Assignment 42

International Journal of Engineering Management
2019; 3(2): 40-45

http://www.sciencepublishinggroup.com/j/ijem

doi: 10.11648/j.ijem.20190302.11

ISSN: 2640-1525 (Print); ISSN: 2640-1568 (Online)

Niosh Lifting Equation for Assessing Manual Material
Handling

Technique in a Warehouse Company

Amaya Flocerfida
1
, Argayoso Kimberly Clariz

2
, Tatlonghari Rachelle Ann

2

1
College of Engineering, University of Perpetual Help System Laguna, Biñan, Philippines

2
Industrial Engineering Department, University of Perpetual Help System Laguna, Biñan, Philippines

Email address:

To cite this article:
Amaya Flocerfida, Argayoso Kimberly Clariz, Tatlonghari Rachelle Ann. Niosh Lifting Equation for Assessing Manual Material Handling

Technique in a Warehouse Company. International Journal of Engineering Management. Vol. 3, No. 2, 2019, pp. 40-45.

doi: 10.11648/j.ijem.20190302.11

Received: June 10, 2019; Accepted: July 11, 2019; Published: August 8, 2019

Abstract: Every warehouse company must protect their employees from possible health risks especially the loaders or carriers
to avoid work related musculoskeletal disorders. This research aimed to determine the factors that affect the safety of carriers or

loaders inside a certain warehouse. Proper lifting techniques were studied to provide safer methods compared to current worker’s

execution or method. The primary data were obtained from the respondents through observations, interviews, and survey

questionnaires such as Nordic Questionnaire. Time and motion study was used to determine how safety affects the time of each

worker in finishing the job. To assess safety, NIOSH lifting equation is used, an ergonomic tool that equates to the required

weight limit and lifting index of the loaders or carriers that execute manual material handling. The results of the study showed

that all the respondents had high lifting index based on the pre-assessment test of NIOSH lifting equation which means that they

are at high risk. After implementation of proper lifting techniques, post-assessment test showed that the respondents had yielded

lower lifting index. The findings revealed that aging and length of stay in the warehouse are factors highly affecting workers’

capacity of lifting and safety. Older workers are more at risk than younger ones when it comes to physical activities. The longer

the exposure in lifting and carrying, the more risks it is for the body. A safety procedure guideline was developed and

recommended to the company to avoid health issues or musculoskeletal disorders among loaders and carriers inside the

warehouse.

Keywords: Work Related Musculoskeletal Disorders, NIOSH Lifting Equation,

Lifting Index

1. Introduction

Manual Material Handling or MMH is one of the most

difficult tasks for the workers and one of the most physically

demanding work because of repetitive movements, awkward

postures, forceful exertion etc. It is the main cause of

work-related musculoskeletal disorder [1]. MMH is the

leading source of injuries in the workplace between 24% and

35% [2]. The work environment can be the main reason why

workers have health problems.

Different kinds of MSDs must be assessed to determine the

appropriate ergonomic tool to be used. The NIOSH or the

National Institute of Occupational Safety and Health

developed a technique to reduce the effects of lower back pain

(LBP) and work-related musculoskeletal disorders (WSMD).

This indicates the work practices guide for manual lifting [3].

To assess the factors that affect the efficiency of the workers in

a certain warehouse in the Philippines, the NIOSH Lifting

Equation was used.

Musculoskeletal Disorders are due to manual material

handling practiced by warehouse carriers or loaders. The risks

were mostly caused by non-ergonomically way of material

handling. It can affect the workers’ safety and pose health

risks. The demographic profile of the workers such as age,

height, and number of years in their current position were

determined as well as the current method being used by the

carriers or loaders in the liquor section of a warehouse.

Relationship between the demographic profile of the workers

41 Amaya Flocerfida et al.: Niosh Lifting Equation for Assessing Manual Material Handling

Technique in a Warehouse Company

and their safety in the workplace was also determined.

Pre-assessment and Post Assessment using NIOSH was

evaluated to determine the best safety procedure guidelines for

recommendation to the company.

2. Materials and Methods

For attainment of the objectives of the study, a descriptive

method of research with primary data gathered from the

respondents through the use of observations and interviews

among the population of the study. A process chart was used

as a representation of the sequence of steps, work flows,

working processes, systems and procedure. It served as a tool

for examining the process in detail to identify areas of possible

improvement. Time and Motion Study was used to measure

the time necessary for a job or task to be completed using the

best method. This tool helped the team to evaluate if there is

an improvement with the pre-assessment and post-assessment

of the study. NIOSH lifting equation used worksheet to collect

data from the respondents.

