Manufacture off-site
Most construction materials and products require secondary processing to produce finished construction products; this can take place on or off the construction site.
All steel construction components are manufactured off-site and delivered to site cut to length, drilled and fabricated to facilitate fast and easy assembly and erection. Consequently there is very little steel wastage on the construction site.
Off-site manufacture has many benefits over site working. Click on one of the following to learn more about the sustainability benefits that come from the manufacture of steel construction products.
Compared with site working, off-site, factory working is much safer. Many processes are fully or semi-automated and factory conditions are generally warm, dry and well-lit. Compare this to site working which, in addition to being less safe for workers, is subject to delays as a consequence of inclement weather.
Factory working also reduces dependence on itinerant workers and lessens the transport impacts of site workers who often face long-distance daily commutes. Factory working fosters the development of family life and local community relationships and encourages staff development and retention.
Steel construction products are efficiently manufactured using hi-tech, computerised equipment that minimises wastage of materials. Computer aided design (CAD) systems are efficiently integrated with manufacturing software to produce quality products efficiently, accurately and quickly.
Any steel waste produced during manufacture, such as off-cuts or turnings, are 100% recycled into new steel.
Factory working facilitates accurate, quality workmanship that results in high quality, reliable products with fewer defects than site working. For example, the typical cost of rectifying defects (snagging) in a traditionally built house is around £2,000 per house.
Factory produced products can more easily be standardised and tested, further improving their reliability.
Corrosion and fire protection coatings for steelwork are increasingly being applied in the factory in preference to on the construction site. This enables greater quality control, i.e. more uniform coverage, reduces wastage through overspray and reduces the time taken on site to apply coatings to the steelwork. Importantly applying coatings in the factory limits delay to follow-on trades on-site, thereby reducing the overall construction programme.
Manufacturers of steel construction products operate on a just-in-time basis. Semi-finished steel products such as hot-rolled sections and steel coil, are delivered to the factory, from stock-holders or direct from the steel mill, promptly processed and finished goods despatched to meet the on-site construction programme.
Just in time deliveries reduce or even eliminate the need for on-site storage of products and materials. Not only does this improve site logistics but also reduces the risk of damage to products stored on site.
Surveys of construction clients have confirmed that predictability is a key issue on large projects. Because steel construction products are manufactured off-site, delivered to site on a ‘just-in-time’ basis, suffer few defects and are erected quickly on site, steel construction is more predictable than many other forms of construction. Time is money and predictable construction programmes mean that clients can plan and finance more accurately using steel construction with lower risk due to unforeseen delays.
Modular construction takes off-site manufacture to the extreme!
Steel-based, modular construction systems afford maximum off-site manufacturing opportunity. Modules can be fitted out with floor finishes and sanitary (and other) fittings in the factory and simply and quickly craned into position on site.
The motivation for using modular construction lies in the business-related benefits that make this form of construction more attractive to the client than alternative forms of conventional site-built construction. In such cases, the design decisions are most strongly influenced by:
- Speed of construction on site. Rapid construction leads to business-related benefits to the client, due to early completion and early return on capital investment.
- Avoidance of disruption and loss of operation of adjacent buildings, such as hotels, and in sensitive sites.
- Buildings or components with a high degree of servicing. These require careful site installation, and pre-compliance trials, which are better carried out off site and off the critical construction path.
- A large number of regular or repetitive units. Factory production can facilitate transportation and can achieve economy of scale in production.
- Planning constraints, such as on delivery times, time of working, noise control on site.
- A short 'weather window', or other site constraints to the construction operation.
- Lack of suitable skills at site. This might be the case at a remote site.
- Client requirements for an exceptionally high degree of quality control. This can best be achieved by off-site manufacture and pre-installation checks.
- A requirement for a single point procurement route. This can be achieved through a design, manufacture and build service, which the modular industry provides.
- Security or other related issues on site. Construction operations can be controlled more precisely when modular units are used.
