24 July 2003
including Change 1, Jan 2004 and Change 2, March 2005
The inspector will request that you, as the owner, or your representative be present
during the inspection. He may request you or your representative to aid in any physical
tests necessary to evaluate the boiler's physical condition.
The inspector will begin by observing the condition of your entire boiler installation,
forming an opinion of the care the equipment receives. On entering the boiler area, he
will first inspect the boiler externally. The general cleanliness and accessibility of the
boiler and its auxiliary apparatus will be noted.
Boiler fittings, valves, and piping will be checked. Any steam or water leak-such as
leakage coming from behind insulation, coverings, supports, or settings-or any evidence
of leakage will be thoroughly investigated and any necessary corrective action pointed
out. You may be asked to remove insulation to locate the source of leakage or to
determine the extent of suspected corrosion.
POWER BOILER INSPECTION
External inspection of power boilers (operating pressures greater than 15 psig) is
slightly different from that of heating boilers. For power boilers, the inspector will
compare the pressure indicated on the pressure gauge with readings on other gauges
in the same system or, if necessary, with a standard test gauge. He will observe the
readings during tests, such as the reduction in pressure when testing the low water fuel
cutoff control. Defective gauges must be replaced.
Next, the inspector will observe the blowdown of the water gauge in the normal manner
and how promptly the water returns. A sluggish response may indicate an obstruction
in the pipe connection to the boiler, which must be corrected. During the water level
gauge test, water and steam connections will be blown separately to ensure both are
clear. The inspector will also determine that the boiler water level indication is accurate.
Safety valves come next. The inspector will check the nameplate data of the safety
valves to assure that they are ASME/National Board certified and that their relieving
capacity is sufficient to safeguard the boiler under full firing conditions. He will also
assure that factory seals have not been broken. If the set pressure does not exceed
400 psi, safety valves are tested by allowing the boiler pressure to rise to the popping
pressure and subsequently fall.
If checking the actual popping pressure and blowdown is not practical, the boiler
operator, while being observed by the inspector, will test the valve for free operation by
using the lifting lever, provided the boiler pressure is 75 percent or more of the set
pressure. This method is the only practical way to test multiple safety valves unless an
accumulation test is made.
At pressures above 400 psi, evidence must be shown that the valves were tested under
pressure or dismantled, overhauled, and tested and their popping pressures and
blowdown adjusted where necessary within a reasonable period of time acceptable to
the inspector. Your best assurance that the safety valves have been properly repaired
or refurbished is to have this work carried out by an organization that holds a National
Board "VR" (safety valve repair) certificate of authorization.