Since the data collected may be discrete and contain actual

numbers, descriptive statistics were used. Pearson R

Correlation was used on this study to determine the

relationship of level of awareness of proper manual material

handling and level of implementation safety procedure. The

formula is stated below:

r � ���� � ��
��
��� ��
� � ��
� √ �� ��
� ��
�

(1)

To test the significance of r, T- test was used,

t � �� � – �
� – �
(2)

3. Results and Discussion

3.1. Demographic Profile of the Respondents

Table 1. Profile of the respondents in terms of age.

Age Frequency Percentage Rank

26-31 6 40 1

32-37 2 13.3 4

38-43 4 26.7 2

44-49 3 20 3

Total 15 100

As shown in the table regarding the age composition of the

respondents, 6 out of 15 respondents (40%) are 26-31 years

old, 4 or 26.7% are 38-43 years old, 3 or 20% are 44-49 years

old and 2 or 13.3% are 32-37 years old.

Age should be considered since it is known that muscular

strength declines from middle age onwards [4]. Middle-aged

people are particularly prone to low-back problems owning to

the instability of their lumbar motion segments. Aging process

leads to a decrease in muscle mass and strength. Loss of

strength is directly connected with reduction of muscle mass.

The muscular system accounts approximately 40% of the total

body mass and human body’s cell mass consists in 75% of

muscle cells [5].

Table 2. Profile of the respondents in terms of height.

Height (cm) Frequency Percentage Rank

154.94-162.08 3 20 2.5

162.09-166.23 6 40 1

166.24-170.38 3 20 2.5

170.39-174.53 2 13.3 4

174.54-178.68 1 6.7 5

Total 15 100%

The above table above shows the height of the respondents

in which 6 out of 15 (40%) stand 162.09-166.23 cm, 3 or 20%

stand 166.24-170.38 cm, 3 or 20% stand 154.94-162.08 cm, 2

or 13.3% stand 170.39-174.53 cm, and 1 or 6.7% stand

174.54-178.68 cm.

Shorter people are less likely to have lower back pain or

break a hip [6]. One possible reason taller people have a bigger

chance of a hip fracture is their high center of gravity. That not

only makes them more likely to fall, but it also may make

them

hit the ground with more force if they do.

Table 3. Profile of the respondents in terms of number of months in the current

position.

Months in the current position Frequency Percentage Rank

68-91 6 40 1

92-115 4 26.7 2

116-139 1 6.7 5

140-163 2 13.3 3.5

164-187 2 13.3 3.5

Total 15 100

The table above shows the number of months in the current

position. Mostly or 6 out of 15 respondents (40%) are in their

current position for 68-91 months, 4 or 26.7% for 92-115

months, 2 or 13.3% for 140-163 months, 2 or 13.3% for

164-187 months, 1 or and 6.7% for 116-139 months.

3.2. The Current Method of the Carriers or Loaders

Figure 1. Process Chart.

The effects of combining the activities of lifting, lowering,

pushing, pulling, and carrying into one work task; the

resulting acceptable loads limits were quite different for the

separate tasks compared with several of their combinations

[7]. Manual handling at work includes lifting, putting down,

International Journal of Engineering Management 2019; 3(2): 40-45 42

carrying or moving, pushing or pulling of loads by one or

more workers during the larger part of the work shift. Despite

current technological advancements manual handling occurs

in almost all working environments, workers are exposed to

the risk of carrying or moving heavy loads for at least a quarter

of their working time.

Figure 2. Therbligs Process Chart.

Figure 3. Current Execution.

The carriers or loaders manually lifted the box by bending

his back to reach the box, grasp it with both of his hands then

lift the box by straightening or lifting his box towards his

body. Basically, the carriers or loader used his back to lift box

not his feet and lift the box with their own way or strategy as

fast as possible to finish their work. The abdominal and

thoracic muscles play a major role in stabilising the spine

when a weight is lifted. When a person leans forward to lift a

weight, a moment of flexion is placed on the spine [8]. The

heavier the weight, the greater the flexion strain.

Figure 4. Floor Plan of Liquor section – warehouse.

3.3. The Result of Pre-Assessment (NIOSH) and

Post-Assessment (NIOSH)

3.3.1. The Result of Pre-Assessment (NIOSH)

Table 4. Results of respondents’ required weight limit pre-assessment.

