Every quotation for an auto duct line includes a drawing of the machine. Almost none of them include a drawing of the building around it. Then the container arrives, the line gets set down wherever there is floor space, and six months later the owner tells me the line is slow. It is rarely the line.
I have laid out around thirty duct shops, from a 400 m² unit in Sharjah to a 3,000 m² plant outside Ho Chi Minh City. The pattern is consistent: the shops that hit their rated output are the ones where the material never travels backwards, the operator never walks more than four metres to reach a control, and the coil has somewhere to sit that is not the fire exit. This article is the checklist I use, with the numbers I use for each item.
A Line 5 machine is usually quoted as something like 28 m long including the coil car. That number is useless on its own, because it excludes the coil storage, the outfeed, and the space you need to get a pallet of finished duct past the line without stopping it.
My rule is to take the machine length from the manufacturer, add 3 m at the infeed for coil handling and 4 m at the outfeed for blanks and folding, then add a 1.2 m service strip along the drive side and a 2.5 m traffic aisle on the other. That is the real envelope. For a Line 5 that comes to roughly 38 m by 7 m, or about 265 m² before you count coil storage and assembly.
| Line model | Machine length | Real envelope | Floor area (incl. aisles) | Coil width | Typical output |
|---|---|---|---|---|---|
| Line 2 | 12 m | 20 m x 5 m | 100 m² | 1,250 mm | 400-600 m²/shift |
| Line 3 | 18 m | 26 m x 5.5 m | 145 m² | 1,250-1,500 mm | 700-900 m²/shift |
| Line 5 | 28 m | 38 m x 7 m | 265 m² | 1,250-1,500 mm | 1,000-1,400 m²/shift |
| U-shape Line 5 | 16 m x 9 m | 24 m x 13 m | 310 m² | 1,250-1,500 mm | 1,000-1,300 m²/shift |
The U-shape numbers deserve a comment. It occupies more floor than a straight line for the same output, which surprises people. What it buys you is a building that is 16 m deep instead of 28 m, and that is often the difference between fitting into an existing unit and renting a new one. If your building is long and narrow, the straight line wins. If it is a square box with a column grid at 8 m, the U-shape is usually the only thing that fits. There is a fuller comparison on the U-shape Line 5 page.
Draw the flow as a single line on paper: coil in, straighten, cut, lock form, fold, assemble, weld, seal, test, pack, out. Now look for places where that line crosses itself. In nine out of ten existing shops I visit, the finished duct has to pass the coil storage to reach the loading door, which means a forklift and a coil car are sharing a 3 m aisle all day.
The distance from the shear outfeed to the folding station should be under four metres, and the distance from folding to the assembly benches under six. Beyond that, operators batch blanks on the floor and carry them in armfuls, and batching is where squareness dies. A blank that sits on the floor for an hour gets walked on, and a walked-on blank has a bent edge that will not sit flat in the folder.
Put the coil rack on the same side as the decoiler, within 6 m of the coil car, and orient the rack so a forklift can approach from the aisle without reversing. A coil rack holding eight coils at 1.25 m wide by 1.5 m diameter needs about 3.2 m by 9 m including the forklift turning circle. Do not put it against a wall with the fork pockets facing the wall. I have seen that mistake three times and every time the operator ends up dragging coils with a chain.
If you process more than 30 tonnes a month, add a second decoiler rather than a bigger rack. Coil changeover on a single decoiler is 8 to 12 minutes including threading, and at 30 tonnes a month you are changing coils twice a day, which is 25 minutes of lost line time you can buy back for the price of a used decoiler.
This is the section that gets skipped in the quotation and discovered by the electrician. Get it right on paper before the floor is poured.
A Line 5 with plasma, dual folding and a TDF station draws around 45 kW connected, with a running load closer to 28 to 32 kW. Specify a 63 A three-phase supply at the line, not 40 A, because the plasma and the folding station will start together more often than you think. Run the supply in a cable tray at 2.4 m, not on the floor, and put a local isolator within 2 m of the main cabinet so a maintenance engineer does not have to walk to the panel room.
Voltage is the other trap. A line built for 380 V 50 Hz run on a 415 V 50 Hz supply in the Gulf will run, but contactor coils, VFD DC bus voltage, and hydraulic solenoid life all suffer. If your supply is 415 V or 440 V, tell the factory before the order, not after. It is a transformer tap change at the factory and a service call on site.
