**3. Application**

The proof of general compliance to the requirements that have been identified as relevant to qualify the BiSA requires ongoing application. As the assessment system is developed as part of an ongoing project, its ongoing application is ensured through the ongoing project integration. However, to depict the basic functionality of the assessment the biobased and biodegradable composite Bio-flexi will be presented in the following. This specific exemplary application is chosen and presented including technology introduction, technical description, assessment results and discussion.

#### *3.1. Bio-Flexi—A Biobased and Biodegradable Composite*

The Bio-flexi innovation is a biocomposite fiberboard manufactured from annually generated agricultural residues' fibers in the form of a flexible high-density fiberboard. The raw agro-fibers were bonded till 90% of mass load, without pre-chemical modification, by a thermoplastic elastic binder (TPE) using classic plastic-industry machinery [90]. The fibers applied were chosen from the agricultural residues stream, namely straw, which is the cheapest non-wood lignocellulosic natural fiber abundantly available worldwide from the cereal crops by-products' streams, mainly out of wheat, rice and maize. As the fibers are not edible, the discussion on competition with food is not relevant here. Other than availability, these lignocellulosic fiber types were applied to actively replace mineral-based flame retardants in plastics, depending on the high natural silica contents naturally present in their chemical composition reaching up to 20% of mass load in certain types as in the case with rice straw. The selected TPE binder was purposely chosen to be biodegradable under industrial compost conditions to give an opportunity to have multiple end-of life options after the end of the useful life time of the developed biocomposite material. These combined parameters were applied to increase the positive environmental feedback of this development during and after the useful life time of application in the building industry. It has at least two end-of-life options as it can be recycled to a number of recycling cycles then industrially composted if further recycling cycles would not be feasible, which is a solution that helps in minimizing wastes' accumulation. Waste accumulation minimization is accordingly hereby achieved twice: once during the production phase, as it is mainly based on agricultural residues fibers and secondly after the end of its useful life time. These end-of-life options are rarely available in the contemporary fiberboards market worldwide, the thing that promotes a wider application of this development in the contemporary building industry replacing a wide range of non-recyclable petro-based building products.

Usage of agro-fibers with these high mass-loads (up to 90% mass load) will help replacing the slow-renewable wood and improve forestry practices. In addition to these ecologic values, the elastic nature of the developed fiberboard enables the possibility of achieving attractive free-form architectural interior designs using cheap alternatives and available production techniques. Flat horizontal applications like flooring systems as in sport halls, yoga mats and others as well as in vertical applications as partitions and interior fittings are possible. Usage of thin veneer covering layers is necessary in different applications to give a covering aesthetic feature, to offer a final reinforcing layer and to close open fiber pores to guarantee durability. The high density developed boards can be provided with minimal thicknesses starting from 1–2 mm and can be transported in the form of rolls to minimize transportation and storage costs. In Figure 3, flexibility and possible applications in both flat- and curved-morphologies are emphasized.

**Figure 3.** Illustration of the flexibility of the Bio-flexi panel when veneered from one side and how it can be veneered from both sides to fix the geometry intentionally (republished: [91]).
