PSI - Issue 72

Anandito Adam Pratama et al. / Procedia Structural Integrity 72 (2025) 377–382

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1. Introduction Structure and material developments are focused on various parties supporting sustainable development goals (SDGs), such as affordable clean energy and industry, innovation, and infrastructure (Prabowo et al., 2016; Prabowo and Prabowoputra, 2020; Prabowoputra et al., 2020;2021; Faghihmaleki and Dezhhosseini, 2021; Harsito et al., 2021; Habib et al., 2023; Hanif et al., 2023; Sudarno et al., 2023; Fajri et al., 2024; Hidajat et al., 2024; Ladokun, 2024). In terms of material, e.g., engineering thermoplastics in forms of poly(butylene terephthalate) (PBT), poly(ethylene terephthalate) (PET), polycarbonate, polyamide, and polymer composites are extensively utilized across industries, including automotive, electronics, aerospace, biomedical, agriculture, and consumer goods in various forms of application (Acquasanta et al., 2011a; Clara et al., 2023; Yildiz et al., 2023; Jevtić et al., 2024; Samardžić et al., 2024; Djakhdane et al., 2024). However, when used in electrical appliances, these materials present the dual risks of electric shock and fire, making establishing clear fire risk assessment criteria essential. According to Krämer and Blomqvist (2007), the IEC 60947-1 standard specifies that insulating materials exposed to thermal stress due to electrical influences must not be adversely affected by abnormal heat or fire conditions. To meet this requirement, the standard recommends using tests like the glow-wire test, hot wire ignition test, and, if applicable, the arc ignition test (Krämer and Blomqvist, 2007). The glow-wire test serves as a fundamental pass/fail method for evaluating the suitability of materials for electrical insulation (Acquasanta et al., 2011b). It assesses the material's susceptibility to ignition when exposed to a heated wire or in the event of a short circuit (Guillaume et al., 2011). Therefore, this paper aims to review glow-wire testing performed on various polymer materials by previous researchers. It focuses on discussing the results of the GWFI and GWIT values and demonstrates the implementation of knowledge in regulatory considerations and standards compliance. 2. Characteristic Polymer Subjected to Glow-Wire Test Below are some studies from over the years that explain the effects of flame-retardant added to polymer materials. Jimenez et al. (2013) conducted a study to explain the fire protection properties of polymer materials by combining both bulk and surface treatment. The material combined PA6,6-GF with aluminum diethyl-phosphinate (AlPi) and an intumescent varnish layer. GWFI testing showed quite significant differences in results, where GWFI was validated at 750 °C for PA6,6-GF plus an intumescent varnish layer, at 850 °C for PA6,6-GF plus 5% AlPi, and validated at 960 °C when both approaches were combined. The addition of AlPi influenced the GWFI test because, with only 5% AlPi mixed in the polymer, the GWFI value increased to 100 °C. This difference can be explained by the configuration of the glow-wire test itself, where when the glowing wire penetrates the specimen, it penetrates the inside of the intumescent coating layer. When it has passed through the layer, it penetrates the polymer. If AlPi does not intrinsically protect the polymer, it will burn, and the intumescent layer will no longer be efficient. According to Jimenez et al. (2013), the results of this glow-wire test are an initial explanation; it is necessary to investigate the chemical system of the specimen to be able to show whether there is an interaction between IC and AlPi or not. In other polymer materials, namely nylon, there is research from Zhang et al. (2015). They conducted several flame retardant properties tests, one of which was using the glow-wire method on nylon 46 (PA46) reinforced with 30% glass fiber and a mixture of flame-retardant substances in the form of decabromodiphenyl ethane (DBDPE). The specimen-making method was carried out in stages using a screw extruder machine with specific settings. the recorded glow-wire test results showed that the glowing wire penetration could not ignite the specimen, so all samples' ignition time, extinguishing time, and ignition duration were 0 s. Thus, the extrusion product that can reach a GWIT higher than 775 °C is declared to have passed the test and can meet the requirements for electrical insulation applications. Further glow-wire testing was conducted by Bulota and Budtova (2016). They comprehensively studied the effects of 40 wt% macroalgae mixed into PLA thermoplastic polymer composites. The GWFI test results showed that the PLA composite (added macroalgae) had a lower GWFI value than neat PLA. Although the GWFI value was low, molten drip did not occur when the material burned in the PLA composite. This is because the melt viscosity of the PLA composite is higher than that of neat PLA. This PLA composite has some potential for use in electrical equipment applications, although other supporting tests still need to be carried out (Bulota and Budtova, 2016). Furthermore, in 2018, Casetta et al. (2018) conducted a study similar to Jimenez et al. (2013), where polyamide six material was combined with glass fiber but blended with magnesium dihydroxide (MDH). The combination of MDH,