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IDL - Bozeman eNEWS - April 2013 - Vol. 6 No. 4

Entries in offices (2)


Daylighting Guide for Commercial Offices - Part 1

Benefits of Daylit Offices

Providing a daylit space creates a healthier and higher quality interior environment.  Increased individual productivity and human comfort is also found with daylit spaces.  Natural daylight allows for mental and visual stimulation necessary for proper regulation of human brain chemistry.  In addition to health benefits, allowing daylight to enter the space shows substantial energy savings throughout the building.

Design Inquiries for Designing Daylit Offices

Before you begin the spatial programming of the building, a few items should be in the forefront of your mind when deciding.  These inquiries include interior surface design and selection, shading for glare control, and shading for thermal comfort and heat gain control.  Interior surface selection has the opportunity to increase the daylight appearance dramatically, while shading control allows the building to effectively take advantage of natural daylight.

Best Practice Foot Candle Levels

Another thing to keep in mind when designing daylit spaces are the common lighting levels for different spaces.  The following footcandle levels describe the “best practice levels,” or in other words, the goals to achieve as opposed to the average level attained. 

            Reception Area:  5 fc   

           Working Spaces for Simple Visual Tasks:  10 fc

            Performance of Visual Tasks of High Contrast and Large Size:  30 fc

            Performance of Visual Tasks of High Contrast and Small Size or Visual Tasks of Low Contrast and Large Size:  50 fc

            Performance of Visual Tasks of Low Contrast and Small Size:  100 fc

Programming Criteria

When spatially programming the space, ask the following of each space:  Is daylight important for this space?  Are views to the exterior important?  How frequently is this space used?  What time of the day and time of the year will the space be occupied?

An example spatial programming might include the following:  Open Office Space – Daylight and view desired, occupants have individual glare control.  Private Office Space – Daylight and view desired, occupants have individual glare control.  Support Spaces – Minimal daylight or view opportunities required.  Building Core Spaces – No daylight or view opportunities are necessary.

After you have specified the spaces that desire daylight, ask the following of each of the daylight spaces:  What are the minimum daylight requirements?  How crucial is direct sun control?  What is the minimum footcandle level for the task that is performed in this space?  What might be the ideal solar orientation?  What might be the best strategy for providing daylight?  Side lighting?  Top lighting?  Are there maximum light levels required?

TIP for Programming Spaces  

“Daylight and view are typically preferred in areas that are most heavily occupied for extended periods of time, such as open office areas.  Corridors, circulation paths, break areas, copy/print zones or other short term gathering spaces may be tolerate of direct sunlight whereas fixed workstations or reception desks will almost never remain comfortable with the presence of direct sun.”

Space Planning

It is well known that open offices are typically occupied for almost the entire work day, while private offices are only occupied one-third of the time.  Also, since open office layouts are communal spaces, the shading blinds are not adjusted frequently.  This differs from private offices where the ownership is clearly defined, and the blinds are adjusted frequently.  The following values are the recommended distances from the glazing (illumination source) needed to provide adequate daylight and views to all spaces in need.

Locate open office areas within 18-20 feet of the perimeter zone (glazing wall) and at areas where direct sun penetration is limited (North) or less varied (South).

Position individual offices where low direct sun may otherwise be problematic (East and West), while allowing for individual control within the space with manual shading devices.

Top Lighting Strategies

Studies show that top lighting provides the most effective daylight into the building.  Designing them to be a diffuse light source easily takes care of any glare potential.  Compared to side lighting, top lighting covers a much larger area of the space.

Stay alert for part 2, discussing window coverings, shading and exposure tips, furniture influence, and daylighting controls.  For read the full article, click here.


Did You Know?

The Seattle Lighting Design Lab has created a series of Commercial Lighting Guides for offices and warehouses. Based on the ASHRAE 30% Design Guides, these 2-page guides provide quick lighting layout solutions for common design problems. Access them here!