Densification and the geometry of change: designing data centres in an age of uncertainty

Overview

This article was published in 2026 by Michael Hope-Jones, MEP director at Bryden Wood, and discusses how rapidly rising rack densities change building form and delivery strategy. It is a consultancy viewpoint: not a standard or measurement report, and its recommendations rest on experience. It is thus a shared planning basis for architecture and engineering teams rather than a firm design rule.

According to the density figures cited, rack density moved from about 3-5 kW to 30-60 kW for hyperscalers and 80-150 kW for AI clusters, with some programmes considering 400 kW and more. Because projects take three to five years to deliver, a hall designed for 30 kW per rack may need to carry twice that at go-live. This uncertainty calls for keeping design decisions flexible at an early stage.

Hope-Jones recommends fixing column grids, load paths and cores early while deferring intermediate floors. Low-density air-cooled halls can be stacked two or three high, whereas high-density liquid-cooled IT belongs on the ground floor because of rack weight. CDU rooms, power and chilled water distribution and heat rejection should sit on upper levels above the high-density halls. The idea of two-speed delivery is to build plant early and fit out white space later.

One lesson drawn is that plant grows disproportionately with power and cooling, often eating the space saved by denser IT. As a limit, the article offers no quantitative calculation method; its figures show a trend and should be verified for a specific project. It still sets out, in a concrete frame, that building geometry, structural loading and delivery strategy must be treated together with density uncertainty.

Key points

1. Rack density moved from about 3-5 kW to 30-60 kW for hyperscalers and 80-150 kW for AI clusters, with some programmes considering 400 kW+.
2. Delivery takes three to five years, so a 30 kW/rack design may need to carry twice that at go-live.
3. Low-density air-cooled halls can be stacked two or three high.
4. High-density liquid-cooled IT belongs on the ground floor because of rack weight.
5. Place CDU rooms, power and chilled water distribution and heat rejection on upper levels above high-density halls.
6. Fix column grids, load paths and cores early while deferring intermediate floors.
7. Two-speed delivery: build plant early, fit out white space later.
8. Plant grows disproportionately with power and cooling, often eating the space saved by denser IT.

Using it in design

• Warn when high-density liquid-cooled racks are placed on upper floors without a matching structural floor-load rating.
• Show plant-space growth alongside white-space reduction when users raise rack density.
• Set column grids and load paths for future density; keep intermediate floors deferrable.
• Plan CDU, power and heat rejection areas above the high-density halls.

Who should read it

Data centre building, structural and MEP designers, programme managers and those setting delivery strategy under density uncertainty.

Publication details

Authors

Michael Hope-Jones

Publisher

Bryden Wood

Year

2026

Document language

English

Source type

Expert / community

Access

Free to read

Licence

Copyright retained; citation only — the publisher’s terms apply to the original document

Citation