Ergonomics done right.®
July 24th, 2012

Ergo Myth: You need to establish a lifting limit

Setting a facility-wide lifting limit is similar to establishing a single speed limit within a community.  As we know, the speed limit varies from neighborhoods and school zones to divided highways and expressways. A single speed limit would simply not be safe for all areas of the community. Likewise, a single lifting limit would not be safe for all material handling tasks.

Rather than assigning a designated lifting limit, facilities should determine the Recommended Weight Limit (RWL) for each material handling task using the revised NIOSH lifting equation.  The RWL is the principal output of the equation and is defined for a specific set of task conditions or specific workstation geometry.  Additionally, the RWL is the defined as the load weight that nearly all healthy workers could lift over a substantial period of time (e.g., up to 8 hours).

The RWL is calculated using the following six multipliers: horizontal multiplier, vertical multiplier, distance multiplier, asymmetric multiplier, frequency multiplier, and coupling multiplier. Since most of the multipliers are measured at the workstation, the revised NIOSH lifting equation can be used to assess existing workstations or in the design of new workstations.

Put the BREAKS on unsafe lifting limits!