Furnaces in general
||No furnace or firebox top,
whether plain or corrugated, shall exceed 7/8 inch in
thickness, and all circular sectioned furnaces when new
shall be as near the truly circular form as the type of
joint will permit.
||The use of Z angle rings for
furnace foundation seems shall be prohibited.
||As an alternative to riveting
furnaces, furnace crowns, uptakes and other plates not
in tension may be jointed by fusion welding provided the
conditions laid down in Regulation 122 to 129 are complied
with. The end connections of such plates to the shell
or shell crown shall also comply with such conditions.
This construction shall not apply to furnaces of Lancashire
and Cornish type boilers consisting wholly of plain sections.