Mechanical engineers are often called upon to design and specify systems related to emergency power generation for protection of life and property in facilities ranging from commercial buildings to hospitals, industrial facilities to mission-critical data centers. Another growing application is in combined heat and power or co-generation systems. While electrical engineers are often responsible for emergency or standby power systems themselves, many ASHRAE members will find themselves asked to design and specify the related auxiliaries, including fuel-oil systems, air-side systems, and engine cooling. Published guidance is somewhat scattered (see References) in various chapters of ASHRAE Handbooks, several NFPA Standards, and even in manufacturer’s literature - but it is not necessarily complete or in a format convenient for the day-to-day mechanical engineer called upon to design these systems. This conference paper reviews and consolidates the necessary features, functions, and design considerations for emergency generator mechanical auxiliaries into a single document format, intended for use by mechanical engineers needing a primer on the topic. Specific topics include fuel oil storage tanks and tank accessories; fuel oil piping, valves, and accessories; leak detection and monitoring systems; fuel oil transfer pumps; exhaust mufflers and piping; return oil coolers; local and remote radiators; and combustion air and radiator makeup-air design tips.