Page 1 of 8 BITS PILANI
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BITS PILANI, HYDERABAD CAMPUS
Report Line o f balance scheduling technique (lobst)
Course No . PHA G 616
Course Title Pharmaceutical Administration & Management
(PAM)
Instructor -in -charge Dr. A kash Chaurasiya
Submitted by Kanchan sonawane(2017H1460158H)
Contents
Introduction: ………………………….. ………………………….. ………………………….. ………………………….. ……… 2
History: ………………………….. ………………………….. ………………………….. ………………………….. ………….. 2
Assumption and Key points in LOBST: ………………………….. ………………………….. ……………………. 2
Application: ………………………….. ………………………….. ………………………….. ………………………….. ……. 3
Advantage: ………………………….. ………………………….. ………………………….. ………………………….. ……… 3
Procedure: ………………………….. ………………………….. ………………………….. ………………………….. …………. 3
Case study 1: ………………………….. ………………………….. ………………………….. ………………………….. ………. 6
Case study 2: ………………………….. ………………………….. ………………………….. ………………………….. ………. 6
Conclusion: ………………………….. ………………………….. ………………………….. ………………………….. ………… 8
Reference : ………………………….. ………………………….. ………………………….. ………………………….. ………….. 8
Figure 1:sequential steps for construction of LOBST charts ………………………….. ………………………….. .. 4
Figure 2:LOBST charts (a) lobst chart (b) activity chart (c) planning chart ………………………….. ……….. 5
Figure 3: LOBST chart with bar chart. ………………………….. ………………………….. ………………………….. … 5
Figure 4:(A) The estimated line of ba lance(B) Dotted line actual line of balance ………………………….. . 6
Figure 5: The estimated line of balance ………………………….. ………………………….. ………………………….. .. 7
Figure 6:LOBST chart for case 2 ………………………….. ………………………….. ………………………….. ………… 8
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Line O f Balance Scheduling Technique (LOBST) or Repetitive
Scheduling Method (RSM)
Introduction :
The line of Balance Scheduling Technique (LOBST) is a linear scheduling method that allows
the balancing of the operations such that each activity is continuously and efficiently performed
for each consecutive unit.
A LOB Chart shows the rate at which the work that ma kes up all of the activities has to be
undertaken to stay on schedule. Charting of the production plan results from detailed study
collectively by plant management, the process engineering staff, and other representatives.
In other words, the production rate of an activity is linear where time is plotted on one axis,
usually horizontal, and units or stages of an activity on the vertical axis .
History :
The LOB Scheduling Technique was originated by the Goodyear Company in the early 1940’s
and wa s developed by the U.S. Navy in the early1950’s for the programming and control of
both repetitive and non -repetitive projects.
Useful for scheduling of projects where delivery is not at one point of time but is spread over
many intervals of time according to prior agreed schedule between manufacturer and customer
e.g. batch of combat aircrafts, batch of computers.
Assumption and Key points in LOBST:
It is done for Limited number of activities wh ich are r epetitive a ctivities. working group is
called “Team”, “Crew” or “Gang”. Default working week is of 5 working days per week and
of 8working hour per day. The Rate of Construction of an activity is the slope of the production
line and it have to keep constant (i.e. the lines of activities should be parallel).
In order to maintain the Rate of Construction to be constant it ha s to provide the needed crews
who can achieve this construction rate (line of balance).
The LOBST is based on the underlying assumption that the rate of production for an activity
is uniform.
1. The production rate of an activity is the slope of the production line and is expressed in
terms of units per time.
2. The LOB method manipulates worker hour estimates and the optimum sizes of crews
to generate the LOB diagram.
3. Worker hour estimates and optimum crew sizes are usually obtained through direct
interaction with a scheduler, the site manager, or related subcontractors who are
knowledgeable enough to reflect the actual conditions of a project and of its constituent
activities.
4. Line of Balance C hart does not show direct relationships between individual activities.
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5. It shows an output relationship between the different operations in that one operation
must be completed at a particular rate for the subsequent relationship to proceed at the
required rate .
6. This usually means the resources required will also be constant and is the ideal scenario.
Application :
LOB has been applied: Resource scheduling and coordination of subcontractors , Highway,
pavement construction project , Modeling production activities for multi?facility projects ,
Transportation projects etc.
The LOBST is based on the underlying assumption that the rate of production for an activity
is uniform.
Advantage :
The LOB technique offers following advantages:
• It allows project managers to see, in the middle of a project, whether they can meet the
schedule if they continue working as they have been.
• It exposes process bottlenecks, allowing the project manager to focus on those points
responsible for slippage.
• It helps avoiding many hiring and procurement problems in issues pertaining to the
flow of labor and material used during construction.
• LOB scheduling has the capability to ensure a smooth procession of crews from unit to
unit with minimal confl icts and decrease idle time for workers and equipment.
Procedure :
The delivery information used and needed in a Line of Balance analysis is of two kinds, planned
and actual. (1) Planned -the contractual delivery requirement , (2) Actual — the delivery actually
made by the producer to the time of the analysis. Planned delivery and actual delivery are
always collected and plotted in cumulative terms of end item sets. The procedure followed is
depicted in figure 1.
Accumulation of data: The plan should cover the span of operations peculiar to the particular
manufacturing process, from work on raw materials through assembly operations to point of
shipment. Prior to any detailed examination or storing and categorizin g of data supplied by the
contractor, a tour should be made of the plant to observe the physical layout, and the actual
processes involved, as well as to observe the physical attributes of the operations.