Required Weight Limit (lb.) Frequency Percentage Rank

10.9-11.92 1 6.67 5

11.93-12.95 3 20 3

12.96-13.98 5 33.33 1

13.99-15.01 3 20 3

15.02-16.04 3 20 3

Total 15 100

It is shown in the table the results of respondents’ required

weight limit from NIOSH lifting equation. Five out of 15 or

33.3% answered 12.96-13.98 lbs., 3 or 20% answered

11.93-12.95 lbs., 3 or 20% answered 13.99-15.01 lbs., 3 or 20%

answered 15.02-16.04 lbs., and 1 or 6.67% answered

10.9-11.92 lbs.. Therefore, there was a high risk to the

respondents.

The primary product of the NIOSH lifting equation is the

Recommended Weight Limit (RWL), which defines the

maximum acceptable weight (load) that nearly all healthy

employees could lift over the course of an 8 hour shift without

increasing the risk of musculoskeletal disorders (MSD) to the

lower back [9]. For risk assessment, the recommended loads

heavier than 25 kg are always to be considered a risk for

Lower back pain while less than 3kg do not pose a risk. For

loads between 3-25 kg, risk assessment shall be performed

using the National Institute for Occupational Safety and

Health (NIOSH) lifting equation. [10]

Table 5. Results of respondents’ lifting Index pre-assessment.

Lifting Index Frequency Percentage Rank

2.73-2.99 5 33.33 1

3.00-3.26 4 26.67 2.5

3.27-3.53 4 26.67 2.5

3.54-3.80 1 6.67 4.5

3.81-4.07 1 6.67 4.5

Total 15 100
It is shown in the table the results of respondents’ required

lifting index from NIOSH lifting equation. Five or 33.3% got

2.73-2.99, 4 or 26.67% got 3-3.26, 4 or 26.67% got 3.27-3.53,

1 or 6.67% got 3.54-3.8, and 1 or 6.67% got 3.54-3.81.

Therefore, there was a high risk to all the respondents.

A Lifting Index (LI) is calculated to provide a relative

estimate of the level of physical stress and MSD risk

associated with the manual lifting tasks evaluated.

Table 6. Results of evaluated respondents’ lifting Index pre-assessment.

Lifting Index Frequency Percentage Rank

LI < 1.0 – Normal risk to employee 0 0 2

LI > 1.0 High risk to employee 15 100 1

Total 15 100%

It is shown in the table the results of evaluated respondents’

43 Amaya Flocerfida et al.: Niosh Lifting Equation for Assessing Manual Material Handling

Technique in a Warehouse Company

Lifting Index. The result LI > 1.0 revealed that 15 out of 15

respondents (100%) are at High Risk and 0 or 0% LI < 1.0 for

Normal risk to employee.

A Lifting Index value of less than 1.0 indicates a nominal

risk to healthy employees. A Lifting Index of 1.0 or more

denotes that the task is high risk for some fraction of the

population [11]. As the LI increases, the level of low back

injury risk increases correspondingly. Therefore, the goal is to

design

all lifting jobs to accomplish a LI of less than 1.0.

3.3.2. The Result of Post-Assessment (NIOSH)

Table 7. Results of respondents’ required weight limit post-assessment.

Required Weight Limit Frequency Percentage Rank

40.61-42.11 1 6.67 4.5

42.12-43.62 2 13.33 3

43.63-45.13 7 46.67 1

45.14-46.64 4 26.67 2

46.65-48.15 1 6.67 4.5

Total 15 100
It is shown in the table the results of respondents’ required

weight limit from NIOSH lifting equation. Out of 15

respondents, 7 or 46.67%) have 43.63-45.13 lbs. required

weight limit, 4 or 26.67% have 45.14-46.64 lbs., 2 or 13.33%

have 42.12-43.62 lbs., 1 or have 40.61-42.11 lbs., 1 or 6.67%

have 46.65-48.15 lbs.. Therefore, there was a normal risk to all

employees.

The primary product of the NIOSH lifting equation is the
Recommended Weight Limit (RWL), which defines the
maximum acceptable weight (load) that nearly all healthy
employees could lift over the course of an 8 hour shift without
increasing the risk of musculoskeletal disorders (MSD) to the

lower back [12]. For risk assessment, the recommended loads

heavier than 25 kg always are to be considered a risk for

Lower back pain while less than 3kg do not pose a risk. For
loads between 3-25 kg, risk assessment shall be performed
using the National Institute for Occupational Safety and

Health (NIOSH) lifting equation [13].

Table 8. Results of respondents’ lifting Index.

