## 5 Discussion  
C2C is a useful approach in concept development and in designing new products. It is assumed to be effective for a deeper understanding of material composition and design for recycling [5]. Nevertheless, it is also important for designers to understand and track the environmental impacts and benefits of their design actions [7; 46]. In this sense, as a tool for providing quantifiable environmental effects and as an instrument for external communication in the context of environmental labels and declarations, C2C Certified still bears certain shortcomings. On the one hand, a flaw in the relation between the certification holder and the user (e.g., a consumer or designer) could arise when the latter does not completely understand that C2C Certified is a benchmark for achieving the C2C principles, rather than a tool for the quantifiable estimation of environmental impacts. Furthermore, when the C2C certificate is taken as a given without attention into the details (i.e., examining the scorecard), users may use it for direct comparability between certified products or to plead for overall environmental preferability over non-certified products, which, as shown in this paper, is not that straightforward. On the other hand, C2C Certified is often perceived by the public as a Type I eco-label [47]. As discussed by [PERSON] and [PERSON] [9], and as also confirmed in the paper at hand, the program shows many similarities to Type I. Nevertheless, when going through the program's documentation, it is significant that ISO 14024 (the standard that defines Type I eco-labels) is never cited under the list of normative references, whereas a reference to ISO 14025 (Type III) occurs many times (see e.g., C2 CPII 2015, C2 CPII 2016a and C2 CPII 2016b [35; 48; 49]). Therefore, in order to provide clarity for an interested public, this paper answered the question of whether C2C Certified is a Type I or Type III (as defined by the respective ISO norms), and parallel to this, it pointed out the benefits and drawbacks of such (non)conformity. C2C Certified is a voluntary, multi-aspect program with a multi-sectorial scope. These typical Type I characteristics are backed by assured access to information about the program setting regarding funding and operation, as well as regarding product certification. In certain respects, the program even goes beyond a typical Type I eco-label, e.g., the binary pass-fail awarding format is upgraded by a rating scheme that ranks the products' performances. However, some of its characteristics show clear non-conformance with the requirements of ISO 14024. First and most importantly, the certification criteria of the program are generic without being product-specific. Thus, a specific evaluation of a product's life cycle is not performed. The standard further requires the elaboration of feasibility studies for the establishment of new product categories or product-specific awarding criteria, which is missing in C2C Certified, as it has a generic, but not product-specific, scope. The missing product-specific life cycle perspective in the certification criteria development ensures that the evaluation of a product focuses only on certain life cycle stages without any product specificity. This bears the risk of misbalance  
Figure 2: Application areas and overlap between C2C Certified, BA, and IBU. between the different certification criteria [8] by shifting burdens between life cycle stages, which is a situation that shall be avoided, as ISO 14024 explicitly states. Similarities between C2C Certified and Type III declarations can barely be found. However, together they can be recognized as complementing tools. As shown in the sector-specific example in this paper, both approaches are applicable in LEED(r) v4, where they complement each other without competing. Thanks to their different application purposes (i.e., a certification of conformance and comprehensive content declaration versus a quantitative list of impacts), they are used to obtain different credits through different conformance paths.