Stego Wrap Vapour Barrier - Not Just For Retarding Water Vapor

It’s no secret that Stego Wrap Vapour Barrier has been used as an effective barrier against water vapor for the last 10+ years. It has been the most widely specified and installed high-performance vapour barrier for the better part of a decade. What you may not know is that Stego’s unique blend of virgin, prime resins combined with our proprietary extrusion methods yields a membrane that has been used in applications where sulfates, methane, radon, chlorinated solvents, hydrocarbons, etc. are an issue. When severe conditions exist that call for the need of a warranted product/system, there is no substitute for the peace of mind that comes with a guaranteed installation. However, when the conditions are such that you decide that a warranted system isn’t required, then, Stego Wrap Vapor Barrier might be used in order to recognize potentially significant cost savings. When might Stego Wrap Vapour Barrier be used? That decision is entirely up to the design professional. However, we have given you a great start… To determine if Stego Wrap Vapour Barrier fits the needs of your next brownfield project, please review the attached tests we have conducted. They include a simulated dry cleaning brownfield (chlorinated solvents), a simulated service station or fuel spill brownfield (BTEX), a severe sulfate contamination site, UV Exposure, as well as standard tests for methane and radon. Stego Wrap Vapour Barrier has been used as a successful membrane in many of the above situations. Since there are no standards in place for acceptable levels of degradation and permeation of many of the brownfield chemicals, the use of Stego Wrap in these situations has been up to the design professional. As discussed above, we now have a nice catalogue of tests to help you decide if Stego Wrap is right for your next brownfield project.

 

Simulated Dry Cleaning

setup

To simulate a dry-cleaning brownfield site, a senior chemist at a research and testing lab prepared contaminated water to contain 3600 ppb perchloroethylene (PCE), 12500 PPB trichloroethylene (TCE), 16200 PPB CIS-1,2-dichloroethylene (C-DCE), AND 1700 PPB trans-1,2-dichlorothylene (T-DCE). Two liters of this mixture were placed in a 49 cm x 23.5 cm wide by 27 cm tall chamber. ASTM 20-30 sand was added to the vessel until it was 5 cm above the original water line. At this level, the sand was damp with no free standing water. Stego Wrap Vapor Barrier (0.38 mm) was placed on top of the damp sand, and the entire surface of the vapour barrier was weighted down with sand-filled plastic bags to ensure full contact of the Stego Wrap with the damp sand. The test vessel was covered and sealed. After 30 days of exposure under ambient laboratory conditions (21-25 °C), the samples were removed for evaluation. 

In English now- We took an actual soils report from an old dry cleaning site and recreated the conditions, sort of. In the actual scenario the water table was 20 feet below the vapour barrier. In our setup we created a contaminated water table just 2 inches below Stego Wrap Vapour Barrier. After a 30 day exposure we examined the material via mass and volume changes as well as tested it for water vapour permeance. 

RESULTS

Mass and Volume:
The chemist conducted mass and volume measurements before and after exposure. The following comes directly from her report: “Almost all of the test coupons exhibited slight changes in mass and volume, no matter what their exposure conditions were. Statistical analysis by t-test showed that the changes for the pollutant-exposed coupons were not significantly different from the changes for the control-exposed coupons.” In other words, Stego Wrap Vapour Barrier’s mass and volume were not significantly affected by the exposure.


Permeance:
The testing lab then sent exposed samples to the industry leader in permeation testing for post-exposure testing. The results were fantastic. The permeance of Stego Wrap Vapour Barrier stayed below the industry’s “Barrier” benchmark of 0.6 ng/(s*m2*Pa). At 0.55 ng/(s*m2 *Pa), Stego Wrap Vapour Barrier’s permeance rose no more than it does for the ASTM E 1745 prescribed conditioning tests (ASTM E 154 Sections 8,11,12, and 13). 

