Rick Morrison

CIRCADIAN RHYTHM AND LIGHTING DESIGN 

CASE STUDY IN THE QUEENSLAND CHILDREN’S HOSPITAL 

Rick Morrison 

All images and copyright belong to original owner and are reproduced here for the purposes of training and education only

All images and copyright belong to original owner and are reproduced here for the purposes of training and education only 

www.projectbeauty.com


C PM HEDEN 

“The nitrogen in our DNA, the calcium in our teeth, the iron in our 

blood, the carbon in our apple pies were made in the interiors of 

collapsing stars. We are made of starstuff.” 

Carl Sagan, Cosmos

All life is 

adapted to 

the cycle of 

daylight 

and night 

This is our 

circadian 

rhythm 


httpsos.noaa.govDatasetsdataset.phpid=110

Human eye 

The eye is not 

just for seeing 

The eye 

receives light 

signals for non 

visual stimulus 


Image: Photograph by Dan Saelinger

EYE EVOLUTION 

The overwhelming majority of life on our planet depends 

on the sun for energy. Because life is so tightly linked to the sun, 

it is no surprise that many organisms (excluding those that live in 

total darkness) have evolved the ability to detect and respond to light. 

Plants turn their leaves toward the sun. Single-celled algae, protozoans, 

and other microbes swim toward or away from light. But it is the animals, 

with our image-forming eyes, that have taken light detection to the next level. 

96% of animal species have eyes. The first animal eyes did little but detect light - 

they helped to establish day/night cycles and coordinate behaviour – 

but more-complex eyes soon evolved. A predator who can see its prey from a 

distance, or a prey animal that can see the shadow of a predator approaching, has a 

clear survival advantage over those who can't. Even a slight improvement in image 

quality provides a significant survival advantage, allowing for the step-by-step 

evolution of increasingly complex eyes. 


www_wakpaper_com__large__Oceans_wallpapers_202

A mirror of the eyes development 

across time 


http://learn.genetics.utah.edu/content/variation/eye/

In 2001 Dr. 

George Brainard’s 

team at Thomas 

Jefferson Medical 

University 

discovered a photo 

receptor in the 

human eye, 

responsible for 

reacting to light 

and controlling the 

production of 

melatonin. Their 

research showed 

that light in the 

range of 447-484 

nm (nanometers) 

is responsible for 

suppressing 

melatonin 

production and 

shifting circadian 

rhythms. 


From seeing without seeing by Corrie Lock

This is the mechanism of our circadian 

rhythm 

So how can this be used in design? 


www-en_wikipedia_org__wiki__Circadian_rhythm

Case History - Queensland Children's Hospital – designed by AECOM 


Image from Conrad Gargett-Lyons Architects and Abigroup Builders

Options for design 

• Dynamic lighting 

Dynamic Lighting brings the dynamics of daylight 

indoors. With seamless changes in brightness and 

warmth it creates a stimulating ‘natural’ light that 

enhances our sense of well-being. A flexible solution 

that can be adapted to different needs and moods, 

enhancing lives with light. 

• Room specific lighting 

Using the Circadian Stimulus wavelength 

to improve the time adaption of shift 

workers by directly applying the 447 – 

484nm Blue Light into a room to provide 

the stimulus described in the research 


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Colour temperature in Daylight 

We experience the full range of white 

every day in nature. 

This is part of the lighting dynamic 


Copyright – Anda bereezky, 2005

Light level Variations in Daylight 

We experience the full range of light 

levels throughout a natural day 

This is part of the lighting dynamic 

Australian Standards extract

Dynamic lighting 

Provided by natural 

light through openings 

and windows 

Contributes to the well 

being of all in the Hospital 


From Conrad Garget-Lyons Architects

Room specific lighting 

• Five rooms on different 

floors for shift working staff 

• Rooms located in the staff 

lounges 

• Each ‘Circadian Room’ is 

designed the same way 

• Separate spaces with 

separate controls and 

choice of white or blue light 

Lighting considerations 

The reason for developing circadian spaces in the Hospital was to 

provide the correct conditions described in research (1, & 4), in which the 

eye would receive the blue wavelength of 447-484 nm. 

