24 July 2003
including Change 1, Jan 2004 and Change 2, March 2005
4) Remove insulation and brickwork as designated by the inspector to determine the
condition of the boiler, headers, furnace, supports, or other parts.
5) Remove the pressure gauge for testing when required by the inspector.
6) Steam or hot water leakage into the boiler can be prevented by disconnecting the
pipe or chain locking the valves at the most convenient point or by other means
approved by the inspector.
7) Before the manhole or manholes are opened and the inspector enters any part of a
boiler connected to a common header with other boilers, close, tag, and preferably
padlock the required steam or water system stop valves and open the freeblow drain
valves or cocks between the two closed stop valves. Disconnect blowoff lines, where
practical, between pressure parts and valves. Open all drains and vent lines.
8) Before internal inspection is begun, the owner or user must determine that the boiler
is safe to enter, is adequately ventilated, and contains no harmful vapors. Applicable
safety rules and local regulations must be followed. A person should also stand by the
boiler all the time the inspector is inside.
With preparations complete, internal inspection begins with insulation and brickwork.
Removing boiler insulation material, masonry, or fixed parts for inspection is not
normally necessary unless defects or deterioration are suspected or are commonly
found in the particular type of boiler being inspected. If evidence of leakage shows on
the covering, the insulating material, masonry, or a fixed part of the boiler may require
removal to ensure a thorough inspection. Even drilling or cutting away parts may be
The boiler temperature must be low enough to ensure that inspecting personnel will not
be exposed to excessive heat. If a boiler has not been properly prepared for an internal
inspection, the inspector will decline to proceed. The inspector begins the detailed
internal inspection by first examining all exposed metal surfaces on the waterside of the
boiler for deposits caused by water treatment, scale, oil, or other substances. Oil or
scale in the tubes of watertube boilers or on the plates over the fire in any boiler is
particularly detrimental. It can have an insulating effect that can lead to overheating,
weakening, and possible metal failure by bulging or rupture. Since even the smallest
amount of oil is dangerous, immediate steps must be taken to clean the affected
surfaces and prevent further contamination, using chemical or mechanical means as
The inspector will examine all stays to determine whether or not they are in even
tension. All fastened ends will be examined for cracks. Stays or stay bolts not in
tension or adjustment must be repaired. Broken stays must be replaced. He will test
firebox stay bolts by tapping one end of each bolt with a hammer. Stay bolts with holes
will be examined for evidence of leaks, which indicate a broken or cracked stay bolt.
Broken stay bolts must be replaced.
Manholes and reinforcing plates, as well as nozzles or other connections flanged or
screwed into the boiler, will be examined both internally and externally. Whenever
possible, observation will be made from the inside to determine whether connections to
the boiler are properly made.