Ergonomics of Beauty parlour Chair

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ERGONOMICS OF BEAUTY PARLOUR CHAIR
KETKI S. AGASHE1, N.R. RAJHANS 2
1. B. Tech student, Production Engg. Department, College Of Engineering, Pune
2. Professor, Production Engg. Department, College Of Engineering, Pune
ABSTRACT
Ergonomics is the scientific discipline concerned with the understanding of interactions
among the human and other elements of the system, and the profession that applies
theory, principles, data and methods to design in order to optimize human well being and
overall system performance.
Although ergonomics seems to be a technical field, its applications are more in our day to
day life. Its applications range from day to day products ranging from utensils to
complicated products like cars and helicopters. The more you learn about it, the more you
understand its importance.
The product under consideration is the beauty parlor chair. The main objective of the
product is to give support to your body while performing some task. While the beautician
is performing her job, the position of the chair should be comfortable to her as well as to
the customer.
The main aspects which are considered here are body angle, head angle, head support,
hand support, height of the chair, head rest etc. The variations in the dimension of the
customers as well as the beautician vary to a great extent. To design a chair which will
suit a variety of customers and variety of beauticians is a very difficult task. The height of
the customer as well as the beautician may vary from 4’10” to 5’9”. Not only height but

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the other dimensions of the body also vary from person to person. An attempt is made to
identify the dimesions which will govern the comfort of the customer as well as the
beautician.The paper gives a fair idea about how the chair should be designed for
comfortable working and relaxing posture.
INTRODUCTION TO ERGONOMICS
Ergonomics is the science of designing user interaction with equipment and workplaces
to fit the user. Proper ergonomic design is necessary to prevent repetitive strain injuries,
which can develop over time and can lead to long-term disability.
The International Ergonomics Association defines ergonomics as follows:
Ergonomics (or human factors) is the scientific discipline concerned with the
understanding of interactions among humans and other elements of a system, and the
profession that applies theory, principles, data and methods to design in order to optimize
human well-being and overall system performance.
Ergonomics is employed to fulfill the two goals of health and productivity. It is relevant
in the design of such things as safe furniture and easy-to-use interfaces to machines.
Ergonomics is concerned with the ‘fit’ between people and their technological tools and
environments. It takes into account user's capabilities and limitations in seeking to ensure
that tasks, equipment, information and the environment suit each user.
To assess the fit between a person and the used technology, ergonomists consider the job
(activity) being done and the demands on the user; the equipment used (its size, shape,
and how appropriate it is for the task), and the information used (how it is presented,
accessed, and changed). Ergonomics draws on many disciplines in its study of humans
and their environments, including anthropometry, biomechanics, mechanical, industrial
engineering, industrial design, physiology and psychology.

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Ergonomics in common man’s language is the science of achieving comfort. Thus
according to this definition, ergonomics depends upon
1. environment
2. posture of the human body
3. ease of operation
Outside of the discipline itself, the term 'ergonomics' is generally used to refer to physical
ergonomics as it relates to the workplace as in for example ergonomic chairs. Ergonomics
in the workplace has to do largely with the safety of employees, both long and short-term.
Ergonomics can help reduce costs by improving safety. This would decrease the money
paid out in workers’ compensation.
IMPORTANCE OF ANTHROPOMETRY
Anthropometry, in physical anthropology, refers to the measurement of the human
individual for the purposes of understanding human physical variation.
Today, anthropometry plays an important role in industrial
design, clothing design, ergonomics and architecture where statistical data about the
distribution of body dimensions in the population are used to optimize products. Changes
in life styles, nutrition and ethnic composition of populations lead to changes in the
distribution of body dimensions (e.g., the obesity epidemic), and require regular updating
of anthropometric data collections.
Anthropometry:
Anthropometry is the science that measures the range of body sizes in a population.
When designing products it is important to remember that people come in many sizes and
shapes. Anthropometric data varies considerably between regional populations.
Percentile Humans:

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Anthropometric dimensions for each population are ranked by size and described as
percentiles. It is common practice to design for the 5th percentile (5th %) female to the
95th percentile (95th %) male. The 5th% female value for a particular dimension (e.g.
sitting height) usually represents the smallest measurement for design in a population.
Conversely, a 95th% male value may represent the largest dimension for which one is
designing. The 5th% to 95th% range accommodates approximately 90% of the
population. To design for a larger portion of the population, one might use the range from
the 1st% female to the 99th% male. Fig: 3.1 as shown below.
Fig 1: Comparisons of percentile males and females
Human body measurements play important role in ergonomically designing an object
intone with the human body. But the collection of measurements becomes a huge data
and also measurement of each body part of each person differs from person to person.
Hence only a few measurements are actually taken and all the other required dimensions
are derived from them.

