How a data centre containment panel is manufactured

A cold aisle containment panel looks like a bent frame with a window in it. In service it has one job: keep 5–30 Pa of pressure difference where the CRAC units put it, across an aisle 600 mm or 1,200 mm wide and 2,000 mm tall, for a decade. Everything in the manufacturing route either protects that pressure boundary or damages it.

Data centre containment panel manufacturing therefore lives or dies on three dimensions: frame squareness, groove width and hole position. Bending is the easy part. Welding moves the frame, coating narrows the groove, and drilling after coating puts metal swarf inside a sealed aisle.

This walk-through follows one part — a 600 mm × 1,200 mm roof panel with a polycarbonate infill, 1.6 mm CRCA frame, powder coated — from the nesting software to the packed crate, with the inspection points that matter and the rework causes we see on repeat orders.

What the panel has to do before it is a drawing

Containment is a pressure and airflow device. Cold air leaves the perforated floor tiles inside the aisle, passes through server intakes and returns to the CRAC through the hot aisle. Every gap in the containment is a bypass, and bypass air is cooling capacity paid for and thrown away.

That sets the real requirements:

• Airtightness at the panel-to-panel and panel-to-rack joints. A 2 mm gap along a 2,000 mm edge is 4,000 mm² of free area, comparable to a 70 mm hole, and it runs at the pressure difference all day.
• Dimensional fit to the rack line. Racks comply with the 482.6 mm (19 in) series defined in IEC 60297-3-100, so the rack width, mounting pitch and overall height the containment frame bolts to are standardised. The panel is not.
• Flatness and stiffness. A roof panel spanning 1,200 mm that sags 5 mm opens the joint at both ends and reads as poor finish on site.
• Finish that survives handling. Panels are stacked, shipped and lifted into a live data hall; the coating takes more abuse in transit than in service.

Rack-level mechanical performance is characterised by IEC 61587-1, which covers static and dynamic load tests on empty racks and cabinets. Containment panels sit outside that scope, which is why the specification has to be written per project rather than inherited from the rack.

What a 2 mm gap actually costs in cooling

Take a ten-rack aisle on 600 mm floor tiles, each delivering 1,200 m³/h, so 12,000 m³/h of cold air enters the aisle. The IT load absorbs most of it and returns through the hot aisle. Now open a 2 mm gap along the full 2,000 mm of ten roof panel joints: 20,000 mm of joint at 2 mm is 40,000 mm², or 0.04 m² of free area. At 15 Pa differential and a discharge coefficient of 0.6, that leaks roughly 430 m³/h — about a third of one tile's airflow, every hour, straight back to the return.

The arithmetic is rough, but the conclusion is not: a joint detail that is 1 mm tighter is worth more than a thicker panel. This is why the drawing should dimension the gasket groove and the panel joint, and why the inspection after coating is a fit check, not a visual check.

Containment panel manufacturing, operation by operation

1. Blanking: laser or press

A 600 × 1,200 mm frame with a glazing aperture, hanger holes and gasket slots is a nested laser part at low volume. On the 12 kW fibre laser, four frame blanks nest on a standard 2,500 × 1,250 mm sheet with the aperture cut-outs sharing a common cut line, which recovers 20–30% of the sheet compared with a fixed punch layout. The 40 ft × 16 ft bed is what lets a long end-of-aisle frame be cut in one piece rather than joined. The cut strategy for enclosure work is covered in laser cutting for electrical enclosure panels, and the same nesting rules apply here.

Above roughly 2,000 panels a year the economics invert. A compound tool on a 200–300 T press punches the blank, the aperture and the hanger holes in one stroke, at 30–60 strokes per minute, with hole positions held by the tool rather than by the nesting software. That consistency is worth more than the piece price on a containment programme, because a hole that moves by 0.4 mm between batches becomes a site fit problem.

2. Bending: the frame is four bends and a groove

The frame is formed on the 200 T, 5-axis CNC press brake with the 4,450 mm bed, which handles the long return flanges on end-of-aisle panels without repositioning. Two numbers decide whether the part comes off the brake flat.

The first is the flange length. On 1.6 mm CRCA with an 8 mm V-die, the minimum flange that can be formed without the punch marking the outside face is about 9.6 mm. Below that, the part needs a smaller die, more bends, or a different corner design.

The second is bend allowance. The developed blank is calculated with a K-factor that depends on the material and the die opening; a 1.6 mm CRCA at 90° with an 8 mm V-die typically gives back about 2.6 mm of bend allowance per bend. Get it wrong by 0.3 mm per bend and a four-bend frame is 1.2 mm out overall before welding starts. The bend allowance calculator takes the die and material and returns the flat length to use in the DXF.

3. Welding: where the frame goes out of square

Frames are welded at the corners, usually MIG on 1.6 mm with a 0.8 mm wire, or spot welded where a lapped corner joint is acceptable. Both processes shrink. A 25 mm MIG weld on 1.6 mm CRCA pulls the joint in by roughly 0.3–0.5 mm per side, and four corners that each pull differently turn a square frame into a parallelogram.

The control is a fixture, not a welder's eye. Corners are located in a checking fixture with fixed stops, the weld sequence runs diagonally opposite corners first, and the frame stays clamped until it cools below about 60 °C. Held that way, a 600 × 1,200 mm frame comes out within 1.5 mm diagonal difference. Welded free-hand on a bench, the same frame typically drifts 3–5 mm, which is enough to stop the infill dropping into the groove.