The determination of the sequence of operations:
A general chronological determination of flow can be made at this stage concerning the
approximate sequence, or order, in which these materials and subassembly groups flow into
final assembly operations. This should then be consolidated onto a flow chart which will
delineate the steps of the process in sequ ence .
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The determination of processing and assembly lead time :
This involves a determination of the total time interval, in each case, between the required
availability of raw material, purchased parts, manufactured parts, subassemblies and the date
of shipment of the completed end item. This time is inclusive, and in addition to required
processing time it includes other aspects such as in -plant storage or handling time.
Chart construction : Having determined the raw materials, parts, fabrication stages,
subassemblies and assemblies with which the Line of Balance study is concerned, and having
obtained the applicable sequence of operations and lead time information, the dat a is presented
graphically in the following manner: The production plan or assembly tree is constructed by
using a time scale in units commensurate with the overall lead time. The time scale is normally
set down in working days rather than calendar days.
program progress chart construction :
once the work has been started the data is plotte d on the same g raph and necessary decision are
taken for scheduling of further work plan.
Figure 1:sequen tial steps for construction of LOBST ch ar ts
ACCUMULATION OF DATA:
THE DETERMINATION OF OPERATIONS TO BE PERFORMED
THE DETERMINATION OF THE SEQUENCE
OF OPERATIONS
CHART CONSTRUCTION
PROGRAM PROGRESS CHART CONSTRUCTION:
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Figure 2:LOBST charts (a) lobst chart (b) activ ity chart (c) planning chart
Figure 3: LOBST chart with bar chart .
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Case study 1:
This case involves the construction of building with 4 floors – each act ivity is sequen tial and
can be performed only after one is completed. – foun dation -brickwork -roof construction and
internal works. It is estimated that 4 floors can be constructed in 20 weeks’ time span according
to resources available.
Figure 4:(A) The estimated line of balance( B) Dotted line actual line of balance
It was seen that the Foundations are was on schedule and almost complete but Brickwork and
Roof Construction were running behind schedule. The Internal Works did not start but the
anticipated rate of work was plotted on the chart and by extrapo lation the first unit was expected
to be completed 3 weeks late. This delay was corrected by increasing the output for the
Brickwork and Roof Construction and the internal Works by either taking measures to increase
efficiency or increasing the resources committed to the operation that were not achieving the
correct output.
Case study 2:
100 -segment pipeline project and the process of planning and scheduling a realisti c, feasible,
and profitable work plan was needed.
For the 6 activity types they initially plan the following for a project with the same soil type:
Table 1: Acti vity distribution
Clearing and survey 5-man crew 1 segment/day 100 days
Trenching 3-man crew ¼ segment/day 400 days
Placing Bedding select material 3-man crew ½ segment/day 200 days
Laying pipe and connecting joints 6-man crew ½ segment/day 200 days
Hydraulic testing 2-man crew 4 segments/day 25 days
Backfill and gradin g 4-man crew 1/3 segment/day 300 days
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Figure 5: The estimated line of balance
The Project was taking almost 700 days , due to completion of Bedding and Laying Pipe until
all of the trenching was done after 408 days and the start of testing delayed until the 383 day s
with multiple crew interference. So, looking at the cha rt in figure 5 Perhaps they could have
delay ed the start of a following crew until there was enough work for them to work
without waiting for the prior crew to provide them work areas as they do not want to have
activity crews standing idle waiting for the next work area.
This was achieved by delaying the start of trade crews to avoid overlapping prior crews so that
they will not be waiting for the next segmen t’s work area.
• The Bedding work was delayed 200 days so that it finishes just after the trenching finishes.
• The Testing work was delayed 375 days so it does not finish before Laying Pipe finishes.
This was the Line -of -Balance or ‘Linear Scheduling’ constructed as showen in figure 6 .
Wher eas they might have thought the project was going to take 110 days, at 11 days/segment,
due to keeping the crews fully working once they start, it would have take n 684 days because
the Backfill and Grading cannot start until the 1st segment is tested. W as this real istic?
From this starting point, a contractor after looking at the above Line -of-Balance chart
instinctively look at reducing the time of the Trenching. Perhaps 2 trenching crews c ould have
to be mobilized thereby reducing the trenching time from 400 to 200 days. Tha t’s worth
consideration.
If Trenching was reduced to 200 days, then Bedding and Laying Pipe can be done without
interruption because all 3 tasks are planned to work at the same space. Backfilling crews w as
also be studied to see if their production migh t be improved.
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Figure 6:LOBST chart for case 2
Conclusion :
A method of showing the repetitive work that may exist in a project as a single line on a graph
shows the duration of a particular activity
The rate at which the work that makes up all of the activities has to be undertaken to s tay on
schedule .
Reference :
1. Application of line of balance scheduling technique (LOBST) for a real estate sector issn:
2278 – 7798 international journals of science, engineering and technology research (IJSETR)
volume 2, issue 1, January 2013.
2. Line of balance for more white papers see:
http://www.Mosaicprojects.Com.Au/whitepapers.Html
3. Implementation of l ine -of-balance based scheduling and project control system in a large
construction company by mika soini ilkka leskehi, olli seppanen.
4.Line of balance, a graphic method of technology office of naval material department of the
navy reproduced by navexosp18 51 , clearinghouse for federal scientific ; technical informal.
5. https://www.scribd.com/doc/24996455/Line -of -Balance
