A message from the Principal – December 2020 Newsletter

Well, what a crazy year 2020 turned out to be!

When the news broke that the virus outbreak was being contained with very drastic measures in the city of Wuhan, China and was reported as having originated in a market selling strange meat including infected bat and other wild meat, most of us probably shrugged our shoulders and perhaps muttered something about people being crazy to eat strange things.  But we were all relaxed because it was far away from us.  How wrong that proved to be.

We have been fortunate to traveled extensively over the years.  Wherever we traveled, there were always many tour groups following their flag waving tour guide.  The world tourist destinations appreciated their visits and wonderful dollars and credit cards and depicts just how much the world has shrunk. Travel is now so easy from anywhere in the world to any destination.

More recently, scientific investigation has revealed that the virus had been present in Italy in September 2019, months before the reported outbreak in China.  Antibodies were found in cancer patients in Milan and Turin.  So who are we to judge?

We had Lockdown 5, then 4, then 3 and 2 and 2.5 and 1 light or whatever it may be called.  However, the economic impact hit every business, others far more even resulting in complete closure.  Many people lost their jobs.  Many relied on relief packages from the government. Then there were others who at the start of lockdown in March, strategised a road forward, realising that the pandemic would not end quickly.  As time went on, it was also realised that the international business and government communities were speaking about an end only in 2023 after mass immunisation!

We strategised, prepared business plans for both BHA School of Lighting and BHA Lighting Design and Consulting.  Thank goodness that we used that time to think into the future.  The result, we have sustained continued student growth in enrolments and we have succeeded in finding new clients and projects both in South Africa and abroad where we have been commissioned to do the lighting design and consult on the use of the exciting new technologies that you, our students learn about and do the system architecture design as well as lighting designs.

Many in the lighting design environment fail to appreciate the wonderful business opportunity that the new technologies present.  The benefits to their clients from the amazing installation and energy savings despite the fact that the procurement cost may be fractionally higher.  The control systems together with the installed lighting equipment give the client the ability to have complete control over energy consumption, occupancy rates, occupancy of meeting facilities, cleaning costs, remote emergency escape lighting testing and reporting, better compliance with all standards, the provision of lighting solutions for the employee and occupant well being and more.

Of course, we design lighting for the COVID-19 environment complete with “sneeze screens”, social distancing, movement routing within the office and more.  You are encouraged to visit  https://www.bhaschooloflighting.co.za/news to read my articles published in South Africa and in the UK, to read more about this subject.

We will soon be able to put 2020 behind us.  When we welcome the 2021 New Year in, let’s pause for a moment and think about those who lost their lives to COVID-19 and those near and dear to us who may also have passed on during the year irrespective of the cause.

We now would like to wish you and your families a very peaceful and happy Christmas, and to our Jewish friends, we wish you Hannukkah Sameach! To our friends who do not celebrate at this time, have a peaceful rest and holiday.

We look forward to seeing you all in 2021, which we certainly hope will be a better year.  Take care!

Welcome to the following new students:

Godfrey Ramutanda, Chartwell Electrical, Westgate – BHASL003C19: Advanced Diploma in Illumination Engineering Course
Peter Jonsson, Borlange, Sweden – BHASL003C19: Advanced Diploma in Illumination Engineering Course
Clayton Davidson, Eurolux, Durban – BHASL001C20: Foundation Lighting Course
Juanita Botes, Eurolux, Durban – BHASL001C20: Foundation Lighting Course

Beth Maina, Lighting Solutions, Nairobi, Kenya – migrated to BHASL003C19: Advanced Diploma in Illumination Engineering Course
Jade de Pontes, Aurora Lighting Africa, Johannesburg – migrated to BHASL003C19: Advanced Diploma in Illumination Engineering Course

To all students past and present celebrating their birthdays this December, we wish you a great day & all the best for the upcoming year.

George Piek – 2 December
Acir Daniel Urban Guimaraes – 4 December
Jayson Serrao – 13 December
Mohammad AlMutanna – 13 December
Themshan Tathtiah – 14 December
Nico Mans – 27 December
Milase Koti 30 December
Rzlyn Asuncion 31 December

Congratulations to the following students on your admission to some of the world’s leading institutions:

Mthulisi Dube, Pretoria – The Institution of Lighting Professionals (The ILP) (UK)
Sharl Wasserfall, Cape Town – The Institution of Lighting Professionals (The ILP) (UK)

Mthulisi Dube, Pretoria – Illumination Engineering Society of South Africa (IESSA)

WEBINARS (CPD Activities) – Join us for the last webinar of 2020

Series 5 Episode 6 – UV Light COVID-19 Disinfection (CPD Activity)

for detailed info, dates & times please click HERE 

Important Note: Series 5 webinar subjects have been specially requested by professionals who have attended the previous series.  You requested, we took note and now we are responding.

