Automated Valves controlled by PLC - Safety


#1

Have safety question concerning line breaking activities on process or steam pipelines. Would like to know if it would be an acceptable practice to allow line breaking activities relying completely on automated valves controlled by software or plc logic? There is no exclusive control at the immediate area where personnel perform the line break and personnel are somewhat reluctant to use manual override that may be on the automated valve to ensure exclusive control and energy isolation. OSHA does have some limited guidance on this that would prohibit this activity relying of PLC that may not ensure effective energy control, Any feedback on this topic or possible recommended practices would be appreciated.