Lifting Index Frequency Percentage Rank

0.91-0.94 3 20 3

0.95-0.98 5 33.33 2

0.99-1.02 7 46.67 1

Total 15 100
It is shown in the table the results of respondents’ required

lifting index from NIOSH lifting equation. Seven or 46.67%

obtained 0.99-1.02, 5 or 33.33% obtained 0.95-0.98, and 3 or

20% obtained 0.91-0.94. Therefore, there was a normal risk to

all employees.

A Lifting Index (LI) is calculated to provide a relative
estimate of the level of physical stress and MSD risk

associated with the manual lifting tasks evaluated [14].

It is shown in the table the results of evaluated respondents’

Lifting Index with (100%) LI < 1.0 – Normal risk to employee

is 15 out of 15 respondents and (0%) LI > 1.0 High risk to

employee is 0.

A Lifting Index value of less than 1.0 indicates a nominal
risk to healthy employees. A Lifting Index of 1.0 or more
denotes that the task is high risk for some fraction of the

population. As the LI increases, the level of low back injury

risk increases correspondingly. Therefore, the goal is to design

all lifting jobs to accomplish a LI of less than 1.0.

Table 9. Results of evaluated respondents’ lifting Index post-assessment.

Lifting Index Frequency Percentage Rank

LI < 1.0 – Normal risk to employee 15 100 1

LI > 1.0 High risk to employee 0 0 2

Total 15 100

Secondly, the supporting tools are the Nordic Standard

questionnaire and the time study. The results of the Nordic

Standard questionnaire revealed that the most hurt part of the

respondent’s body are the lower back, upper back, shoulders,

and arms. The percentage of answering yes in pain are: Neck

33%, Shoulders 87%, Arms 87%, Wrists/Hands 73%, Upper

Back 87%, Lower Back 93%, Hips/Thighs 67%, Knees 53%,

and Ankles/Feet 33%. This also shows that most of them did

not seek medical help or attention for their felt pain and only 1

out of 14 of the respondents has consulted a physician.

The Time Study covers the time of each worker to transfer

boxes from rack to pallet with given 5 trials. The

pre-assessment with their current lifting technique and the

post-assessment with the researchers’ recommended lifting

techniques. As shown on the two results, the average of each

worker to do the task only has small difference in time.

Pre-assessment has an average of 5.5572 seconds and the

Post-assessment has an average of 5.355867. Most of the

workers show a lower time average with the post-assessment

using the researchers’ lifting techniques.

3.4. The Relationship Between Demographic Profile and

Safety of the Carriers or Loaders

Table 10. Gathered Data for Demographic Profile and Safety.

Worker Age Height Length of stay Lifting Index

1 26 170.31 73 2.735

2 28 162.08 75 2.738

3 28 170.35 80 2.740

4 29 162.44 79 2.807

5 30 168.23 82 2.939

6 31 178.68 90 3.002

7 32 166.55 93 3.109

8 37 175.48 113 3.174

9 38 158.36 95 3.200

10 38 168.45 93 3.266

11 41 170.26 135 3.323

12 43 162.48 145 3.396

13 44 166.29 163 3.397

14 46 154.29 165 3.560

15 49 170.40 187 3.997

It is shown in the table 10 the relationship of the

International Journal of Engineering Management 2019; 3(2): 40-45 44

demographic profile and safety of the respondents. The

demographics came from the company and the data of safety

came from the lifting index of the NIOSH lifting equation. It

shows that all the data and information gathered by the

researchers are diverse.

It is shown in Table 11 that the age and length of stay have a

very strong positive relationship with safeness. Older workers

are more at risk than younger ones when it comes to physical

activities. The longer the exposure in lifting and carrying, the

riskier it is for the body. The height and safety have a very weak

negative relationship with safety that contradicts the findings of

Ratini that shorter people are less likely to have lower back pain

or break a hip. One possible reason taller people have a bigger

chance of a hip fracture is their high center of gravity. That not

only makes them more likely to fall, but it also may make them

hit the ground with more force if they do.

Table 11. Relationship of Demographic Profile and Safety.

