Reg. 547 c, Reg. 547 d
wrapper plate sides shall preferably be tapered. The water
space at the bottom between the firebox and the shell
shall be not less than 2 ½ inches.
Where the firebox tube plate or firehole plate is flanged
for connection to the wrapper plate, the weld shall be
located between the commencement of curvature of the flange
and first row of screwed stays.
Rings for firehole mouthpieces or foundation rings shall
be made of mild steel.
Z Sections shall not be used for foundation rings. The
attachment of the firebox to the outer casing shall be
in accordance with Figures XII/29,
The method of attachment of firehole mouthpieces shall
be in accordance with Figure XII/32 or, where the outer
casing and the firebox plate are flanged towards the water
side to form the firehole, a ring of screwed stays located
at not more than half the average pitch of the stays distant
from the commencement of the curvature of the flanging
shall be provided (see Figure
Water-cooled combustion chambers
|The attachment of
the combustion chambers tube plates and back plates to
the wrapper plate shall be in accordance with Figure XII/17,
XII/18, XII/19, XII/20 and where the tube plate or back
plate is flanged for connection to the wrapper plate the
weld shall be located between the commencement of curvature
of the flange and the first row of screwed stays.
The method of attachment of furnace or flue tubes shall
be in accordance with figures XII/14, XII/15 or XII/16
and access openings shall be in accordance with Figure
XII/32 or XII/38.