portions of the boiler drums shall be insulated with 75 mm 3 inches
of suitable mineral wool blanket or block insulation. Manholes
and other inspection and access openings, identification plates,
and stamps shall have insulation finished neatly against a metal
ring provided for this purpose.
b.
Bridge walls exposed on all sides to radiant heat and to the
products of combustion shall be constructed of super-duty
refractory not less than 450 mm 18 inches thick, conforming to the
boiler manufacturer's requirements; walls having only the front
side exposed to radiant heat and to the products of combustion
shall have front facing and cap constructed of 225 mm 9 inches of
super-duty refractory and a back facing of not less than 225 mm 9
inches of low-duty firebrick. Base of the wall shall be common
brick.
c.
Settling chamber [, equipped with suitable means for frequent
cleaning without shutting down the boilers,] shall be provided
below the last pass of each boiler for the removal of fly ash.
d.
Expansion joints shall be provided where indicated and else-where
as required to permit all brickwork to expand freely without
interference with the boiler. Joints shall be of adequate width,
tightly sealed against leakage, and free from mortar, with the
outer 100 mm 4 inches sealed with resilient mineral wool suitable
for 930 to 1095 degrees C 1,700 to 2,000 degrees F. In addition,
to allow for expansion of the inner face, a series of 3.2 mm 1/8
inch wide vertical openings spaced 1.8 m 6 feet apart shall be
provided on the furnace side of the wall. Proper provision shall
be made for expansion and contraction between boiler foundation
and floor.
e.
Firebrick shall be laid up in air-setting mortar. Each brick
shall be dipped in mortar, rubbed, shoved into its final place,
and then tapped with a wooden mallet until it touches the adjacent
bricks. Mortar thick enough to lay with a trowel will not be
permitted. Maximum mortar joint thickness shall not exceed 3.2 mm
1/8 inch and average joint thickness shall not exceed 1.6 mm 1/16
inch.
f.
Plastic refractory shall be installed in accordance with the
manufacturer's recommendations and by workmen skilled in its
application.
2.2.3.4
Watertube, Waterwall (Packaged Type) Unit
Boiler setting, refractory, insulation, and casing shall be in accordance
with ASME BPVC SEC I.
2.2.4
Boiler Fittings and Appurtenances
Boiler fittings and appurtenances suitable for a steam working pressure of
[_____] Pa psig and [_____] degrees C [_____] degrees F shall be installed
with each boiler in accordance with ASME BPVC SEC I.
2.2.4.1
Water column
Water column with straight-through type drain valve shall be provided.
Water column shall be complete with gauge glass, high- and low-water alarm,
SECTION 15559A
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