Data Centre Cabinet Structure: Frames, Load Ratings and Seismic Bracing

A data centre cabinet is a structural element before it is an enclosure. It carries a load that may be measured in hundreds of kilograms, it sits in a row where a lean cannot be tolerated, and in many regions it has to survive a seismic event without opening or toppling. None of those are sheet metal details, but all of them are decided in the sheet metal design.

Load Cases You Should State

A cabinet brief that says "heavy duty" tells the fabricator nothing. State the load cases instead.

Specifying the cases, rather than a single number, is what allows the frame to be designed rather than over-built.

Frame Stiffness and Section Choice

Stiffness comes from the geometry of the section and from how the corners are closed.

• Closed box sections in the vertical posts resist torsion far better than open sections of the same mass.
• Corner gussets and plates close the load path where the posts meet the top and base.
• Cross bracing is the most mass-efficient way to resist racking in an open frame.
• Base frames should carry the load into the fixing points rather than relying on the panels.
• Welded construction gives a stiffer, squarer frame than a bolted one, at the cost of shipping volume.

The design target is a frame that stays square under the worst load case, because rails, doors and baying all depend on squareness.

Rails, Depth and Adjustment

• Provide front and rear rails with a range of adjustment that covers the equipment you expect.
• Mark the depth positions, because unmarked rails are repositioned by trial and error.
• Use a positive lock rather than friction, so a loaded rail cannot creep.
• Keep the 19-inch hole pattern consistent front and rear, and agree the unit numbering convention.
• Allow for cable management depth behind the rear rail when setting the adjustment range.

Bracing, Baying and Row Stability

A cabinet is rarely installed alone, and the row is the real structure.

• Bay the cabinets with defined fixing points between adjacent frames, so the row acts as one stiff body.
• Use a common plinth where the floor requires it, so that levelling is shared rather than per cabinet.
• Brace the end cabinets of a row, since the ends carry the greatest racking load.
• Tie the row to the structure where the specification requires it, rather than relying on floor friction.
• Keep the baying face flat, because two cabinets that do not meet cleanly cannot be bolted into one line.

Floor Fixing, Plinths and Anchors

• Decide whether the cabinet sits on levelling feet, a plinth or a castor base, and design the base accordingly.
• Provide fixing holes at four corners as a minimum, with positions shown on the drawing.
• Consider a raised-floor interface where the cabinet spans a tile grid, so the load is transferred to the structure rather than to the tile.
• Keep the anchor specification with the cabinet specification, because a braced cabinet on an unspecified anchor is unverified.
• Where castors are used, put a defined parking or levelling arrangement under the load points.

Structural Interfaces with Containment

Structural design and airflow containment meet at the front and rear of the cabinet.

• Provide a flat, defined mounting face for containment doors and blanking panels.
• Keep the mounting features away from the frame's stiffening elements so both can exist.
• Allow for the roof aperture of a fan unit or a containment interface without cutting on site.
• Blanking panels are an airflow device, so the cabinet should make them easy to fit and keep in place.

How the Structure Is Verified

Verification is cheapest before production, which is why the load cases belong in the brief rather than in a later conversation.

A Structural Brief That Gets Results

1. Load cases, including the concentrated case and any seismic requirement. 2. Floor type, fixing method and anchor specification. 3. Whether the cabinets will be bayed, and the baying interface. 4. Equipment depths and the cable management depth behind the rails. 5. Containment and airflow interfaces at the front and rear. 6. Volumes and whether a type test is required.

Our Approach to Cabinet Structure

• We fabricate welded and folded frames, plinths, base frames, gussets and bracing, and the baying interfaces between cabinets.
• We dimension the rail patterns, fixing points and baying features from a single datum so that a row assembles straight.
• We will tell you when a requested load case cannot be met by the proposed frame section and fixing arrangement.
• We do not perform seismic certification testing and we do not supply the anchors; those are specified and certified by the project engineer and an independent test house.
• Every quotation states which operations are completed in our plant.

Send the load cases, the floor conditions and the row layout, and the cabinet can be designed as a structural component rather than a box with rails in it.

Frequently Asked Questions