MIL-HDBK-1022A
12.5.3
Control Systems. Pump houses and hydrant systems
typical of the Panero (circa 1952) and Pritchard (circa 1958)
designs utilize hard-wired, high-voltage mechanical relays.
Control systems installed from the pump house to the lateral
control pits, emergency stops, and pit activation switches are
typically high voltage. Age, elements, and exposure to fuels
may deteriorate control system wiring and render it no longer
reliable or safe to operate. Consider control system
replacement whenever a significant portion of the pump house
is repaired or when fire, safety, or electrical codes indicate
a hazard exists. Generally, hard-wired relay logic systems
are expensive to build and maintain and do not offer the
flexibility of PLC based systems. Control systems should be
of low voltage design incorporating industry standard PLCs.
If control facilities are isolated from the pump house (not
subject to atomized fuel) and the facility has positive
ventilation, then non-explosion proof fixtures may be
incorporated into the design. Existing control wiring has
probably deteriorated and numerous conduits are no longer
intrinsically safe. Replace control wiring and wherever
possible run control wiring in overhead conduit. If
necessary, replace kill switch and emergency stop circuits as
part of the pump house rehabilitation. Cable wiring systems
are easier to install and troubleshoot and should be
considered whenever the wiring to hydrant system is replaced.
12.5.4
Electrical Systems. Replace secondary electrical
systems, including lighting and motor conductors and motor
control centers, as part of pump house repairs. Ensure
circuits within the pump house, exposed to the possibility of
atomized fuel, comply with the provisions of NFPA 30 and are
classified Class I, Division 1. If the motor control center
is isolated from the pump house (not subject to atomized fuel)
and the facility has positive ventilation, then the area may
be derated and non-explosion proof lighting fixtures may be
incorporated into the design. Existing secondary wiring has
probably deteriorated and numerous conduits are no longer
intrinsically safe. Replace motor wiring and wherever
possible run control wiring in overhead conduit.
12.5.5
Lateral Control Pits. Lateral control pits are
typically concrete structures with heavy metal-hinged lids
containing valves, pumps, filters, and piping associated with
the supply of fuel from a pump house to a hydrant outlet.
Repair or replace pits to prevent the accidental release of
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