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Testing Pressure-Sensitive Tapes: Rounds Two and Three

Posted April 2, 2014 3:20 PM by Peter Yost
Related Categories: BuildingGreen's Top Stories, Sticky Business

Tension and pressure, tears and creeps. The Wingnut Test Facility (WTF) gets dope-slapped in our latest round of experiments.

Peter and Dave put tapes to the test at Building Energy 2014.
Photo Credit: Walter Pearce

NOTE: Want to get into more sticky business like this? Read the whole blog series!

The Wingnut Test Facility, or WTF, conducting new PSA tape testing in preparation for the NESEA BE14 Demonstration Stages, learned how half a dozen or so tapes are performing on half a dozen different substrates. We also learned, to our surprise, that pressure, or “bellowing,” may not be as important a factor as the wing nuts first thought. (For background on WTF and its prior tape tests, see “Shocking Truth About Tapes Emerges from Wingnut Test Facility!”, and to find GreenSpec listed tapes, see Flexible Flashing.)

Dave Gauthier and I decided two things at the end of our last round of testing:

  • We needed a more-realistic, longer-term, “straight-pull” tension test.
  • We needed a test that reflected the “bellowing” pressures that tapes see in real installations, driven by wind events.

3 New Ways to Learn Building Enclosure Commissioning

Posted November 11, 2013 3:03 PM by Peter Yost
Related Categories: BuildingGreen's Top Stories, Sticky Business

With the need for BECx rising, the industry is working to train designers and other specialists to do the job.

This elementary school assembly could have been air-sealed at the top of the wall, simplifying the assembly and providing air-barrier continuity. BECx would have found a mistake like this early; as its prominence grows, the industry is struggling to meet demand for this expertise. When a fogger was used to identify where the building was leaking, fog was seen leaving the building through all the pathways shown here. Image: Pie Consulting EngineeringRecent BuildingGreen resources give a pretty good picture of just what building enclosure commissioning (BECx) is and how its use is on the rise in high-performance buildings. But a logical follow-up question I get asked a lot is: how can I get the necessary education to become proficient in BECx—or actually get credentialed or certified as a BECx agent or expert?

There are several questions wrapped up here, and I want to take them one at a time to keep this complex topic at least somewhat straight.

Caution sign: Construction in progress

Although there are a number of significant efforts under way on BECx, this is a relatively new field, at least in terms of standards, courses, professional exams, and credentials or designations.

All of these issues need to be addressed for different target audiences—trade professionals (in vocational education), technicians (two-year schools), and construction managers/engineers/architects (four-year university programs)—as well as different building professional designations: a building enclosure commissioning agent versus a building enclosure specialist.

4 Insider Tips for Choosing Flashing Tapes, from a Real-Life Engineer

Posted September 11, 2013 3:10 PM by Peter Yost
Related Categories: GreenSpec Insights, Sticky Business

A research engineer at Pella Windows finally offers some adult supervision for our benchtop tape tests.

Pella used several test methods to develop its SmartFlash system.

This post is part of a series on adhesives, sealants, tapes, and gaskets. Click here to view all the posts.

When the Wingnut Test Facility (WTF) took its tape testing protocols on the road, as I reported in my last post, a stranger stepped forward to politely offer some “adult supervision.”

It’s true that there aren’t any industry standards for testing tapes in dirty, wet, or cold conditions, says Jaron Vos, a research and field engineer for Pella Corp. That doesn’t mean manufacturers are ignoring the issue.

Welcome to the real world

According to Vos, in 2001 when Pella was developing its SmartFlash Tape, the company’s researchers focused on conditions they thought the tape would encounter during real use by real installers. They tried to replicate those conditions in the lab and got feedback from installers.

“It’s not that ASTM and similar test standards are not useful,” though, says Vos. “In fact, we used AAMA’s 711 extensively for measuring performance after trying to replicate jobsite or service life conditions.”

Shocking Truth About Tapes Emerges from Wingnut Test Facility!

Posted May 2, 2013 10:10 AM by Peter Yost
Related Categories: GreenSpec Insights, Sticky Business

Think you understand pressure-sensitive adhesives? Think. Again. (EDITOR’S NOTE: Do not try this at home.)

WTF at BuildingEnergy 13! Children, do not try this at home.
Photo Credit: Courtesy Peter Yost

My last post in this series on adhesives, sealants, and tapes ended with this line:

“We hope to follow up this baseline ideal conditions testing with more field-like conditions.”

Introducing the WTF research troupe

Well, it took a while, but we finally got a venue for some more testing of pressure-sensitive adhesive (PSA) tapes: the Northeast Sustainable Energy Association annual conference, BuildingEnergy 13.

NESEA premiered its Trade Show Demo Stages this year, calling the stage demos “Recess for building and energy professionals—Let’s play!” Sure seemed like the appropriate forum for us to premiere the Wingnut Test Facility (WTF), a new round of “benchtop” tape testing with a focus on field conditions: wet, cold, dirty, and just about all of the above.

