Safe working load
Also called SWL
The maximum load that a piece of equipment, mat, sling or lifting accessory is designed to carry safely, already incorporating an appropriate factor of safety. Safe working load should always be read together with the specific conditions it applies to — configuration, radius, ground support — since it is not necessarily a single fixed figure for every situation.
From our specifications
Our own range shows why the conditions matter as much as the number. The 25 ALIMATS® configurations are published at 38 t to 80 t safe working load, and each figure belongs to a specific build-up of one to five layers over a stated plan area — the same aluminium in a different configuration is a different rating. A safe working load quoted without its configuration is not a specification.
Source: alimat_configurations — the 25 published ALIMATS® configurations
Where it matters on site
Two habits do damage here. The first is derating a published figure “to be safe”, which double-counts a factor of safety that is already in it and quietly changes the plant that will fit the job. The second is treating spare capacity as available: a mat rated well above the reaction is not evidence the ground beneath it will take the pressure. Note also that lifting accessories are often marked with a working load limit (WLL) rather than an SWL; the two are used loosely in the trade and the marking on the item is what governs.