”The office spaces are underutilizing their access to day lighting. By changing the interior reflectance and adding architectural features we can create a better distribution of day lighting in the space.”

Inquiry questions:

- Are the dark carpets and black desks limiting the day lighting from reaching the interior of the space?

- Is the perimeter of the space over lit by the large windows?

- Would a skylight over the middle of the space create enough light to eliminate ambient electrical lighting over that part of the space during the day?

Methodology

In order to study how changes to the space would affect the day lighting, we first needed to find what is actually happening in the space. Using daylight meters on an overcast day, we took footcandle measurements within the two office spaces. These measurements were taken at desk height on a 5’ by 5’ grid throughout the space. It should be noted that without the help of Janelle and Erik (Glare Team) we would not have been able to complete this task. Other measurements taken that day were reflectance of materials and outside footcandles.

We then made a day lighting model of one side of the office because both sides were symmetrical. Using different inserts of partitions and flooring we were able to study the effects of existing materials and configurations for the two offices. The day lighting model was put into an artificial sky where 12 sensor locations were taken simultaneously for each test. The seven tests included changing floor reflectance, adding higher reflective ceiling panels, adding light shelves, and adding skylights. Each of the seven tests was completed with both office configurations for a total of 14 tests. Between each test a preliminary analysis was done to inform how the next test should be altered to achieve a better lighting distribution.

Recommended Daylight Factor:

Ordinary seeing tasks such as reading and filing....................................................1.5-2.5%

Moderately difficult tasks such as prolonged reading and machine use....................2.5-4.0%

Difficult tasks such as drafting and fine inspection...................................................4.0-8.0%

(Table 5.2 MEEB)

1. 35.7
2. 18.7
3. 18.2
4. 38.3

1. 34.2
2. 19.6
3. 19.3
4. 38

5. 6.1
6. 1.7
7. 1.2
8. 6.8

9. 20.2
10. .4
11. .5
12. 26.4

Model represents actual reflectances in existing eco-trust office spaces.

South side

- Floor: 10%

- Walls: 70%

- Ceiling: 50%

North side

- Floor: 30%

- Walls: 70%

- Ceiling: 50%

- Floor: 50%

- Walls: 70%

- Ceiling: 90%

Comparing the existing office spaces to recommended reflectances, the existing floors and ceilings are low. How this effects the day lighting distribution is seen in the graph above. There are extremely high levels of light at the perimeter windows with a sharp decrease in lighting levels as you move away from the perimeter. This is because the dark reflectances of desks, floors, and ceiling are absorbing the light rather than reflecting it deeper into the offices.