Introduction

The Ecotrust building located in Portland, Oregon committed itself to a LEED set of design principals early in the project. Even though the LEED design principals focus more on materials and products rather than energy, some attention was given to the day lighting. The third floor of the Ecotrust building has large windows around three sides of the perimeter. However, the day lighting seems quite poor because of the amount of ambient and task lights on during the day. Seeing how the occupants were using the space began to spark interest with four of us. Shades being pulled seemed to make us think about glare issues. Task lights on everywhere was obviously a lack of adequate lighting. With dark carpets and black desks scattered throughout the spaces we thought we might have found one of the problems.

After talking with the owners of the space we found there were plans at one time to put in skylights over the middle of the space. Would this be enough to solve all the problems in the space? As the questions kept coming in about the space, two separate categories evolved. One study could be done on day lighting and another on glare. Splitting our team into two groups of two, this study focused on day lighting.

The day lighting study of the third floor Ecotrust building focused on the day lighting of the two separate offices on the north and south. We felt the office spaces were underutilizing their access to day lighting because they had windows extending around three sides of the perimeter but the middle of the office space was very poorly day lit.

During our visit, many questions arose about the day lighting:

Was the interior reflectance of materials affecting the light reaching the middle of the space?

Was there too much daylight at the perimeter?

How much would a skylight help over the middle of the office space?

Why did people at the perimeter offices have shades pulled while people at the interior had two task lights turned on?

Could we change the reflectance of materials without sacrificing the character of the exposed wood in the space?

Hypothesis:

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

Important Findings:

- Changing interior reflectance had only a minor effect on the day lighting distribution.

- Introducing light shelves had only a minor reduction in the day lighting at the perimeter because the windows still had too much area exposure under the shelves.

- Adding a skylight over the middle of the space helps even out the distribution of the daylight in the space.