Owing to the superior thermal insulating attributes of rigid polyurethane foam (RPUF) compared to other insulating materials (expanded and extruded polystyrene, mineral wool), it remains the most dominant insulating material and most studied polymer foam. Like other polyurethane foam, RPUF is highly flammable, necessitating the incorporation of flame retardants (FR) during production to lower combustibility, promoting its continuous use as insulation material in construction, transportation, and others. The popular approaches for correcting the high flammability of RPUF are copolymerization and blending (with FR). The second method has proven to be most effective as there are limited trade-offs in RPUF properties. Meanwhile, the high flammability of RPUF is still a significant hindrance in emerging applications (sensors, space travel, and others), and this has continuously inspired research in the flame retardancy of RPUF. In this study, properties, and preparation methods of RPUF are described, factors responsible for the high flammability of PUF are discussed, and flame retardancy of RPUF is thoroughly reviewed. Notably, most FR for RPUF are inorganic nanoparticles, lignin, intumescent FR systems of expandable graphite (EG), ammonium polyphosphate (APP), and hybridized APP or EG with other FR. These could be due to their ease of processing, low cost, and being environmentally benign. Elaborate discussion on RPUF FR mechanisms were also highlighted. Lastly, a summary and future perspectives in fireproofing RPUF are provided, which could inspire the design of new FR for RPUF.

The use of polymer composite materials in the aeronautics and automotive sectors has increased dramatically, and their fire behaviour has become a critical parameter in terms of fire safety. On this premise, it is critical to demonstrate that these composite materials constitute elements whose safety justifies a high level of confidence. This is based on their combustibility and the rate at which flammable and toxic gaseous species are emitted. Thus, strict fire safety regulations are enforced by the relevant authorities concerned because of their potential fire risk. This study analysed papers published between 1970 and 2021 that described the devices used to characterise the thermal behaviour of composite materials at various scales. The objective was to highlight the thermophysical phenomena, making it possible to accurately assess the flammability and thermal stability of polymer composite materials. The results of this research reveal that the small-scale facilities provide detailed understanding and mastery of the thermal reaction properties of the composites. While with the medium scale, the extended fire reaction parameters, which are the key indicators of the fire safety performance, can be determined. On a large scale, the tests were carried out using devices such as the NexGen burner recommended by the FAA. Therefore, with such assays, it is possible to assess the rates of thermal degradation as well as quantified pyrolysis gases. However, compared to other scales, there were very few works on a large scale. In addition, by focusing on the polluting nature of synthetic composite materials, there is also few research studies aimed at designing new polymer composite materials from biological sources.

Reliable interpretation of fire pattern indicators is essential for wildland fire origin investigations, yet experimental validation is scarce. Damage Differential in the context of this study refers to the measurable changes in combustible and noncombustible objects after fire exposure, enabling the comparison and contrast of fire-caused effects on different faces or zones of artifacts, as described in NWCG PMS 412 (2025, 2016, 2005) and NFPA 921. The principle was quantifiably applied using image analysis and statistical methods (ANOVA) to evaluate directional reliability under controlled wind and fuel conditions. Our approach aims to reduce subjective interpretation by linking observed damage to specific fire dynamics and environmental factors. This study presents laboratory-scale wind tunnel experiments evaluating the directional behavior of commonly used indicators. Statistical analysis using ANOVA revealed that wind speed, fuel load, and artifact orientation each had a significant influence on fire indicators ( p < 0.001). Findings show that while indicators can yield reproducible directional cues, their reliability is bounded by specific interactions between fire intensity and airflow conditions. A complementary field-scale study is underway to evaluate fire patterns in operational settings, thereby strengthening the scientific basis for evidence-based wildland fire investigations.