Automatic block valve

Can anyone share philosophy of Automatic Block Valve and emergency block valve?
What are considerations in view of piping design.?
Back in the day (before I retired) we used to call these "ESV" (Emergency Shut-Down Valves).
These were normally the standard line class block valve fitted with a rapid action motor or pneumatic operator.
The valve, the operator and the control cables were covered with fireproof insulation.

In an emergency these valves would either close or open (as required) automatically and the plant would be shut-down. 
Automatic block valve can act as your first layer of protection and once
the alarm condition is reached (e.g. high level), the valve is shut by
means of a software interlock.

The emergency block valve would
act as your final layer of protection and the valve should be shut by
means of a separate hard-wired interlock.

You can have the same
valve performing both applications. e.g. A high level from a level
transmitter will shut the valve. If this instrument fails, a separate
high high level switch will shut the valve.

I have also seen an
application where the above 2 functions are performed by the same valve
by having 2 different solenoids each receiving a different signal.
Many plants use gate valves for isolating units at the battery limits
etc.  Large gate valves require many turns of the handwheel to
open.  Automated valves may use electric actuators to permit remote
operation.  An operator may also push buttons to open or close such
valves.  Usually a manual hand wheel is also provided as an override
when power is lost.  Such a valve would fall into the automated
isolation valve description.  Some quarter turn pneumatic valves are
also operated using a vane actuator (perhaps gas over oil with stored
energy) or double acting pneumatic actuator (perhaps with an air storage
cylinder and double check valves on the supply).  Lacking a spring
these automated valves would not be suitable as emergency shutdown
valves.

A pneumatic actuator on a quarter turn ball or butterfly
valve is more common for an emergency shutdown valve.  The emergency
shutdown valve should be able to close with no power or air supply.

From the originalgatevalve
.