24 July 2003
including Change 1, Jan 2004 and Change 2, March 2005
Alternatively, the owner or user may elect to make the actual popping test just
described. If the valve has a discharge pipe, the inspector will determine whether the
drain opening in the pipe is free to an atmospheric exhaust area.
When inspection reveals that a safety valve is leaking, sticking, or not opening and
closing properly, the boiler will be taken out of service. The valve must then be
replaced or repaired.
The inspector will next observe how the low water fuel cutoff or feed controls respond
when the drain is opened; he will check how promptly the system returns to normal, as
when the alarm or the feed pump stops. A sluggish response may indicate an
obstruction in the pipe connections to the boiler. If the controls, where provided, are
inoperative or the correct water level is not indicated, the boiler will be taken out of
service until the unsafe condition has been corrected.
Piping, connections, and fittings will also be carefully examined by the inspector to
ensure that there is provision for expansion and adequate support. Steam and water
piping and fittings will be examined for leakage. Any leakage or other defects must be
corrected. (To avoid water hammer, the locations of the various stop and drain valves
should not allow water to accumulate when the valves are closed.) Excessive vibration
will be noted and corrective action required.
Connections between individual boilers and the main steam header will be checked for
strain caused by the boilers' changing position due to settling or other causes. The
inspector will verify that all pipe connections and fittings are properly rated for the
service conditions they encounter. He will also observe the blowdown of the boiler in
the normal manner, check for freedom of the piping to expand and contract, and ensure
that there is no excessive vibration.
During all tests, the inspector will determine whether the actual operating and
maintenance practices he observes are acceptable. He will discuss any defects or
deficiencies in the boiler or in operating and maintenance practices with the owner or
user at this time and recommend corrections.
Since most internal conditions to be observed by the inspector are common to both
power and heating boilers, the internal inspection procedures are essentially the same
for both types. (Remember, when a boiler is to be prepared for internal inspection, the
water must not be withdrawn until the setting has been sufficiently cooled at a rate to
avoid damage to the boiler.)
The owner or user should follow these steps to prepare a boiler for internal inspection:
1) Draw off all water and thoroughly wash out the waterside.
2) Remove manhole and handhole plates, washout plugs, and inspection plugs in
water column connections as required by the inspector. Cool and thoroughly clean the
3) Remove all grates from internally fired boilers.