How To Get the Most from Offsite

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How To Get the Most from Offsite

Take advantage of what offsite construction can offer.

Address the challenges of using offsite.

Take a holistic approach that utilises what offsite can offer.

What are Critical Success Factors?

The key things that you have to do to make sure benefits are realised & challenges are addressed effectively.

Benefits of Offsite Construction over Traditional Construction

80% improvement in health & safety.

Significant improving in working conditions in factory environments.

Up to 60% less road traffic movements.

Up to 80% less energy used on site.

Up to 90% less waste.

Up to 25% less energy-in-use.

Up to 60% faster construction programme.

Significantly improved cash-flow.

Up to 80% less snagging & defects.

Advantages of Offsite Construction

Speed - most significant offsite benefit, quicker the building is up, the quicker the turnover for the client which clients will want.

Quality and predictability - must understand the client/project drivers.

Health and safety - manage the changed risks (e.g. transport, craneage) & sort out what needs to be done before it starts.

Sustainability

Less disruption - important for sensitive sites.

Less labour on site - important for tight sites & when labour is expensive or skilled labour is unavailable.

Speed

Process must be managed to ensure time/speed benefit is realised.

Quality - Better in Factories Because:

Better control

No bad weather

Stable workforce

Easier to train

Easier to retain

Note: Poor design cannot be expected to produce good quality by making it in a factory.

Health & Safety

Factories used to be much safer than sites but the manufacturing industry now has more fatalities than the construction industry.

Factory environments do reduce the hazards but it is the installation of offsite units which have much higher consequence incidents than the more frequent but low consequence incidents of traditional construction.

Sustainability

Factories provide greater control of energy & emission performance.

Factors provide greater control of waste & recycling management.

Offsite products are of better quality & more likely to perform as designed.

Social Sustainability - factories require multi-skilled people so can employ differently-able people & factories can be placed near local labour pool & attract people that sites can't.

To reduce the emissions associated with transportation, local assembly & flat pack methods are often considered.

Solving Skills

Factories require a new multi-skilled workforce.

Sites will require new installation, setting out and project management skills.

Designers for manufacture and designers for installation will be required.

'Construction Managers simply do not have the skills required to get the best out of offsite' (Kristina Smith - CM)

Case Study - Tesco & Yorkon

Yorkon delivered & installed a 1,430m2 Tesco supermarket in 18 hours to help the community o Workington following the Cumbria floods.

Manufactured in less than a week following instruction from Tesco.

Open & trading 13 days after starting on site.

Offsite Manufacture of M&E Modules

15% faster than traditional.

Cost neutral outcome at worst.

60-75% first fix M&E now offsite.

70-100% of plant rooms now offsite.

Load size restrictions.

No limits to what can be done offsite - only constraints are site logistics and access.

3D CAD & BIM enable projects to be designed with offsite in mind from the outset.

Early engagement is required during design & planning.

4 Types of Offsite M&E:

Multi-service horizontal modules

Vertical structural risers

Sectional plant rooms

Modular wiring systems

Challenges of Offsite Construction

Cost

Design restrictions - standardisation, lack of flexibility & adaptability, restricted use of space.

Maintenance access

Risk (technical & business)

Cost

Project teams often don't understand where the real cost & value of offsite is hidden.

IMPREST is a tool that can reveal the hidden costs & value benefits.

Works best where it is used as part of a facilitated workshop.

IMPREST can be used in the following ways:

As a decision support tool early in a project.

As a cost & value awareness tool for project teams.

As an evaluation tool towards the end of a project to record where costs have been expended.

As a training tool for new teams.

As a demonstration of value benefits by suppliers.

As a rigorous method of producing business case studies

To compare two alternative methods (usually onsite and offsite)

Costs considered by the IMPREST measurement tool:

Construction/Manufacture Costs:

Materials

Labour

Plan

Access

Complex (rectification work, prototyping...)

Project Costs:

Site preliminaries

On-site logistics

Overheads

Professional (design, planning, management)

Complex (H&S, security, sustainability...)

Case Study - East Midlands Modular Housing

Supersture was +30% more expensive.

Substructure -25%

Preliminaries -50%

Design Fees -50%

Overheads -30%

Addressing the Cost Challenge

Be real about the costs.

Measure what you are doing.

Find a way of ensuring 'you' or the people that matter benefit from the cost savings that occur.

Addressing the Design Restrictions Challenge

Design must be 100% before units go into production.

Flexibility can be incorporated if discussed with suppliers early on.

There is a restricted use of space for whole modular buildings but other types can have more flexible layout options.

Caledonian Mixed Approach - coordinated use of in situ and offsite processes enables a wide variety of designs to be achieved.

Height Restrictions - 32 storey modular apartments in New York is the tallest modular building in the world.

Addressing the Maintenance Access Challenge

A study evaluating the total maintenance labour & material costs of toilet pods showed precast was cheaper than traditionally built pods over three years in use.

Addressing the Risk Challenge

Past Failures - Terrapin Classrooms (1960s); Ronan Point (1968); Casper, Leeds (2007)

Are more stringent than traditional (Buildoffsite Registration Scheme - ensures accredited organisations meet the benchmarked standards expected by clients)

Business Risk - UMS set up prefabricated pods factory in 2002 but is due to shut as 'dealing with fluctuations in demand has proved too costly for a fixed-cost factory.

Case Study - Laing O'Rourke

£100 million investment in state-of-the-art prefabrication factories.

Competitors suggest the volume of work is not enough to justify the investment.

Competitors suggest Laing O'Rourke trie to press clients into using offsite when they themselves have no interest because they have invested so much into offsite they have to find a use for it.

Laing O'Rourke state they use the engineering solution most appropriate to each project & believe their design for manufacture philosophy will great benefits to the industry.

Critical Success Factors for Offsite

Make your decisions early

Freeze the design at the right time

Involve suppliers early - to ensure offsite methods can be incorporated.

Design for manufacture & installation - must consider practicalities of sliding pods into position.

Concentrate on interfaces

Sort logistics

Don't accept second best

Manufacturing continuity

BIM

BIM and Offsite Construction

The biggest growth in construction productivity will come from automated offsite activities that BIM will enable.

UK Governments requirement for BIM by 2016 will likely cause an increase in the usage of offsite.

It is argued that factory conditions will enable precisely designed digital objects using BIM to be realised efficiently.

Others believe offsite is the missing link for ensuring design intent is translated into a manufactured solution.

Others suggest there are many factors determining where & how to use offsite but BIM will help designers to take account for all these factors and make an informed decision.

Overall, it was clear that the success of organisations is dependent on how organisations implement BIM & offsite in the model they operate.

The majority of research suggests BIM will positively effect offsite but one consultant has suggested BIM will not enable or hinder offsite as BIM applies equally to on and offsite work.

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