CHAPTERl
I.
PERIODIC
INSPECTION
Insurance regulations or local
laws
will require a
periodic inspection
of
the
pressure vessel
by
an
authorized inspector. Sufficient notice
is
general-
ly
given
to
permit removal
of
the
boiler from
service and preparation
for inspection.
!WARNING
To avoid
the
hazard
of
electrical
shock,
which
could
cause
serious personal
injury
or
death,
we recommend the use
of
a low
voltage flashlight
during
an inter-
nal
inspection.
Preferably,
in-
spectors should
work
in pairs.
When
shutting down,
the
load
should be reduced
gradually
and
the·
pressure vessel cooled
at
a rate
that avoids damaging
the
temperature differen-
tial that can cause harmful stresses. Vessels
~hou!d
not
norm~lly
be
drained until
all
pressure ·
IS relieved
-agatn
to
prevent uneven contraction
and
temperature differentials that can cause ex-
panded tubes
to
leak. Draining
the
unit too quick-
ly
may
cause
the
baking
of
deposits that
may
be
present on
the
heating surfaces. Some heat, how-
ever,
may
be
desirable
to
dry out
the
interior
of
the
boiler.
If
the
internal inspection
is
being made
at
the
request
of
an
authorized inspector,
it
is
well
to
learn
from
him whether
he
desires
to
observe the
conditions prior
to
cleaning or flushing
of
water-
side surfaces.
Be
certain that a supply
of
manhole
and
handhole
gaskets
is available, along with
any
other gaskets
or items needed
to
place
the
unit
back
into opera-
tion after inspection.
Have available information on
the
boiler design,
dimensions, generating capacity, operating
pres·
sure or temperature, time
in
service, defects
75()..150
THE
PRESSURE VESSEL
found previously,
and
any
repairs or modifica-
tions.
Also have available for reference records
of previous inspections.
Be
prepared
to
perform
any
testing required
by
the
inspector including a hydrostatic test.
After proper cooling and draining
of
the
vessel,
flush out
the
waterside with a high pressure water
hose. Remove any scale or deposits
from
the
waterside surfacea
and
check for internal or ex-
temal corrosion
and
leakage.
The fireside surface
also should
be
thoroughly
cleaned so that metal surfaces, welds, joints, tube
ends, fittings and
any
previous repairs can
be
readily checked.
Be
sure that system valves
and
valves to expan·
sian tank (hot water), steam valves, feedwater
valves, blow-off valves,
all
fuel
valves, valves
to
expansion tank,
and
electrical switches are shut
off prior
to
opening bandholes, manhole, front or
rear doors,
and
crawlway plug. Adequately vent
the
pressure vessel prior
to
entry.
Qean out
the
low
water cut-off piping,
the
water
level controls and cross-connecting pipes.
Replace water gauge glass and clean out water
cocks and
tri...cock:s.
Also check
and
clean drain
and
blowdown valves and piping.
Check
all
water
and
steam piping
and
valves
for
leaks, wear, corrosion, and other damage.
Replace or repair
as
required.
CHAPTER 2·13
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