Knowledge

Not every building needs one. Knowing when yours does, and at which design stage to ask, saves money and avoids late surprises in the permit process.

The main deliverable of a wind study is a coloured map. Here is how to read it like a reviewer, and the questions worth asking about it.

Whether a square is lively or deserted often comes down to wind. Comfort and safety are the two questions a wind study answers, and they are not the same question.

A tower does not shelter the street below it. Often it does the opposite. The mechanism is called downwash, and it is behind most of the windy corners we are asked to fix.

When a wind study finds a problem, the next question is what to do about it. Some measures work far better than their reputation, and some popular ones barely work at all.

The Netherlands is the only country with a national standard for wind comfort in the built environment. NEN 8100 dates from 2006, and if you build in the Benelux, your wind study will most likely be judged against it.

The reference wind comfort criteria in the United Kingdom, and the vocabulary most international projects use when they talk about where people can sit, stand and walk.

In 2019 the City of London became the first city to publish its own wind microclimate guidelines. They show where urban wind regulation is heading, well beyond London.

The wind your weather app reports and the wind that hits a facade at sixty metres are not the same thing. Understanding why protects you from the most common error in quick wind assessments.

Aircraft are shaped so air can follow them. Buildings are not, and that single fact explains why small design moves can have outsized effects on wind, loads and noise.

Wind is a load case like any other, except that it changes with every metre of height and every corner of the shape. The Eurocode computes it, up to the point where it tells you to go simulate.

Can a wind turbine pay for itself between buildings? Sometimes yes, often no. The physics is unforgiving, but it also tells you exactly where to look.

Between the weather forecast and what you feel on a given street sits the microclimate: the local weather a city makes for itself, block by block. Whoever shapes a city shapes it, deliberately or not.

On a summer night the centre of a city can be five to ten degrees warmer than the fields around it. The difference is made by design decisions, which means design can unmake it.

Whether people linger on a square in April or flee it in July is written in the microclimate. Outdoor comfort can be measured, mapped, and designed for, season by season.

Climate change arrives in a city twice: as a warmer regional climate, and as a microclimate that amplifies it. The second part is the one urban design can still act on.

You commission a wind study, and the work behind it is CFD: computational fluid dynamics. Here is what that actually involves, and what separates a reliable simulation from a pretty picture.

A ventilation system can meet its flow rate targets and still leave half the room breathing stale air. Age of air is the quantity that exposes this, and the one worth asking for.

For a manufacturer of ventilation systems, every physical prototype room is expensive and every failed certification test more so. A validated digital test room changes that arithmetic.

How do you prove that the air over an operating table is as clean as the design promised? Two tools do most of the work: particle counts against ISO classes, and smoke.