Budget 400 to 600 litres per minute free air delivery at 0.7 MPa for a Line 5 with pneumatic clamping, notching, and a corner matic. That is more than most small shops have. A 7.5 kW screw compressor with a 500 litre receiver and a refrigerated dryer is the minimum I would install. Undersized air shows up as slow clamping, which shows up as out-of-square blanks, and the operator will never connect the two.
Put a dedicated regulator and filter at the line, and a drain leg at the lowest point. Water in the air line is the number one cause of sticky solenoid valves in humid climates, and it always happens in the rainy season when you are busiest.
The line needs a flat slab, not a special one. 150 mm of reinforced concrete at C25 or better, flatness within 3 mm over 3 m, and no step at the joints. The decoiler pit, if you use one for coil loading, should be 400 mm deep with a sump. Isolated foundations are unnecessary below about 4 tonnes per module; above that, check with the factory. I have seen a line installed on a 100 mm slab in a leased building, and it ran fine for two years, but the anchor bolts pulled out when the building was resold and the new tenant tried to move it.
Duct shops underestimate headroom. The line itself needs about 2.2 m. What needs more is the coil handling. If you plan to load coils with an overhead crane, you need 5.5 m under the hook for a 1.5 m coil on a 1.2 m cradle, plus the crane beam. If you plan to use a forklift, you need 3.5 m clear and a floor that will take a 5 tonne wheel load.
My preference for shops under 1,500 m² is a coil car plus forklift, no crane. It is cheaper, it does not block the roof structure, and it keeps the coil handling at floor level where the operator can see it. Cranes make sense above about 40 tonnes a month of coil consumption, where the cycle time of reaching up and down starts to matter.
A line producing 1,200 m² a shift produces roughly 150 to 200 duct sections. Each one needs a flange, a gasket, four corners, and somewhere to sit. That is not a small space requirement.
Allow one assembly bench of 2.4 m by 1.2 m per 400 m² of shift output, plus a test rig if you are doing pressure class work. A leakage test rig for 1,000 Pa class duct needs a clear area of 3 m by 2 m with a 2.5 m ceiling, because the test section has to be assembled and capped at full size. Put it near the loading door, not in the middle of the shop, so a failed section does not have to travel back through production for repair.
Packing needs 40 to 60 m² for a line of this size, with room for a 6 m flatbed to back up to the door. If you are exporting, add a crating area and a place to store plywood and steel strapping that is not the walkway. I have watched a shop lose a full day because the only free floor was in front of the line, and the line could not run while the crate was being built.
If you are starting from an empty building, do it in this order. Mark the line envelope on the floor with tape first and walk it for a week with the real forklift, because tape is cheaper than concrete. Then pour or repair the slab only where the machine feet land, plus the coil car path. Then run the cable tray and the air main overhead, before the machines arrive, because doing it afterwards costs three times as much. Then install, then build the benches around the installed line rather than the other way round.
And leave 15 percent of the floor empty. Every shop I have seen that grew successfully had slack in the layout. Every shop that was packed to the walls at day one ended up stacking duct in the office corridor within two years. If you are still choosing between line models, the Line 3 page and the mini auto duct line show the smaller envelopes, which is often the better starting point for a first shop under 500 m².
Usually yes, but the line has to run parallel to a bay rather than across it, and you lose the ability to feed coil from the end. Plan on a U-shape or on a shortened straight line with the coil car in the bay next door. Measure the actual clear span, not the grid dimension, because a 300 mm column eats into both sides.
No. A pit makes coil loading easier with a coil car and lowers the line entry height, but it adds drainage problems and makes the machine harder to relocate. On a leased floor, skip the pit and use a ramp-type coil car.
2.5 m of clear height is comfortable for the line and for anyone working on top of it. If you are using an overhead crane for coil handling, work backwards from the hook height: coil diameter plus cradle plus 1 m of sling, plus the crane beam depth.
If your climate goes above 35 degrees Celsius, yes. A line under an uninsulated metal roof runs its hydraulics 10 to 15 degrees hotter, and hydraulic oil life drops by roughly half for every 10 degrees above 60. Insulation pays back in oil and seal life alone, before you count operator comfort.