In particular, the ability to provide about 40 lux of blue light to the eye 

was desirable, as described in the research (1 & 4). 


Original work by Rick Morrison


Original work by Rick Morrison 

Space 

Lighting 

The lighting design involved a mix of linear 

recessed wall washers fitted with dual purpose 

LED chips – to provide white light and alternatively 

switched blue light 

And recessed downlights for multi tasking the 

space 

To effectively reflect different colours – the 

interior walls and ceiling must be finished in 

a highly reflective but neutrally white 

colour, to prevent colour bleed and 

distortion. 

This reflection should also be ‘lambertian’ 

or diffusing, to encourage ambient scatter, 

and reduce specular reflections

Modelled with AGi32 

Each room was 3D 

modelled. 

Calculations of several 

metrics were taken on 

• Walls 

• Ceiling 

Metrics calculated 

• Illumination 

• Diffuse Luminance 

• Vector Scalar Ratio 



Vector scalar values 

The Vector Scalar Ratios (VSR Ratios) are a 

method of measuring the ambient flow of light 

inside the space, which would be the light that 

is to land on the eyeball. The VSR ratios were 

calculated using objects in the model space. 

3D zero reflectance cube objects, 150mm 

across, were placed above the seats at the 

staff table and in the entry. These are typical 

positions for people’s faces. A calculation point 

is applied to each surface of the “cubes”, and 

the results are tabled in the spreadsheet which 

calculates the Esr, and then the VSR ratios. 

Positions of the cubes in the model are shown 

in Fig.7. Referring to AS/NZS 1680.1:2006, 

section 4.2.3 Vector/Scalar Ratio, a Vector 

Scalar Ratio of 1.2 to 1.8 is satisfactory for 

seeing faces. Figure 4.1 in the same standard 

provides information on the strength of the 

ratio, with 0.5 being very weak and 3.0 being 

very strong. 



Lighting Specifics 

Calculations 

• Table – 340 lux 

• Walls – 90 – 160 lux 

• VSR – 1.0 to 1.3 

• Ambient light – 70 to 

87lux 

Equipment & Control 

• LEDS used are - Cree® 

XLamp® XR-C LED. 

These have a radiant flux of 

300mW, which translates into 

18.1 lumens per blue chip. The 

light fitting has 33 blue chips 

per metre which provides 597.3 

lumens per metre. 

• Recessed led lighting 

made in Melbourne 

• Control is by Dali 

interface from a simple 

wall panel push button 

display 

• Two scenes – 

• Blue Light 

• White Light 



Lighting 

How much blue light is needed? 

Research indicated 40 lux for 80 minutes 

Since the shift workers were already awake 

We designed the Circadian Lighting to provide 80 lux to the eye 

Time suggested is 20 minutes 



Conclusion. 

• Light has been shown to be vital or primary to human wellbeing. 

• Natural circadian rhythm response to short wavelength light can be used in 

design to successfully create a space able to provide the stimulus described by 

the various publications of circadian research. 

• Each Circadian Space in the Hospital Project is designed to provide an ambient 

light level onto the observer’s eye of approximately 80 lx, which is comfortably 

above the minimums described. (1, 3, 4) 

• The Circadian Spaces described are being built for the Queensland Children’s 

Hospital Project, which opens for business in 2014. 

• Once the rooms are in use, the proposed survey (refer to appendix A) will be 

instigated, and the survey results collected on a weekly basis. 

• Every six months the survey results will be collated into data and the design 

will be reviewed accordingly. It is planned to publish subsequent follow-up 

papers with the progressing results. 



THANK 

YOU

Rick Morrison

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