Kingdom of Saudi Arabia King Saud University College of Engineering Industrial Engineering department ERGONOMICALLY DESIGN, DEVELOPMENT, AND IMPLEMENTATION OF SCHOOL FURNITURE FOR SAUDI SCHOOL STUDENTS Supervised by: Dr.Mohammad Ramadan Prepared by: Abdullah AL-Abdulkarim

INTERDUCTION Time spent in school by students. Time spent in school by students. Range of furniture sizes. Range of furniture sizes. Objective of the project. Objective of the project.

PROBLEM OBJECTIVE (LBP) is major health problem in many countries. (LBP) is major health problem in many countries. Sitting Position. Sitting Position.

LITERATURE REVIEW Frank et al. (1971) revealed some common guide lines: Frank et al. (1971) revealed some common guide lines: 1. Avoid compression of thighs. 2. Avoid flattening the lumbar spine. 3. Distribute weight equally on weight- bearing bony prominences in the buttock. 4. Allow adjustment to be made in the dimension of the chair such as height and angle of inclination.

LITERATURE REVIEW Mandal (1982) Select an alternative design by proposing a chair with significant forward tilt of the seat pan combined with raised and tilted desk with an inclination of 0-20 o. Mandal (1982) Select an alternative design by proposing a chair with significant forward tilt of the seat pan combined with raised and tilted desk with an inclination of 0-20 o.

PHASES OF THE PROJECT  Phase one: Collecting the Anthropometrical data from students.  Phase two: design of the school furniture, and applying different design sets on the subjects while performing different activities, and check if the different sets effect the discomfortability rating.

SAMPLE SIZE CALCULATIONS n = (z σ / h) 2 Description: n = required sample size. z = confidence level at 95% (standard value of 1.96); in a case of the sample size is less than 50 and the normality of the population is not likely, an appropriate value of t must be used. σ = estimated standard deviation. h = the precision requirement in the actual dimension (x - µ = 10 mm).

DATA COLLECTED Total Qassim -girls Riyadh- girls Qassim- boys Riyadh -boys Total We need to collect more 1017 from male and 1885 from female subjects with confidence level of 95%.

DESIGN Range of Four sizes would give better quality for Saudi children in the 6-18 years old groups. Range of Four sizes would give better quality for Saudi children in the 6-18 years old groups. Four groups for boys as well as for girls using different colors to differentiate between them. Four groups for boys as well as for girls using different colors to differentiate between them.

DESIGN OF MALE STUDENTS

DESIGN OF FEMALE STUDENTS

PHASE TWO Experimental work was done: Experimental work was done: having four male subjects in the age range of (9-12)years old. having four male subjects in the age range of (9-12)years old. measuring their weight, and height. measuring their weight, and height. Putting the electrodes in the concerned places on their bodies. Putting the electrodes in the concerned places on their bodies. Measuring the length between electrodes. Measuring the length between electrodes.

PHASE TWO  The subjects were asked to sit 15 min performing each activity on each set.  After the subject perform the activity for 15 min he rest for 30 min and then perform the 2nd activity and so on.  Picture for subjects while performing their activities on each set were taken.

PHASE TWO  Pictures of students while experimenter taking their heights, weight, and measuring the length between electrodes on the subjects bodies:

PHASE TWO  The combination of different sets are: Set (1): High chair and high table. Set (2): 1 st mid chair and 1 st mid table. Set (3): 2 nd mid chair and 2 nd mid table.(same design for group 9-12 years old male students) Set (4): low chair and low table. Set (5): Low chair and High table. Set (6): High chair and high table.

PHASE TWO The activities performed on the set by the subject were: (1) Reading, (2) writing, and (3) Looking at the black board.

PHASE TWO  Calculating the angles needed and input it in the biomechanical evaluation of lifting tasks program.  Unfortunately after using the output of this program in SPSS program shows that there is no significant differences between different sets.  It only shows that there is significant difference between the activities performed.

PHASE TWO  We use Questionnaire technique to take the opinion of the subjects for every activity they performed on every set(the questionnaire were given to them after they finish their 15 min on performing the activity on every set.  The Questionnaire was asking the student how their neck, shoulders, thigh, and feet feel after every activity and give discomfortability rating from 1 which is very very comfortable to 7 which is very very uncomfortable.

PICTURES OF SUBJECTS ON DIFFERENT SET

RESULTS  After inserting the Questionnaires results in the SPSS program and applying two-way within subject factorial design.  NECK: sets shows significant effect on discomfortability rating F(5,15)=9.63; P<0.000  After applying Duncan test to check what set is better we found set number 3 is the best at the neck. As shown in the next Figure:

RESULTS Effect of number of sets on the discomfortability rating at neck

RESULTS  SHOULDERS: it shows that there is an interaction between sets and activities F(10,30)=2.57; P<0.022  One-Way ANOVA test is applied to analysis the interaction, we found that set 3 is the best for the Looking at the blackboard and writing activities and set 2 is the best for the reading activity as shown in the next Figure.

RESULTS Effect of sets by activities on the discomfortability rating at the shoulder

RESULTS  THIGH: it shows that there is significant effect on the sets F(5,15)=67.93, P<  Duncan test is applied also here to show what set is the best for the thigh.  Set 3 is the best for the thigh as shown in the next Figure.

RESULTS Effect of the sets on discomfortability rating at the thigh

RESULTS  FEET: it shows significant effect on the sets F(5,15)=25.39, p<0.000  Duncan test was also employed here and it shows that the best set for the feet is set number 3 as shown in the following Figure.

RESULTS Effect of the sets on discomfortability rating for the feet

CONCLUSION  Number of student in the experiment was not sufficient for determining the main effect with high level of confidence level, however, the trend of set has been determined for the subjects I had.  Set number 3 is the appropriate set for the subjects I had which mean the design of the school furniture I did is correct.