Over the years, in general safety and reliability areas various risk assessment methods and safety standards have been developed and only few of them defined appropriate to human robot interaction field. In this paper we integrating several approaches related to risk estimation and safe design of human centered robotic workcell. Analyzing various concepts and results in areas: Human factor, hazard analysis, risk assessment, safety technology, we conclude with several ideas about how aspect of safety in the field human robot interaction could me provided and enhanced.