|Reg. 201, Reg. 202
Manholes and Mudholes in Flat Plates
Where a flat plate is flanged to stiffen it at a manhole or
sighthole, to permit same working pressure as would be allowed
upon an unpierced plate, the depth of the flange measured from
the other surface shall be at least equal to -
(T x W)1/2 = depth of flange in inches
T = the thickness of the plate in inches, and
W = the minor axis of the hole in inches.
Solid screwed stays
For screw stays to combustion chambers and fire boxes and for
longitudinal and cross stays the maximum working pressure for
the stays is to be calculated from the appropriate one of the
following two formulae :-
|W. P. =
|| (D - 1.28 /
|W. P. =
||C x D12
W.P. = the working pressure in lbs. per square inch.
D = the diameter of stays over threads in inches,
D1 = the diameter of body of stay at its smallest part in
N = the numbers of threads of stay per inch,
A = the area in square inches supported by one stay for area to be supported by stays near tubes in firebox tube plates
of locotype boilers, see Regulation
C = 7100 for steel or special wrought iron screw stays to
combustion chamber of fireboxes.
C = 8640 for steel longitudinal or cross stays fitted with
C = 4700 for copper screws stays to fireboxes.
Where stays are made with enlarged ends and the body of the
stay is smaller in diameter that at the bottom of the thread
the working pressure shall be calculated from the second formula.