Daylighting in the history of architecture. Church of light by Tadao Ando

Architect: Tadao Ando Building: Church of Light Year of construction: 1987-89 Site: Osaka, Japan Address: 4 Chome-3-50 Kitakasugaoka, Ibaraki-shi, Ōsaka-fu 567-0048, Japan Climate station: Osaka Latitude: 34.82 Longitude: 135.54

The Church of Light is located in a residential suburb of Osaka, Japan.

This building has been seen as an iconic piece of architecture for its essential and sculptural design.

The church is sun oriented and probably is one of the most beauty geometry operation of intersection that the architecture has ever seen.

The intersection in between the cross shape and the wall give birth to a cross cut into the concrete wall. This light shape is working as a reverse sundial, instead of shadow marking the passing of time, it is the light that remembers us our time passing journey on earth.

This is probably the strongest feature of this architectural poetics and this could not happen without a good quantity of shadows; is this Japanese vision of the world opposite to our western-one? Maybe.

The intersection of a freestanding concrete wall and the rest of the pure rectangular structure is the second and last lighting-architectural feature. This diagonal wall is literally cutting the volume of the church creating an entrance to the worship place, it is so important the fact that this second cutting element is never touching the other walls of the chapel, it comes into and goes out as a ray of light. The freestanding wall is bounded by the light, the architect designed it to underline its importance thanks to light strokes.

So let’s see it through the lenses of modern computational power, it’s not so romantic, but interesting for sure.

Let’s begin with a luminance (cd/m2) output which describes the upcoming vernal equinox of 2018. We can see here in the movie #1 the false color logarithmic scale luminance representation.

Movie #1

In the false-color scale level on the left of the screen, the blue-cyan represents a candles/sqm range (0.001-3) which is in the Mesopic region of vision. With this amount of light, our eyes are going towards the grayscale nocturnal vision, losing a part of the perception of the red and yellow environment colors and acquiring a wider range of perception into the blue environment colours.

Everything above the green false-color scale level (a value around 3 cd/sqm depending on the age and the physiology of the person) falls in the field of full color vision, called: Photopic.

Movie #2

In the movie #2 there is a visualization across two solstices and an equinox of what is the lighting effect, this output has not to be taken as exactly realistic in the intensity of light, it’s just a good approximation, it is correct instead from the point of view of the global effect and it is correct the light-path too.

Image #1

In the image #1 and #2, we show the natural light illuminance (lux) values throughout the year.

We decided to describe the building at first with an annual metrics called: Average Illuminance.

Average Illuminance is the simplest annual metric we can use to begin working on an analysis.

First, it measures illuminance levels at each point (actually each point is a 60x60cm part of the building area) in this space during daylight hours over the course of one year.

Then it averages all the hourly illuminance grid values.

The average illuminance is 234.88lux and the peaks values are 678 and 45 lux.

This output is totally along the line of what we expected from a very theatre-like church as the one designed by Mr. Ando.

Image #2

In particular, in the first four meters near the altar the levels are under 100lux. These values are today considered out of the admissible range.

Yet if you want, you can still physically read with 50lux: it's a sort of candlelight.

Image #3

In the images #3 and #4 we give a look again to the illuminance but thanks to another metrics called: Continuous Daylight Autonomy (cDA).

cDA represents the percentage of annual daytime hours that a given point in a space is above a specified illumination level, we selected 100lux (~10fc) as an adequate level for a church.

Continuous Daylight Autonomy awards partial credits in a linear fashion to values below the threshold defined by the user. cDA is useful for energy saving, this value that tells which is the electric lighting-percent that we can substitute with natural lighting.

An overall assessment indicates that the 78.29% of the church area is over the threshold value of 100lux. In the image #5 and we can see the church as it was inaugurated and in the image #6 after few years. It is clear as the users felt the need to integrate the natural light and the electric lighting system designed with a reinforcement floor lamp system directed to the presbytery of the church, this is the darkest area of the church and also the secret of its beautiful light effect. Image #4

The indirect message we can deduce from it is that this very high level of clean design create a stunning sculpture and a fantastic spiritual place for the people who use everyday that worship place. This high level of abstraction and purity put in second place functional lighting and acustic users needs; this is totally understandable though.

Image #5

In 1987 the possibility of computer electric lighting simulations where not applicable to these level of complexity and what was assessed by the use of physical models (daylighting) was totally achieved, the emotional experience of this sacred place is very well known around the world.

Image #6

What we could implement, if we should design a similar place again today, it would be an electric lighting project totally shaped onto the request of a similar daylighting analysis.

So the first step is to prioritize the natural lighting design into a church (it is just obvious why) and then to complement the remaining functional/emotional features with the electric lighting project, which today is made of totally different elements: modern lighting fixtures are in first place easily dimmable, then network connected, low UV emitting and last but not least minimal in their volume.

contact www.kairosdesign.photography if you are interested in a similar daylighting accurate project for your building design,

warm regards

Michele Bruno lighting designer