unit; however, protection is not provided when
the electrodes are not immersed.
Annually, check the anode condition and replace
the anodes as necessary. Also, check the current
flow; if it has diminished since the previous
inspection, the anode probably needs to be
Annually, in freezing climates, protect
electrodes from ice, which may tear them from
their hangings or damage them. If ice formation
is severe, turn off the current, remove the
electrodes, store them until the freezing season is
past, and then reinstall them.
Annually, test the effectiveness of the cathodic
protection system in one of two ways.
1. Scrape and polish a spot on the tank wall at a
point always immersed. At quarterly intervals,
lower the water and inspect the spot; if
protection is adequate, the spot will remain
2. Suspend two polished mild steel test plates in
the tank at an elevation where they will always
be immersed (use No. 6 galvanized steel wire).
Ground one plate to the tank wall, but have the
other plate insulated from the tank. The extent of
corrosion on the grounded plate will come close
to the corrosion of the protected tank; the extent
of corrosion on the other plate is a measure of
the corrosion that would occur if the tank were
As pneumatic tanks are usually on smaller
installations, they may be too small for interior
inspection, except for observations through a
removable hand plate. The size, therefore, shows the
inspection procedures to be followed. Standard
inspection procedures are as follows:
Quarterly, inspect the air pump and motor to
make certain both are operating properly. Check
the operating record to determine the time cycle
of air pump operation. If the records show a
decreasing time cycle, check for possible air line
Quarterly, check valve operations; particularly,
check the pressure-relief valve. Repair or
replace as necessary.
Annually, check the tank for signs of
corrosion, both internally and externally. If
corrosion products are apparent, take the
1. If the tank is large enough to permit the entry
of personnel, paint the inside with corrosion-
resistant paint, or line it with cement. If the
tank is too small to permit entry, consider
changes in operation or in chemical treatment
to reduce corrosiveness of water. Corrosion is
most likely in areas alternately exposed to air
2. Paint the exterior as needed.
Every 6 months, ladders, walkways, guardrails,
handrails, stairways, and risers should be inspected for
rust, corrosion, poor anchorage, loose or missing
pieces, or other deterioration or damage. Standard
inspection procedures include the following:
Be sure to check ladders inside as well as outside
the tank. Replace worn, corroded, or missing
parts; check for deteriorated lugs and rungs as
necessary; and, make other repairs to ensure
safety for the operators. Check revolving
ladders on the roof for the condition of
connection at the final hookups.
Ensure that bolts, screws, rivets, and other
connections are tight.
Inspect the condition of the altitude valve
vault and the valves for proper operation.
Repair, clean, and paint all equipment when
Check the water level indicator for improper
operation and repair when necessary.
Inspect the cathodic protection equipment and
repair when necessary (follow instructions
given in previous portions of this chapter).
At semiannual intervals, check the electrical
connections to lights, cathodic protection,
and so forth, for breaks in the conduit.
Remove the conduit inspection plates and
examine the internal connections for tightness
and adequacy; also check relays for weak
springs, worn or pitted contacts, and defective
operation. Repair and eliminate all undesirable