Lean construction

Lean construction is based on concept of lean manufacturing. It is about managing and improving the construction process to profitably deliver what the customer needs, I have outlined the elements of lean manufacturing and suggest how these might be adapted to deliver lean construction in practice.

Lean Manufacturing:

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.

The lean Principles:

* Eliminate waste.

* 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.

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 Pre-mature 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 analyze 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 manufacturer and supplier during design development.

Lean Production:

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. Lean manufacturers have moved away from traditional relationships with their suppliers to partnering arrangements with a smaller number based on good communications and open-book accounting. These relationships work by both parties sharing philosophies of continuous improvement (especially in the area of defect reduction, cost and timeliness of delivery) and sharing business and development strategies sufficient for both parties to know enough about each other to make forward planning effective.

Critical success factors:

* The lack of reliance on formal contracts

* The use of benchmarking of suppliers’ performance against each other on a range of generic criteria

* The development of close relations with first tier suppliers

Applying lean thinking to construction:

The lean principles can only be applied fully and effectively in construction by focusing on improving the whole process. This means all parties have to be committed, involved, and work to overcome obstacles that may arise from traditional contractual arrangements.