Internal pressure: no. External pressure or other situations where there might exist longitudinal compressive stresses: the L/D ratio comes into the calculations, but there is no limit per se.
Sorry, I forgot that for dished head with a skirt, then the skirt (or flange) of head shall be calculated as a cylinder per UG-28. For the dished portion of head you use UG-33.
Firstly hubert, ASME Section VIII itself is not concerned with L/D ratio except when considering vacuum design. Check the formulae for thickness calculations. Secondly, the L/D ratio will, or should, result from process considerations and not just from a general guideline.
You’ve also not stated the function of the vessel. A slug catcher will likely have a different L/D ratio than a separator, or a compressor suction drum, for example. The process requirement will generally dictate whether a vessel needs to be long and skinny, short and fat, or vertical/horizontal.
What's the L/D of a sphere? Are we to design all spheres to a 3:1 ratio? And how, precisely would one do such a thing?
What's the L/D of a common household propane container - as with the 20 pound tanks usually used for grills in the US?
The ASME is a mechanical organization. Whether or not the container functions as the process engineer intended it to is not a concern for Section VIII. Sounds to me as though your client got some rule of thumb from a process engineering perspective and is now trying to ask "intelligent sounding" probing questions since he has little experience to base a conversation on.
Please see Pressure Vessel Design Manual by Dennis Moss 4th Edit. Procedure 2-16: Optimum Vessel Proportions and you can find L/D ratio 3, 4 and 5. The maximum volume for the least surface area, and weight..............and more.
Shipping clearances, lifting capacity, overhead crane clearances, available plate lengths and rolling capacities, available head sizes enter into it.
If there is no other criteria, specify volume only and let fabricators pick the most economical dimensions- which may vary from fabricator to fabricator, from place to place.
Industry practice for optimum dimensions for horizontal and vertical vessels, at least from a cost perspective, is for L/D to range from a minimum of 3 to a max of 6 - this is usually applied to vapor liquid separators and gas scrubbers. Higher L/D (approaching 6) leads to a lower plate thickness and easier fabrication in most cases.