Reduction of Fatigue of Employees by Application of Ergonomic Principles

IJSRD - International Journal for Scientific Research & Development| Vol. 4, Issue 05, 2016 | ISSN (online): 2321-0613

Reduction of Fatigue of Employees by Application of Ergonomic Principles Dr.S. Bharath1 Dr.G.S.Prakash2 Rohan Shetty3 Prajwal R Gowda4 1 Associate Professor 2Professor & Head 3,4Student 1,2,3,4 MS Ramaiah Institute of Technology, Bengaluru, India Abstract— The study was carried out at the Injector Manufacturing unit of an MNC company located at Bengaluru, India. The logistics unloading section was considered for this study in order to reduce stress and fatigue caused to the operator(s) due to load handling of components. The operator/driver had to drive the truck to the unloading bay and unload the materials on to a pallet from where he would have to place it in an intermediate location after the quantity check. All of these activities are to be completed within a specified time interval and is usually carried out by a single operator. The load handled by the operator is a cumulative factor of the weight of the crates, operating scenarios, lifting height and grip distance. The cumulative load handled by the operator was observed to be almost 3 times the allowed specifications. The data collected was analyzed in terms of lifting index for the particular activity and for the whole task. Based on the lifting index obtained and analysis of the input parameters, a standard work style is determined and 3 common proposals were made as to reduce the stress caused to the operator in the long run.

Key words: Load Handling, Cumulative Load Handled, Lifting Index, Lifting Height, Grip Distance

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Using lift-assist devices like scissors lift tables or load levelers.  Using more sophisticated equipment like powered stackers, hoists, cranes, or vacuum assist devices.  Guiding your choice of equipment by analyzing and redesigning work stations and workflow.

NIOSH and Cal/OSHA are dedicated to finding the bottom line in state-of the-art research and turning the results into practical guidance for improving the safety and health of all workers.

II. PROBLEM STATEMENT The present case in the Logistics Area -1 (LOG1) department involved operator’s to handle heavy loads for unloading and loading the materials onto the pallets and trucks and vice versa. Each milk run has a designated driver and the truck. The driver himself unloads all the materials from the truck manually. The operator then manually unloads the trays onto the pallet following which with the help of a hand trolley he further pulls the pallet on to and intermediate location for a quantity check after which the trays are arranged in supermarkets.

I. INTRODUCTION Manual Material Handling (MMH) work contributes to a large percentage of the over a million cases of musculoskeletal disorders reported annually in the India.

Musculoskeletal disorders often involve strains and sprains to the lower back, shoulders, and upper limbs. They can result in protracted pain, disability, medical treatment, and financial stress for those afflicted with them, and employers often find themselves paying the bills, either directly or through workers’ compensation insurance, at the same time they must cope with the loss of the full capacity of their workers.

Scientific evidence shows that effective ergonomic interventions can lower the physical demands of MMH work tasks, thereby lowering the incidence and severity of the musculoskeletal injuries they can cause. Their potential for reducing injury related costs alone makes ergonomic interventions a useful tool for improving a company’s productivity, product quality, and overall business competitiveness. But very often productivity gets an additional and solid shot in the arm when managers and workers take a fresh look at how best to use energy, equipment, and exertion to get the job done in the most efficient, effective, and effortless way possible. Planning that applies these principles can result in big wins for all concerned.

Illustrated inside you will find approaches like:  Eliminating lifting from the floor and using simple transport devices like carts or dollies.

Fig. 1: Initial Lifting condition, bending level of employee is inappropriate leading to fatigue & pain at abdomen and back regions on a regular basis.

Considering the above scenario, the objective of the study was to:  Review the literature on manual load handling as per NIOSH guidelines and its concepts.  Carry out analysis on the current scenario.  Understand and reason the current analysis.  Eliminate the problems caused in current analysis by appropriate implementation of ergonomics  Implement and Validate.

III. METHODOLOGY & INFERENCE Task analysis is the process of learning about ordinary users by observing them in action to understand in detail how they perform their tasks and achieve their intended goals. The task of lifting was observed carefully and the constituting parameters affecting each of the tasks were noted down accordingly. The various attributes are noted and motion study is deployed to understand the minute details in order to understand any factor that might be causing fatigue in the operator directly or indirectly.

