  About Central Boilers Board •Contents Chapter Wise • Contents Regulation WiseIndian Boilers Act 1923 Reg. 184
SHELLS

Spacing of rows of rivets

a) In joints, whether lapped or fitted with butt straps, in which there are more than one row of rivets and in which there is an equal number of rivets in each row, the distance between the rows of rivets shall be not less than-

Zig-zag riveting :-
 0.33P + 0.67D = distance between centre lines of rows (R) Eqn. (12)

Chain riveting :-
 2D = distance between centre lines of rows (R) Eqn. (13)
b) In joints in which the number of rivets in the outer rows in one-half of the number in each of the inner rows, and in which the inner rows are chain rivets the distance between the outer rows and the next rows shall be not less than as required by equations (12) and (13) whichever is the greater, and the distance between the rows in which there are the full number of rivets shall be not less than 2D(R1).
c) In joints in which the number of rivets in the outer rows in one-half of the number in each of the inner rows and in which the inner rows are zig-zag, the distance between the outer rows and the next rows shall be not less than-
 0.2P + 1.15D = distance between centre lines of outer and next rows (R) Eqn. (14)

The distance between the rows in which there are the full number of rivets shall be not less than :-
 0.165P + 0.67D = distance between centre lines of inner rows (R1 ) Eqn. (15)

Where
P is the pitch of the rivet in the outer rows.

D is the diameter of the rivet holes in inches or the mean of the diameter of rivet holes when the distance to be determined is between two rows of the different diameters.
d) Should the distance between rows of rivets be less than as prescribed above the plate percentage determined by equation (2) shall be modified thus –

100 [ P - (     2 -       actual distance       )           D ]
prescribed distance
= modified plate percentage
P                                                                 Eqn. (16)
e) In all cases the clear space between a rivet hole and the edge of a plate shall not be less than the diameter of the rivet holes, i.e. the centre of the rivet hole shall be at least 1-1/2 diameters distant from the edge of the plate (E);

Provided that if this condition be not observed, the strength value of the rivet affected shall be reduced in the proportion of the actual distance between the outer edge of the rivets and the edge of the plate to the prescribed distance     About Central Boiler Board Foreword • List of Amendments Ibr Forms • Home • Search • Help • Contact Us