Analysis and Modeling of Ignitability of Polymers in the UL-94 Vertical Burning Test Condition

Wang, Yong; Zhang, Jun; Jow, Jinder; Su, Kenny

doi:10.1177/0734904109099999

Cited by 18 publications

(20 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, the existence of the UL94 flame disturbs the observation and the gas phase temperature measurement. In this paper, the experimental steps presented in the published studies [14,15] were adopted to measure the ignition times of specimens heated by the UL94 flame. In order to facilitate understanding of the try-by-try ignition time measurement method, the experimental steps were described as follows.…”

Section: Measurement Of Ignition Times For Specimens Heated By the Ulmentioning

confidence: 99%

Influences of specimen size and heating mode on the ignitability of polymeric materials in typical small‐scale fire test conditions

Wang

Zhang

2011

Fire and Materials

Self Cite

View full text Add to dashboard Cite

SUMMARY Small‐scale fire tests including the Underwriters Laboratories 94 (UL94) vertical burning test and the cone calorimeter test are widely used. In this paper, the ignition times of materials heated by the conical heater of a cone calorimeter and the UL94 flame were measured. It was found that for polymer bars heated by the UL94 flame, the ignition time is relatively short and increases with the specimen thickness. But the contribution of the specimen thickness to the delay of the ignition time is limited. The intrinsic properties of materials play a more important role in the ignition time than the specimen thickness. In addition, respectively corresponding to one‐dimensional, two‐dimensional, and three‐dimensional heat transfer, three heating modes of the UL94 flame were presented and compared with the conical heater. It was found that whether the heat source is the conical heater or the UL94 flame, the ignition time depends on the heat flux and the multidimensional heat transfer. The ignition time decreases with the increasing heat flux, and the magnitude order of the ignition time might drop when the heating mode changes from one‐dimensional to multidimensional heat transfer. Copyright © 2011 John Wiley & Sons, Ltd.

show abstract

Section: Measurement Of Ignition Times For Specimens Heated By the Ulmentioning

confidence: 99%

Influences of specimen size and heating mode on the ignitability of polymeric materials in typical small‐scale fire test conditions

Wang

Zhang

2011

Fire and Materials

Self Cite

View full text Add to dashboard Cite

show abstract

“…Differentiated assessment and mechanistic aspects of burning are not considered. In the literature, some studies deal with the quantitative analysis of the testing conditions or the materials' behaviour in the UL 94 test, but more detailed or modelling approaches are rare .…”

mentioning

confidence: 99%

Modelling the vertical UL 94 test: competition and collaboration between melt dripping, gasification and combustion

et al. 2014

View full text Add to dashboard Cite

SUMMARYAn experimental and numerical investigation of the effect of bisphenol A bis(diphenyl phosphate) (BDP) and polytetrafluoroethylene (PTFE) on the fire behaviour of bisphenol A polycarbonate/acrylonitrile butadiene styrene (PC/ABS) in the vertical UL 94 scenario is presented. Four PC/ABS blends were discussed, which satisfy different UL 94 classifications due to the competing effects of gasification, charring, flame inhibition and melt flow/dripping. For numerical investigation, the particle finite element method (PFEM) is used. Its capability to model the complex fire behaviour of polymers in the UL 94 is analysed. The materials' properties are characterised, in particular the additives impact on the dripping behaviour during thermal exposure. BDP is an efficient plasticiser; adding PTFE prevents dripping by causing a flow limit. PFEM simulations reproduce the dripping and burning behaviour, in particular the competition between gasification and dripping. The thermal impact of both the burner and the flame is approximated taking into account flame inhibition, charring and effective heat of combustion. PFEM is a promising numerical tool for the investigation of the fire behaviour of polymers, particularly when large deformations are involved. Not only the principal phenomena but also the different UL 94 classifications and the extinction times are well predicted.

show abstract

“…Modelling the ignitability of polymer in the UL‐94 vertical burn test has shown that the ignition time, that is, the time taken for a sample to ignite, has a linear relationship with the initial sample temperature . As a result, samples that do not ignite during the first flame application are more easily ignited during the second application because of their higher initial temperature.…”

Section: Discussionmentioning

confidence: 99%

“…It has also been observed that flammability tests, where the external heat flux is not substantially (10 kW m −2 ) higher than the minimum radiance required for sustained flaming to occur, may not be statistically significant . Modelling this process has predicted the ignition time to decrease with an increasing flame temperature . In this case, a larger flame should result in the polymer becoming much hotter during the test.…”

Section: Discussionmentioning

confidence: 99%

PEEK polymer flammability and the inadequacy of the UL‐94 classification

2011

View full text Add to dashboard Cite

SUMMARY Fire safety is dependent on reliable information on material properties, particularly relating to burning behaviour. The Underwriters Laboratory UL‐94 test is a widely used simple Bunsen burner test for vertically upward flame spread. Aryl polyetheretherketones (PEEK) are polymers of exceptional thermal stability, typically decomposing at around 600°C and forming 50% carbonaceous char residue. Tests on seven PEEK polymers, and two related materials, in independent laboratories have revealed large inconsistencies in both the final broad classification and the scatter within each set of test results. In many cases, this variance is so large that if samples from the same batch of many of the materials were repeatedly submitted to test laboratories, this would ultimately result in one set remaining below the maximum burn time criteria, and so meeting the least flammable V‐0 rating. Initial data are presented indicating that a larger ignition source actually results in shorter burning times and more consistent burning behaviour. The reported behaviour of PEEK indicates that the inconsistencies reported here are not a function of inconsistencies in the material itself but rather a consequence of the low applied heat flux of the test method being very close to the critical heat flux for ignition of the PEEK polymer, which is rather high. With higher applied heat fluxes, this generates sufficient heat for a protective char to form, creating an effective barrier to further flame spread. Copyright © 2011 John Wiley & Sons, Ltd.

show abstract

Analysis and Modeling of Ignitability of Polymers in the UL-94 Vertical Burning Test Condition

Cited by 18 publications

References 23 publications

Influences of specimen size and heating mode on the ignitability of polymeric materials in typical small‐scale fire test conditions

Influences of specimen size and heating mode on the ignitability of polymeric materials in typical small‐scale fire test conditions

Modelling the vertical UL 94 test: competition and collaboration between melt dripping, gasification and combustion

PEEK polymer flammability and the inadequacy of the UL‐94 classification

Contact Info

Product

Resources

About