The adoption of Australian Standard AS 4739-2017 left some critical safety gaps in potential collisions that could have serious consequences.
In the Window on Safety Series, Sika’s Steven Theron looks at a missed opportunity for better and safer repairs.
A hidden danger on Australian roads lies in the potential for replacement windscreens to compromise vehicle safety, a concern first highlighted in the 2016 Australasian Road Safety Conference paper “Replacement Windscreens – a serious vehicle and road safety issue.”
Ongoing analysis reveals that the current standard still has critical shortcomings, particularly concerning the standards for the aftermarket glass installation process.
These deficiencies create a situation where vehicles may be returned to the road with a windscreen replacement that does not meet the Original Equipment Manufacturer’s (OEM’s) designed safety standards.
This situation creates a potential risk that the vehicle’s insurability may be compromised. Furthermore, its roadworthiness may be affected if the replacement does not adhere to the OEM’s designed safety standards.
The 2016 conference paper highlighted that the earlier AS 4739-2002 standard, while stipulating a return to OEM standards, failed to specify adhesive characteristics. This allowed for the use of aftermarket adhesives that do not provide the same level of structural bonding performance as those used by OEMs.
As 4739-2017’s failure to rectify this issue has serious consequences: the use of non-OEM equivalent adhesives directly compromises vehicle safety and, fundamentally, the roadworthiness of the vehicle.
As 4739-2017’s Section 5, “DIRECT GLAZING ADHESIVE SEALANT SYSTEMS,” is particularly problematic. Section 5.1(a) states that an adhesive sealant “shall meet vehicle manufacturers performance specifications,” it introduces an “OR” clause: “OR be a direct glazing adhesive sealant specifically engineered for the fixing of direct glazed automotive safety glass for light vehicles.”
This “OR” clause allows the use of adhesive sealants that, while designed for windscreens, may not meet the specific performance criteria of the OEM.
The implications of this are significant. Modern vehicles rely on the windscreen as a crucial structural component. It contributes to roof crush resistance and ensures proper airbag deployment. If a replacement windscreen is installed with an adhesive sealant that does not meet OEM specifications, these safety features may be compromised. In a collision, this could lead to catastrophic consequences.
Furthermore, many modern vehicles feature advanced driver-assistance systems (ADAS) with cameras and sensors mounted on the windscreen. Using windscreens and adhesives that do not meet OEM specifications may result in these systems not being properly calibrated, impairing their functionality and further compromising safety. The correct positioning and bonding of the windscreen are critical for the accurate operation of ADAS features like lane departure warning, automatic emergency braking, and adaptive cruise control.
Section 5.1(b) of the standard which states the adhesive sealant shall “meet or exceed the frontal impact test requirements of FMVSS 212 to establish safe drive away times,” exacerbates the problem. Many insurance companies and industry personnel are under the impression that because the adhesive sealant has passed FMVSS 212, it meets Australian Standards and is therefore fit for purpose. While FMVSS 212 is relevant for determining the minimum safe drive-away time, it does not guarantee that the replacement returns the vehicle to OEM specifications for overall structural integrity as FMVSS 212 merely tests windscreen retention in a crash. There is no reference to returning the vehicle back to the OEM’s original design specifications.
Aftermarket adhesives failing OEM standards
The concerns surrounding the lack of specific OEM adhesive requirements in AS 4739-2017 are substantiated by findings presented at the 2016 Australasian Road Safety Conference. The paper “Replacement Windscreens – a serious vehicle and road safety issue” included data from Henkel Teroson, a leading adhesive manufacturer, which starkly illustrated the disparity between current after-market products in Australia and the specifications of major European OEMs.
Table 1 revealed that several readily available direct glazing adhesives in the Australian market failed to meet the Shear Modulus (DIN EN 14869-2) and Tensile Strength (DIN EN 53504) specifications set by major European OEMs. This independent analysis underscores the inherent risk in allowing the use of adhesives that are not explicitly proven to meet the stringent structural demands defined by vehicle manufacturers. The fact that commonly available products do not measure up to established OEM standards further emphasizes the urgent need for a more robust and specific Australian standard.
