INDOOR ENVIRONMENTAL OPTIMAL DESIGN BY USING COMBINED DSS FOR QUANTIFIED AND FUZZY VALUES S.Milutinovic 1 and M.Manic 1 Faculty of Occupational Safety, Nis, Yugoslavia ABSTRACT The quality of indoor environment depends upon combined effects of architectural - constructive elements’ functions (for example: daylight level, thermal comfort, acoustical comfort, load - bearing capacity, aesthetic value, price, etc.). Those functions at the same time are defined by their parameters (geometrical parameters of the building elements, parameters of the building materials, etc.). We tried to optimize the choice of architectural - constructive elements and their parameters in order to optimize their functions and design procedure. The method we used is multiple criteria optimization using AHP method. Some of criteria (daylight level, illumination equability, PMV factor, asymmetric radiant temperature, price) can be quantified, and for some of them we suggested fuzzy values for optimization. The criteria that can be quantified are modeled by using different procedures. The combination of normal and fuzzy criteria demanded a procedure for fuzzy values ranking. The procedure we used is satisfaction function of fuzzy values. The ranking algorithm is developed and modeled. Developed software is flexible, combined tool for optimization in architectural design, usable in occupational and environmental safety. INTRODUCTION The design, as a phase of space creating, comprises defining and disuniting of contents - processes, which have been occurred in. decomposition of some construction into the complexes and construction elements demand the knowledge of their characteristics and functions. The principle of pre-safety comprises that all projected and built constructive elements and complexes must be in a function of occupational safety and fire protection. Because of that, the optimal demands for designing of architectural - constructive elements have to be reconciled yet in the phase of designing and construction of buildings, in such a manner that all necessary pre-safety and fire safety measures have to be satisfied. All that architectural - constructive measures have to be adjusted to technological processes, which will be occurred in that spaces, as well as the hazards and the injuries of that processes. THE SYSTEM APPROACH The quantitative and qualitative value of parameters, which define architectural - constructive elements and their behavior under the activity of external factors, defines the parameters of functions of those elements at the same time. It is well-known that the working conditions, as well as quality of workspace in the workrooms, depend upon functions of architectural - constructive elements. In current theory and practice, as well as in Yugoslavian occupational safety laws, constructive elements are internal and external walls, floor and roof constructions, daylight openings, door and the other.