Independent Variable (x) Dependent Variable (y) Pearson Value Relationship T-Value T-Test Results α = 0.05

Age

Lifting Index

0.9629 Very Strong Positive 12.86520825 Significant

Height -0.1356 Very Weak Negative -0.49347061 Not significant

Length of Stay 0.9258 Very Strong Positive 8.83041895 Significant

4. Conclusions

In this paper, the ergonomic problems encountered in

manual material handling in a warehouse was studied. It was

found out all of the carriers or loaders employed in the liquor

section of the warehouse are male. The height, age, and length

of stay of the carriers or loaders in the company are diverse so

the researchers used this data and information in assessment

relating to their safety. It was also revealed that they are

already exposed to stress and safety issue related on lifting

loads. It can be noted that the current execution in manual

material handling of the carriers or loaders is ergonomically

incorrect which means they are more prone to work related

musculoskeletal disorders. From the Pre-assessment of the

NIOSH Lifting equation, all of the carriers’ or loaders’ lifting

index are greater than 1 which indicates that they are at high

risk meaning they are lifting the boxes above the

recommended weight limit or with incorrect execution of

lifting or carrying. As obtained from the Post-assessment of

the NIOSH Lifting equation, all of the carriers’ or loaders’

lifting index are less than 1 that indicates they are at normal

risk. It was also found out that the age and length of stay in the

current position of the respondents’ highly affect their safety.

Aging can affect the ability of the workers to do manual

material handling and other physical activities. Older workers

are more at risk than younger ones when it comes to physical
activities. The longer the exposure in lifting and carrying, the

riskier it is for the body. Due to absence of company’s Safety

Procedure Guidelines, the carriers or loaders of the warehouse

have higher risk of developing Musculoskeletal Disorders that

may cause long term health issues and lessen the workers’

effectiveness at work.

Some corresponding recommendation can be made

according to the above conclusions. For the profile variables

of the workers that may affect carrier’s or loader’s safety at

work, the weight and health conditions or medical history

must be considered. To widen the scope of the study, other

persons involved in manual material handling such as truck

loaders should also be considered. Other ergonomic tools such

as Manual Handling assessment charts as MAC too and

WISHA lifting equation of revaluating manual material

handling may also be used to compare results.

References

[1] Triyanti, D. (2017). Risk Assessment of Manual Material
Handling. Materials Sciences and Engineering.

[2] A. Burciaga-Ortega and J Santos-Reyes. (2010). Manual
Handling Operations Risk Assessment safety, Accident, and
Reliability Analysis (SARACS). 189.

[3] Shahu, R. (2016). The NIOSH Lifting Equation for Manual
Lifting and its Application. Journal of Ergonomics.

[4] A. Pinder, G. Frost and H. Hill. (2011). Prospectove Evaluation
of the NIOSH Lifting Equation.

[5] K. Keller and M. Engelhardt2013Strength and muscle mass
loss with aging process. Muscle, Ligaments and Tendons
Journal 346-350.

[6] F. Elfeituri and S. Taboun. (2012). An Evaluation of the NIOSH
Lifting Equation. International Journal of Occupational Safety
and Ergonomics.

[7] P. Gidikova and G. Sandeva2016MANUAL HANDLING
RISK ASSESSMENT AND MORBIDITY
STRUCTURETrakia Journal of Sciences360-366.

[8] Middleworth, M (2011). Process benefits of Ergonomics in the
Workplace. Ergonomics Plus Inc. march 21,
http://ergopluc.com/workplace-ergonomics-benefits/.

[9] P. Kuijer, J. Verbeek, B. Visser, L. Elders, V. Roden, V.
Wittenboer2012An Evidence-Based Multidisciplinary Practice
Guideline to Reduce the Workload due to Lifting for Prevening
Work-related Low Back PainNIOSH Lifting Equation.

[10] Baba Md Deros, D. D. (2015). A Study on Ergonomic
Awareness among Workers Performing Manual Material
Handling Activities.

[11] H. Mohammadia, M. Motamedzadeb, M. Faghiha, H. Bayat, M.
Habibi and S. Musavi. (2015). Manual Material Handling
Assessment Among Workers. International Journal of
Occupational Safety and Ergonomics.

[12] M. Babu, M. Uthayakumar and K. Murugabhoopathy. (2014).
International Journal of Innovative Research in Science,
Engineering and Technology. Assessment on Ergonomics Risk
during.

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Technique in a Warehouse Company

[13] Health, N. I. (2012). National Institute for Occupational Safety
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[14] R. Gandhi. (2016). Manual Material Handling: A classification
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Biography

Flocerfida is the Dean of the College of Engineering in University of Perpetual Help System Laguna. She actively

participates as one of the CHED’s Assessor for Quality Assurance of Higher Educational Institution’s Vertical

Typology and Institutional Sustainability Assessment, and a member of Regional Quality Assessment Team for

Engineering Education. She was conferred as an ASEAN Engineer and awarded as 2017 Outstanding Chemical

Engineer. She is also one of the Accreditors of Philippine Association of Colleges and Universities-Commission on

Accreditation. She is also a Consultant for Environmental Management of Laguna International Industrial Park, Inc.

