Debate About PVB Study

[Delta Kits]

Right now, we have an ongoing debate between the National Windshield Repair Association and the Independent Glass Association about a study that was conducted in conjunction with the IGA about the affects of moisture on the PVB layer (laminate).

Posts about this are kind of spread out, so I will attempt to put them all in one place.

The original study can be found here

[Delta Kits]

A Sign of Weakness and Desperation
William A. Batley, NWRA President

Recently, Tim Smale published an article on behalf of the IGA that raised some old issues about the safety of windshield repair. When I read the article entitled,

[Delta Kits]

Staying Focused on the PVB Issue
By Tim Smale, C.E.O. of the Independent Glass Association

As expected, William Batley, President of the National Windshield Repair Association (NWRA) offered a defensive response to Solutia

[CarGlass]

there are to many other variables to decide if a car wreck and a death is to be blamed on a windshield repair ..... gezz i cant even believe this is a subject.... ive been tearing cars apart for 21 years and to make such a big deal from an industry standpoint about windshield repairs, "is it a saftey problem ?" .. well is rather rediculous,,,,,,,, believe me, there are a lot of other problems to be worried about in the area of saftey in the windshield replacement business, such as crapy installations on a crapy rust bucket car using crapy glass and installation materials,,,, ive seen it all... and it does worry me about some of what i have seen over the years..... thats my nickles worth.. hope is helps.. keith, The CarGlass Co. CarGlass44@hotmail.com

[Delta Kits]

Questionable procedures and skewed results from IGA and Solutia
By Paul Syfko, Glass Medic


The recent IGA report on the safety of Windshield Repair was misleading and inaccurate.
*The test procedures were flawed
*The desired result dictated the procedures
*The data presented is inconsistent and inaccurate
*The conclusions are not credible
*The principle of testing

The fundamental principle of testing is to discover a predictable outcome for a given situation. When designing a test, one should control all the variables so as not to skew the results.

However, it is clear that Solutia wished to prove that moisture intrusion causes excessive spalling, so they performed tests that were designed to deliver that result. This type of testing is flawed, as the result dictates the procedures, whereas accuracy and credibility demand the opposite.

Variables not controlled

The sample windshields do not appear to have been controlled.
They were all weathered/conditioned differently and were different brands. In addition, the pummel test was performed incorrectly and inconsistently. It appears that at least two samples were tested at the edge of the glass, whereas the pummel test specifically demands that testing be done in the center of the 12 x 12 specimen.

It is likely that these two samples failed due to moisture intrusion though the exposed PVB at the edge of the glass and not because of moisture intrusion at the break. It is well known that the amount of exposed PVB at the edge of the glass is 1,000 times greater than that exposed due to a break.

Clearly, these samples were preconditioned to fail. A proper test can only be conducted on windshields that remain in the vehicle.

Inaccurate and inconsistent reporting
The reported results of these flawed tests are, themselves, flawed.

The moisture measurements of the control and repaired areas do not follow the graph in figure 1 of the report. The graph reports that a moisture level of greater than 0.6 % will cause the laminate to fail. However, base samples (un-repaired) #1 and #4 passed the test with moisture levels higher than 0.6%. The moisture level in all #3 samples was lower than 0.6%, but the base samples passed and the repair sample failed.

No relevance to safety

Due to poor test design, flawed pummel tests and inconsistent moisture measurements, the IGA

[Delta Kits]

(Supplied by Peg @ NWRA)

8-19-03

An open letter to:

Tim Smale

IGA Board of Directors


The IGA study "How Safe is Windshield Repair?" has created a firestorm of reaction. After observing the publication of letters and postings between the IGA and members of the windshield repair community, I would like to weight in on some of the issues being discussed.


There are well reasoned and documented refutations of "spalling" as a windshield repair problem including the widely publicized Institute of Highway Safety study. Not referring to the Institute of Highway Safety study in your comments raises questions about the motives behind the IGA/Solutia study. Using the IGA

[Delta Kits]

(Published in Delta Kits' WiseCrack Newsletter September-October Issue)

By now you

[speedmaverick]

I have a question. If you place a piece of lammy against an iron anvil and then pummel it, how is it possible for it to spall at all if its sandwiched against the iron anvil? Am I missing something here? I have made my livelyhood outside of windshield repair by setting up test sessions. There is too much info missing here for me to make a decision about the proceedures used, but it is obvious to me there is a HUGE conflict of interest going on here!!!! This seems to me that someone wants to slow down the repair industry. There has always been a conflict of interest between the repair & replacement industry. I have to admit that I started as a repair company and then added replacements later on. But I was always repair first, only replace if truely needed school of thought. I gave up on the replacement part because I see a lack of vision (or at least a lack cohesiveness) in the repair industry and have made a personal and business commitment to take the repair industry to another level. So as a group, lets stop the monopoly the glass replacement industry is trying to establish!!!!!

Jake Speed
A-1 Windshield Repair

PS Delta, thanks for hosting this forum.

[CarGlass]

brent thanks for a good reply to the fiasco with the IGA and the NWRA with respects to the PVB issue.. and i do agree with your questoion about which is more safe?.. a repair or a replaced windshield?.. well after 21 years of replacement and about 10% of that doing repairs, a repaired windshield in a vehicle is more safe due the the amount of HACKERS in the replacement industry.. and ive SEEN it all.. and its not pretty, lol , i would estimate about 60% (maybe more) of replaced windshields need to be replaced again due to non safe materials and installation practices done on the vehicle.. good work and thanks again.... Keith Elder

[CarGlass]

speed !!... hi this is keith.... i live in fuquay.. and i work in north raleigh.. ive got some questions to ask ya.. mail me please when you have time,,
CarGlass44@hotmail.com