Liability and lack of explicit requirements
A significant concern with AS 4739-2017 is the lack of explicit liability assigned for the use of adhesive sealants that do not meet OEM specific performance criteria. While AS 4739-2017 Section 5.1(a) offers a note stating, “If unable to obtain a suitable direct glazing adhesive sealant that is endorsed by the vehicle manufacturer [OEM approved] consultation with the direct glazing adhesive sealant supplier is recommended,” this provides only guidance, not a mandatory requirement for OEM compliance.
This contrasts sharply with the American Standard ANSI/AGSC/AGRSS 005-2022, which takes a stronger stance on liability. ANSI/AGSC/AGRSS 005-2022 Section 5.3 mandates that “Those engaged in automotive glass replacement must use either an OEM approved retention system, or an equivalent retention system as certified in writing by the equivalent retention system manufacturer directly or through a private labeller.” This requirement places a clear responsibility on the installer to use an appropriate system, with a mechanism for verification.
Under AS 4739-2017, adhesive sealant suppliers could just tell say that their products are “fit for purpose,” and consequently bear no formal liability tied to a written commitment, leaving installers and insurers with limited means to ascertain true OEM equivalence. This ambiguity can create a liability gap, potentially jeopardizing vehicle safety and complicating legal recourse in the event of failures.
Insurance ramifications
The core tenet of vehicle insurance is the restoration of a damaged vehicle to its pre-accident condition, a process that necessitates strict adherence to OEM standards, particularly for safety-critical elements such as windscreen fitment. A critical assumption held by insurance providers is that their contracted windscreen replacement companies utilise OEM compliant adhesive sealants as these meet Australian Standards. Conversely, windscreen fitters often operate under the belief that their use of adhesive sealants meeting FMVSS 212 standards for windscreen retention inherently satisfies OEM standards.
However, a significant liability arises if a non-compliant adhesive sealant is identified as a contributing factor to the severity of an accident or the malfunction of crucial safety systems. This discrepancy immediately raises fundamental questions regarding:
Insurability: Was the vehicle, in its post-repair state deviating from OEM standards, actually insurable from the outset?
Roadworthiness: Should a vehicle repaired with non-compliant materials have been permitted to return to Australian roads?
Liability: In the event of an accident and resulting injuries where the failure of a vehicle safety system is linked to an incorrect fitment, who bears the ultimate responsibility, the adhesive supplier, the insurance company or the windscreen fitter?
This situation underscores a potential disconnect between insurance industry assumptions, fitter practices, and the paramount importance of adhering to OEM standards for vehicle safety and regulatory compliance.
Recommendations for change
To address these critical flaws, AS 4739-2017 requires urgent revision. Section 5.1(a) must be amended to prioritize OEM specifications and eliminate the dangerous “OR” clause. The NOTES section must state that the adhesive sealant supplier must certify in writing that the product meets or exceeds the OEM’s specific performance criteria. This ensures accountability, verification, and liability.
Conclusion
AS 4739-2017 represents an effort by the working group to update the previous standard, and their work is acknowledged. However, in its current form, it still presents a risk to Australian motorists. By allowing the use of windscreen adhesive sealants that do not meet OEM safety performance standards, it compromises vehicle safety, potentially affects insurability and warranty, jeopardizes roadworthiness, and it risks the proper functioning of critical ADAS systems. The independent findings from Henkel Teroson underscore the prevalence of aftermarket adhesives that fail to meet established OEM specifications, highlighting the urgent need for a more robust standard. While the update to AS 4739 -2002 was a step forward, a further, more comprehensive revision is a crucial missed opportunity that must be addressed to truly ensure the safety and integrity of windscreen replacements in Australia.
Disclaimer: The information provided herein is for informational and educational purposes only and should not be construed as professional guidance concerning the use, application, or suitability of our products. All decisions regarding product use and application should be made in consultation with a qualified professional.