COSTEFFECTIVENESS OF ERGONOMIC INTERVENTIONS IN PRODUCTION DE LOOZE MP1

COSTEFFECTIVENESS OF ERGONOMIC INTERVENTIONS IN PRODUCTION DE LOOZE MP1
USING COSTEFFECTIVENESS ANALYSIS TO EVALUATE TARGETING STRATEGIES THE CASE



SUBMISSION GUIDELINES FOR FULL PAPER – NES 2007

Cost-effectiveness of ergonomic interventions in production

De Looze M.P.1, Koningsveld E.P.A.1, Fritzsche L.2, O’Sullivan L.3, Levizzari A.4


1TNO, The Netherlands, 2Daimler AG, Ulm, Germany,

3University of Limerick, Ireland, 4Centro Ricerche Fiat, Turin, Italy

E-mail: [email protected]


Ergonomic measures to reduce or eliminate the risks for developing musculoskeletal disorders, usually affects the performance at work as well, e.g. productivity or quality. The costs and benefits that can be associated with ergonomic measures are highly diverse in nature. Prior to investing in any ergonomic measure, it is useful to be aware of all costs and benefits. The benefits in particular are often hard to predict.

This paper describes an Internet-based software interface that might be of help for the production line manager or industrial (cost-) engineer. It guides him to an ergonomic measure that is relevant for his specific situation, and gives support in assessing all the relevant costs and benefits.


Key-words: cost-benefit analysis, production industry, ergonomic measures



  1. Introduction


The presence of risk factors for developing musculoskeletal disorders in the production industry, particularly where products are manually assembled, are well recognized in the ergonomics literature. Among these are: awkward body postures, high repetitions, monotony of activities, limited rest breaks, and high force exertions (Buckle and Devereux 2002).

Ergonomic interventions should be focused on the elimination of these factors. Meanwhile, to increase the probability of interventions to be implemented, they should not interfere with performance parameters like productivity, efficiency, quality or order lead time. Obviously, the ergonomic interventions creating a win-win situation by not only reducing risk factors but also increasing performance, are highly preferred. Examples of such interventions have been described in the production and ergonomics literature (e.g. Rhijn et al. 2002, Oxenburgh 2004)

For production managers, it is most relevant to be informed about all the potential benefits prior to buying and implementing any ergonomic intervention. Only then they can make a proper cost-benefit analysis on which a decision can be based.

To predict (prior to implementation) to what extent ergonomic interventions would reduce the presence of risk factors, is not too difficult in many cases. It becomes more complicated however to asses any effect of the intervention on the potential benefits related to decreased absenteeism and disability. Similarly, it is not straightforward in practice how and to what extent performance might be affected by ergonomic interventions.

Many models to analyse the cost effectiveness of ergonomic interventions have been developed. The application of these in practice is quite limited however due to the complexity of the models and the time requirements to gather the right data meeting the model’s specifications (Koningsveld et al. 2005).

This paper describes a cost-benefit tool that is easily applicable and helps people from the production industries (managers, engineers) to make the cost-benefit analysis required to make a well-based decision, prior to investing in any ergonomic measure. The tool has been developed within the EU project CyberManS in collaboration with some large European automotive companies.



  1. Objectives of the tool


The tool has been developed for the production industries where products are (partly) manually assembled. These products may concern small, medium-sized to large products (let’s say from shavers, coffee machines to cars).

It was the intention behind the tool that the target user group consisting of pruction (line) managers, production planners, industrial (cost) engineers, would be able to apply the tool independently, without the help of any health&safety specialist or ergonomic expert. This implies that the tool gives no answer to in-depth questions, but instead should be considered as a first scan into the problem, the potential (ergononmic) solution and the costs and benefits involved. The tool is specifcally focussed on problems that are related to the exposure to risks for developing musculoskeletal disorders. The tool will be accessible by the Internet in 2009.


The tool helps the user:

By doing so, the tool may serve several goals:



3. Description of the tool


Figure 1 presents the opening page of the tool and the general structure of the tool. The choice of analysing the own case or considering example cases is illustrated as well as the various steps when analysing the own case, namely (i) specifying the problem/risk, (ii) presenting the possible solutions and (iii) making the cost and benefit analysis.


To help the user to specify his problem, the user has to indicate whether the problem that is experienced concerns the body posture (static or repetitve) or some type of manual maetrials handling. Within both categories, the problem is specified by indicating which sub-categories are present (e.g. bended or twisted trunk, elevated arms, bended or twisted neck and/or lifting, carrying, pushing, pulling, hand tool use).

In the next step, the information that is required to make a first risk-evaluation on the basis of the existing guidelines (e.g. ISO11226, ISO11228, NIOSH lifting equation) is asked for. An example is shown in figure 2, where the required information is asked in order to evaluate the risk associated with a static or repetitive, bended or twisted trunk posture.

