Debate About PVB Study

[Delta Kits]

PVB Issue
By Tim Smale
IGA Chief Executive Officer

The IGA's recent investigation into damaged windshields has been largely misunderstood and caused confusion in our industry. I would like to take this opportunity to reaffirm the issue and the IGA's position on the matter.

The primary issue we are investigating is the tendency for poly vinal butyral (PVB), the plastic inner layer between the two pieces of glass in a windshield, to absorb moisture when a windshield is damaged, and the subsequent safety risks. The IGA's focus is not whether or not windshield repair is safe. I emphasized this to you in my last letter and again last week when I met with windshield repair professionals and the National Windshield Repair Association Board of Directors in an attempt to clarify our concerns. I mentioned in those meetings that the headline in the IGA's announcement of the Solutia study, "Is Windshield Repair Safe?" was potentially misleading and may have led up to the assumption that the IGA was against windshield repair. I apologize for any misunderstanding that this headline may have caused, and want to ensure you that we are staying focused on the PVB issue.

To recap, the IGA commissioned a study of PVB's absorption of moisture when it is exposed to air, and the subsequent potential for the broken windshield to dislodge glass particles, called spalling, upon impact (see photo). The primary purpose for the PVB interlayer in windshields is to improve safety by holding the glass together when impacted so it doesn't spall and cause injury. Solutia, a PVB manufacturer, was a logical source for the study since they are PVB experts and use standard procedures to test the quality of their product. Solutia's test of seven repaired windshields concluded that spalling does occur if PVB has been exposed to moisture in the air. Right from the beginning, I have cautioned that Solutia's test is not conclusive since it was performed by what some would feel is a biased party, and the sample size was small. The results indicate that further study is necessary.

The conclusion I originally made, which I will state again, is simply this - is what Solutia states in their report cause for concern? And if their findings are true, what does this mean for our industry, and does it affect windshield repair? Let me state clearly that our original intent was to merely seek industry comment and conclusion to the matter, not to take a position whether or not it is true or false. We simply do not have enough information to come up with any conclusion other than the fact that more investigation is warranted.

The testing and conclusions performed by Solutia were consistent with a similar study commissioned by the National Glass Association (NGA) in 1993. I have learned in recent weeks that in 1993, the NGA formed a committee to investigate these matters and there are various interpretations as to whether or not the issue was resolved at that time. Those who feel that the issue was resolved are criticizing the IGA for investigating what they feel is a resolved issue.

Some repair manufacturers believe the issue has been resolved based on private testing of their own products. Understandably, they do not want to share the results with us for fear of it getting into the hands of their competitors. Most of these companies are IGA members, and these reputable companies stand behind their studies and are confident that their testing is conclusive, unbiased, and refute the Solutia findings. A few of them have invited me to review their test results in order to learn more about why they feel that way.

Other people believe it's a resolved issue based on a study by the Insurance Institute for Highway Safety (IIHS). The study concluded that damaged, unrepaired windshields that were soaked in water for one week spalled upon impact in approximately equal amounts as damaged, unrepaired windshields that weren't soaked in water. From this they concluded, "The risk of interior windshield glass spalling from non-collision impacts does not increase when damaged windshields receive even extreme exposure to moisture." While their test was statistically impressive, I cannot understand how it resolves the issue. I learned in a recent visit with OEM windshield manufacturing engineers that PVB absorbs moisture rapidly (called moisture absorption) when exposed to air, but the moisture spreads slowly to other areas beyond the damaged section (called moisture migration). One engineer told me that it would take years for moisture to migrate 1/4" beyond the damaged area in a windshield, and even soaking it in water would not speed the migration. This tells me that the IIHS study results were to be expected; since moisture migration in PVB is very slow, one would not expect windshields that were water-soaked for one week to spall more. To me, the IIHS study conclusion only emphasizes that broken windshields spall upon impact.

Since the studies I have reviewed are not conclusive, and could be perceived as biased since manufacturers of windshields, PVB, or repair products sponsored them, I believe that we need more information. We need strong evidence one way or the other to know if PVB's absorption of moisture in broken windshields is a safety concern or not. I suggest that our industry bands together and commissions an independent lab to perform a battery of conclusive tests, thereby eliminating the potential for bias.

Above all, I am hopeful that the damaging remarks and misunderstandings toward me personally and the organization I serve are now behind us, and we can all work together to understand and answer this important question. I will continue to keep you informed about any updates to this issue, and am interested in knowing your thoughts. Although our primary focus remains on steering and underpayment by insurers, I will continue to ask our industry to provide the answers you have been asking for regarding these issues.

In service to Independents,

Tim Smale, IGA C.E.O.
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Tim Smale
IGA Chief Executive Officer