The Lean Principles
•Precisely specify value from the perspective of the ultimate customer
•Clearly identify the process that delivers what the customer values (the value stream) and eliminate all non value adding steps
•Make the remaining value adding steps flow without interruption by managing the interfaces between different steps
•Let the customer pull – don’t make anything until it is needed, then make it quickly
•Pursue perfection by continuous improvement
What is lean construction?
Lean construction is a philosophy based on the concepts of lean manufacturing. It is about managing and improving the construction process to profitably deliver what the customer needs. Because it is a philosophy, lean construction can be pursued through a number of different approaches. This fact sheet outlines the elements of lean manufacturing and suggests how these might be adapted to deliver lean construction in practice.
Lean manufacturing was initially pioneered and developed by the large Japanese car manufacturers. It has been implemented by a number of Japanese, American and European manufacturers with considerable success, and has been widely applied outside the automotive industry.
Lean is about designing and operating the right process and having the right systems, resources and measures to deliver things right first time. Essential to this is the elimination of waste – activities and processes that absorb resources but create no value.
Waste can include mistakes, working
out of sequence, redundant activity and movement, delayed or premature inputs, and products or services that don’t meet customer needs.
The primary focus is on moving closer and closer to providing a product that customers really want, by understanding the process, identifying the waste within it, and eliminating it step by step.
Production and management principles
Lean is focused on value, more than on cost, and seeks to remove all non-value adding components and (especially) processes whilst improving those that add value. It aims to define value in customer terms, identifying key points in the development and production process where that value can be added or enhanced. The goal is a seamless integrated process (value stream) wherein products ‘flow’ from one value adding step to another, all driven by the ‘pull’ of the customer.
The idea of ‘right first time’ is essential to the lean philosophy. ‘Right’ in this context means making it so that it can’t go wrong. This approach involves an extremely rigorous, questioning analysis of every detail of product development and production, seeking continuously to establish the ultimate source of problems. Only by eliminating the cause at source can the possibility of that fault recurring be removed.
Design and product development
Lean manufacturers have developed systems for product development which first identify the right product (in terms of customer needs), and then design it correctly so that it can be manufactured efficiently.
‘Design’, in manufacturing terms, is concerned with the development and integration of systems and components into coherent, efficient and buildable products, not just the styling of the exterior appearance, a task which is often undertaken by external agencies. Tools have been developed to capture and analyse customer perceptions and requirements for product quality and performance. These tools also enable product development and manufacturing performance targets to be established. Design development targets include reductions in design changes and process iterations.
Critical success factors
•Design is informed by extensive data on the performance of products, systems and components
•Carry-over to new models of a high proportion of systems and components from previous models
•Front-loading of resources towards design to prevent problems during manufacture
•Concurrent working between manufacturing
Lean manufacturers arrange production in closely located ‘cells’ so that work flows continuously, with each step adding more value to the product. The standard time for all activities is known and the objective is to totally eliminate all stoppages in the entire production process. However, only optimum stocks of material are kept as buffers between processing stages. For this system to be effective, every machine and
worker must be completely capable of producing repeatable perfect quality output at the exact time required. Workers are responsible for checking quality as the product is assembled, and in some instances given authority to stop production if defects arise. In this way, quality problems are exposed and rectified as soon as they occur.
The workforce is kept informed of progress towards their production and cost targets by use of information displays so that everyone is able to see the status of all operations at all times. Work teams in lean manufacturing are highly trained and multi-skilled, and
many of the traditional supervisory and managerial functions have been devolved to them.
Critical success factors
•In depth understanding of production processes and resources involved in them
•Responsibility and authority placed with the workforce
•Real time feedback on performance
•Training and multiskilling
•Supply chain management & supplier relationships
•Lean manufacturing is based on the elimination of waste, including time lost waiting for missed/delayed supplies, unnecessary storage and the value tied-up in large stocks of parts waiting for assembly. ‘Just in time’ (JIT) delivery is therefore a vital element, and to deliver this lean manufacturers have had to develop their network of suppliers. Significant efforts are applied to encourage them to adopt the same lean manufacturing principles and systems, often company-wide, rather than solely related to that part of the suppliers’ operations that affect the manufacturer.
•Supply chain management and rationalisation of the supply chain to integrate all parties who contribute to the overall customer value into a seamless integrated process.
•Transparency of costs – the elimination of waste in both processes and activities requires a clear and complete understanding of costs to ensure decisions on customer value can be taken. Confidentiality of cost and cash flows must be addressed.
•The concept of partnering, all involved parties contributing to a common goal with the boundaries between companies becoming less critical.
•Benchmarking to establish ‘best in class’ production methods and outputs
•Establishment of a stable project programme, with clear identification of critical path.
•Risk management – to manage risks throughout the project
•Just-in-time delivery of materials to the point of use eliminates the need for on-site storage and doublehandling
•Clear communication of project plans
•Training, teamwork, multi-skilling
•Daily progress reporting and improvement meetings
•A well motivated, well trained, flexible and fully engaged workforce.
In summary lean construction is a philosophy based on the concepts of lean manufacturing. It is about managing and improving the construction process to profitably deliver what the customer needs. Its success in the organisations ability to marry the tools and techniques with a culture that drives a behaviour of improvement, collaboration and the desire to provide the customer with what they value.
1. Accelerating Change – A report by the Strategic Forum for Construction Chaired by Sir John Egan
This report outlines recommendations for creating a sustainable, customer focussed industry, that is vibrant, profitable, productive and competitive.
2. The Machine that Changed the World – By James Womack , et al HarperBusiness (1991)
This book resulted from a detailed study into how Toyota radically reduced cost and increased quality
by re-engineering its production system
3. Lean Thinking – by James Womack and Dan Jones, Free Press (2003)
This second book defines the concept of lean thinking. In it, the authors set out to assess how widely the Toyota concepts had been adopted across manufacturing and what scope remained.