Dear Richard & Dave
I found two allowable equations in US unit & SI unit _ API 617 for COMPRESSORS
US unit 3F+M<=927D where F_lb, M_lb-ft, D_inch
SI unit F+1.09M<=54.1D where F_N, M_N-m, D_mm
I tried to convert from US system to SI system but I didn’t get that above equation.
But I manually calculated with both the formulas, both the results (% of Allowable) are matching.
What is the technical background of those equations, why conversion is not possible?
please correct me, if I am wrong.
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Thanks,
Durga