SWL (Safe Working Load)
The maximum load a piece of lifting equipment, rigging gear, or crane component is certified to lift in service, set as a fraction of the equipment’s ultimate breaking load.
SWL — Safe Working Load — is the maximum load that a piece of lifting equipment or rigging is certified to lift in normal service. It's set by the manufacturer or a competent person as a fraction of the equipment's ultimate breaking load (UBL) or proof load, with the ratio (the design factor) chosen to give a safety margin against the worst-case combination of dynamic loading, wear, and material variability.
The term SWL applies to discrete pieces of equipment: a single sling, shackle, hook, beam, or fitting. The crane itself doesn't have a single SWL — it has a load chart, which gives a different rated capacity at every configuration (see the load-chart entry). When you see SWL on a piece of rigging or a beam, that number is the maximum mass that piece is rated to carry, full stop.
Modern industry terminology has largely replaced SWL with WLL — Working Load Limit — to make the distinction between the rated working load and an operator's working-out of a "safe" load in a specific context. WLL is identical in meaning to SWL but the language signals that the number is a manufacturer's static rating, not a guarantee that any lift up to that mass is automatically safe. In rigging documentation you'll see both terms used; treat them as equivalent.
For Kranly buyers, the SWL or WLL stamping on slings, shackles, and other rigging accessories is what makes them legally usable in a lift. Unmarked rigging is not usable; missing or worn-off markings should be replaced or the gear retired.