The build plan, as described in the previous article in this series, is a critical activity. It states clearly what jobs are going to happen on site each day and the materials needed to carry out those jobs. "Just in time" is the method by which materials are always delivered in time and in the most efficient way.
Today, the motor industry is famous for its just-in-time material-management process, yet the path it had to travel to reach this position was enormously long compared with the journey that would be needed in construction. In construction, the number of standard, short-lead-time products is large. In the motor industry, most products are made to a specific model and careful tuning of the entire process is a prerequisite for its working.
The motor industry of the 1970s was characterised by long lead times for the car and the components needed to make it. Any change in the production plan would lead to component excesses or cars made with component shortages.
Huge warehouses on assembly sites held months of inventory, which were millions of pounds doing nothing. The supply chain was separated from the assembly, unable to respond to the immediate needs of production. To allow this to change, buffer stocks had to go, lead times had to be reduced and suppliers throughout the chain had to be driven by immediate requirements.
In construction, management of materials is seen as a secondary issue. But the cost of material waste, the way excesses encumber site activity and materials in wrong places cause excess handling and stop fluent working, all contribute significantly to inefficiency.
The following principles need to be developed:
- The build plan has to drive material deliveries.
- Suppliers need to be aware of the build plan – but this is only useful if the build plan itself is reliable. The supplier should be involved in preparing the required deliveries in the most user-friendly fashion possible – that is, the most efficient transport size, load, routing, timing and so on.
- Least possible packaging compatible with handling requirements and damage avoidance.
The path the motor industry had to travel to reach just in time management is long compared with the journey for construction
- Segregation and marking of products by job and job location.
- Load management considerations such as ease of off-loading and movement on site.
- Equipment set-up on site that reflects in size and timing the availability of the materials and their receipt and distribution.
- Material deliveries to site should be organised to avoid peaks and troughs so that mechanical and human resources are neither over- or under-loaded.
- A delivery principle that seeks to provide a total service to the component-installation team, so that material is placed in predesignated areas and kept in an orderly fashion.
A special approach will always be needed for small, regularly used consumable items. Here, the plan is not going to detail the exact volumes to be used on site, but their availability is essential for work to continue.
The experience we have had so far suggests that the creation of a place where the site's small-item needs can be held reduces waste and untidiness and allows the installers to benefit from an automatic daily material feed.
Huw Jones is project leader for Unipart and FX Coughlin's lean construction consultancy. He can be contacted at firstname.lastname@example.org.