Line of balance (LOB)
Line of balance (LOB) is a management control process used in construction where the project contains blocks of repetitive work activities, such as roads, pipelines, tunnels, railways and high-rise buildings. LOB collects, measures and presents information relating to time, cost and completion, and presents it against a specific plan.
LOB assists project management by:
- Comparing a formal objective against actual progress.
- Examining the extent of any deviations from specific plans, in terms of knock-on effects.
- Identifying in advance problematic areas where corrective action may be required.
- Forecasting future performance.
The LOB technique was created by the Goodyear Company in the early 1940s, before being adopted and developed by the U.S. Navy in the early-1950s. It was subsequently developed for industrial manufacturing and production control, as well as the basic concepts behind planning and scheduling in the construction industry.
An LOB diagram shows the repetitive project work as a single line on a graph. It differs from a bar chart which shows a particular activity’s duration, by showing the rate at which the work has to be undertaken to stay on schedule, as well as the relationship of one trade or process to the subsequent trade or process.
The project timeline is represented along the x-axis of the LOB diagram. The work areas that define the project are represented along the y-axis. This is the starting point for the LOB schedule:
In the figure below, it can be seen that Activity A lasts a 10 weeks. The productivity of A, spread across each of the work areas, is 2 weeks per floor.
If Activity B has a productivity rate of 1 week per floor, then it can begin work at the end of the second week.
As Activity B continues, at the end of the week 4 work can begin on the second floor; at the end of week 6 work can begin on the third floor, and so on. The horizontal red dashed lines represent the breaks in Activity B work, where the workforce is waiting for Activity A to clear the way for them to continue. In this example, starting Activity B as soon as possible will result in a lost productivity of 4 weeks.
The diagram below shows that by delaying the start of Activity B for 4 weeks, the workforce can continue uninterrupted, and hence are more productive. This enables a better understanding of how workforces follow one another through activities.
The advantages of LOB include:
- Allowing a clearer understanding of the amount of work taking place at a certain time in a specific place.
- Resources can be optimised for a large number of repeated work activities.
- As all information is available for each activity, it allows easier cost and time optimisation analysis.
- It is relatively easy to modify, update and change the schedule.
- It allows better management of subcontractors and resources.
- It allows problem areas to be identified in advance.
[edit] Find out more
[edit] Related articles on Designing Buildings Wiki
- Activity schedule.
- Advanced manufacturing.
- Block planning.
- Clash avoidance.
- Critical path method.
- Design coordination.
- Gantt chart.
- Key dates.
- Logistics management.
- Milestones.
- Pareto analysis.
- Programme for building design and construction.
- Project manager.
- Resource leveling.
- Scheduling construction activities.
- Time-location chart.
- Time management of construction projects.
[edit] External resources
- CPM Tutor - Line of balance
Featured articles and news
HBPT and BEAMS Jubilees. Book review.
Does the first Labour budget deliver for the built environment?
What does the UK Budget mean for electrical contractors?
Mixed response as business pays, are there silver linings?
A brownfield housing boost for Liverpool
A 56 million investment from Homes England now approved.
Fostering a future-ready workforce through collaboration
Collaborative Futures: Competence, Capability and Capacity, published and available for download.
Considerate Constructors Scheme acquires Building A Safer Future
Acquisition defines a new era for safety in construction.
AT Awards evening 2024; the winners and finalists
Recognising professionals with outstanding achievements.
Reactions to the Autumn Budget announcement
And key elements of the quoted budget to rebuild Britain.
Chancellor of the Exchequer delivers Budget
Repairing, fixing, rebuilding, protecting and strengthening.
Expectation management in building design
Interest, management, occupant satisfaction and the performance gap.
Connecting conservation research and practice with IHBC
State of the art heritage research & practice and guidance.
Innovative Silica Safety Toolkit
Receives funding boost in memory of construction visionary.
Gentle density and the current context of planning changes
How should designers deliver it now as it appears in NPPF.
Sustainable Futures. Redefining Retrofit for Net Zero Living
More speakers confirmed for BSRIA Briefing 2024.
Making the most of urban land: Brownfield Passports
Policy paper in brief with industry responses welcomed.
The boundaries and networks of the Magonsæte.