Ergonomics

ERGONOMIC IMPROVEMENT ON THE MECHANICAL ENGINEERING MACHINE SHOP OF CEBU INSTITUTE OF TECNOLOGY – UNIVERSITY

A Project in
IE 421 ERGONOMICS
Presented to the Faculty of the Industrial Engineering Department
Cebu Institute of Technology – University, Cebu City, Philippines

In Partial Fulfillment of the Requirements for the Degree
BACHELOR OF SCIENCE IN INDUSTRIAL ENGINEERING

By:

Ivy C. Abarquez
George Vincent A. Bantonari
Mark Rey C. Booc
Vienna Mae C. Borces
Jossie M. Magno
Norben B. Manatad
Julie Pearl D. Pelayo

October 2012

|TABLE OF CONTENTS |
| |
|CHAPTER |TITLE |PAGE NUMBER |
| | | |
| |List of Figures ………………………………………………………. |…… ii |
| | | |
|I |Rationale of the Study ………………………………………….... |…… 1 |
| | | |
|II |Objectives ………………….………………………………….……... |…… 3 |
| | | |
|III |Statement of the Problem ….…………………………………… |…… 4 |
| | | |
|IV |Research Methodology ………………………...……………….. |.….. 5 |
| | | |
|V |Presentation, Analysis and Interpretation of Data…….. |…... 7 |
| | | |
|VI |Conclusion …………………………………………………………… |…….. 16 |
| | | |
|VII |Recommendation …………………………………………………. | .…. 17 |

LIST OF FIGURES

|FIGURE NO. |TITLE |PAGE |
| | | |
|1 |Machine Shop Layout ………......……………….…………………………………… |7 |
|2 |Number of Points for Area A ....……………….…………………………………... |10 |
|3 |Number of Points for Area B .….………………..………………………......…… |11 |
|4 |Number of Points for Area C …………………………….…………………....…. |12 |
|5 |Illumination of Area A ………….………………………….………………….……... |13 |
|6 |Illumination of Area B ………….………………………….………………….……... |14 |
|7 |Illumination of Area C ………….………………………….………………….……... |15 |
|8 |Proposed Layout for Area A ….………………………….………………….……... |17 |
|9 |Proposed Layout for Area B ….………………………….………………….……... |18 |
|10 |Proposed Layout for Area C ….………………………….………………….……... |19 |

I. Rational of the Study

Machining is any of various processes in which a piece of raw material is cut into a desired final shape and size by a controlled material-removal process. The machine shop provides design consultation, precision machining, and fitting and assembly, all on both prototypes and custom-designed parts. (http://mc-78.machineshop.utoronto.ca/). In a machine shop, physical factors such as lighting, noise and heat are present in all human activities and when they exceed certain limits, they can damage health (Rodríguez & Alonzo 2004).

Inadequate lighting is a major risk factor, because even though every activity requires manual, intellectual and visual skills, about 80% of the information reaching the brain to perform everyday tasks is visual. Furthermore, light directly influences the worker’s disposition towards the task and therefore affects production. Light is particularly critical when a task requires precision: in that case, a poorly lit room quickly causes fatigue (Guerrero et al. 2006). Other effects of bad lighting, because of insufficient or excess, are stress, headaches and visual disturbances (Rodríguez & Alonzo 2004).

Sound is a vibration of an elastic medium, perceived as unpleasant. It has long been known that loud noise produced by industrial machinery produces various pathologies. The main increase in exposure to noisy work environments came after the English industrial revolution and, for example in the USA, it affects 30 million people (Hernández & Gutierrez 2006). More recently it has been realized that slight noise also is an environmental pollutant that can cause physical and psychological disorders in the short, medium and long term (Ahmed et al. 2001, Standard INTE 31-09-16-97). One of the most important and studied effects of noise is hearing loss, but noise also produces previously unknown or underestimated disorders that include loss of concentration, sleep disorders, learning deficit, stress, cardiovascular problems, chronic fatigue, communication interference, and aggressiveness (http://estatico.uned.ac.cr/investigacion/publicaciones/cuaderno1/documents/QuintoArce-Lighting.pdf).

