Will the System Perform? Mock-Up  
Testing Answers The Question  
n the ever-changing world of com-  
While sealants can be used as a bar-  
mercial glazing,mock-up testing has rier against air,water,thermal,etc.,they  
become a must for many projects.  
The complexity of the systems,con-  
are also used for structural purposes.  
“If there’s a sealant failure it could lead  
cern about failure, as well as a need for to problems in any of those categories,”  
familiarity with the process all have Runkle says,explaining this could result  
contributed to growth,” says John Run- in a water leak into the building.  
kle, vice president, building sciences  
with Intertek-ATI in York, Pa.  
“But on the structural side, numerous  
systems rely solely on the sealant to ad-  
This type of testing ensures the com- here the glass to the backup structure (i.e.,  
pleted project will perform as intended. SSG),”he says.“A failure in that joint could  
Failures could occur for many reasons. lead to glass breakage or falling out.”  
Some are more serious than others,  
particularly those related to structural cladding system design development is  
silicone glazing (SSG). done via engineering analysis, such as  
Forner adds that most of the  
Tammy Forner, senior associate, predicting structural behavior, rates of  
manager – northeast,for CDC in Farm- thermal transfer, etc.  
ington, Conn., says in her experience,  
“It’s in the assembly and installation  
sealant installation and adhesion issues of the engineered components of a  
contribute to about three-fourths of cladding system where control of the  
mock-up failures.  
process can be lost,” she says.“A critical  
Those result overwhelmingly in un- component of assembling the compo-  
desirable air infiltration or water pene- nents into a fully functioning cladding  
tration,” she says,explaining that issues system depends on workmanship while  
can include seals being missed during installing construction sealants, either  
installation or assembly; use of incor- as joint adhesives/fillers or as structural  
rect sealant; an insufficient amount of adhesives.This elevates the importance  
sealant; or missed/improper tooling.  
of pre-construction adhesion and com-  
Forner also attributes two-thirds of patibility testing by the sealant manu-  
the sealant problems she’s seen to in- facturer on all substrates to which  
stallation-related problems and one- sealants will be applied, as well as the  
third to adhesion issues.  
According to Runkle,those sealant is- blers and installers of cladding systems.”  
sues include failures of adhesion or co- So what happens after a mock-up  
skill and professionalism of the assem-  
hesion failures. A cohesive failure, he fails and what are the steps to resolve  
says, is a failure within itself, while ad- the issues?  
Mock-up testing can help projects hesive failures occur at the bond line  
avoid a number of issues in the field. between sealant and substrate.“Adhe- small scale testing is done.  
These can include (from top to bottom) sive issues often are workmanship re- “You try to see if it’s an isolated oc-  
Runkle says macroscopic testing or  
adhesion failure of the EIFS finish coat lated. A cohesive concern is often currence or something pervasive and  
to base coat (horizontal) as well as related to improper joint geometry.This we use this testing to determine that.  
cohesive sealant joint failure (vertical); can be a function of installation,but it’s Then it’s typically a remove-and-replace  
failed sealed joints, likely due to a also a little higher weighted on the de- situation and you re-test.”  
chemical reaction; and cracking or sign side … it’s hard to get the ideal  
Forner says that the resolution of  
crazing in the sealant joint.  
geometry and that can lead to failure.” sealant issues is dependent upon a  
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A mock-up typically includes a number of procedures to test for system  
performance. These often include membrane adhesion and water testing.  
number of factors. These can include: well and sometimes they don’t.We’re see-  
A complete and correct documenta- ing an increase [in testing] because there  
tion of the underlying cause of loss are more sealant and air barrier manu-  
of adhesion by the sealant manufac- facturers than ever before. [The materi-  
120 minutes, you’ll see  
why we’ve become the  
favorite of architects and  
installers alike.  
turer and the responsible installer;  
als of] aluminum and glass have not  
Collaboration on the part of the sealant changed much, but performance of the  
manufacturer and installer to improve greater combinations of materials have  
quality assurance processes and re- changed substantially.”  
train workers in correct surface clean-  
ing, priming,joint design and packing tions are much more significant than ever.  
and sealant installation procedures; The complexity and number of trades in-  
Developing a sealant adhesion testing volved is adding to the challenge,as well.  
He adds that the types of material op-  
protocol to confirm that sealant instal-  
lation issues have been resolved; and  
“One reason mock-ups are so impor-  
tant is because when you’re looking at  
Continued monitoring of sealant ad- the entirety of a building, the number  
hesion by random testing to confirm of trades on the outside is incredible,”  
that issues continue to be resolved.  
he said.“The decision to have a mock-  
Re-testing is next. Forner says if the up typically is made by the architect in  
sealants are replaced in a mock-up the context of the owner’s requirements  
specimen, best practice is to allow at and budget, but it’s not uncommon for  
least two weeks for the sealants to de- the general contractor to propose a  
velop full adhesion and cure.  
mockup. They realize it’s a way to  
temperatures are below 50 degrees F,”  
she says.  
Often more time is desirable if air achieve early learning.”  
The use of mock-up testing has  
grown tremendously, and will likely  
Mock-ups can test other perform- continue to play a critical role,especially  
ance areas such as material compatibil- as glazing systems continue to evolve.  
ity, as well.  
“Once you’ve been through it and un-  
“On the material incompatibility side derstand [the mock-up system pro-  
we have so many more products than vides] early learning and ensures you’re  
ever before,”Runkle says,explaining that not making mistakes that will delay the  
air barriers,for example,traditionally are project … you quickly see the buy-in,”  
made from materials distinct from those he says.  
Aluflam USA  
Phone 562-926-9520 | Fax 562-404-1394  
used in sealants.“Sometimes they stick  
-Ellen Rogers s  
March 2016 | USGlass, Metal & Glazing