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The Dimensions used to design a product are of two types:
1. Static
2. Dynamic
Static dimensions relate to the stationary body measurements (e.g. height of the elbow
from the floor) while the dynamic dimesions relate to the movement capability of the
body parts body parts (e.g. angle of wrist in relaxed position).
Some of the common anthropometric dimensions are:
1. Standing eye height
2. Standing shoulder height
3. Standing elbow height
4. Standing knuckle height
5. Standing fingertip height
6. Sitting height
7. Sitting elbow height
8. Knee height and thigh depth
9. Shoulder width
10. Hip breadth
11. Chest depth
12. Vertical reach (sitting and standing)
13. Grip circumference
14. Reach
RELATION OF THE BODY POSTURE WITH ERGONOMICS
Body postures considered for ergonomically designing an object are mainly two: 1.
standing, 2. sitting
An ergonomically designed object works well in both the postures. If it is not an
ergonomically designed product then it causes postural problems such as:

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1. extreme postures and pain
2. lower back pain
3. back pain and muscular fatigue
4. spinal problems in sitting and standing
5. fatigue and discomfort
6. loss of control over muscle function
CASE STUDY
The subject very near and dear to women is the beauty parlour. The main objective is of
visiting the parlour is of relaxation. If the chair on which the customer is sitting is not
comfortable to the customer as well as the beautician, it is a most annoying experience.
The customer has a chance to comoplain. But the beautician is performing the same job
on the chair for different customers through out the day. Hence the comfort of the
beautician is more important as compared to the customer. A parlor chair must provide
comfort to the customer and its dimensions must be suitable for the beautician in order to
work properly. The customer should fit snugly in the chair, and it should have a relaxing
effect on her. It should make her feel happy and calm.

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The person working should be comfortable enough to work for long duration without
strain in muscles or any kind of body pain.

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The person having the treatment should not be akward to be in the same position for
longer duration and should be happy at the end of the session.

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PROBLEMS IN COMMERCIALLY AVAILABLE PARLOR CHAIRS
Most of the parlour chairs are available in various sizes and there are some adjustments
also available with the height, head rest and head angle.
Thestudy conducted identifies the dimensions related to the work posture and the
customersitting posture. The adjustments already available are not considered but the
ranges available for the adjustments need to be considerd before the beautician starts
working.
The major thrust area here is –
1. The dimensions of the chair,
2. The dimensions of the beautician
3. The dimensions of the customer.
All these dimensions should work in co-ordination to have a comfortable feeling to the
customer as well as the beautician.
CLASSIFY DIMENSIONS ACCORDING TO THE THREE AREAS AND THEN
TRY TO CORELATE THEM
Height of the chair: Height of the chair is not suitable for the person sitting on it if she is
shorter than the average female height, as it is not possible to adjust the level of the chair,
and it is also uncomfortable for the beautician to work with.
No headrest is provided, which leads to the discomfort of the person sitting in it.
Backrest angle is either non-adjustable or is not adjusted properly.
Handrest – the angle that the hand makes with the body is not very ideal from the point of
view of the customer’s shoulder-comfort.

