61:08:05:17Computation of maximum allowable working pressure -- Nonstandard boilers.

Nonstandard boilers with welded seams may not be operated at pressures exceeding fifteen psig for steam or thirty psig for water. The maximum allowable working pressure for a nonstandard boiler without welded seams must be computed according to the following formula: (1) The maximum allowable working pressure for nonstandard boilers is a function of the strength of the weakest section of the structure. The strength is computed by multiplying the ultimate tensile strength of the shell plate, psig, by the minimum thickness of the weakest course of shell plate, in inches. This sum is then multiplied by the efficiency of the longitudinal joint as specified by subdivision (2) of this section. The result of this calculation is then divided by the product of the inside radius of the weakest course of the shell or drum, in inches, multiplied by the factor of safety permitted by § 61:08:05:17.04. The final result of this calculation indicates the maximum allowable working pressure in psig; (2) When stated symbolically, this formula reads: TStE = maximum allowable working pressure, psig RFS where: TS = ultimate tensile strength of shell plates, psig. t = minimum thickness of shell plate, in weakest course, in inches. E = efficiency of longitudinal joint: For tube ligaments, E is determined by the rules given in section I of the ASME Boiler and Pressure Vessel Code, July 1, 2021. For riveted construction refer to the ASME Boiler and Pressure Vessel Code, July 1, 2021. For seamless construction, E is considered one hundred percent. R = inside radius of the weakest course of the shell, in inches. FS = factor of safety permitted.

Source: SL 1975, ch 16, § 1; 8 SDR 87, 8 SDR 134, effective July 1, 1982; 12 SDR 151, 12 SDR 155, effective July 1, 1986; 30 SDR 48, effective October 16, 2003; 50 SDR 47, effective October 16, 2023.