How do you design a new compressed air ring main for an auto body shop?

German Autocentre is Sheffield’s home of used German cars. Whether it’s a BMW, a Mercedes, an Audi, VW, Porsche or MINI, the company has been building its reputation for quality and value from its Sheffield Rd base.

Yet every great dealership needs technical backup, and German Autocentre has just added a second garage and body shop (in Darnall) to complement its existing facility in Attercliffe.

Air compressor power is a core ingredient for any auto repair business. Garages tend to be filled with air impact wrenches, drills, ratchets, nailers and staplers. Body shops in particular will also need air sanders and paint sprayers.

Each of those tools needs feeding from the central compressor, and as we explain in this case study, the most efficient way of doing that is with a new ring main. Our challenge was to supply the right compressor and the right ring main to ensure the autocentre had all the power it needed, without overengineering the setup in a way that would increase running costs for the future.

Considerations in compressed air

The whole point of a ring main is to ensure each workstation gets an equal flow of air at a consistent pressure. That’s particularly important in an auto body shop, where erratic pressure can lead to real issues with delicate processes like paint spraying.

The key to ensuring that consistency is to get the design right at the outset. We’re aiming to ensure any pressure drop, even at the point most remote from the air compressor, is kept to an absolute minimum (no more than 0.1 bar), even with multiple users drawing from the compressor at the same time.

To achieve that, you need to look at the ingredients of your system. German Autos agreed with our recommendation of a powerful 22kW Boge C2-2 LF, a highly reliable, highly versatile screw compressor. We also knew that German Autos would need 11 branch lines to feed its engineers’ workstations, spray booths etc.

To connect the two while avoiding pressure drop, we calculated the required flow rate, taking into account the total length of the ring main and the number of required bends and couplings (all of which will have an effect on flow and pressure). That led us to a 40mm main.

It’s simple enough to spot the compressor and air receiver in these images. It’s rather more difficult to pick out the ring main, which is another point of the exercise. Because while air power is critically important, most businesses will want the pipes and ducting to remain discreet and unobtrusive.

Launching a new business, factory or workshop that needs air power? From air compressor supply to rind main design and much more, contact us or call 0114 243 2347