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Seat – width and area provided on the seat should be slightly greater than that required
for the average class.
Footrest should be adjustable along with the height of the chair.
Overall comfort should be increased by giving better cushioning.
BASIC ERGONOMIC PRINCIPLE
It is generally most effective to examine work conditions on a case-by-case basis when
applying ergonomic principles to solve or prevent problems. Sometimes even minor
ergonomic changes in the design of equipment, workstations (see section A, Workstation
for more details about this topic) or job tasks can make significant improvements in
worker comfort, health, safety and productivity. The following are a few examples of
ergonomic changes which, if implemented, can result in significant improvements:
 For assembly jobs, material should be placed in a position such that the worker's
strongest muscles do most of the work.
 For detailed work which involves close inspection of the materials, the workbench
should be lower than for work which is heavy.
 Hand tools that cause discomfort or injury should be modified or replaced.
Workers are often the best source of ideas on ways to improve a tool to make
using it more comfortable. For example, pliers can be either straight or bent,
depending on the need.
 A task should not require workers to stay in awkward positions, such as reaching,
bending, or hunching over for long periods of time.
 Workers need to be trained in proper lifting techniques. A well designed job
should minimize how far and how often workers have to lift.
 Standing work should be minimized, since it is often less tiring to do a job sitting
than standing.

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 Job assignments should be rotated to minimize the amount of time a worker
spends doing a highly repetitive task, since repetitive work requires using the
same muscles again and again and is usually very boring.
 Workers and equipment should be positioned so that workers can perform their
jobs with their upper arms at their sides and with their wrists straight.
DESIGN ASPECT AND TYPES OF HUMAN MEASUREMENTS
1. Age group – the data has been collected for females of the age group of 18-60
years.
2. Base of the chair –
 Height from the floor, which includes height of hand position from the
floor of the person working, and dynamic movements of her hands.
Considering the position of the person sitting, the lowest height (5th
percentile) should be considered, along with the bending angle of the knee
(50th percentile)
 Width of the base – waist width (50th percentile).
 Length of the base – length of the leg from the hip bone till the knees (50th
percentile).
 Center of gravity of the whole system i.e. chair with the person (in any
position) must lie in the available area of the seat. A support must be
provided at that point while fabricating the chair.

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3. Backrest –
 Height of the backrest – length of shoulder bone till the hip bone (95th
percentile).
 Width of backrest – Shoulder to shoulder length (95th percentile).
 Angle of backrest with respect to seat - Adjustment points according to
comfort in different positions – Dynamic dimension of angle
made by the backbone with the hip bone.
4. Headrest –
 Height of the headrest from the base of the chair – Height of hands from
the floor of the person standing (5th percentile).
 Angle made by headrest with the backrest – Comfortable angles of the
head with the cervical section of the spine.
 Distance between the head of the person sitting and the person standing –
Length of the hand from the middle fingertip to the elbow
(5th percentile). Dynamic dimension of the angle made by the hands of
person standing is also considered.
5. Handrest -
 Height of handrest from the base of the chair – length of the hand of the
person sitting(95th percentile)
 Shape of the handrest and its positioning with respect to the base –
dynamic dimensions o shoulder angle, elbow angle, wrist angle are to be
considered.

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6. Footrest –
 Height of the footrest from the base of the chair – length of the leg from
the knee to the toe (50th percentile)
Conclusion
1. The dimesions required to be taken care of
2. How it can be made comfortable to the beautician
3. How it can be made comfortable to the customer.
ACHIEVEMENTS BY CHANGE IN DESIGN
1. Better working system
2. Better body posture
3. Effort reduction of the beautician hence better results
4. Job satisfaction of the beautician
5. Comfort satisfaction of the customer
6. Reduction in restlessness of the customer
FUTURE ASPECTS
As the satisfaction of the customer is achieved, the customer runs to the parlour
for relaxation hence the improvement in marketing strategy of the parlour is achieved.
Better aspects of the objects lead to better living. Ultimately the achievement of high
order of comfort at affordable price is what matters the most to the field of ergonomics.

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REFERENCES
1. Peter R. M. Jones & Marc Rioux, 1997, Three dimensional surface anthropometry
– Applications to the human body, Optics and Lasers in Engineering 28: 89-117
2. Ryszard Paluch, 1996, Are body dimensions affecting working body posture,
International Journal of Industrial Ergonomics 17: 1-9
3. R. S. Bridger, Introduction to Ergonomics, McGraw Hill International Editions.
4. International Labour Office, Introduction to Work Study, International Labour
Office, Fourth Edition.