Fibrous alternative insulating solutions and their environmental impact: a review

Purpose This paper mainly aims to address questions related to the technologies used to produce thermal and sound insulating solutions from alternative and recycled fibers, by reviewing the current literature. This review also identifies the types and origins of fibers most commonly used in the reviewed papers, while fostering discussion on environmental impact assessment and the production of alternative insulating solutions already reported in the literature. Design/methodology/approach A literature review was carried out on two platforms: Scopus and Science direct. The period investigated was from 2013 to 2023, and only research articles and reviews were considered. Findings The most frequently used fibers are natural virgin fibers (mainly wastes from other industries or abundant local resources). The importance of alkaline treatment in some natural virgin fibers was highlighted in several studies. The most commonly applied consolidation techniques are thermosetting, needle-punching and the use of binders. The choice of these processes influences key parameters for sound absorption and thermal insulation. Natural and recycled fibers show strong potential to become excellent alternatives to replace conventional commercial products. Originality/value This paper is original because, in addition to reviewing the literature, it classifies the materials and technologies used to produce alternative insulating solutions. It therefore promotes discussion based on the categories of materials reported and considers the environmental impact assessments presented by the authors.