Shedding Light: Lighting Design Considerations for Offices – monthly column featured in Sparks Electrical News (Crown Publications)

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Oh, my word, where does time go? It is August already and I still have so much to do and achieve this year. Do you feel the same?

It has not been the easiest of times as we remain in the grip of the pandemic, but the good news is that by focusing on the positives, some amazing opportunities appear. Keep focused, stay positive, do not be distracted by negative conversations and most of all Stay Safe.

In last month’s column, I mentioned a number of aspects of lighting design that were only touched on. This month I will focus on only a couple of those important facets of lighting design to encourage improved lighting design in office spaces.

A quick recap. We have the following to consider in our lighting design:

  1. Horizontal illuminance – light measured on the desk or primary task area in lux.
  2. Horizontal illuminance – light measured on the secondary task area in lux.
  3. Horizontal illuminance – light measured on the remaining areas such as pause areas, photocopier or printer area, communication route or walkways.
  4. Equivalent Visual Efficiency (EVE) – light on the horizontal primary task area taking the age of occupants into account and focuses on visually demanding tasks.
  5. Circadian Light (CL) and Circadian Stimulus (CS) – measurement of light entering the eye of occupants for their well-being.
  6. Glare avoidance – discomfort glare, disability glare and reflected glare.
  7. COVID-19 protocols – occupant protection, social distancing, and other measures such as one way traffic circulation and providing safe movement around personal spaces at work- stations.
  8. “’Sneeze Screens’ – calculate impact on light levels.
  9. Daylight – daylight autonomy, continuous daylight autonomy, daylight factor.
  10. Standards and compliance.
  11. More …

I am sure that many of the readers will not have appreciated that there was so much to consider when doing a lighting design.

Let me start by saying that there are many misunderstandings about the application of the most common South African National Standards. The standards primarily impact the horizontal measurements on the task area.

The biggest problem that I find is understanding what represents the task area, or rather, the primary task area. It is so important to fully understand this because the standards only refer to task area in the tables. The tables do not refer to secondary or movement areas.

But … here it is. Think about your own office task area. Do you include your credenza, your extra meeting table, and chairs? No. The primary task area is where you do 95% of your work. When experts from around the world have analysed the workplaces, the primary task area has been found to be 0.5m² to 1m². That means that it is the only part that should be lit to the levels stated in the tables in the standards. The remainder of the wider task area should be lit to about 60% of the primary task are illuminance level. Then, once away from the desk, the level can be 20% of the primary task area but not less that 100lux which is needed to light the movement area/walkways within the office and pause areas.

Remember that we are living in the time of a major pandemic in the world. Finally, I will briefly touch on the need to include measures to comply with the protocols for workplaces. This will include having to reposition workstations to ensure that social distancing is applied which will include safe personal space. This measure can be in the form of taped or painted markings on tiled floors or tape carpets or inlaid different carpet to designate safe personal space. Where possible, single direction routes around the office, or where only one passageway is in use, create bi-directional routes.

For more detail, here is a link to an article that I wrote for Lighting in Design, published by Crown Publications;

I will continue taking you on a journey through the considerations when doing a lighting design for offices. The main topic will be Equivalent Visual Efficiency (EVE).


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