in the main line. Where necessary, provide remote-operated
valves on storage tank inlet and outlet lines, suction and
discharge of transfer pumps, and transfer lines at fuel piers
and other locations.
Pump Controls. Operation of pump suction and
discharge valves may be a part of the automatic sequence for
the starting of a centrifugal pump and for shutting it down,
remotely, locally, or by a protective shutdown device.
Remote-operated valves can be either motor-operated or the
solenoid pilot-type, hydraulically operated diaphragm control
valves. Equip these valves with green and red (open and
closed) indicating lights at their pushbutton control
locations. Consider the use of PLCs on more complicated
Transfer Pumps. Parallel transfer pumps supplying
an issuing facility with varying demand flow rates must be
sequenced automatically by flow-sensing sequence equipment.
Lead pumps can be started by a pushbutton at an issuing
facility, or automatically by a pressure switch actuated by a
decrease in system pressure as might be caused by opening a
valve at the issuing facility. This method requires the
system to be pressurized at all times and is normally
incorporated in the Type III hydrant system design.
Incorporate the following control features:
a) Automatically controlled pumps with emergency
stop buttons with lock-key reset at issuing stations and at
the central supervisory control station.
b) Automatic shut-off of transfer pumps on loss of
suction or no flow for more than 3 minutes. Upon automatic
shut-off, a corresponding alarm at the central supervisory
control station is activated.
Provide the following controls:
a) A stop-lockout button at each remotely operated
pump for maintenance operation.
b) Indicator lights at the control station to give
positive indications both when a pump is operating and when it
is not energized. Use the "push-to-test" type.