2km pipework system for Honda
November 1st 2007

Legris' rapid assembly Transair compressed air pipework system allowed installation over the Honda production lines in tandem with the rest of the development and now permits fast modification by Honda personnel as required When Honda needed over two kilometres of compressed air pipework for a 130 million extension to its production facility at Swindon, the project team chose Legris' Transair system for its ability to meet a number of essential criteria. In addition to the need for cost efficiency, on-time delivery and quality, Honda needed to know that the supplying company could work around other contractors on the site.

The pipework had to be installed over the production lines at the same time that the lines themselves were going in. That required a system that could quickly be amended as the other work was going on.

Once installed, Honda needed to be able to change the system easily to meet future demands. Under those circumstances, traditional galvanised pipework, with its need for threaded connections, was not an attractive option.

Compressed air is vital to automotive manufacturing and Honda relies heavily on a clean, plentiful supply at Swindon where the expanded facility has increased annual production capacity to 250,000 automobiles annually.

Two compressors are in service at any one time at Swindon, driving up to 7,500 cfm of air through an eight-inch steel ring main suspended in the roof of the new facility. Total compressor capacity on the site is in excess of 20,000 cfm.

The task to supply the Weld and Assembly Frame areas was to involve taking drops of 40mm Transair pipework from the steel pipe to create sub ring mains directly over the production areas.

These would in turn feed machine and power tools through coiled tubing.

In addition to the two and a half kilometres of the push-to-fit Transair pipework, the project would require individual drops of over 300 double compressed air outlets to the work stations and the installation of some 80 ball valves.

Transair combines Legris' push-to-fit coupling technology with rigid aluminium pipework to create a system that is rapid to install and modify, and which is also corrosion resistant. A further advantage is that all components are completely reusable.

Once installed, the system can be modified by the user with no specialist knowledge, making it particularly suitable for the changing needs of industry where new supplies of compressed air must be introduced to different workplaces with the minimum of downtime.

Unlike galvanised steel systems, Transair is not prone to corrosion which leads to contamination of the compressed air supply, nor to the deterioration through uv light which causes cracks and leakages to plastic pipework systems.

Available in six sizes from 101mm to 16.5mm, flow rates for Transair pipework are also greater than for galvanised systems of larger diameters, while pressure drops are far lower than for plastic systems.

Swan neck savings It was in the weld and assembly area that the "swan neck" design of of Transair's drop connector was to play an important part, allowing connection in either a vertical or horizontal position and still preventing condensate from entering the system. The swan neck is just one fitting, and with a twin wall bracket Honda was able to replace its original design which called for four elbows and an equal tee. In addition to savings on costs, time and parts, the fitting offered greater reliability and efficiency as there were fewer opportunities for leakage.

The quality of compressed air and the system that carries it are of major importance to Honda, where out of two shifts working an 18-hour day the company allows itself downtime of just three minutes. The air is filtered at each point where it flows from the steel ring main into the Transair system, with all filters incorporating pressure reducers.

Because of the various installation schedules, the Transair pipework had to be erected over the production line area before those lines actually existed. This meant working over the deep trenches which were going to house the conveyors. The light weight of Transair enabled the installers to carry the operation easily, whereas the weight of galvanised pipe would undoubtedly have caused problems. As Transair is a push-fit system, sections could be disassembled and reassembled in a matter of minutes. As the corrosion resistant aluminium tubing is already powder coated blue, there was no also no requirement to paint it.

Once installed, the Transair system was tested using bottled nitrogen and found to be completely leak-free. Primary distribution pipework pressure is 9 bar and testing was carried out at 1.5 times that pressure to 13 bar. "Although the pressure to the secondary fit Transair is reduced to 7 bar, it had to be assumed that the working pressure could be 9 bar to allow for regulator failure," says Stuart Moon of Legris distributor Harrier Pneumatics.

Part of the project included training for Honda's maintenance personnel to enable them to modify the Transair installation as required. The team has been able to take advantage of the product's push-fit connection technology to rearrange some of the production areas and to add to them as part of an on-going project.

More articles from Legris Limited: