Building Requirements for an Inclined Wind Tunnel

Before a concept design gets drawn, there's a cheaper question worth answering first: does the building you already have, or the site you're already looking at, even have a plausible shot at housing an inclined tunnel? Answering that early saves both sides months of a conversation that a site visit could have ended in an afternoon.

1. Height and span — the two numbers that decide everything else

An inclined tunnel is the most demanding of the common tunnel architectures to site, because it needs both the structural height a vertical tunnel demands and the long footprint a horizontal tunnel demands, in the same building, at the same time. The working zone has to be long enough to hold a glide path, not just tall enough to hold a body against gravity — which is why the chamber ends up as an elongated inclined volume rather than a compact column.

Concretely, this rules out most standard commercial or retail shells and points toward industrial-height structures : warehouses, former manufacturing halls, aviation hangars, and similar buildings originally built for equipment or vehicles rather than people. The reference facility for this technology — Inclined Labs' Stockholm site — is housed in exactly that kind of building: a structure at Bromma originally built for military aviation research in the 1930s-40s, later repurposed.

2. Floor and foundation loading

A wind tunnel is, structurally, industrial machinery — drive motors, fan assemblies, ducting and the tunnel's own structural steel all bear on the floor and foundation beneath them, concentrated in specific locations rather than spread evenly. A building whose floor was designed for office or retail loads, rather than for heavy manufacturing equipment, is a real constraint, not a formality — it is one of the first things worth checking against an actual structural drawing, not an assumption based on the building's general size.

3. Electrical supply

An inclined tunnel's fan drive is industrial-scale electrical load, supplied through a proper three-phase industrial connection, not a standard commercial-building service. Whether a candidate site already has adequate power available — or whether bringing in a new supply becomes its own civil-works project — is a question worth answering before a concept design, since utility upgrades can carry their own long lead times independent of the tunnel itself.

4. Noise

Large fan drives are genuinely loud, and an inclined tunnel runs its fans for the duration of every operating hour, not intermittently. Site selection has to account for this from the outset: proximity to residential neighbours, the building's own acoustic properties, and whether additional acoustic treatment is realistic within the available budget and space. This is a site-and-neighbourhood question as much as an engineering one, and it's far easier to solve by choosing the right building than by trying to retrofit acoustic treatment onto the wrong one.

5. Retrofit versus new build — how to actually decide

The Stockholm precedent is a reminder that existing industrial buildings are a real, proven option , not a compromise — large old halls with generous height and heavy floors are exactly the building stock this industry can reuse economically. But retrofitting only pays off when the building's fundamentals already fit:

If height and span already work , a retrofit usually beats new construction on both cost and schedule — the expensive structural problem is already solved.
If floor loading or electrical supply need major upgrades , the retrofit's apparent savings shrink fast, and the comparison against new construction has to be run on real numbers, not on the intuition that "using an existing building is always cheaper."
If the building needs its envelope substantially altered to accommodate the tunnel's height or length, that work itself starts to resemble new construction in cost, even inside an existing shell.

We cover the general version of this trade-off in more depth in our

article on retrofit versus new build

6. What this means for your programme

Send us your building's height, span, floor drawings if you have them, and available electrical capacity , and we'll give you an early, honest read on whether it's a plausible fit before either of us invests in a concept design.

Sources and notes

Inclined tunnel site and structural requirements (need for both vertical-tunnel-scale height and horizontal-tunnel-scale footprint in one building; industrial floor loading from concentrated equipment mass; industrial-scale three-phase electrical supply; continuous fan noise as a site-selection factor) are TunnelTech engineering practice.
Reference facility precedent (Inclined Labs' Stockholm site at Bromma, housed in a structure originally built for military aviation research in the 1930s-1940s): consistent with our published article on

engineering an inclined wind tunnel

, sourced there to Indoor Wingsuit Flying Stockholm, Indoor Skydiving Source and Inclined Labs.