Security is one of the crucial challenges in the design and development of IoT applications. This paper presents an approach that focuses on existing security standards to evaluate and analyse the potential risks faced by IoT systems. It begins by identifying system assets and their associated vulnerabilities and threats. A list of security objectives and technical requirements are then defined to mitigate the risks and build a secure and safe system. We use our approach to assess risks in the robotic system for supporting the movement of loads in a warehouse."