ARCHITECTURAL CONCEPTS: CIRCULATION
This article is part of our series on key Architectural Concepts.
You can check out the rest of the series here, and if you have any questions or comments about your experience with circulation, leave a comment below!
WHAT IS CIRCULATION?
“Circulation: movement through space”
Before I began studying architecture, the word circulation meant very little to me, other than bringing to mind science classes spent learning about the movement of blood around the human body.
In architecture, the concept of circulation isn't so different - it refers to the way people, the blood of our buildings, move through space.
In particular, circulation routes are the pathways people take through and around buildings or urban places. Circulation is often thought of as the 'space between the spaces', having a connective function, but it can be much more than that. It is the concept that captures the experience of moving our bodies around a building, three-dimensionally and through time.
In this article, I will look at what circulation is, and how you can design for it - using the rules and breaking them too. I also touch on how architects represent circulation, often using diagrams, and how circulation relates to Building Code Requirements.
Components of Circulation
Although every space a person could access or occupy forms part of the circulation system of a building, when we talk about circulation, we typically don’t try to account for where every person might go. Instead, we often approximate the main routes of the majority of users.
To simplify further, architects typically divide their thinking according to different types of circulation, which overlay with one another and the overall planning. The type and extent of these divisions will be project dependant, but might include:
direction of movement: horizontal or vertical;
type of use: public or private, front of house or back of house;
frequency of use: common or emergency; and
time of use: morning, day, evening, continuous.
Each of these types of circulation will require different architectural consideration. The movement might be fast or slow, mechanical or manual, undertaken in the dark or fully lit, crowded or individual. The pathways might be leisurely and winding, or narrow and direct.
Of these types of circulation, direction and use are often critical to a building layout.
DIRECTION
Horizontal circulation might include hallways, atria, paths, entries and exits. It is also affected by the furniture layout, or other objects in the space such as columns, trees, or topographic changes. This is why architects usually furniture as part of a concept design, because it is critically linked to the flow, function and feeling of the space.
Vertical circulation is how people move up and down within the building, so includes things like stairs, lifts, ramps, ladders and escalators which allow us to move from one level to another.
USE
Public circulation is the areas of the building which are most widely and easily accessible. In this guise, circulation is often overlapped with other functions, such as a lobby, atrium, or gallery, and is enhanced to a high level of architectural quality. Issues of visibility, how crowds move, and clear escape paths are key.
Private circulation accounts for the more intimate movements within the building, or the more ugly ones which require a degree of privacy. In a house this might be the back door, in a large building the back of house, staff offices or storage zones.
DESIGNING CIRCULATION
There are two rules of thumb when it comes to designing circulation. The key circulation pathways should:
be clear and unobstructed;
follow the shortest distance between two points.
The reason for these two rules of thumb is fairly obvious: people want to be able to move around a building with ease and efficiency, and without feeling or being lost.
But, once you've got these rules sorted,
you're welcome to break them.
Sometimes for architectural reasons you'll want to interrupt a direct circulation path with an item of furniture or a change in level to define a change in place, make people slow down, or provide a focus point. Similarly, circulation doesn't necessarily have to follow the shortest distance between two points. Rather, it can take into account the sequence of spaces, thresholds, and atmospheres encountered through movement, which prepare you for the transition from one space to the next. Circulation can be choreographed, to add architectural interest.
In this way, circulation is also intricately linked in with Programme, or what activities take place, another key Architectural Concept which we will touch on in this series.
efficiency and layout of circulation space
Circulation space is sometimes seen as useless space, adding needless area and cost to a project. As a result, the word efficiency often goes hand in hand with circulation.
Commercial office buildings and apartment buildings, for example, will typically seek to minimise the amount of circulate space, and give this space back to the tenancies or apartment interiors which are leasable, and thus, profit generating. In these cases, where the buildings are often tall, the vertical circulation is often designed as a core at the centre of the building, with stairs and lifts packed tightly together, and short corridors on each level leading away from this core to the individual apartments or offices.
Expressed circulation, Pompidou Centre
In contrast to this method, where all the circulation is located centrally and often hidden, circulation can be externally expressed and shown off of the façade or within the building. Even in smaller buildings, such as houses, circulation areas such as a staircase can become architectural features of the home.
A celebrated example of this technique is the Pompidou Centre in Paris, designed in high-tech style by Richard Rogers and Renzo Piano. Here, you can see the translucent escalators with red undersides snaking across the exposed façade of the building, the ever changing movements of people making the building present and active in the square.
and finally: representing circulation
Circulation is often represented using diagrams , with arrows showing the ‘flow’ of people or the proposed openness of spaces. You might use different colours or types of lines to describe the varying movements - check our our Circulation board on Pinterest for ideas.
Although a critical part of design, circulation is often not directly represented in a final Architectural Drawing Set - it is in the white space and gaps between structural elements. However, there are some instances where exit pathways do need to be shown, such as in the design of a public building where the routes people will take to exit the building in case of fire need to be clear for evaluation against the Building Code.
Circulation & the building code
In New Zealand, circulation is largely managed under the New Zealand Building Code Compliance Document Clause D1: Access Routes, which you can download here. This document sets out performance standards for a range of circulation elements, including stairs and landings, hallways, doors, handrails, balustrades, ramps and ladders.
Although at Architecture School, your design projects might not require you to spend days checking for code compliance, this document can be a good place to start to at least get the angle of your stairs looking vaguely legitimate, and to understand how wide hallways should be to facilitate different kinds of movement - two aspects of your project which will be obvious to critics examining your project plans and sections.