They actually invited us to come do our tape testing on stage!

Our crack slapstick lab staff

Fellow WTF founder, Dave Gauthier (President of Vantem Panels here in Brattleboro) and I set up the testing this way (download the spreadsheet for details):

  1. Cold, wet application (no primer)—We put on our jackets and adhered the various tapes to rough OSB outdoors when it was about 28°–36°F (temps rose as we worked; see comments in spreadsheet). “Wet” meant this: we sprayed water from a standard spritzer bottle, then wiped off the OSB with our bare hands—to mimic what might be considered “prepping” the surface on a typical jobsite….
  2. Cold, wet application (with primer)—We used two priming materials: Pro Clima’s acrylic primer and 3M’s Super 77. We chose the Pro Clima primer because it is appropriate for acrylic tapes, and we had prior experience with it and could easily get ahold of a relatively small quantity from the supplier. We chose the multipurpose 3M Super 77 spray adhesive for the modified bitumen membrane and the butyl rubber flexible flashing product (a specialized primer would have to be specially ordered in quantity).
    After all the test samples were set up, we stuck them in a freezer, keeping them below freezing until we transported them to the NESEA demo stage in a cooler.
  3. Dirty application—To reflect another common jobsite condition, we took the substrates outside, smeared mud on them, and then “prepped” the surface by wiping off the excess with the palms of our hands. We did this testing inside at room temperature.

Hidden Seam Failures? We Put Flashing Tapes to the Test

Posted August 30, 2012 7:54 AM by Peter Yost
Related Categories: GreenSpec Insights, Sticky Business

Flashing and air barrier seam tapes get buried deep in our walls where we rely on long-term performance without monitoring them. Are they doing their jobs?

Companies do their own more sophisticated testing, like this tensile test on ZIP Tape. The company has a whole video on its testing procedures, but it's more fun to try this at home!
Photo Credit: Screen shot from ZIP System video

NOTE: Read this whole series here.

Service life of tapes can determine the service life of an entire high-performance building assembly.

Performance testing of adhesives and sealants used in our weather barriers is improving due to new field-testing research, as we’ve written about before. However, the improvements in testing haven’t reached a critical product area: pressure-sensitive adhesive (PSA) tapes used for sealing seams in flashing, housewrap, and generally creating continuity in air and weather barriers. “I am unaware of any work being done on this issue, either laboratory or field tests,” says Christopher White, of the National Institute of Standards and Technology (NIST).

The most commonly cited adhesion tests for pressure-sensitive adhesive (PSA) tapes are as follows:

  • ASTM D3330 – Standard Test Method for Peel Adhesion of Pressure-Sensitive Tapes
  • ASTM D903-98-04 – Standard Test Method for Peel or Stripping Strength of Adhesive Bonds
  • ASTM D1876-01 – Standard Test Method for Peel Resistance of Adhesives
  • ASTM D3654 – Standard Test for Shear Adhesion of Pressure-Sensitive Tapes
  • ASTM D3330 – Standard Test Method for Peel Adhesion of Pressure-Sensitive Tapes

But none of these tests is ideally suited for lab-testing high-stretch construction flashing tapes, and none go anywhere near testing under field conditions. And since just about all tapes are used in concealed weather and air barrier systems, we really need a field-service-life prediction test.

 “Workbench tests” of flashing tapes

So we took matters into our own hands—or rather, our own workbench. Lately I have been just sticking a slew of tapes on different building materials and gauging how hard it is to pull them apart.

Adhesives and Sealants: Performance First, but Materials Matter

Posted August 22, 2012 1:10 PM by Brent Ehrlich
Related Categories: GreenSpec Insights, Sticky Business

Exterior adhesives and sealants are formulated for performance, but some contain chemicals that pose risks to unprotected workers or the environment

The silicone found in many window caulks is not much of a health risk to onsite workers, but the chemicals used to produce silicon are coming under greater scrutiny.
Photo Credit: ArmaCo Construction

 NOTE: Read this whole series here.

As discussed throughout this series, adhesives and sealants used outside the building envelope have to adhere to the substrate and seal gaps, and they often need to be as durable as the building itself. Performance is the primary concern, and the chemical constituents often take a back seat. Unlike products used on the interior—where VOCs and other potentially hazardous chemicals can concentrate to create indoor air quality problems for occupants—for exterior products, exposure risk is mostly limited to workers who manufacture and apply the products.

Sealing Without Stickum: Gaskets Make a Place for Themselves

Posted August 15, 2012 7:44 PM by Peter Yost
Related Categories: GreenSpec Insights, Sticky Business

Compressible gaskets keep air and water barriers continuous without liquid sealants or adhesive tapes. But they don’t all last equally well.

This Holst Architecture-designed Passive House project, Karuna House, includes gasketing on the sill plate—common in Northern Europe for decades but fairly new to the U.S.
Photo Credit: Hammer & Hand

NOTE: Read this whole series here.

In the U.S., we tend to put a lot of faith in caulks, tapes, and wet-applied sealants. But in Europe it’s a different story.

