Attendees focused on education during the final day of the Insulating Glass Manufacturers Alliance (IGMA) 2014 Winter Meeting, held at the JW Marriott Union Square in San Francisco. With a variety of seminars encompassing topics from safety and investigating failures, there was no shortage of information surrounding proper practices for insulating glass (IG) units.
Opening Friday morning, Mike Burk of Quanex made a presentation entitled “For Your Safety and the Safety of Those Around You.” Starting off dressed in improper personal protective equipment, Burk explained why anyone handling glass units needs to wear proper attire and observe safe practices. “It takes more than one person to safely lift a large piece of glass … The person who may be killed may not necessarily be the person who did something wrong.
“Consistently, the person who causes the accident is not the person who suffers the injury or fatality,” he added.
Next, Bill Briese of GED Integrated Solutions made a presentation called “Glass Washing and Cutting Techniques.” Briese told attendees that many times the failure with a unit begins with the glass. Lites that are cleaned improperly or exposed to organic materials, compromising adhesion, can lead to failures, even with otherwise excellently assembled units.
He noted that use of proper cutting fluid is particularly important for ensuring good edge quality.
“The purpose of cutting fluid is when you score the piece of glass, you’re inserting a little bit of this fluid into the fissure,” he said. “What that cutting fluid does is fill the void that’s created … If it evaporates too quickly then cracking will start to occur and you’ll get a poor breakout.”
Additional tips include using as little downforce as possible and also making sure you’re using high-quality filtered water to avoid calcium deposits and other complications from hard water.
Because he was absent from the event, Lingnell presented John Greenzweig’s findings on sealants and desiccants in insulating glass. According to the presentation, “Sealant failures allow excessive moisture into IG, create optical problems and a loss of insulating value.”
“If the primary sealant performance is compromised, durability is dependent on the secondary sealant,” stated Greenzweig in the presentation.
As for desiccants, “Desiccant capacity increases as temperatures decrease. If gas is adsorbed, negative deflection increases. Desiccant capacity decreases as temperatures increase. If gas is desorbed, positive pressure increases.” Greenzweig’s desiccant recommendations by sealant type include 3A for a hot melt sealant, 3A or 3a/13X or 3A/silica gel blend for two component polyurethane in a single- or dual-seal configuration, 3A or 3a/13X or 3A/silica gel blend for secondary: polysulfide and primary polyisobutlyene (PIB), and 3A for secondary: silicone/reactive hot melt/hot melt and primary: PIB.
“Spacers and Integrated Spacer Systems and Internal Muntins/Grids” was presented by Tracy Rogers of Quanex. He opened by stating that spacer systems were first patented in 1865 using warm-edge technology, so essentially the industry has come back around to the way it started. As a system, spacer technology includes the spacer, desiccant and sealant. The spacer functions as a way to “maintain space between glazing lites, dry gas in space to prevent moisture condensation, prevent moisture from penetrating space, retain gas fills within space, maintain hermetic seal about IG perimeter” and extend the life of a unit.
There are two types of spacer systems he said, single seal and dual seal. With a single seal, the “primary sealant acts as a moisture vapor barrier, gas retention barrier and provides structural integrity. [For a] dual seal, [the] primary sealant acts as a moisture vapor barrier and gas retention barrier while secondary sealant provides structural integrity (may also supplement primary sealant),” noted Rogers. Modes of IG failure include condensation/seal failure, chemical fogging, gas loss and sightline intrusion.
John Kent of the Insulating Glass Certification CounciI (IGCC) then discussed insulating glass product certification. According to Kent there are three types of certification: self-certification (enhanced warranty), second-party certification (self-certification with an independent test) and third-party certification which he said is the highest level of credibility. Self-certification, which is for the fabricator only, is the basic level of certification. Kent said it, “uses testing to an industry standard to enhance what is essentially a product warranty. The manufacturer administers his own testing and certification program and performs his own in-house inspections as a part of his quality control process. When you only specify test procedures, you are accepting self-certification. Building codes allow self-certification with independent test reports.
For second-party certification products are “tested at an independent laboratory or supplier facility. Certification is granted by a second party, often affiliated with the fabricator – supplier or association. The affiliate association staff performs both the administrative and inspection functions. Potential exists for influencing the affiliate interest if the manufacturer is a member or a financial relationship exists,” according to Kent.
Third-party certification, Kent said, is the highest level of product certification. “The certifying or inspection agency is independently under contract to the administering agency, often an association to which the manufacturer may belong. There is no direct link between the certifying/inspection agency and the manufacturer.
“The IGCC®/IGMA® Certification Program for Durability and Gas Content is a third-party certification program,” he added.
In the second-to-last presentation, Barry explained “Why Glass Sometimes Breaks.” The simplest explanation, he said, is “the load is greater than the strength of the glass … The strength of a piece of glass with a crack in it is essentially zero.”
He added, “We don’t know the exact strength of any piece of glass.”
According to Barry, “Fractographics can find the cause [of breakage]. It only takes enough time, enough money and having all the broken pieces near the fracture origin.”
Finally, Lingnell made a presentation about Field Investigations of Insulating Glass. Lingnell said to investigate a failure you first must obtain information to assist in the investigation, including: glass performance, project maintenance, discussions with the owner or representative familiar with the problem, review with the installer/contractor/fabricator when appropriate for details, study plans and specifications and review architectural drawings. Additionally, examine all compatibility issues, including: examining materials around IGU, determining whether IG sealants are in contact with any materials in the glazing system and what they are and figure out if vapor, solvents or runoff materials have come in contact with the IG sealant system. Further, when examining the IGU, Lingnell said you must: review the probable cause of the failure, determine the potential for future failures, examine for water infiltration, study the IG seal for degradation, remove the glass from the framing system, disassemble the unit, frost point other units, examine units that do not exhibit failure and bring the unit(s) back to the lab for a more detailed analysis.