Manual Handling of Loads (MMC), refers to the activities of carrying, supporting, lifting, storing, pushing and pulling a weight by one or more workers.
The Employer must carry out the Manual Handling of Loads Risk Assessment (MMC DVR), analyzing the activities that may lead to the occurrence of lower back disorders.
The MMC DVR must be prepared taking into consideration certain factors including, for example:
- Work environments
- Load characteristics
- Individual factors
- Physical effort required
- Rhythms, frequency and resting times
Based on the findings that are made in the workplace, we go on to further the assessment with the most suitable methodology.
The following are the most well-known and widely used methods of evaluating Manual Handling of Loads.
UNI ISO 11228 STANDARDS AND RISK ASSESSMENT OF MANUAL HANDLING OF LOADS, PUSH-PULL AND REPETITIVE MOVEMENTS
UNI ISO 11228-1 “Ergonomics – Manual handling – Part 1: Lifting and moving.”
With regard to the assessment of risk from manual handling of loads, the UNI ISO 11228-1 standard suggests an approach similar to the well-known NIOSH (1993) method, comparing, for each lifting action, the so-called Recommended Maximum Weight to the weight actually handled, through an equation that, starting with a maximum liftable weight under ideal conditions, considers the possible existence of unfavorable work factors by introducing into the equation multiplicative factors that for each factor considered can take on values between 0 and 1.
The risk factors considered in the UNI ISO 11228-1 standard and the NIOSH method correspond to the main occupational risk elements mentioned in Annex XXXIII of Legislative Decree 81/08.
UNI ISO 11228-1 proposes various initial weights in relation to the intended population of users (males, females, adult workers, special workers). For the application of the method generally 25 kg for men and 20 kg for women are considered as maximum ideal weights.
UNI ISO 11228-2 “Ergonomics – Manual handling – Part 2: Pushing and pulling.”
Regarding the assessment of risk due to pulling-pushing actions, UNI ISO 11228-2 provides guidance for the assessment of risk factors considered relevant to manual pushing and pulling actions, and provides two assessment methods: a “general” method and a “specialized” method.
The so-called “general” approach can basically be traced back to the “Snook Ciriello” method and is based on the use of experimental table-tables from which to derive recommended limit values to be compared with measured values of towing and/or pushing actions. This method for assessing the risk associated with push-pull actions requires being able to measure the force required to carry out such activities.
The “Specialist” Method is a complex method that allows for assessment based on the demographic and anthropometric data of the population under consideration. Because of its complexity, it is in fact a method of little practical use.
MEASUREMENTS FOR ASSESSING THE RISK FROM TOW-PUSHING (THE DYNAMOMETER)
The dynamometer, a force-measuring instrument, is used for the measurement and evaluation of efforts that produce exposure to the risk of biomechanical overload of the musculoskeletal system (and in particular of the spine), such as the actions of pulling, pushing and carrying on the plane, as well as those of lifting and/or lowering loads.
UNI ISO 11228-3 “Ergonomics – Manual handling – Part 3: Handling of small loads with high frequency.”
ISO 11228-3 and ISO TR 12295 deal with risk assessment of repetitive movements.
The methodology normally applied for risk assessment of repetitive movements consists of two phases: the first phase consists of initial screening based on the use of a check-list proposed by ISO TR 12295, and if necessary, the second, more detailed phase is continued, which refers to established and complex internationally recognized methods of analysis, with an expressed preference for the OCRA (Occupational Repetitive Actions) Method.
Such analysis requires specific verification of all “micromovements” made, which can be carried out using video footage.