Three frame details decide whether it stays square after the clamps come off. A lapped corner with two spot welds resists pull-out better than a butt joint on 1.6 mm, because the lap carries load in shear rather than putting the weld in tension. A gusset formed into the corner, 40 × 40 mm, adds stiffness for about 20 g of material and holds the corner angle through handling. A stiffener spot welded across the roof panel at mid-span removes the bow that makes a bench flatness check meaningless. Each is a drawing decision, and each is cheaper than a welded, straightened and re-coated frame.

4. Deburring, pretreatment and coating

After welding, the frame is dressed at the welds, degreased and taken through the seven-tank pretreatment line, then powder coated in the 18 ft × 14 ft booth at 60–80 µm and cured. Two details matter more than the face finish.

The hollow section. A bent frame forms a closed or semi-closed box. Cleaner and rinse water enter it and bleed out during the cure, leaving a stain line and, on a bad day, a blister on the visible face 40 mm above the weld. The fix is a 6 mm drain hole in the least visible flange, positioned before pretreatment, or an open corner design.

The glazing groove. The groove that receives the infill and gasket is cut 0.5–1 mm wider than the infill so the gasket has room to compress. A 70 µm powder film on each wall takes 140 µm off that clearance, which is why groove dimensions on a coated panel are specified after coating, not before. If the drawing gives the groove width before coating, add the film to the tolerance or mask the groove.

5. Final assembly and packing

Whether the infill, gasket and brush seals are fitted by the panel supplier or at the cabinet builder changes the packing, not the frame. Fitted panels need face protection and a crate that keeps the infill off the frame; unfitted panels stack flatter and travel cheaper. Either way, holes are cleared with a hand reamer rather than a drill wherever a thread or a close fit follows, because a drill pushes swarf into a groove that nobody cleans. Panels are packed face to face with foam interleaves and corner protection; a stack of ten panels at 8 kg each is 80 kg of edge loading on the bottom frame.

The limits to put on the drawing

Where containment panels fail, and who pays

Squareness drift after welding. The most common rework on a containment order. Detectable in 30 seconds with a tape across both diagonals: the two readings must match within 1.5 mm. A frame 3 mm out will not take the infill, and the frame is already coated at that point.

Groove too tight after coating. Discovered at assembly, after the frame has been through the line. Either the groove is masked from the start or the part is reworked by scraping film out of a 3 mm slot, which damages the coating and the adhesion at the edge.

Weld distortion on long roof panels. A 1,200 mm panel welded at both ends with no fixture bows in the middle by 2–4 mm. It is flat when checked on the bench and rocks on the rack.

Zinc contamination on pre-galvanised frames. Welding burns the zinc; the fume is a health control issue and the burnt zone is bare steel. If it is not dressed, pretreated and coated, the weld line rusts first, and the rust runs down a white data hall wall.

Coating on the earth bonding points. Containment is usually bonded to the rack earth. A 70 µm film at a bonding pad is an insulator; specify masked pads or a stud.

When to press-form instead of laser blank

The decision is annual volume against tooling cost. A compound tool for a roof panel frame is a tooling line item that only pays back on volume; at 500 panels a year it never does, and the laser is faster to change when the aisle width changes. At 2,000–3,000 panels a year with a stable design, the tool amortises inside two years and removes the hole-drift problem entirely. Between the two, a single-stage tool for the hanger holes with laser profiling for the aperture is a common compromise.

What we do not do is fire-rate or acoustic-test a containment assembly. Those certifications come from a third-party test on the installed system. We manufacture and inspect the frame and the coated panel to drawing; the site performance is a system result.

When a fabricated steel panel is the wrong route

Three cases that should go elsewhere.

Extruded aluminium framing. A contained aisle with extruded aluminium posts and a glazed infill is a different supply chain; we form and weld sheet, not extrusions. Mixing a fabricated steel frame into an extruded system usually fails at the joint, not at the panel.

Insulated or foamed cores. A panel with a PU or mineral-wool core for fire or thermal duty is an insulated panel product with its own certification. Our part is the steel skin and frame; the core and its rating are not ours to supply.

Site-measured retrofit containment. A retrofit in a live hall often needs panels cut to a measured opening rather than to a drawing. That is a site fabrication job with a template, and a factory-built panel with ±0.5 mm hole positions is the wrong tool for it.

What Ganesh actually runs

Containment frames are lasered on the 12 kW machine, formed on the 200 T 5-axis brake with a Delem control and a 4,450 mm bed, welded in fixtures built by the in-house tool room, and coated on the seven-tank line with DFT and cross-hatch checks. Three CLOOS robotic cells and more than 30 manual MIG, spot and SPM stations handle repeat frame welding where the volume justifies it, and ISO 9001:2015 and ISO 14001:2015 govern the process control and the effluent side of the pretreatment line.

The data centre racks product page covers the frames, enclosures, cable management and blanking plates that share this route, and bending for rack frames and cabinets explains how the bend sequence changes when the frame has to stay square. For load and panel-count planning, the rack load calculator gives the numbers a facilities team will ask for.

What the rack drawing has to settle

1. Aisle width, rack height and the rack standard the frame bolts to, with the fixing pitch.
2. Material and thickness per member, and whether pre-galvanised is acceptable.
3. Frame squareness as a diagonal difference, not as an angle.
4. Flatness over a stated length, measured after coating.
5. Glazing groove width, and whether the dimension applies before or after coating.
6. Masking zones: groove, bonding pads, any face that takes a gasket.
7. Weld specification and the finish required at each weld, including pre-galvanised touch-up.
8. Drain hole position for every closed section.
9. Packing: panels per crate, interleave, corner protection, and whether infill is fitted before dispatch.

Most containment rework traces to items 3, 5 and 8 being left to the supplier's judgement. None of them is expensive to specify. Send the drawing and the aisle layout to request a quote, and the data centre hub has the related guides on rails, blanking panels and louvre design.