**2. Background**

Risk is a function of the probability and the consequence of an unwanted top event in terms of possible damage to a target (i.e., property, environment, and people) [7]. Many researchers attempt to integrate risk analysis into computer-aided design applications. Määttä studied the applications of the virtual environment to analyze the safety of new designs in a steel factory [8]. Abshire and Barron review real-world applications of virtual maintenance and present the provided facilities using the virtual environment and digital prototypes for Failure Mode Effect Analysis (FMEA) during the design process [9]. Gallego et al. implemented an interesting geometric risk assessment method using the linguistic variables for occupancy degree and occupancy time to model the number of people exposed to a harmful agent (HA) [10]. Hendershot uses contour maps to calculate the risk by superposing the impact zones and population distribution for 11 regions [11].

Many efforts are taken to model barriers as an essential concept that, due to their variety, is very difficult to be modeled in geometric forms. The barrier concept was initially based on the successive works of domino theory back in the 1930s, Haddon in 1966 and Gibson in 1961, which developed the idea of an accident as an abnormal or unexpected release of energy [12]. It identifies and evaluates the associated hazards of the harmful agents [13]. Barrier analysis contributes to the energy analysis and represents the barrier as the protector of the target from dangers [14]. When avoiding or eliminating the dangerous agent and hazards is impossible, the designer adds a series of safety barriers to reduce the risk of the undesired outcomes to an acceptable level [15]. Polet and Zhang et al. state that the barriers prevent events or accidents, resurrect the target, and mitigate the severity of adverse consequences [16, 17]. Hollnagel distinguishes the protector and the preventive barriers. It defines a barrier as the "equipment, constructions, or rules that can stop the development of an accident" [18]. The same idea is the origin of the bow-tie diagram when categorizing the barrier effects by prevention and mitigation effects [19].

Tinmannsvik et al. modeled an accident that occurs by failing control barriers, controlling the hazards, and defense barriers that protect the target due to the transformation of the latent failures to the realized losses [20]. Fithri et al. conducted occupational safety and health risk analysis in manufacturing companies using FMEA and FTA methods [21]. The proposed model by Choe and Leite describes accident causation and improves accident investigation methods [22]. With construction domain knowledge, they offered a safety risk generation and control model representing the dynamic safety risk.

Despite many efforts, modeling the material and immaterial barriers reminds the fundamental challenges of modeling the risk in 3D computer applications.

#### *Risk Analysis, a Fuzzy Analytic Approach DOI: http://dx.doi.org/10.5772/intechopen.108535*

Guimaraes and Lapa (a) and Guimarães and Lapa (b) used fuzzy inference systems to estimate risk priority numbers by aggregating the expert opinions in the failure mode and effects analysis (FMEA) method [23, 24]. Huang et al. developed a fuzzy set approach to integrating human error evaluation results in the event tree analysis [25]. Sadeghi et al. review the applications of design theories and methodologies and design tools and techniques to analyze and identify work situations to improve human safety in manufacturing system design [26]. Echeverri et al. (a) developed a design process's risk analysis models by considering technological and human factors and using essential functions and the production system's internal energy flow [27]. The proposed model integrated elements from the different design approach, considering cost, time, and performance, incorporating safety factors through energy functions and organizational rearrangements. Echeverri et al. (b) developed a multi-criteria design framework considering energy flow through components to characterize its behavior via Energetic Technical Functions [28]. Fargnoli reviewed the research addressing design for safety in the industrial context, focusing on those research approaches to integrate human factors within design activities [29]. He concluded that there is a research gap between theory and practice. He proposed a unified design for the safety process to support integrating human factors in design activities more practically.

The present paper introduces an analytic risk analysis approach by defining the danger, the target zones, and the effects of the barriers by geometric shapes.