Announcement: Series 6 Topics & Dates to be announced in January 2021

Join the BHA School of Lighting’s Alumni and Follow us on LinkedIn – https://www.linkedin.com/company/bha-school-of-lighting/

You can also follow us on our Facebook page – https://www.facebook.com/bhaschooloflighting/


Since the discovery of the ipRGCs (intrisically photoreceptive Retinal Ganglion Cells) in the human eye in 2002, numerous papers have been written and weeks and days of research have been conducted in many parts of the world by some of the leading emeritus scientists.  You would not be wrong if you said that it was ongoing because that is a fact.

Fagerhult including their subsidiary iGuzzini, Tridonic and Zumtobel sponsored research for Prof Ellen Katherine Hansen at Aalborg.

At the end of the three year project which began in 2017, Prof Hansen found that when more dynamic lighting was combined with natural and artificial light, it resulted in enhanced worker comfort and productivity.  It combined biological, aesthetic and functional aspects to form a basis for the design process.

When reading the report, I fully expected the research to focus on trying to mimic the outdoor environment in much the way that we have learnt about circadian or human centric lighting which is what I have taught for a number of years.  I was surprised to learn that the studies found that artificial lighting was needed to create shadow patterns and emphasise the three dimensionality of objects on work planes.  Another finding was that it was important to create working islands or light zones for individual users.  This was so exciting that I almost burst with pride because I have been teaching this technique for office lighting since 2014.

There was one difference.  I have taught that the task lighting should be 4000K/5000K and ambient lighting 4000K and other areas 3000K.  This study set the direct task area to 3000K and ambient lighting to 5000K to 6000K.  As evening drew near, the ambient lighting was reduced to 4000K and eventually to 3000K.  Of course the illuminance levels were adjusted even when natural light influenced the direct task area.

In my own opinion, I believe it is better to tune the CCT on the direct task area on the desk from a high CCT say 5000K reducing to 3000K towards the end of the working day and to use other CCTs in the ambient areas but at reduced illuminance levels as I have always taught.

In another paper written by Allison Thayer of the Lighting Research Centre (LRC), she believes that the lighting world should move beyond CCT to discuss circadian stimulus values.

Image credit: Graphic by Allison Thayer, Lighting Research Center (LRC).

The simple explanation of the picture is that the visual system is concerned with instantaneous visual cues but in contrast the circadian system accumulates photons throughout the 24 hour day, registering a lot of light during the day and no light at night.  If the circadian system is upset, it will become confused and will fail to trigger the correct responses such as when to sleep, when to eat and when to be alert for work.  It can in fact even suppress good eating routine  which can lead to other disorders in humans.  Of course we all have learnt or at least heard how the lack of a good eight hour sleep at night can weaken our immune responses, ageing and result in other ailments which could even be stated as side-effects of an upset circadian system.

Our circadian system does not understand CCT or lumens.  So, what does our circadian system understand?

We are informed that we need to extend our lighting vocabulary to include Circadian Light (CLA) and circadian stimulus (CS).  And here is another surprise for you, we nowneed to take the light that falls on the vertical plane which is for the light that enters the human eye into account rather than only the horizontal plane which we are accustomed to doing to comply with standards.

Of course, we have a number of challenges to overcome.  Our lighting design software was not developed to take these new metrics into account. However, with a little experimentation, we have found that Relux Desktop is able to measure the circadian light (CLA).  This will be included in the brand new manuals that we are writing for the training that we give our students on Relux desktop during their second year studies. The new Photonfy spectrometer which has all of the standard measurements usually provided by the SPIC (Spectral Irradiance Colourimeter) 200B or 300, but now also measure (CLA) and CS.  In addition it measure the full spectrum of measurements for growlighting.  It is a unit which only costs USD 699.  It connects via Bluetooth to a smartphone or USB to a computer to allow for futher detailed analysis..  The unit weighs a mere 55g and is 92.8mm (H) x 38.2mm (W) and 20.5mm (D).  It is able to connect via the internet.

So…. How do we know how to calculate CS?  The answer is simple using SPD curves of the light source in the luminaire and some useful formulae.  If you would like to know more about the methods used to calculate both (CLA) and CS, readers are welcome to contact me.