After understanding what lighting or illumination and noise are, the researchers tend to evaluate the lighting and noise level of the Mechanical Engineering laboratory specifically the machine shop (also known as mechanical shop) of Cebu Institute of Technology – University with the hazard these may bring not only to the faculty but most importantly to the students.

II. Objectives

This study is conducted primarily for the following. 1. to evaluate illumination and noise level of the Mechanical Engineering machine shop; 2. to identify and measure illumination through the use of a light meter; 3. to identify and measure noise level through the use of a sound level meter; and 4. to establish proper illumination and noise level in the machine shop, if necessary.

III. Statement of the Problem

To aid in the pursuit of this study, the following questions are considered. 1. What are the current illumination and noise level in the workplace? 2. Do the current illumination and noise level appropriate for the workplace? 3. Is there any precautionary measures done to prevent improper illumination and avoid destructive noise, if applied?

IV. Methodology

From the recommended light level in different workplaces by OSHA, laboratories and mechanical workshops should be 500 lux and 750 lux respectively.

A group effort was initiated to assess if the Cebu Institute of Technology – University Mechanical Engineering machine shop conforms to OSHA standards in terms of illumination and a further assessment was made to if arrangement of lamps or lightings are acceptable.

Aside from illumination and arrangement, concerns with noise were also considered because it may affect students’ performance in making mechanical works. Instruments calculating noise levels measure decibel units.

These materials were used in the assessment of Cebu Institute of Technology – University Mechanical Engineering machine shop: • Light meter - an instrument for measuring the intensity of light • Sound level meter - an instrument designed to respond to sound in approximately by the same way as the human ear and to give objective, reproducible measurements of sound pressure level (http://personal.cityu.edu.hk/~bsapplec/sound6.htm) • Tape measure / meter stick - a ribbon of cloth, plastic, or metal with linear-measure markings, often in both imperial and metric units (http://www.wordiq.com/definition/Tape_measure)

To assess arrangement of lightings in the shop, these are measured: • Length - length of room • Width - width of room • Height - mounting height, i.e. the vertical distance between the working plane and the luminaire.

Length, width and height are used as inputs in computing the room index (RI) which is the ratio of room plan area to half the wall area between the working and luminaire planes. This can be taken using the formula:

RI =

The measurements should be in meters.

V. Presentation, Analysis, and Interpretation of Data

Noise Level

The noise levels (in dbA) were taken per area using the sound level meter. The data were gathered every 3 minutes. There were 10 samples taken in areas A and B while 30 samples were taken in area C for it has a bigger space. The areas are shown below.

Figure 1: Machine Shop Layout

The blue part represents Area A. The green portion is for Area B. Lathe machines are placed in both areas. The pink shade stands for Area C.

|AREAS |NOISE LEVEL (dbA) |OSHA RECOMMENDED NOISE LEVEL (dbA) |
|A |71.95 |90 |
|B |70.16 |90 |
|C |80.48 |90 |

Table 1: Noise Level of the Three Areas

The table above shows the average noise level of the different areas. The Occupational Safety and Health Administration (OSHA) has established a standard noise level for non-precision manufacturing workplace. The standard for this workplace was the case study’s basis since the Mechanical Engineering laboratory class was not using the lathe machines in their laboratory activity.

Illumination

The illumination or illuminance of the workplace was taken per workstation basing on the calculated room index (RI).

For area A:

RI =

RI =

RI = 1.5154

For area B:

RI =

RI =

RI = 1.7213

For area C:

RI =

RI =

RI = 1.8939

The figure on the next page shows the number of points for measuring illuminance with 10% accuracy.

Area A

Figure 2: Number of points for Area A

The x represents the points which serve as the basis of getting the illumination of the area. The length of the area is 8 meters and its width is 4.84 meters. The allowance of ½ meter per side is being established.

