was bad or good. I do wish there was another study that compared all the “majors”. Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP Senior Member Username: specman Post Number: 965 Registered: 03-2003 Posted on Friday, August 12, 2011 - 03:40 pm:    The testing was not done by the university; it was sent to a well-known testing lab (Mocon, Inc.), which tests for permeability using the procedures in ASTM F 1249, which is referenced by ASTM E 1745, the standard for plastic vapor retarders for slabs-on-grade. If the standard in this test is the same one used by the manufacturer's third-party lab, then somebody has faulty results. Depending on who the manufacturer used, I'm leaning towards Mocon being the most reputable. Ron Geren, AIA, CSI, CCS, CCCA, SCIP www.specsandcodes.com Ellis C. Whitby, PE, CSI, AIA, LEED® AP Senior Member Username: ecwhitby Post Number: 118 Registered: 03-2003 Posted on Friday, August 12, 2011 - 04:02 pm:    Ronald; Thanks for pointing out who did the testing. anon (Unregistered Guest) Unregistered guest Posted on Friday, August 12, 2011 - 05:34 pm:    Mocon is a self-proclaimed world leader in permeation testing, package integrity testing, aroma, odor and flavor testing. If under slab vapor retarders were used for food packaging, I'd be more interested in the results of the study. Maybe Stego should rebrand their product and sell it as zip lock baggies and such.... Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP Senior Member Username: specman Post Number: 966 Registered: 03-2003 Posted on Friday, August 12, 2011 - 05:52 pm:    A standard is a standard. It doesn't matter if the material is used to wrap bologna or to prevent vapor transmission under slabs--the standard doesn't care. Since the standard is used for both applications, the results should generate similar results for the same material each time, as long as the procedure in the standard is adhered to each time. Ron Geren, AIA, CSI, CCS, CCCA, SCIP www.specsandcodes.com anon (Unregistered Guest) Unregistered guest Posted on Friday, August 12, 2011 - 06:52 pm:    That's right! A standard is a standard! ASTM E 1745 allows permeance to be tested in accordance with either ASTM E 154 Section 7, OR ASTM F 1249. At least one of the manufacturers whose products were listed in the Mocon study laboratory tested them in accordance with ASTM E 154 Section 7. All is good in their independent testing using this test method - with a reputable, certified testing laboratory. I asked for these and received them, nothing I could see to be concerned about in the test report. But I have many concerns about the Stego test. Stego's negative selling tactics are WELL known (did anyone see the muppet lab puncture test they had set up at one of the CSI National conventions? Laughable.) And the reps have been whining for YEARS that their competitors have no third party testing for their products. Now that they do have third party testing, what does Stego do? Commission a "blind" study - using their rules - to show that competitors products (again) don't measure up??? And do they use a testing facility that regularly engages in building product testing for their "blind" test? No, they do not. They go where they know results will favor them, using one of the allowable test methods, and offer the APPEARANCE that competitor's products are inferior. Something's rotten in Denmark. Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP Senior Member Username: specman Post Number: 967 Registered: 03-2003 Posted on Friday, August 12, 2011 - 07:38 pm:    It doesn't matter if a lab has construction material experience or not. The standards are set up so that any lab with the proper equipment and that follows the procedures will come up with similar results. As Lynn pointed out, if the manufacturer used another method (ASTM E 154 in this case), then it could be expected that results would be different. But, I don't see how the two approved methods could generate such widely different results. From what I can see, Stego established very little in the way of "rules" that were to be followed. Does Stego have a motive? Of course, they want to see how their competitors stack up against their products and to make that information available to the public. If they had directly purchased, prepared, and tested the samples, the entire study would no doubt be in question--thus, their blind study. Manufacturers test their competitors' products all the time, but they keep it internal for R&D purposes and not directly for marketing. If the Stego study is as they advertise, then I have no problem with it. If Stego's competitors don't agree with it, then they can conduct their own study and publish it. My opinion is that since we've heard very little to nothing from competing manufacturers, then there could be some kernel of truth (or more) to the Stego study. As to this discussion, I've stated my position and will finish my involvement. Ron Geren, AIA, CSI, CCS, CCCA, SCIP www.specsandcodes.com David Axt, AIA, CCS, CSI Senior Member Username: david_axt Post Number: 1240 Registered: 03-2002 Posted on Friday, August 12, 2011 - 07:48 pm:    My questions are 1) What is acceptable manufacturing tolerance deviations? 2) Are the differences in the published and tested results significant? We are dealing with really small numbers here. Does it really matter? Even at the higher tested numbers the membranes are very impermeable.