 

Simulated Hydrocarbon Site

Setup:

To simulate a hydrocarbon contaminated brownfield site, a senior chemist at a research and testing lab prepared contaminated water to contain 1,000 ppb of each benzene, toluene, ethylbenzene, and xylene. This cocktail is commonly referred to as BTEX and represents hydrocarbons seen in many of today’s brownfields. Two liters of this mixture were placed in a 49 cm x 23.5 cm wide by 27 cm tall chamber. ASTM 20-30 sand was added to the vessel until it was 5 cm above the original water line. At this level, the sand was damp with no free standing water. Two layers of Stego Wrap Vapour Barrier (0.38 mm) were placed on top of
the damp sand, and the entire surface of the vapour barriers were weighted down with sandfilled plastic bags to ensure full contact of the Stego Wrap with the damp sand. The test vessel was covered and sealed. After 30 days of exposure under ambient laboratory conditions (21-25 °C), the samples were removed for evaluation. 

In English now- We took relatively large amounts of often-seen hydrocarbons resulting from fuel spills and old service station sites and put them into a water table just two inches below a sample of Stego Wrap. This can be considered an extreme situation in that water tables are not typically that close to the slab and vapour barrier membrane. After a 30 day exposure we examined the material via mass and volume changes as well as tested it for water vapour permeance.

RESULTS:

Mass and Volume:
The chemist conducted mass and volume measurements before and after exposure. The following comes directly from her report: “Almost all of the test coupons exhibited slight changes in mass and volume, no matter what their exposure conditions were. Statistical analysis by t-test showed that the changes for the pollutant-exposed coupons were not significantly different from the changes for the control-exposed coupons.” In other words, Stego Wrap Vapour Barrier’s mass and volume were not significantly affected by the exposure. So, physically, the Stego Wrap was virtually unaffected.

Permeance:
The testing lab then sent exposed samples to the industry leader in permeation testing for post-exposure testing. The results were fantastic. The layer in contact with the contaminated sand came out with a permeance right at the industry’s barrier threshold of 0.6 ng/(s*m2*Pa). The top layer was completely unaffected by the exposure. The resulting permeance was 0.48 ng/(s*m2*Pa), the same as Stego Wrap Vapour Barrier’s baseline permeance result. 

 

Sulfate Exposure

Setup:

Two separate tests were conducted to measure Stego Wrap Vapour Barrier’s ability to be used in sulfate-rich environments. They are described below:

Test A – Sulfate Exposure. To simulate the worst possible sulfate exposure, a senior chemist at a research and testing lab prepared water contaminated with 10,000 PPM of SO4 (sulfate.) This sulfate concentration was chosen because it was rated as “very severe” (the highest or worst classification) by UC Berkeley professors conducting research for the Caltrans Long Life Pavement Rehabilitation Strategy (LLPRS) Program. The Chemist took this worst case scenario concentration and soaked samples of Stego in it for 28 days. Upon removal, the samples were analyzed for changes in mass, volume, tensile and water vapour permeation.

Test B – Sulfate Permeation. In addition, Stego Wrap (0.38 mm) samples were tested for sulfate permeation. Measurements were taken at 24 hrs, 72hrs, 7 days, 2 weeks, 4 weeks, and 5 weeks of exposure.

 

TEST A RESULTS

Mass & Volume:

The chemist conducted mass and volume measurements before and after exposure. The following comes directly from her report: “Almost all of the test coupons exhibited slight changes in mass and volume, no matter what their exposure conditions were. Statistical analysis by t-test showed that the changes for the pollutant-exposed coupons were not significantly different from the changes for the control-exposed coupons.” In other words, Stego Wrap Vapor Barrier’s mass and volume were not significantly affected by the exposure.

Tensile:

The tensile strengths of the samples after the 28-day extreme sulfate exposure were 12.1 kN/m and 13.0 kN/m for cross and machine directions respectively. These results were no different than the water-exposed control samples. For another point of comparison, consider that to be labeled as Class A per ASTM E 1745, new-material tensile need only test at 7.9kN/m. Conclusion: Extreme sulfate exposure has little to no effect on Stego’s physical integrity in below-slab applications. 

Water Vapor Permeance:
The testing lab then sent exposed samples to the industry leader in permeation testing for postexposure testing. The results were fantastic. The permeance stayed right at Stego Wrap Vapour Barrier’s baseline permeance of 0.48 ng/[s*m2*Pa]. Extreme sulfate exposure had no effect on Stego Wrap Vapour Barrier’s ability to retard water vapour.

