(2) The
external visual inspection and
testing must include as a minimum
the following:
(i) The tank
shell and heads must be inspected
for corroded or abraded areas,
dents, distortions, defects in welds
and any other conditions, including
leakage, that might render the tank
unsafe for transportation service;
(ii) The
piping, valves, and gaskets must be
carefully inspected for corroded
areas, defects in welds, and other
conditions, including leakage, that
might render the tank unsafe for
transportation service;
(iii) All
devices for tightening manhole
covers must be operative and there
must be no evidence of leakage at
manhole covers or gaskets;
(iv) All
emergency devices and valves
including self-closing stop valves,
excess flow valves and remote
closure devices must be free from
corrosion, distortion, erosion and
any external damage that will
prevent safe operation. Remote
closure devices and self-closing
stop valves must be functioned to
demonstrate proper operation;
(v) Missing
bolts, nuts and fusible links or
elements must be replaced, and loose
bolts and nuts must be tightened;
(vi) All
markings on the cargo tank required
by parts 172, 178 and 180 of this
subchapter must be legible;
(vii)
[Reserved]
(viii) All
major appurtenances and structural
attachments on the cargo tank
including, but not limited to,
suspension system attachments,
connecting structures, and those
elements of the upper coupler (fifth
wheel) assembly that can be
inspected without dismantling the
upper coupler (fifth wheel) assembly
must be inspected for any corrosion
or damage which might prevent safe
operation;
(ix) For
cargo tanks transporting lading
corrosive to the tank, areas covered
by the upper coupler (fifth wheel)
assembly must be inspected at least
once in each two year period for
corroded and abraded areas, dents,
distortions, defects in welds, and
any other condition that might
render the tank unsafe for
transportation service. The upper
coupler (fifth wheel) assembly must
be removed from the cargo tank for
this inspection.
(3) All
reclosing pressure relief valves
must be externally inspected for any
corrosion or damage which might
prevent safe operation. All
reclosing pressure relief valves on
cargo tanks carrying lading
corrosive to the valve must be
removed from the cargo tank for
inspection and testing. Each
reclosing pressure relief valve
required to be removed and tested
must open at the required set
pressure and reseat to a leak-tight
condition at 90 percent of the
set-to-discharge pressure or the
pressure prescribed for the
applicable cargo tank specification.
(4) Ring
stiffeners or other appurtenances,
installed on cargo tanks constructed
of mild steel or high-strength,
low-alloy steel, that create air
cavities adjacent to the tank shell
that do not allow for external
visual inspection must be thickness
tested in accordance with paragraphs
(i)(2) and (i)(3) of this section,
at least once every 2 years. At
least four symmetrically distributed
readings must be taken to establish
an average thickness for the ring
stiffener or appurtenance. If any
thickness reading is less than the
average thickness by more than 10%,
thickness testing in accordance with
paragraphs (i)(2) and (i)(3) of this
section must be conducted from the
inside of the cargo tank on the area
of the tank wall covered by the
appurtenance or ring stiffener.
(5)
Corroded or abraded areas of the
cargo tank wall must be thickness
tested in accordance with the
procedures set forth in paragraphs (i)(2),
(i)(3), (i)(5) and (i)(6) of this
section.
(6) The
gaskets on any full opening rear
head must be:
(i)
Visually inspected for cracks or
splits caused by weather or wear;
and
(ii)
Replaced if cuts or cracks which are
likely to cause leakage, or are of a
depth one-half inch or more, are
found.
(7) The
inspector must record the results of
the external visual examination as
specified in §180.417(b).