COSTEFFECTIVENESS OF ERGONOMIC INTERVENTIONS IN PRODUCTION DE LOOZE MP1

















Figure 1. Structure of the tool


COSTEFFECTIVENESS OF ERGONOMIC INTERVENTIONS IN PRODUCTION DE LOOZE MP1


















Figure 2. Information sheet to be fiilled in in order to make first-order risk assessment


As soon as the problem is defined and the risk is evaluated as being ‘yellow’ or ‘red’, a list of ‘solutions’ is presented to the user. These might concern organizational changes (like job rotation), modifications of work stations, or the introduction of ergonomic aids (see some examples in Figure 3).


COSTEFFECTIVENESS OF ERGONOMIC INTERVENTIONS IN PRODUCTION DE LOOZE MP1

COSTEFFECTIVENESS OF ERGONOMIC INTERVENTIONS IN PRODUCTION DE LOOZE MP1

Figure 3a. Equipment by which a product can be moved off line, turned and lifted

Figure 3b Modified workstation (cockpit) by which materials are brought within easy reach of the worker


For the selected solution, the tool supports the user to make a cost-benefit analysis. In five steps, the information is gathered to make the overview of costs and benefits.


1. General input information

In this step, it is important that the production area is defined. Here, the area on which the cost-benefit analysis will be performed is limited to a specified number of individual work stations lines or cells. In addition some general information is asked for, like:


2. Investments, depreciation, grants & operational costs

Next, all required investments and potential costs associated with the selected ergonomic measure are addressed. The tool presents the categories such that no item will be forgotten. The user fills in the estimated values. Among the categories are consultancy costs, decision process costs, purchases, installation costs, training costs, depreciation costs per year, interest costs, funding and costs to acquire funding, maintenance costs, energy costs, and consumables


3. Benefits - productivity & quality

The third step addresses the productivity and quality benefits that can be expected to happen if the ergonomic measure is implemented.

Here the effect on productivity is estimated from the time required to make a product, the expected time gain per product, and the percentage of time gain that can be used as added value time.

Likewise, the effect on quality is estimated from the total rework time required, the expected time gain and the percentage of time gain that can be used as added value time, in addition to other quality costs, e.g. call back of orders).

Here, it might be difficult for the user to estimate the time gain (or loss). The tool invites the user to think of any potential (positive or negative) productivity effects, which does not always happen in practice. Moreover, the user may look into the case examples for some support.

4. Occupational Health

To estimate the (reduced) costs associated with the ergonomic intervention, the user has to estimate the level of change in the physical and mental work load on a 5-point scale running for seriously decreased to seriously increased. Information about the selected measure is provided to help the user in making the estimation. From this estimation and on the basis of the absenteeism rate in the current situation, the average cost of a worker's man hour for temporary workers, the learning times and some other factors, the tool calculates the reduction in lost working days and the change in costs to replace sick workers due to the ergonmic intervention.


5. Qualitative benefits

All variables thusfar are expressed in terms of time and money. In addition, there might be some positive effects that can hardly be represented in money. Nonetheless, they might be important for the comapny to recognize. Therefore in the final step, the tool addresses these factors, which are: the potential for self-development of workers, the work attractiveness, company's position in the labour market (recruitment strength), the potential to appoint special groups (elder workers, disabled), and the flexibility.


Conclusion


Over the past decades, many models have been developed to evaluate the cost effectiveness of ergonomic interventions and health and safety measures (Koningsveld et al. 2005). The extent to which these models are applied in practice however are limited. Many models are rather complex and inflexible. For instance data must meet the specifications that are defined by the model, which is often hard to achieve. To our opinion, the inaccessibility of cost and benefit data for the decision makers in industry, often stands in the way of implementation. Therefore, the CyberManS consortium developed this tool. As indicated, this tool provides the support for the user to get an overview of relevant costs and benefits. Some difficulties however may remain. In many cases it might be difficult for the user to predict the benefits in terms of productivity and quality. A data base comprising the necessary information from case studies might be of help here. Some case examples are incorporated in the tool. More cases studies on the cost-effectiveness ergonomic measures are needed to to fill in the currently white spots.


References


Buckle PW, Devereux, JJ, 2002, The nature of work-related neck and upper limb musculoskeletal disorders. Applied Ergonomics 33, 207

Koningsveld EAP, Dul J, Rhijn JW van, Vink P, 2005, Enhancing the impact of ergonomic interventions. Ergonomics 48, 559-580

Oxenburgh M., 1991, Increasing Productivity and Profit Through Health and Safety, North Ryde, NSW:CCH, Australia Ltd.

Rhijn JW van, Looze MP de, Tuinzaad GH, Groenesteijn L, Groot MD de, Vink P, 2005, Changing from batch to flow assembly in the production of emergency lighting devices. International Journal for Production Research 43, 3687-3701.


This paper resulted from the EU funded project CyberManS (IST-NMP-2, STREP n°016712).





Tags: costeffectiveness, ergonomic, looze, interventions, production