Process safety exists throughout the lifecycle of the device, including but not limited to design, commissioning, normal production, and shutdown maintenance stages. This chapter focuses on the principles that process professionals should follow during the design stage. By analyzing and studying the device, installing safety protection devices, and formulating related operating procedures, the safety of operators and the normal operation of production devices can be ensured. For other safety and health issues, such as ignition source control, device layout, gas detection systems, fire detection systems, sound and light alarm systems, forced ventilation systems, fire systems, noise control, and escape evacuation channels, etc., refer to relevant safety professional literature, which is not repeated here.