Area B

Figure 3: Number of points for Area B

The x represents the points which serve as the basis of getting the illumination of the area. The length of the area is 6.53 meters and its width is 6.15 meters. The allowance of ½ meter per side is again being established.

Area C
Figure 4: Number of points for Area C

The x represents the points which serve as the basis of getting the illumination of the area. The length of area C is 29.95 meters and its width is 4.84 meters. The same allowance of ½ meter per side is being established.

Since the layout of the lathe machines did not match the above figures, the illuminance was taken on lathe machines closely the same with the above layout. The figures on the next pages shows the illumination of the shop.

Area A
Figure 5: Illumination of Area A

Rotated 90 degrees, this will be the top view of area A. The yellow boxes represent the lights. The boxes with numbers are the lathe machines and those in red ink are the illumination (in lux) measured by the light meter.

Area B

Figure 6: Illumination of Area B

Rotated 90 degrees, this will be the top view of area B. The yellow boxes represent the lights. The boxes with numbers are the lathe machines and those in red ink are the illumination (in lux) measured by the light meter.

Area C
Figure 7: Illumination of Area C

The yellow boxes represent the lights. The boxes with numbers are the lathe machines and those in red ink are the illumination (in lux) measured by the light meter.

VI. Conclusion

According to the results, the noise level of the machine shop in the Mechanical Engineering laboratory did not exceed 90 dbA which meant that the shop was not hazardous without any use of the machines. The areas A, B and C’s noise levels were 71.95 dbA, 70.16 dbA and 80.48 dbA respectively. However, when the researchers gathered data, the lathe machines were not used. Thus, this could not be accepted as perfectly conforming to the standards. In this case, the machine shop was not still safe of any noise hazards.

In conducting the illumination measurement, data were taken in every machine or in every work stations. Based on the evaluation, the machine shop did not pass the standard illumination. The shop’s illumination only varied from 20 lux to 343 lux, very outlying from the standard 750 lux.

*The data were taken on a day with favorable weather.

VII. Recommendation

Based on the gathered results, the researchers recommend the following layout of lights for the Mechanical Engineering machine shop and fabrication, welding and foundry area.
Figure 8: Proposed Layout for Area A

The x represents the workstation while the yellow circles are for the lights.

Figure 9: Proposed Layout for Area B

The x represents the workstation while the yellow circles are for the lights.

Figure 10: Proposed Layout for Area C

The x represents the workstation while the yellow circles are for the lights. All the lights should be equally distributed based on the proposed layout and should conform to the standard, 750 lux.

Cost-Benefit Analysis:

Assuming the results were of real machine shop, the benefits of lighting improvements especially in this case where illuminanation did not meet the standard level are: • Increased worker productivity; • Energy cost savings; • Operation and maintenance cost savings with longer equipment life; and • Reduced environmental impact.

In the health and safety aspects, a well-designed illumination system intends to eliminate problems on fatigue and glare as well as decrease energy and financial costs.

The costs of improving lighting or illumination system include, but not limited to, the fluorescent light or bulb purchased with the OSHA recommended illumination (in lux) and the rearrangement of workplace layout.

Assuming that the shop has 30 workers with budget of PHP 10,000 each injury obtained and the number of injured will be reduced to 10 workers, the cost-benefit analysis will be completed as follows.

Benefit/Cost =

=

= 1.3333

This means that the shop can benefit 33.33% of the cost of improvement. Quantifying the above figure, the savings will be up to PHP 50,000 out of the cost of improvement of PHP 150,000.

----------------------- length x width

height x (length + width)

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length x width

height x (length + width)

8m x 4.84m

1.99m x (8m + 4.84m)

length x width

height x (length + width)

6.53m x 6.15m

1.84m x (6.53m + 6.15m)

length x width

height x (length + width)

29.95m x 4.84m

2.20m x (29.95m + 4.84m)

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Existing cost – Proposed cost

Cost of Improvement

30 workers(PHP 10,000) – 10workers(PHP 10,000)

PHP 150, 000