Mich. Admin. Code R. 408.4212 - Maximum allowable working pressure
TStE/RFS = Maximum allowable working pressure, psi
where TS = ultimate tensile strength of shell plates, psi.
t = minimum thickness of shell plate, in weakest course, inches
E = efficiency of longitudinal joint:
For riveted construction, E shall be determined by the rules based on the ratio which the strength of the joint bears to the strength of the solid plate.
For fusion-welded construction, E shall be determined by the rules applying to the class of welding used.
For tube ligaments, E shall be determined by the rules based on the ratio of the cross-sectional area of the ligaments to the entire section of the plate.
For seamless construction, E shall be considered 100%.
R = one half the insude diameter of the weakest course of shell or drum, inches
FS = factor of safety permitted by these rules.
Iron rivets in single shear .............. 38,000
Iron rivets in double shear .............. 76,000
Steel rivets in single shear ............. 44,000
Steel rivets in double shear ............. 88,000 When the diameter of the rivet holes in the longitudinal joints of a boiler is not known, the diameter and cross-sectional area of rivet shanks may be selected from table 1, or they may be ascertained by cutting out 1 rivet in the body of the joint.
SIZES OF RIVETS BASED ON PLATE THICKNESS
Thickness of plate, inches 1/4 9/32 5/16 11/32 3/8 13/32 Diameter of rivet after driving, inches 11/16 11/16 3/4 3/4 13/16 13/16 Thickness of plate, inches 7/16 15/32 1/2 9/16 5/8 ....
Diameter of rivet after driving, inches 15/16 15/16 15/16 1 1/16 1 1/16 ....
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