Question: 

• What reference substantiates the calculation method used for lifting lugs on AutoPIPE Vessel's Vertical Pressure Vessels (top head or cone lugs)?

Answer:

• Lug shear checking around the hole and welds checking are based on CM66.
• Lug shear checking around the hole verifies that the lug plate material surrounding the pin hole can resist shear and bearing stresses without tear-out or excessive deformation, while weld checks ensure the attachment welds can safely transmit the lug loads into the vessel; both evaluations are performed using the CM66 methodology, which provides conservative allowable stresses and failure criteria for vessel lug design
• What is CM66?  “Règles de Calcul des Constructions en Acier (CM 66)” (Rules for the Calculation of Steel Structures). A widely accepted reference for lifting lugs, support lugs, and vessel attachments.