# Life Cycle Approach to Shopping Mall Redevelopment: A Model for Service Life Design
## 3 Discussion and Results
### Decision-Making (DM) on the Final Outcome of the Remodeling Action of the Building  
The decision to initiate remodeling is made based on an analysis of the causes of sustainability degradation, whether of the entire building or specific components. This study includes the material, spatial, and financial scope of sustainability requirement violations, and proposed interventions are positioned along the building's service life timeline. The decision-making process is grounded in multi-criteria evaluation, with criteria selected according to the level of compliance with sustainability requirements, as outlined in Table 2. From an architectural perspective, these criteria can be grouped by significance and similarity. The primary group includes structural integrity criteria, encompassing safety and durability, as well as ecological and health criteria, all of which are directly regulated by technical, environmental, or health standards. The secondary group includes criteria such as functionality, cost-efficiency, and esthetics, often referred to as \"soft\" requirements, as they allow for greater tolerance or postponement of fulfillment depending on business operations.  
The timing of sustainability degradation plays a key role in decision-making. A breach of any primary requirement at any point during the service life may necessitate immediate closure of the facility, unlike secondary requirements, which may allow continued operation. From an architectural standpoint, the most critical metric within the primary group is the shortest time to failure, defined as the interval between the start of operation and the point when a primary criterion is no longer met.  
Material selection can be determined through life cycle analysis of the structure, balancing the durability, mechanical performance, and resistance to aggressive environmentswith environmental concerns by choosing materials that have a minimal ecological footprint. At the same time, cost and social criteria--such as thermal comfort, esthetic value, and construction speed--must be considered. Optimal material selection results from the integration of ecological, economic, and social factors. LEED (Leadership in Energy and Environmental Design) standards specify that materials should be renewable, low-energy in production, and low-polluting, with minimal emissions of harmful substances throughout their lifecycle.  
The environmental impact of materials spans their entire life cycle--from resource extraction and transportation to manufacturing, on-site assembly, operation, maintenance, and end-of-life waste management. The production of construction materials and building processes requires significant energy and water consumption, generates large amounts of waste, contributes to greenhouse gas emissions, causes both indoor and outdoor pollution, and leads to the depletion of natural resources. Nearly 3 billion tons of raw materials are consumed annually for building construction. Additionally, energy is expended for the extraction, processing, transport, and assembly of materials. The energy consumption for structural material production can be expressed via a relative energy index, where wood is assigned a baseline value of \"1\". Comparative values for concrete, steel, and aluminum are presented in Table 2.  
The emission of harmful gases is represented using a relative carbon dioxide emission index, where the CO\({}_{2}\) emissions from wood production are assigned a baseline interactive value of \"1\". The corresponding relative emission values for the production of concrete, steel, and aluminum are presented in Table 3.  
Verification of load-bearing structures is conducted in accordance with current European structural regulations, which encompass the control of the Ultimate Limit State (ULS), Serviceability Limit State (SLS), and Durability Limit State (DLS) during the design, construction, and operational phases of the building.