Argayoso Kimberly Clariz is a graduate of Bachelor of Science in Industrial Engineering at University of Perpetual

Help System Laguna. She has special skills in drawing and layout applications using AUTOCAD and knowledgeable

in SAP. She is also a Certified Lean

Six Sigma Yellow Belt.

Tatlonghari Rachelle Ann is a graduate of Bachelor of Science in Industrial Engineering at University of Perpetual

Help System Laguna. She is proficient in Microsoft Office such as Word, Excel, Powerpoint, SAP and Certified Lean

Six Sigma Yellow Belt.

International Journal of Transportation Engineering and Technology
2017; 3(4): 49-52
http://www.sciencepublishinggroup.com/j/ijtet
doi: 10.11648/j.ijtet.20170304.11
ISSN: 2575-1743 (Print); ISSN: 2575-1751 (Online)

Importance of Warehouse Layout in Order Fulfilling
Process Improvement

Yu Zhang, Syed Abdul Rehman Khan

School of Economics and Management, Chang’an University, Xi’an, China

Email address:
2646592586@qq.com (Yu Zhang), sarehman_cscp@yahoo.com (S. A. R. Khan)

To cite this article:
Yu Zhang, Syed Abdul Rehman Khan. Importance of Warehouse Layout in Order Fulfilling Process Improvement. International Journal of

Transportation Engineering and Technology. Vol. 3, No. 4, 2017, pp. 49-52. doi: 10.11648/j.ijtet.20170304.11

Received: October 2, 2017; Accepted: October 26, 2017; Published: November 20, 2017

Abstract: The warehousing layout has strategic importance in the firms’ supply chain management strategy and service
level. Usually, firms design their warehouse, which can increase service level, reduce order fulfilling process time and cost.

This research discussed the warehouse layout for improvement in order fulfilling process time. Researchers discussed the case

study of Mury distributor, which deals in plastic pipes and some electric products. The results indicate that Mury distributor’s

employees were not well-trained in their work and several times they deliver wrong products, which also become a cause of

delay in customer’s orders. The findings also show that shelves and racks were not as per the requirement of the items and after

model building and layout changes increased to the efficiency and service level.

Keywords: Distributor, Order Fulfilling Process, Warehouse, Supply

Chain

1. Introduction

In today’s world warehouses can create significant value

addition for the organizations, but if management knows how

to use effectively and efficiently another wise warehouses

only can add a huge cost only in whole system of supply

chain management [1]. The order fulfillment process has a

significant role in warehouse management. Companies give

importance to order filling process for enhancement of

customer services. The biggest reason of switching customer

is “unsatisfactory services”. In today’s competitive world

customers are demanding immediate (in short time) accurate

deliveries in terms of right quality and right cost. That’s why

companies are more focus over “delighted customer

services” but challenge which companies face is cost. The

bottom line of every company is earned a healthy profit, so

companies least preferred to add cost in the system in terms

of hiring more workforce and buying any automated system.

The priority of top management is to minimize the system’s

cost and achieves to the following objectives: provide

delighted services to the customers, building good and long

term relationships with customers and earned healthy profit.

Usually handle to the fulfillment process, there are two

different methods: The first is in-house (using company self-

infrastructure) and the second is outsourcing (fulfillment

services provider) [2-4].

The process of order fulfillment initiate from the “point of

sales inquiry” and end at “delivery of product to the

customers” According to [5-6] for every warehouse the most

labor intensive activity is order picking and as per the

estimation the order picking expense is 55% of the total

warehouse operation cost, because the travel time, finding

and selecting the right item and transport towards point of

shipping. The picking the items from the storage area for the

purpose of to fill customers order is called order picking. As

per [7] the order picking is up to 60% of the total labor

activities in the warehouse because majority warehouses are

taking human services for the “order picking”. In simple term

order fulfillment is how seller responds after receiving orders

from customers till delivery [8]. In this research will identify

the problems face during the order fulfillment process and

how companies can minimize their cost and improve their

order fulfillment process.

Mury distributors established during 1876 in U. S. Majorly

Company deal in plastics pipes and electronics related items.

