TStE / RFS = maximum allowable working pressure psig
where:
TS = ultimate tensile strength of shell plates, psig
t = minimum thickness of shell plate, in the weakest course, in inches
E = efficiency of longitudinal joint:
For tube ligaments, E shall be determined by the rules given in section I of the ASME code.
For riveted construction, refer to the national board inspection code, 1998 edition.
For seamless construction, E shall be considered to be 100 percent.
R = inside radius of the weakest course of the shell, in inches.
FS = factor of safety permitted.
Nonstandard boilers with welded seams shall not be operated at pressures exceeding 15 psig for steam or 30 psig for water.
PSIG
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 rivets, after driving, may be selected from the following table, or as ascertained by cutting out one rivet in the body of the joint:
Table sizes of rivets based on plate thickness
thickness of plate-inch 1/4 9/32 5/16 11/32 3/8 13/32
diameter of rivet after driving-inch 11/16 11/16 3/4 3/4 13/16 13/16
thickness of plate-inch 7/16 15/32 1/2 9/16 5/8
diameter of rivet after driving-inch 15/16 15/16 15/16 11/16 11/16
Kan. Admin. Regs. § 49-51-3