3.4.5 Manual Trip (Emergency Shutdown)
A manual trip shall be provided to isolate all fuel sources. ...
Where existing field panels do not allow for safe access and egress during an emergency situation, or where the radiant heat from a heater fire may prohibit access, it is recommended to have a secondary manual trip outside of a 50 ft (16 m) zone. A design consideration is to install a manual quarter turn tight shutoff valve outside battery limits [> 50 ft (> 16 m)] clearly marked for emergency isolation.
A minimum of two emergency shutdown locations is recommended. Therefore, if a manual trip location outside of a 50 ft (16 m) zone is not available, then a remote manual trip from a continuously manned location (always recommended) such as a central control room may be required (e.g. DCS remote trip).