the hot gases generated by the associated combustion equipment. Hot gases
shall be drawn [through] [over] the tube banks by an induced draft fan.
Gas flow shall be controlled by a system of automatically actuated dampers
that will route the hot gases through the tube section and out the stack as
required to satisfy the operational procedures. Boilers shall be [either]
[fire-tube] [or] [single or multiple drum, bare-tube, water-tube, natural
circulation]. Sootblowing systems with coordinated controls shall be
provided.
2.1.3.1
Radiant Heating
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NOTE: The following is a guide to determine maximum
radiant heat release:
Boiler Type
Maximum kW/square meter
Controlled circulation
water-tube boilers 394.3
water-tube boilers 315.5
Fire-tube boilers 315.5
Boiler Type
Maximum Btuh/sq ft
Controlled circulation
water-tube boilers 125,000
water-tube boilers 100,000
Fire-tube boilers 100,000
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The maximum effective radiant heating surface shall be limited to [_____]
[_____] kW/square meter Btu input per square foot/hour.
2.1.3.2
Combustion Gas
The combustion gas temperature at the furnace exit (boiler entrance) shall
be a minimum of 56 degrees C 100 degrees F less than the ash fusion
softening temperature (reducing atmosphere) of any ash contained in the
fuel. For boilers attached to waste incinerators this shall not exceed
1093 degrees C 2000 degrees F.
2.1.3.3
Radiant Heating Surface
Effective radiant heating surface for water-tube boilers shall include the
flat projected area of bare, metal covered or metallic ore covered tubes
and headers, 90 percent of the flat projected area of extended metal or
metallic surfaces from the tubes, and the flat projected area of those
portions of the first two rows of exit tubes receiving radiant heat from
the fire. The flat projected area is defined as the external diameter
times the length of the tube. The flat projected area of the extended
surfaces shall not include the metal blocks not integral with tubes,
extended surfaces less than [_____] mm inch thick or more than [_____] mm
inch in length, and the portion of the extended surface which is more than
one tube radius from the tube from which it extends. For fire-tube steel
firebox boilers it shall be the total water-backed area within the furnace
boundaries exposed to the flame. The mean circumference shall be used for
corrugated crown sheets.
SECTION 15846A
Page 19
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