Lean Thinking Ltd – Written evidence (OMC0026)

Offsite construction/manufacturing can be one of the most tangible ways of radically reducing project time.

The end to end project time accounts for close to 80% of the project cost and over 90% of the project risk. Therefore, off site if focused on compressing time offers an enormous opportunity for reducing project cost and risk.

To realise and optimize use of off site to compress time two key factors should be considered:

1. The use of offsite should be very specifically focused:

• The best way to look at off site manufacturing /construction is to think of it as just a method or technique amongst many other production improvement techniques.
• The underlying principle of offsite that can deliver radical time reduction is, as well known in other industries, parallel processing.
• In a project environment the benefits of parallel processing to compress time can only be realised if whatever is considered for offsite is on the critical path.
• Non critical path activities built off site may provide limited cost reduction. Ie through possible reduction in site scaffolding which may also have positive safety implications. These benefits however have to be balanced against the safety and cost of the substantially extra craneage time on site.
• If very large chunks of the build on the critical path are taken off site then the on site project time is just shifted to the factory. The production time in a factory and the predictability of on time completion will then depend on the quality of the factory production system.

2. The use of offsite should be amalgamated with all the other modern methods of management and production in to one system whilst focusing on compressing time.

• Such a system is the only way to achieve the 2025 governments target and the productivity improvement.
• The current reality is that the use of off site increases year on year but 70%-80% of projects still continue to run late and over budget. This is partly due to the fact that offsite as with other methods is utilized in isolation and mixed with the current broken construction processes and as the result the benefits are lost.

Productivity benefits:

Improving productivity in construction is very complex and requires many considerations. Currently on projects the operatives on average are working only 30% of the time. Ie fixing or assembling. This could be the same in a factory.

Improving the productivity of individuals on site, in a factory or in a design office will mean that projects will take twice as long and productivity of the project will go down.

There is an erroneous assumption that productivity is always higher in a factory than outside on a project and all factories have consistently high levels of productivity.

It is very possible for productivity to go down when building offsite. Apparently a study has shown offsite to be less productive in some circumstances that on site.

Many of offsite factories can be described as construction sites in a shed. They use the same inefficient processes with the same fragmented sub-contractors used on projects.

Offsite units do at times arrive on site late, incomplete and of poor quality requiring manufactures gangs to complete or make good the work on the construction site. This can take longer than on site build by sub-contractors coordinated by the main contractor.

The overall impact of weather on off site productivity would need research.

Impact of weather and climate on productivity

A factory environment can provide protection against wet and cold weather.

Weather conditions can however work against modular offsite units as the loading, unloading and assembly means substantially longer cranage lifting periods which can frequently be winded off.

It is possible that more time is lost due to wind than rain and low temperatures through out the year.

Safety Advantages

Is it safer to use the same processes in a shed? In some cases the use of modular is likely to mean less or no site scaffolding but on the flip side it means much longer periods of lifting during assembly on site.

Standardization

Standardization should be treated as a separate production technique that can help compress time.

The main benefit of standardization is design time saving.

Other industries have moved to mass customization but in construction we are still thinking Henry Ford. Any colour as long as it’s black.

Some offsite manufacturers are promoting standardization mainly due to the limitation of their factory production processes to customize.

The greatest benefit of standardization would come from standardizing the project delivery system/process rather than the product ie what we build.

Government Policy and Recommendation:

Off site or parallel processing is only one of many techniques that collectively can radically improve project performance. Most often each technique is used in isolation and hence delivers zero project improvement. Most of the benefits will be sub-optimized and with little or no impact on the project time or cost.

Any policy to be set to improve productivity should be directed to utilizing a standardized system of project delivery focused on compressing project time. Such a system must utilize as a minimum the collective benefits of all the latest management, production and motivational techniques used by other industries, sports etc.

The system as a minimum must utilize principles such as One Piece Continuous Flow, Critical Chain, scientific work prioritization, Short feedback and learning loops, horizontal accountability, BIM etc.

In terms of offsite such a system must be able to demonstrate that it has considered at the project opportunities for utilizing any form of off site in order to compress time.

25 April 2018