You probably asked why CCT is not effective when designing lighting for circadian effectiveness.  Well, I will show you an example from the report which clearly illustrates how different CCT light sources deliver vastly different results.


Now look at the diagram – left top are SPD curves, right is a Chromoticity Chart showing the points on the Planckian Locus for each and bottom left shows the resulting CCT on the top line and vertical illuminance to reach 0.3 CS for the human eye.

It will be noted that both light sources have the same CCT but when looking at the SPD curves, it can be seen that they differ significantly. The red line has a peak wavelength of 605nm and the green line has a peak wavelength of 635nm.  The CS result is very different with the green at 240lx and the red at 575lx.

I know that the students who have completed Module 8 will have a much better understanding than most readers who have not studied lighting.  This will become even more clear to students after studying Module 14 which deals with Standards and Compliance and the spectral quality of light.

Before completing this article, it is time to look at the diagram for the Visual and Circadian systems complete with the addition of the matrix discussed above.


As will be observed now, the two systems each need different types of input or stimulus to be effective.

This has been an absolutely amazing study.  I have accumulated the reports from various sources after which I brought facts and findings together, some of the studies and reports originated from as far back as 2002.  Has the basic data changed? No, not at all BUT more data, facts and findings have been added as the academics, scientists, physiologists and lighting researchers gain a better and richer understanding of this fascinating subject.

What remains for us is to ensure that we make developers, architects, engineers, interior architects and designers, lighting designers and students know, understand and enable them to utilise dynamic and human centric lighting in all new projects.  All who are responsible for the development of lighting standards owe it to the occupants of all buildings, to take all of the data included in the research documents into account.  The single biggest point that they need to remember is that the standards of old such as SANS 10114-1 have served their purpose and now need to be relegated to the archives and library shelves.  An entirely new dynamic approach is needed to produce guidelines rather than rigid standards.

I hope that your interest in this subject has been stimulated and that you now have a very different perspective on lighting.


A published PNNL study finds that medical-surgical staff desire more control over lighting for visual acuity that affects job performance as well as patient comfort.

A study undertaken by Pacific Northwest National Laboratory (PNNL) researchers surveyed 138 representatives of medical-surgical nursing staff as to environmental lighting factors and needs in med-surg patient rooms. Four hospital sites were compared, with various combinations of lighting equipment, controls, and number/form factor of fixtures. I’m not going to summarize the site differences here; you can get the details of the environment-of-care specifications in the PNNL report.

An earlier analysis focused on the quantitative aspects of the questionnaire, whereas the current work analyzes open-ended responses that, to my understanding, more closely reflect how a lighting designer/specifier might query the end-user customer for a lighting project in a healthcare setting.
The open-ended responses allowed the researchers to characterize themes of importance to the survey respondents, along with sub-categories of accessibility, light levels (both natural and electric), and more.

The three questions that were evaluated in the current results were:

  • For a typical patient room in which you work, what do you think is the best thing about the lighting?
  • For a typical patient room in which you work, are there any changes to the lighting that you think would help you in performing your professional duties, or that would have a positive effect on your work experience?
  • For a typical patient room in which you work, are there any changes to the lighting that you think would help the patients have a more positive experience— based on your observations and/or patient feedback?

A key theme that emerged from the responses was control, across all four facilities under the study. “Despite the differing standards in the four facilities, nurses generally perceived a sense of control, for themselves and their patients, to be most important, followed by adequate daylighting (preferably through windows),” the report stated.

With regard to what could improve performance of duties and work experience, the researchers observed that “It would seem, as it did in our previous study with the same sample measuring quantitative aspects, that most nurses desire better control in order to increase or decrease light level, indicating that their perceptions of brightness and control are very closely related as attributes that ought to be optimized in patient rooms.”

Again, with regard to the patient experience, survey participants revealed that control of lighting, mainly with regard to light levels for both performance of tasks to the patients’ benefit as well as dimming capability for their comfort, was important to that experience. One of the common issues in patient rooms is inaccessibility of lighting controls and switches because of care-management equipment blocking access. The researchers noted that controlling lights from the bed itself, where the majority of care activity takes place, was a related sub-category to the control theme.

Of course, there is much more valuable detail in the study and the published conclusions. The US Department of Energy-funded PNNL study was conducted in conjunction with McCunn & Associates Consulting and published in Health Environments Research & Design. 

The LED and solid-state lighting (SSL) industry can take these evaluated perspectives many steps further down the road, with white-light tunability and even colored light for specific needs.


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