c.
Boiler is shut off.
Boiler dampers shall be operated by a controller-actuated motor based on
the [boiler steam pressure] [boiler water temperature]. Boiler and dump
stack dampers shall be reverse acting, i.e., when the boiler damper is
open, the dump stack damper will be closed.
2.3.9
Blowoff Tank
Blowoff tank [shall be constructed of 4000 psi reinforced concrete as
specified in Section 03300A CAST-IN-PLACE STRUCTURAL CONCRETE, and shall be
fitted with a bolted steel manhole cover and frame. Blowoff pipe, vent
pipe, and drain pipe to sewer shall be installed in pipe sleeves built into
the concrete. Space between the pipe and sleeves shall be filled and
caulked with lead wool or similar material to make a water-tight
connection. Tank shall be divided into two sections by a baffle to form a
sediment chamber] [shall be constructed of steel].
2.3.10
Boiler Feed Pumps
Boiler feed pumps shall be sized and designed for the specific application.
Pumps having a combined rating of flow and head that results in a
horsepower rating less than 186 kW 250 bhp shall be furnished to meet the
design requirements of API Std 610. The pump shall be either end-suction
or top suction, top-discharge and be supported at the center line. Pump
size with higher ratings than the above shall be horizontal-split case,
multistage centrifugal pumps. All pump ratings shall have, nominally, an
excess capacity of 10 percent above the maximum continuous rating of the
service. The required net positive suction head (NPSH) at the pump design
flow, head, and speed shall not exceed 80 percent of the available system
NPSH at the same flow, assuming a low level in the storage tank. The
guaranteed NPSH requirements shall reflect 3 percent breakdown criteria.
The pump's head-capacity (H-Q) curve shall be constantly rising to shutoff
with no point of inflection. There shall be no restriction to operation at
any point from continuous flow to design flow. Pumps shall be turbine
type, bronze fitted throughout, with impellers of bronze or other
corrosion-resistant metal as approved. Pump barrel assemblies shall be
fitted with lifting rings. Capacities and characteristics shall be as
indicated.
2.3.10.1
Casings
Casing construction shall be either volute or diffuser design and shall be
supported at its centerline. Pumps shall have integrally cast suction and
discharge flanges that shall be drilled to meet the design pressure of the
application. The maximum operating temperature, for design purposes, of
any feedpump shall not be less than 204 degrees C 400 degrees F. Casings
shall be drilled, tapped, and provided with vent, gauge, and drain
connections. Pumps designed for this service shall not require cooling at
ratings below 370 kW 500 bhp. This applies to both frame cooling or seal
cooling. Below 370 kW 500 bhp, pumps shall employ antifriction radial and
thrust bearings lubricated by flinger rings in a sealed housing. Seals
shall be mechanical and air-cooled flush piping conforming to API Std 610,
Plan 23. Above 370 kW 500 bhp, pumps shall employ a single cooling circuit
for both cooling and the oil being delivered by a forced-oil system to
sleeve radial bearings, and a floating shoe thrust bearing, coupled with
the seal coolers for both stuffing boxes. Mechanical seals shall also be
provided, and an extra seal replacement kit shall be provided for each
SECTION 15846A
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