It has been observed that the degree of contact between layers and the reside stresses caased by pre-tension winding of ribbons does not influence bursting pressure of flat steel ribbon-wound pressure vessels. This suggests the idea that the desirzble design criteria for vessels of this type should beaed on bursting failure made. Le. wall thickness, should be determined by bursting pressure which it strongly influneces by friction between layers and laminar effects, It is shown that the probabiliry of bursting failure of vessel for which the bursting pressure is not Iess than 2.5 dedgm pressure, is less than 10-10. An example demonstrates that a design procedure basent on this information not only has significant economic advantages, but also can indi. care bursting probability.