SWL vs MBL

Safe Working Load is the maximum in-service load assigned to a piece of lifting or mooring equipment; Minimum Breaking Load is the load at which failure occurs in test conditions. SWL = MBL divided by a safety factor that depends on equipment type and applicable code — for general lifting under ILO Convention 152 the factor is 5; for mooring lines under OCIMF MEG4 the line design break force concept replaces the simple ratio with a more nuanced approach. Markings on lifting equipment must show the SWL clearly and unambiguously.