This technical report sets forth a framework for describing service conditions for actuators and their accessories (i.e., solenoid valves, limit and proximity switches, positioners, etc.). The document identifies common hazards (i.e., thermal stress, pressure extremes, chemical exposure, mechanical shock and vibration, etc.) and service conditions; it identifies common approaches to reduce the risk of each hazard (i.e., material selection, coating selection, etc.); and it identifies common technical industry standards that may qualify devices as resistant to the hazard.

This framework may be applied to:

• actuator design specifications

• the mounting hardware required to affix the actuator to the valve

• the accessories that monitor and adjust actuator position

Excluded from this framework are recommendations specific to nuclear applications, which have detailed specifications that require each actuator design to be qualified to one or more environmental extremes such as acceleration and vibration from seismic events, radiation exposure, submersion, and extreme temperatures.

This technical report does not replace or supersede user specifications for each application. Users should specify details for each application environment (i.e., specifications that include ingress hazards, hazardous area classification, certification requirements, and other local conditions such as ambient temperature range, humidity, seismic requirements, etc.) and for actuator performance (i.e., design type, safety factor, travel speed, fail position, override options, etc.), along with any documentation requirements (i.e., material certifications, sizing calculations, etc.).