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Reg. 186
SHELLS
Compensation for Manholes and other openings
The percentage of compensating section shall be determined by
the following formulae:-
| 200(W - D) x Tr
|
= Percentage strength
of compensating section |
Eqn. (18) |
| (L + 2D) x Ts |
| 80 x A x N
|
= Percentage strength
of rivet section |
Eqn. (19) |
| (L + 2D) x Ts |
Where
W is the width of compensation ring in inches measured in the
direction of the longitudinal axis of the boiler,
L is the length of opening in shell in inches measured in the
direction of the longitudinal axis of the boiler,
D is the diameter of rivet holes in inches,
Tr is the thickness of compensation ring in inches,
Ts is the thickness of shell plate in inches.
A is the area of one rivet hole in inches,
N is the number of rivets on one side of the longitudinal line.
When the rivets are in double shear 1.875 times the single rivet
section shall be allowed.
Parts of raised manhole mouthpieces within four inches of the
shell shall, in addition to the ring, be included in the compensating
section. |
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