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Reg. 390 j
Ligaments between tube holes
| The ligaments between tube holes in the
heads of all types of fire-tube boilers and in shells
of water-tube boilers should be examined. If leakage is
noted, it may denote a broken ligament. |
Reg. 390 k
Steam Pockets
| Steam pockets on surfaces are sometimes
found in new or replacement work, and wherever this is
possible or likely the Inspector should make observation
and, if any are found, recommended the necessary changes. |
Reg. 390 l
Pipe Connections and Fittings
The steam and water pipes, including connections
to the water column, shall be examined for leaks, and
if any are found it should be determined whether they
are the result of excessive strains due to expansion and
contraction, or other causes. The general arrangement
of the piping in regard to the provisions for expansion
and drainage, as well as adequate support at the proper
points, shall be carefully noted. The location of the
various stop valves shall be observed to see that water
will not be pocketed when the valves are closed and thereby
establish cause for water-hammer action.
The arrangement of connections between individual boilers
and the main steam pipes shall be especially noted to
see that any change of position of the boiler due to setting
or other causes, will not produce an undue strain on the
piping.
It shall be ascertained whether all pipe connections to
the boiler possess the proper strength in their fastenings,
whether tapped into the boiler, a fitting, or flange riveted
to the boiler.
The Inspector shall determine whether there is proper
provision for the expansion and contraction of such piping,
and that there is no undue vibration tending to crystallize
the parts subjected to it. This includes all steam and
water pipe; and special attention should be given to the
blow off pipes with their connections and fittings, because
the expansion and contraction due to rapid changes in
temperature and water-hammer action create a great strain
upon the entire blow off system, which is more pronounced
when a number of blow off pipes are joined in one common
discharge. The freedom of the blow off connection on each
boiler shall be tested whenever possible by opening the
valve for a few seconds, at which time it can be determined
whether there is excessive vibration. Blow off pipes should
be free from external dampness to prevent corrosion. |
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