Thermal variability in outdoor exposure tests

Fischer, Richard M.; Murray, William; Ketola, Warren D.

doi:10.1016/0033-0655(91)80004-3

Cited by 22 publications

(7 citation statements)

References 2 publications

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“…The high variability in service life data, the presence of censored times-to-failure, and the effects of competing risks on the failure of a coating system are common to many materials, components, and systems (see, for example, the citations in Nelson [1990]). These factors dictate the way data can and must Large variations in the appearance of nominally identical panels exposed to the same service environment have been reported by Papenroth [1978] and Fischer et al [1991b]. The sources of this variation were later ascribed to measurement errors [Braun, 1987] and variations in the exposure conditions [Fischer et al, 1991b], while the contribution to the total variability from the degradation process was considered to be small.…”

Section: Service Life Data Attributesmentioning

confidence: 94%

“…These factors dictate the way data can and must Large variations in the appearance of nominally identical panels exposed to the same service environment have been reported by Papenroth [1978] and Fischer et al [1991b]. The sources of this variation were later ascribed to measurement errors [Braun, 1987] and variations in the exposure conditions [Fischer et al, 1991b], while the contribution to the total variability from the degradation process was considered to be small. Perera [1992, 1993] and Crewdson [1993], however, also observed considerable variability in their loss-of-appearance time-to-failure data which they did not associate with experimental error.…”

Section: Service Life Data Attributesmentioning

confidence: 94%

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Methodologies for predicting the service lives of coating systems

Martin¹

1994

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EXECUTIVE SUMMARYOver the last two decades, the organic coatings industry has undergone rapid technological and structural changes. These changes have been induced by legislative actions such as restrictions pertaining to hazardous chemicals, toxic effluents, and volatile organic compounds. The consequence of these changes has been the displacement of almost all commercially-important, well-established coatings (largely highsolvent coatings) by newer systems, the formulation and application of which arc based on different chemistries and technologies. Unlike the displaced coatings, however, the new coatings do not have performance histories and the only accepted method for generating performance data is through an extensive outdoor exposure program. Since outdoor exposure results typically take five years to obtain, a desperate need exists for a methodology which is capable of generating timely, accurate, and reliable service life estimates of a coating system. This report reviews the attributes of the service life prediction problem which are common to all materials, components, and systems in an effort to establish a set of criteria for assessing the adequacy of existing or proposed service life prediction methodology for coating systems. The current durability methodology and the reliability-based methodology are then evaluated against these criteria.The proposed cnteria include the ability to 1) handle high variability in the time-to-failure data for nominally identical coated panels exposed in the same service environment, 2) analyze multivariate and censored time-to-failure data, 3) establish a connection between laboratory and field exposure results, and 4) quantitatively predict the service life of a coating system exposed in its intended service environment.The current durability methodology was developed prior to the recognition of the proposed criteria and, as such, was not designed to satisfy these criteria. Efforts to correct its deficiencies have been made over the last 80 years, but success has been elusive. The failure of the current methodology has generally been ascribed to inadequacies in laboratory-based aging tests, specifically, the inability to simulate weathering conditions in the laboratory. However, we suggest that the failure of the current methodology can be attributed to its being based on faulty premises, inadequacies in experimental design, and the lack of reproducibility of the weather over any time scale.An alternative, reliability-based methodology is reviewed and assessed. This methodology has a strong theoretical basis plus a history of successful applications in the electronics, medical, aeronautical, and nuclear industries. A number of experiments with coatings has already been conducted using this methodology. The results indicate that this methodology can be applied in predicting the service life of coating systems and that it satisfies the proposed service life prediction criteria. Implementation of a reliability-based methodology will require substantial changes in the cu...

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Section: Service Life Data Attributesmentioning

confidence: 94%

Section: Service Life Data Attributesmentioning

confidence: 94%

Methodologies for predicting the service lives of coating systems

Martin¹

1994

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“…7,8 Thermal variations across a single exposure rack can lead to significant variability in gloss retention and chalking results. 9 Geographical variations over even short distances can be so great that exposures at two test sites in the same city can give different results, 8 and the results from exposures at entirely different locations often correlate very poorly.…”

Section: Correlation With Exterior Weathering Resultsmentioning

confidence: 98%

Rapid assessment of TiO2 pigment durability via the acid solubility test

Diebold

Kwoka

Mehr

et al. 2004

J Coat. Technol. Res.

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The influence of titanium dioxide on the durability of paint resin (often referred to as "TiO 2 durability") is of importance in many exterior coatings applications. Not only is it essential that a given grade of TiO 2 exhibit good durability, it is also important that it exhibit this durability consistently, since the economic consequences of even an occasional bad lot of TiO 2 can be enormous to a coatings manufacturer. To address this important issue, a rapid, highly predictive release test for certain classes of superdurable TiO 2 pigments has been developed to ensure good product consistency.

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“…Fischer et al 12 conducted exposures of PVC specimens in Florida and Arizona in open and backed racks and black boxes. Temperature of samples at various positions in the racks was controlled by thermocouples.…”

Section: Thermal Variabilitymentioning

confidence: 99%

Principles of Uv Degradation

Wypych¹

2015

PVC Degradation and Stabilization

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Thermal variability in outdoor exposure tests

Cited by 22 publications

References 2 publications

Methodologies for predicting the service lives of coating systems

Methodologies for predicting the service lives of coating systems

Rapid assessment of TiO2 pigment durability via the acid solubility test

Principles of Uv Degradation

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