What Does Recommended Weight Limit (RWL) Mean?
A recommended weight limit (RWL), within the NIOSH lifting equation, is a measure used to define the maximum safe weight for specific lifting tasks. Adhering to the RWL is intended to prevent the risk of back injuries for most employees. The RWL is calculated using an equation that takes into consideration several variables beyond just the weight of the item to be lifted. As a result, the RWL may be less than the baseline weight or load constant (LC) that an individual can safely lift under ideal conditions. Recommend weight limits are an important value to consider when evaluating job design and assessing ergonomic risk factors in the workplace.
WorkplaceTesting Explains Recommended Weight Limit (RWL)
The Center for Disease Control and Prevention's National Institute for Occupational Safety and Health (NIOSH) defines recommended weight limits (RWL) based on an equation that incorporates several variables. This equation is referred to as the NIOSH lifting equation. The final value represent the amount of weight that can be safely lifted under the circumstances of the specific lifting tasks if performed over a full work day. For instance, most workers under ideal conditions can safely lift 51 pounds. However, if the individual must lift the load from the floor to chest level, then the lift becomes more difficult. In this situation, a worker is more likely to suffer a back injury or other harm if lifting similar loads throughout the entire work day.
As additional variables are included in the recommended weight limit equation, the total weight of the load must be reduced in order to prevent the risk of injury to the average worker. Six factors considered when calculating RWL. These variables include a horizontal and vertical multipliers representing the height and width of the lift zone and a distance multiplier representing the distance the load must be carried. Additional factors include the number or frequency of the lifts, whether the lift will be made at an angle, and how the load will be held. Numeric values for each of these variables are provided in charts created by NIOSH.