6. Availability of utilities required for
construction.
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1.3.1
Effective Radiant Heating Surface
Heat exchange surface, exclusive of superheat elements, which is directly
exposed to radiant heat of the flame on one side and to water or
water-steam mixture being heated on the other. Effective radiant heating
surface shall be calculated on the side receiving heat and shall consist of
plain or finned tubes and headers which may be bare, metal covered, or
metallic-ore covered. Refractory covered surfaces shall not be counted.
Computations shall be made as follows:
a.
Flat projected area of bare, metal covered, or metallic-ore
covered tubes and headers shall be considered as effective radiant
heating surface.
b.
Metal and metallic surfaces extending from tubes or headers shall
be considered to have an effective radiant heating surface equal
to 60 percent of their flat projected area except that the
following extended surfaces shall not be considered as effective
radiant heating surface.
(1)
Metal blocks not integral with tubes or headers.
(2)
Extended surfaces less than 6 mm 1/4 inch thick.
(3) That portion of the extended surface more than one tube or
header radius from the tube or header from which it extends.
(4)
Extended surfaces larger than 32 mm 1 1/4 inches.
c.
Flat projected areas of portions of first two rows of furnace exit
tubes that receive radiant heat from the fire shall be considered
as effective radiant heating surface.
1.3.2
Flue Gas Velocity
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NOTE: The maximum velocity to prevent erosion will
vary according to whether boiler is multipass or
single pass, the type of stoker and the type of
fuel. See DM-3.6, Table 4, Maximum Velocities (MPS
FPS) in Convection Sections for Coal, Wood or Solid
Waste Boilers.
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Velocity of the gas entering the convection section shall not exceed [10]
[15] [18] [23] meters per second (m/s) [35] [50] [60] [75] feet per second
(fpm).
1.3.3
FRP
Fiberglass reinforced plastic.
1.3.4
Furnace Volume
The cubic volume of the space provided for combustion of the fuel between
SECTION 15502N
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