Non-Pigging Products
Standard Isolation Valves
Standard isolation valves are used to isolate the piggable sections from the non‑piggable sections of the transfer line.  For example, standard isolation valves would be used to isolate the adjacent supply and discharge lines from the main pigged transfer line. 
Utility Line Isolation Valves
Pigs movement is controlled by controlling the flow of compressed air or liquid being used to push the pig through the line.   Utility valves are mounted on lines supplying the air or liquid used to push the pig and on the lines used to vent the pigging system.    
Air Regulators and Drying Filters
When pig movement is controlled through the use of compressed air, a pressure regulator is needed to control the air pressure and volume.  Regulated air pressure will be used to control pig travel rates in both filled and empty transfer lines.  Since different pressures are needed for pushing pigs in filled lines vs. returning pigs to the pig launcher in an empty line, separate air pressure regulators are normally needed.  When pigging systems are exposed to cold environments, dry air is needed to prevent condensation and freezing of regulators and air operated components such as valve actuators.   Clean dry air is provided by the use of desiccant (water removing) and particulate removing filters.
Pressure monitoring gauges are needed to provide operators with a visual indication of the line pressures that exist in the system. Gauges are used by the operator to confirm that proper operating procedures have been completed and the system is depressurized before attempting to gain access to pigs.
Check Valves
Depending on system design and layout, strategically placed check valves assure that pigged products and residuals pushed from the line can not migrate back into the system from higher elevations.