Company has 48 employees, and has 1750 active industrial

account as well annual sales of almost $ 16.5 Million; it is

considered a large size distributor. Company which started as

50 Yu Zhang and Syed Abdul Rehman Khan: Importance of Warehouse Layout in Order Fulfilling Process Improvement

a small partnership between Louis and Juli, now has become

a giant in the industry.

2. Warehouse Role in Modern Supply

Chain

Role of warehouse in the supply chain is not new, before

usually warehouses were using only storage purpose. But

from last few decades it is become broader horizon.

According to the [1] following activities are commonly use

in today’s warehouse; same day shipment (its common in

many warehouses), postponement, late configuration, Cross-

dock, Transshipment facility, Returned Goods, Make Bulk or

Break Bulk, Consolidation, accurate deliveries to customers,

flexibility, timeliness, respond quickly over customer’s

request, labeling and tagging is also very important and play

vital role in tracking and selecting the right material on the

right time during fulfillment of the customer’s order [9].

Usually, Customers do not care “warehouse is company

owned or it is operating by third party” in modern SC (supply

chain) warehouses are contributing 99% accurate and

perfectly respond over customers’ request [1, 10]. According

to the overview of warehousing in North America [1]

“contract warehousing” in U.S is 60% of commercial US

market. Third party role in the warehouses are growing, and

firms would like to take advantages of third party in terms of

cost minimization, storage space, flexibility, specialized labor

and technology. As well firms also can change the

warehousing network without burden of fixed (warehouse)

expenses, but interesting retailers and distributors are not

willing to use of third party [10]. Usually the common

characteristics for the successful warehouse operations are;

investment in the people by the training and provide them

more skilled regarding their job responsibilities, measure

performance of individual employee and use evaluation

process to gage the service level and cost, usage of latest

technology (software & hardware) as per the warehouse

requirement to increase the visibility and velocity (speed) of

the operations.

In the process of order fulfillment the important part is

“Order Picking”. And usually in the warehouses many time

waste in finding and selecting the right material. Order

picking can be done by several methods. Commonly uses are;

Batch or picked by article, to fulfill the multiple orders the

multiple products selected and then products sorted in the

area of staging and consolidate with other products to fulfill

the customer’s order, Discrete Order; on the basis of per

customer’s order only specific products selects, Waves; in the

method products are gathered on basis of specific routing or

shipping criteria, Reverse-Order; it is used when portion of

order held to consolidate with other order. Reverse order are

somehow related with cross docking.

3. Problem in Warehouse

Warehouse of the Mury distributor was 12000 square feet

approximately. And company was dealing in 44700 items,

and there were many items which were very expensive and

some was very low cost items. Major problem of which

company was facing are delaying in order filling process.

There were few basic reasons which we analyzed after the

visit to the warehouse and observed activities in warehouse.

All picking and selecting the products works has been done

by labor force (no automation), waste many times in finding

the right products and sometimes the picker transport wrong

products towards shipping department, which was also

caused of delaying in filling customer orders. Due to the

delaying in customer deliveries, customers were disappointed

from the services provided by the Mury distributor. And in

last few years company has lost many customers, one more

reason what we have identified is that “height of shelves” is

not as per the labor are working there, and it was also one

major reason in delaying in finding and picking. As per the

[11] the top shelf in the warehouse should be as per the short

height worker. Who will work there because a person height

of 5 foot and 5 inches can pick to the material and items as

high as 6 feet and 11 inches.

4. Design & Layout of the Warehouse

In the warehouse available space was 12000 square feet

approximately, and utilization of the warehouse space is

85%. In simple words, in real case we cannot utilize 12000

square feet space for the storage purpose. The company’s

policy for the storage and picking is creating significant

impact on the warehouse design and layout. Following are

the three approaches for pick the items (by hand):

a. The picker can enter from one aisle and exits from the

same aisle.

b. The picker can enter from the one aisle and exits from

the other aisle

c. The picker can enter from the one aisle and exits from

the middle of the aisle.

The third one is very convenient for the picker, because

in the third one approach the picker (employee) usually

work towards middle of the warehouse as well he can

cover much area in little time and can pick many items in

very short time. The shipping and receiving work steps

play a critical role for the warehouse design. Because

from the shipping area after assembling and finalizing the

customer orders, it is shipped to the customers, so

shipping area should be accessible conveniently for picker

to transport the items towards shipping departments.

As we have mentioned before warehouse space was

12000 square feet and firms can maximum utilize 10200

square feet. Before we go towards solutions and

recommendation we need to understand the problem from

every aspect, so we also conducted couple of interviews

with warehouse manager and shift in-charge, and also we

observed to the warehouse activities performed by labor

specially finding to the products, picking and shipping.