 

TEST B RESULTS


Sulfate Permeance:
No amount of sulfate was detected in any of the 6 readings during the permeation testing.

 Conclusion

Stego Wrap Vapour Barrier is also an excellent sulfate barrier.

 

UV Exposure Testing

Background:

We don’t typically recommend leaving Stego Wrap in the sun for longer than 30 days. However, we set out to perform the following post-UV exposure testing to see what really happens in the field. While all project conditions are different and can have unique challenges that can affect the UV degradation (i.e. chemical overspray), the following testing is designed to give the project team an idea of Stego’s ability to withstand prolonged UV exposure.


SETUP

A sample of Stego Wrap Vapour Barrier (0.38 mm) was laid on top of a roof in Hawaii from September 2010 to September 2011. It was exposed to the elements for this 12 month time frame to test the permeance and tensile degradation from UV weather exposure.


RESULTS

Color: The yellow color was completely washed out, turning the Stego sample into a milky white color. This is a known phenomenon due to the environment-friendly dye used in Stego Wrap. This new dye is much better for the environment, but does not have the staying power it used to.

Tensile: The ASTM D882 tensile strength of the sample after the 12 month exposure was 11.2 kN/m. This reflects a 20% degradation in tensile strength. If we assume linear degradation, this is only a 1.6% degradation per month. For another point of comparison, consider that to be labeled as Class A per ASTM E 1745, new-material tensile need only test at 7.9 kN/m. Conclusion: This 12 month UV exposure had little effect on Stego’s physical integrity in below-slab applications.

Water Vapour Permeance: We also tested the exposed sample for water vapour permeance on a Mocon Permatran 3-33G (ASTM F1249 Compliant) module. The results were fantastic. The permeance stayed below the industry barrier benchmark of 0.6 ng/(s*m2*Pa). After the 12 month UV exposure, Stego Wrap maintained its barrier qualities.


Conclusion: While the color doesn’t last, the characteristics that make Stego Wrap the best vapour barrier in the industry, are minimally affected if at all. The permeance maintained barrier levels and the tensile strength stayed well above the ASTM E 1745 Class A benchmark. Again, while we don’t recommend Stego Wrap be exposed longer than 30 days, these tests show that, in this case, the properties remained relatively constant over the 12 month time frame.


We hope this information helps in your evaluation of using Stego Wrap in your next project where UV exposure is of concern.
If you have any questions regarding the test setups or results described above, please contact Joe Marks, Director of Engineering at Stego Industries. joemarks@stegoindustries.com.

 

Color: Yellow
Thickness: 15 mils
Type: Vapor Barrier
ASTM E 1745: Class A
Composition: Multi-Layer Extruded Polyolefin Membrane
This summary conforms to the requirements of ASTM E 1745-11 section 9.3. Sampling for tests conformed to section 8.1. All product testing performed or witnessed by independent labs:

DESCRIPTION  ASTM DESIGNATION RESULT UNITS DATE
Punture D1709 2266 grams 7/31/2012
Tensile (Machine Direction) D882 13.1 kN/m 7/31/2012

Tensile (Transverse Direction)

D882 12.4 kN/m 7/31/2012
Push-Through Puncture D4833 171.5 Newtons 7/31/2012
Permeance (Baseline) F1249 0.492 ng/s*m2*Pa 7/31/2012
Permeance (After Wetting, Drying, Soaking) E154  0.561 ng/s*m2*Pa 7/31/2012
Permeance (After Heat Cond.) E154 0.521 ng/s*m2*Pa 7/31/2012
Permeance (After Low Temp. Cond.) E154 0.555 ng/s*m2*Pa 7/31/2012
Permeance (After Soil Organism Exposure) E154 0.544 ng/s*m2*Pa 7/31/2012
Radon Diffusion Coefficient N/A 5.5 X 10 m2/s 3/13/2013
Methan Permeability D1434-V 192.8 mL(STP)/m2*day 3/7/2013