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Reduction of Fatigue of Employees by Application of Ergonomic Principles (IJSRD/Vol. 4/Issue 05/2016/057)

The Parameters which were considered during this Table 1: Horizontal Multiplier study included the following: Duration  Horizontal Location of the Hands (HM) F >1 But <2 >2 But <8 <1 HOUR Horizontal multiplier, HM= 25/H; for H<=25CM, LIFTS/ Hour Hours HM=1 IF H=>63CM, HM=0 MN V<75 V>75 V<75 V>75 V<75 V>75 Equation = STRWL=LC*VM*DM*HM*AM*CM*FM CM CM CM CM CM CM  Vertical Location of the Hands (VM) <.2 1.00 1.00 0.95 0.95 0.85 0.85  Asymmetric Angle (AM) 0.5 0.97 0.97 0.92 0.92 0.81 0.81  Frequency Multiplier (FM) 1 0.94 0.94 0.88 0.88 0.75 0.75 Equation= STRWL+LC*VM*DM*HM”*AM*CM*FM 2 0.91 0.91 0.84 0.84 0.65 0.65 H H 3 0.88 0.88 0.79 0.79 0.55 0.55 HM HM CM INCH 4 0.84 0.84 0.72 0.72 0.45 0.45 <25 1.00 <10 1.00 5 0.80 0.80 0.60 0.60 0.35 0.35 28 .89 11 .91 6 0.75 0.75 0.50 0.50 0.27 0.27 30 .83 12 .83 7 0.70 0.70 0.42 0.42 0.22 0.22 32 .78 13 .77 8 0.60 0.60 0.35 0.35 0.18 0.18 38 .74 14 .71 9 0.52 0.52 0.30 0.30 0.00 0.15 40 .69 15 .67 10 0.45 0.45 0.26 0.26 0.00 0.13 42 .66 16 .63 11 0.41 0.41 0.00 0.23 0.00 0.00 44 .63 17 .59 12 0.37 0.37 0.00 0.21 0.00 0.00 46 .57 18 .56 13 0.00 0.34 0.00 0.00 0.00 0.00 50 .54 19 .53 14 0.00 0.31 0.00 0.00 0.00 0.00 52 .52 20 .50 >15 0.00 0.28 0.00 0.00 0.00 0.00 54 .48 21 .48 Table 2: Frequency Multiplier 56 .46 22 .46  Grip Condition (GC) 58 .45 23 .44  Load (L) 60 .43 24 .42  Duration (Dur) 63 .40 25 .40  Gender(G) >63 .00 >25 .00 Grip Description Cm condition Load length<40cm; load height<30cm; good handles or hand hold cut-outs. Easy to handle loose parts Good and objects with wrap around grasp and without excessive wrist deviation.

1.0 Load length<40cm; load height<30cm; and poor handles or hand-hold cut-outs or 90degree finger Fair flexion. East to handle loose parts and objects with 90 degree finger flexion and without excessive 0.95 wrist deviation Load length>40cm;load height>30cm;or difficult handle parts or sagging objects or asymmetric centre Poor of mass or unstable contents or hard to grasp object or use of gloves 0.90 Table 3: Grip condition Some of the assumptions were made during the course of the study keeping in mind the NIOSH guidelines which are:  The task is completed by a single operator.  The shift size is considered to be 0-1 hour.  No sudden or jerky movements.  He handles one crate/tray/corrugated box at a time.  Sliding activity on the pallet is not considered in the analysis.  Grip conditions were considered to be fair.

Fig. 4: Dolly Loading-2 Key Problems in the logistics department were observed and captured and documented. The methodology were used and the following inferences were arrived at:

Fig. 2: Loading from supplier

Fig. 3: Dolly Loading-1

A. Key Inference from Problem Statement The table below shows the summary of the cumulative load handled by the operators along with the corresponding lumbar spine index and lifting indexes

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Reduction of Fatigue of Employees by Application of Ergonomic Principles (IJSRD/Vol. 4/Issue 05/2016/057)

Cumulative Lumbar Lifting load Spine Load Index Point 1 1585.4kg 3.71 3.85 Point 2 2143.89kg 3.58 3.58 Point 3 4510.16kg 3.43 3.84 Point 4 858.86kg 3.21 3.41 Point 5 2511.66kg 4.64 5.08 Table 3: Summary of Input Data It can be observed that the cumulative load handled by the operators is very high owning to a lot of serious health hazard, the cumulative load mentioned in the above table is the load handled by one operator only, in case of 2 operators handling the loads for a particular truck the cumulative load is approximately twice that of the cumulative load handled by an operator, this is the case because of alternate working.

Due to the sub standard work methods, the lumbar spine index and the lifting index is way out of the permissible working limits, by following appropriate work techniques like keeping the load close to the body, prevention of angular twists, appropriate intermediate location height these can be reduced to permissible limits, this parameter were altered in the IGEL software to propose appropriate improvement scenarios for the project.

The only way to decrease the cumulative load acting on the operator is by completely eliminating the lifting tasks involved, this can be done by using the completely/partially palletizing the trays that come on the truck (in case the whole truck cannot be palletized it is recommended that any tray weighing more than 12 must be palletized in order to reduce the cumulative load handled.).

