Hydro Plant Risk Assessment Guide

Hydraulic Hoist
Items to examine or note from maintenance records with regard to the cylinders and hydraulic
system include: seals (rod), stem packing, gate drift, corrosion on cylinder rod or case, condition
of the hydraulic control panel (relief valves, check valves, four-way valve, lower/raise valve),
gate location indicating devices, hydraulic system leaks, condition of the hydraulic pumping unit
(HPU) and accumulators, condition of attachment mounts or beams, flexible hydraulic hoses,
hydraulic couplings, general coating condition where applicable, condition of the hydraulic fluid,
and replacement parts availability. Have the hydraulics been exercised on a regular basis
Results are analyzed and applied to Table 4 to arrive at an appropriate Gate Operator (Hydraulic
Hoist) Physical Condition Indicator Score.
Table 4 – Gate Operator (Hydraulic Hoist) Physical Condition
Hydraulic Hoist Condition
Results
Indicator Score
Seals, stems, cylinders, hydraulic piping/valves/controls, and gate
position indicators are updated or in good condition with replacement
parts available; coating is in good condition; hydraulic oil is in good
3
condition; hydraulic system has been tested and exercised regularly; no
gate drift while suspended from the cylinder. No external oil leaks.
Seals, stems, cylinders, hydraulic piping/valves/controls, and gate
position indicators are in good condition; protective coating is in
adequate condition; hydraulic oil condition is adequate; hydraulic
system has been tested and exercised regularly; no gate drift while
suspended from the cylinder.
Seals, stems, cylinders, hydraulic piping/valves/controls, and gate
position indicators are in adequate condition; coating is in adequate
condition; hydraulic oil condition is contaminated or hasn’t been tested;
hydraulic system has not been tested but is exercised regularly; no gate
drift while suspended from the cylinder.
Seals, stems, cylinders, hydraulic piping/valves/controls, and gate
position indicators are in poor condition; coating is in poor condition;
hydraulic oil condition is contaminated or hasn’t been tested; hydraulic
system has not been tested or exercised regularly; the gate drifts while
suspended from the cylinder. External oil leaks into the water.
2
1
0
Electric-Driven Mechanical Hoist
This section covers only fixed hoists. Items to examine or note from maintenance records
include: condition of wire rope/chain, condition of sockets on wire ropes, linkages, gearbox
condition, leaks, motors, brake condition and adjustment, motor controls, indicators, backup
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