A User-Friendly Approach to the Calculation of Safety Factor for Pressure Vessel Design – A Case Study

The design, manufacture, and operation of pressure vessels is of great technological importance. The pressure vessels are designed and operated on the basis of the maximum safe fluid pressure, design stress, the material s breaking or flexural strength, and an adequate factor of safety (FoS). The users of pressure vessels generally have to rely on manufacturers’ information for the vessel’s safety. This case study reports how the user of a pressure vessel can independently calculate the factor of safety (FoS) based on the vessel’s operating and design parameters .The operating and the geometric design parameters of a fiberglass water-filter tank have been experimentally determined. A CAD software: SolidWorks was employed to develop engineering drawing for the water-filter tank; which enabled us to compute the internal radius of the pressure vessel; and the data so obtained is used to calculate the longitudinal and hoop’s stresses. The stresses have been graphically analyzed on the basis of various fluid pressures in the range of 390-700 kPa. The application of design formulae for the pressure vessel resulted in the computation of the design stress to be around 42 MPa . The calculation for FoS is based on flexural strength of fiberglass taken as 193MPa. The FoS value so obtained has been compared with the literature; and the safety, in the operation of the pressure vessel is confirmed.