In case of dollies, they can be mounted on dolly tracked which can easily be operated using a hand trolley thereby completely eliminating lifting. This can be observed as change in engineering controls.

Route

B. Solution Methodology The Recommended weight limit (RWL), lifting index (LI) method and IGEL analysis was used to guide ergonomic design in several ways:  The individual multiplier can be used to identify specific jobs-related problems. The relative magnitude of each multiplier indicates the relative contribution of each task factor (e.g. - horizontal, vertical, frequency, etc.)  The RWL can be used to guide the redesign of existing manual lifting jobs or to design new manual lifting jobs. For example, if the task variables are fixed, then the maximum weight of the load could be selected so as not to exceed the RWL: if the weight is fixed , then the task variables could be optimized so as not to exceed the RWL.  The LI can be used to estimate the relative magnitude of physical stress for a task or job. The greater the LI, the smaller the fraction of workers capable of safely sustaining the level of activity. Thus two or more job designs could be compared.  The LI can be used to prioritize ergonomic redesign.

For example, a series of suspected hazardous jobs could be rank ordered according to the LI and a control strategy could be developed according to the rank

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ordering (i.e., jobs with lifting indices above 1.0 or higher would benefit the most from redesign.)

The work sequences of the operations were analyzed and the corresponding data were collected. The data collected on the loading bay and the truck floor are tabulated and keyed in individually into the IGEL software to determine if the task is permissible. The overall workspace data is put under the particular workplace and checked for the overall cumulative load, lumber spine load and lifting index is calculated and observed.

IV. RESULT

The revised NIOSH lifting equation has been shown to have limited applications in many realistic manual lifting situations. While considering twisting, it falls short of modeling lifting tasks performed under limited ceiling heights. Further, it provides a recommendation that is substantially lower than the average weight accepted by all 13 participants who participated in this study. The lack of agreement appears to be more for higher lifting frequencies.

The difference between the Maximum Acceptable Weight Limit (MAWL) of the present study, as well as other previous studies, and the RWL demonstrated the need for developing population capability data that take into account more realistic task characteristics.

The current analysis showed us that the lifting indexes were above the value 3 which is high risk in any circumstances, using the IGEL software and by careful variation of parameters proposals are made as show in the previous chapters, with partial palletization of heavy weights risks can be completely eliminated, with change in administrative controls like using 2 operators in place of one considerably decreases the lifting index but not as much as palletization thus still leaving it in the possibly risk zone.

The only way to decrease the risks due to handling heavy weights is by not handling them itself.

Lumbar Spine Load Improvement Cumu percentage RO Improved lative UT Exis load Single 2 Single 2 E ting (kg) Operato Oper Operato Oper r ator r ator Poin 1585.

3.71 0.94 1.5 75 59.57 t1 4 Poin 2143.

3.58 0.94 2.08 73.74 41.89 t2 89 Poin 4510.

3.43 0.96 2.85 72.01 16.91 t3 16 Poin 858.8 3.21 0.99 2.01 69.16 37.38 t4 6 Poin 2511.

4.64 0.95 2.78 79.52 40.08 t5 66 Table 4: Result V. RECOMMENDATION BASED ON SOLUTION & CONCLUSION To conclude, it can be stated that there are two fundamental rules to be observed while lifting 1) Keep the load as close to the body as possible; and 2) Avoid twisting.

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Reduction of Fatigue of Employees by Application of Ergonomic Principles (IJSRD/Vol. 4/Issue 05/2016/057)

These rules most convincingly embrace the research substantiated lifting principles. These rules propose that everything practical has been done to 1) Eliminate the lifting task altogether; 2) Use a mechanical aid instead of manual lifting; 3) Minimize the forces required; and 4) Allow the lift to be done without twisting.

The reason current analysis had high lifting indexes cannot be only traced back to the weight of the tray handled but also the various parameters like grip conditions, workspace restrictions, training for the employee .By following appropriate standard working methods during load handling, not handling weights heavier than 12kg, keeping the Cumulative load below 1000kg and with the implementation of battery operated trolleys in place of normal trolleys significant risk factors can be avoid as a result of decrease in fatigue in the operators day to day tasks.

Keeping in mind the inputs provided by the operator it can also be concluded that they lacked Training in terms of handling heavy loads and how to handle them, this can be because of the fact that the operators/transporters are subcontractors, proper guiding and training both in and out of the organization can result in improved relationship between the employee and the organization.

Final conclusions suggest that the only way the risk can be decreased is by completely eliminating the heavy weights from being manually handled, this can be done palletizing all the heavy weights directly from the supplier base. Other alternative includes the inclusion of a second operator which eliminates the risks of injury to an extent but not completely.

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