Thermosetting resins are used in many applications due to their great mechanical properties, chemical resistance, and dimensional stability. However, the flammability of thermosets needs to be improved to minimize fire risk and meet fire safety regulations. Some commercially available flame retardants have an adverse effect on people’s health and the environment. Thus, the development of novel, more sustainable flame retardants obtained or derived from biomass has become an objective of contemporary research. The objective of this study is to summarize recent progress on bio-based flame retardants for thermosetting resins so as to promote their prompt development. Groups of biomass compounds with a potential for flame retardant industrial applications were introduced, and their thermal degradation was investigated. The authors focused mostly on the thermal degradation of composites containing bio-based flame retardants determined by thermogravimetric analysis, their tendency to sustain a flame determined by a limiting oxygen index, and fire behavior determined by a cone calorimeter test. The results showed that the mode of action is mostly based on the forming of the char layer. However, in many cases, there is still a necessity to input a high amount of additive to achieve significant flame retardancy effects, which may adversely impact mechanical properties.

Numerous fires occurring in hospitals during the COVID-19 pandemic highlighted the dangers of the existence of an oxygen-enriched atmosphere. At oxygen concentrations higher than 21%, fires spread faster and more vigorously; thus, the safety of healthcare workers and patients is significantly reduced. Personal protective equipment (PPE) made mainly from plastics is combustible and directly affects their safety. The aim of this study was to assess its fire safety in an oxygen-enriched atmosphere. The thermodynamic properties, fire, and burning behavior of the selected PPE were studied, as well as its mechanical and electrostatic discharge properties. Cotton and disposable aprons were classified as combustible according to their LOI values of 17.17% and 17.39%, respectively. Conall Health A (23.37%) and B/C (23.51%) aprons and the Prion Guard suit (24.51%) were classified as self-extinguishing. The cone calorimeter test revealed that the cotton apron ignites the fastest (at 10 s), while for the polypropylene PPE, flaming combustion starts between 42 and 60 s. The highest peak heat release rates were observed for the disposable apron (62.70 kW/m2), Prion Guard suit (61.57 kW/m2), and the cotton apron (62.81 kW/m2). The mean CO yields were the lowest for these PPEs. Although the Conall Health A and B/C aprons exhibited lower pHRR values, their toxic CO yield values were the highest. The most durable fabrics of the highest maximum tensile strength were the cotton apron (592.1 N) and the Prion Guard suit (274.5 N), which also exhibited the lowest electrification capability. Both fabrics showed the best abrasion resistance of 40,000 and 38,000 cycles, respectively. The abrasion values of other fabrics were significantly lower. The research revealed that the usage of PPE made from polypropylene in an oxygen-enriched atmosphere may pose a fire risk.

This paper presents a review of flame retardants used for glass/polyester laminates. It concerns flame retardants withdrawn from use such as compounds containing halogen atoms and flame retardants currently used in the industry, such as inorganic hydroxides, phosphorus and nitrogen-containing compounds, antimony, and boron compounds, as well as tin–zinc compounds. Attention is also drawn to the use of nanoclays and the production of nanocomposites, intumescent flame retardant systems, and mats, as well as polyhedral oligomeric silsesquioxanes. The paper discusses the action mechanism of particular flame retardants and presents their advantages and disadvantages.

Smoke generated in the combustion process of plastics reduces visibility and contains toxic products causing severe health problems for and may be hazardous to both people and the environment. Therefore, the awareness of smoke specification is important. This paper presents two most common small-scale methods for measuring smoke parameters. The cone calorimeter method and single-chamber test, respectively, standardized by ISO 5660 and PN-EN ISO 5659-2 were reviewed. Fundamentals of these methods and measurement techniques were described. Di-verse smoke parameters obtained from these methods were collected and specified. Attention was also drawn to the relevance of these parameters to standard requirements for various industry fields such as rail transport or shipbuilding.

Sewage sludge may pose a fire risk. The safe storage of biomass waste is a challenge due to self-heating processes. This study aims to assess the propensity to spontaneously combust of sewage sludge in order to determine safe storage and transport conditions. The evaluation of spontaneous ignition hazard was assessed according to EN 15188, by the determination of the self-ignition temperature. Certain parameters assumed to affect the inclination of sewage sludge to self-ignite, including the moisture content, bulk density, elemental composition, and particle size, were discussed. The results showed the risk of self-ignition during the storage and transport of sludge dust and pellets. The usage of the smallest basket volume resulted in the highest self-ignition temperatures, which were 186 °C and 160 °C for sludge pellets and dust, respectively. The comparison of the two forms of thermally dry sludge showed, that despite sludge pellets being easier to store and handle issues, the more favorable conditions for the management in terms of fire risk is sludge dust. Its temperatures for safe storage are slightly higher. The results highlighted that future research should focus on the hazards of silo fires and explosions in terms of silo fire prevention and management.