Some Gaskets can be used in place of tapes or liquid sealants, mainly as part of residential air barrier systems. According to Lee Jaslow of Conservation Technologies, a leading U.S. distributor of high-performance gaskets and one of the high-performance gasket listings in GreenSpec, the market for gaskets in residential construction is small but growing, with increased interest due to high-performance rating systems such as Passive House.

Sustainable Sealants: The Challenges of Predicting Service Life

Posted August 8, 2012 3:39 PM by Peter Yost
Related Categories: GreenSpec Insights, Sticky Business

Caulk joint sealants can be a major deciding factor in how long your building envelope lasts. Is there a better way to predict how long they last?

Mounted on the roof at NIST, this "weathering engine" tests sealant durability.
Photo Credit: National Institute of Standards and Technology

NOTE: Read this whole series here.

Durability, or service life, is critical to the overall performance of liquid caulk joint sealants in the water and air barriers in our buildings.

If we can figure out how long sealants actually last then we can come up with a prudent inspection schedule—and have a good idea of how they’ll fail and how to replace them. The good news about sealants is that they are generally exposed to view—unlike flashing tapes, which are generally buried and inaccessible. (More on tapes in a future post.)

Fairly assessing durability or service life

We are always hoping for that one magic test that fairly, accurately, and realistically portrays one or more performance attributes of our building materials.

The trouble is that, while field tests can be more realistic, they tend to introduce many uncontrolled or non-measurable conditions. And the trouble with laboratory tests is that they set, control, and measure many conditions, making them often far from what actually goes on in the field.

It turns out that we have plenty of useful standardized laboratory tests for both liquid sealants and tapes that we use in our weather and air barriers. That’s the good news. The bad news is that we haven’t had useful tests for the field service life prediction of those same sealants and tapes—until recently.

Stickiness Explained! Making Building Tapes and Membranes Stay Put

Posted July 10, 2012 5:34 PM by Peter Yost
Related Categories: GreenSpec Insights, Sticky Business

When you use tape to seal a seam or flash a sill, you need peel-and-stick performance—not “stick-and-peel.”

...or is it? Our confidence in tape might be a little misplaced.

NOTE: Read this whole series here.

While liquid sealants most often are used on the exposed surfaces of building enclosures, pressure-sensitive adhesive tapes (member link) and membranes are used one or even two layers deep in the building assembly to seal the margins of weather-resistive and air barriers and at penetrations such as window openings.

Their location means that they cannot be inspected, repaired, or replaced; we need to know that they will maintain their integrity and function for the full service life of the assembly.

What makes stuff “sticky?”

It’s pretty easy to take pressure-sensitive adhesion (PSA) for granted; from band-aids to masking tape to peel-and-stick membranes, we use them pretty much every day. But the science of PSA is complex and even a bit uncertain.

How to Choose a Sealant That Works

Posted June 12, 2012 4:30 PM by Peter Yost
Related Categories: GreenSpec Insights, Sticky Business

Any sealant can perform well in the right application, but knowing which to pick for your job is another thing. Our guide to sealants and how to use them.

NOTE: Read this whole series here.


Photo Credit: DAP

When selecting a sealant, these properties are typically the most important:

  • movement tolerance (rated by Class per ASTM C920, with 25 meaning joint movement of 25% of the linear width dimension of the sealant bead)
  • substrate compatibility
  • workability, particularly based on temperature
  • paintability and its converse—substrate staining
  • relative cost
  • service life
  • material constituency and hazardous content

There are seven basic types of liquid sealants, largely based on their chemistries and subsequent strengths and limitations. Each sealant’s suitability to an application is based primarily on its performance properties, the properties of the substrates, and cost.

Also Read

EPA Takes Action on Spray-Foam Health Risks
Spray-Applied Latex: A New Tool for Air Sealing
GreenSpec Products: Thermal and Moisture Protection
How Blower-Door Tests Measure Airtightness

 

Latex

Latex sealants are water-based, easy to tool, easy to clean up, paintable, and relatively less expensive than other types of sealants. Some premium latex sealants may be appropriate for exterior use (appropriate service life) and are rated for movement in classes 12½ and 25. Latex sealants may be best suited to interior finish applications.

Acrylic

Acrylic sealants are also paintable but are solvent-based and more difficult to tool. They are used more in commercial and exterior applications than latex and have very limited movement capacity (Class 7½). Acrylic sealants tend to be used in commercial construction in low-movement joints. Their cost tends to be in the low to moderate range.

Butyl

Butyl sealants are solvent-based, synthetic rubber materials demonstrating strong adhesion to a wide variety of substrates. They have excellent weathering characteristics but tend to be stringy and difficult to apply. They generally have limited movement accommodation (Class 7½ ). Butyl sealants are sometimes used in curtainwall systems where adhesion to rubber materials is required. The cost of butyl sealants tends toward the moderate range.

The next group are sometimes called “high-performance” sealants and are most often used in commercial building assemblies.

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