After the in-depth analysis we went towards solutions.

The major questions which we was facing is “how many

International Journal of Transportation Engineering and Technology 2017; 3(4): 49-52 51

racks, shelves should be for the storage of 44700 products

in the available space. As per the nature of the products

we have selected the very suitable racks which pair of

vertical sides, horizontal beams. We selected this rack

because it is most suitable for the products and usually

products was in small and medium sizes it is also

convenient for the picker, and picker can pick the products

from the back side or from the front side so ultimately it

will also support to save time during “Picking” work.

After the selection of the rack and shelves usually no we

need to calculate how many racks we need to stored 44700

products in the given constraint of space. So for the

accurate findings and results we are going to use

mathematical model by Heragu, [12]. The following is the

notation, which will be used in model.

X and Y = number of rows and column in the spaces of

rack.

A = multiplier, a (multiple) sum of the horizontal rack

spaces, length of the total required aisle.

B = multiplier, a (multiple) sum of the vertical rack spaces,

width of the total required aisle.

This mathematical model will minimize the one way travel

time by picker to collect to the required products is

formulated as follows [12].

Minimize =
�(
�
) � � (��
)

�
(1)

Subjected to the following

XYZ ≥ n；

and X, Y are integers

The total space available for storage exceeds the minimum

requisite, it will be ensured by first constraint. The number of

columns and rows should take on integral values and it will

cover by second constraint.

Y = �n(a + 1) / [Z(b + 1)] (2)

X = �n(a + 1) / [Z(b + 1)] (3)

After run to the mathematical model, now we will apply

this model. In this case, in which a = b shows that

warehouse is square shape. The warehouse of the

company is a rectangle length and width with 125 and 82

respectively. In the model two parameters ratio is a/b =

125/82 or a=1.52b roughly, so here we are using

reasonable values which is presented in [12], a=0.45 and

b=0.30 we have set these values for further calculation.

Then second parameter which we need to decide is

“needed shelf spaces” are 585 at an avg. size of 8079

cubic inches we chose n = 2×585 = 1170 (double of the

shelves would avoid products cover and make convenient

for the storage of received goods and also convenient for

the picker). And final parameter of the mathematical

model can determine by the given information and the

number of levels (measurement is Z). In this model Z = 7.

As we have discussed before the normal person can reach

as high as 6 feet 11 inches. So now we are going to drive

this mathematical model.

Calculations

Y = �1170(0.45 + 1) / 7(0.30 + 1) = 13.63 (4)

X = �1170(0.30 + 1) / 7(0.45 + 1) = 12.24 (5)

5. Research Findings and

Recommendations

As per the research findings, Mury Distributor’s

employees was not trained and skilled. In fact, many times

employees transport wrong products towards shipping area

which was the cause of delay in customers’ orders, picking

all worked was done by manually no technology used (error

margin was high). As well shelves and racks were not as

per the requirement of the products. This model has shown

the accurate number of racks which is required in the

warehouse “minimum 14 column and 12 rows” This

calculation will help to utilize the storage area in a better

way with few and no congestion. This results will also help

to solve storage problem “some shelves were over loaded

and some was empty” and after implementation of this plan,

company will be able to respond quickly to the customer

orders.

6. Conclusion

In the today’s supply chain management warehouse plays a

vital role to fulfill the customers’ requirement in terms of

delivery to right customer and on time delivery. In short

words, warehouse creates direct impact over customer

service level and due to the efficient and effective warehouse

operations, firms can improve their overall performance and

service level. On the other hand, effective and efficient

warehousing operations also create positive image and

reputation of firms in the customers’ eyes. In this article, we

have discussed the problem of one distributor and provided

couple of recommendations with the help of mathematical

modeling and suggested to re-design the layout of warehouse

for the better space utilization of the warehouse and to

minimize the customer’s order fulfillment process time.

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Biography

Ms. Yu Zhang is affiliated with School
of Economics and Management,
Chang’an University, Xi’an, China. Ms.
Zhang has been published more than 15
research papers in international scientific
journals and conferences.

Mr. Syed Abdul Rehman Khan is
affiliated with Chang’an University,
China, and Business Research and
Institute, USA. Mr. Khan has completed
his PhD in 2014 and he has been
published more than 35 research papers in
highly scientific journals including SCI
and EI indexing. Further, Dr. Khan has
attended more than 20 international

conferences as a keynote speaker and/or committee
member.