AREN 3540 Illumination I
Deliverable: You are to submit a report (PDF format uploaded to Canvas) that addresses the following
request for a hospital room lighting analysis. Include an introduction to the design problem, a description
of your analysis process, and clear documentation of your final solution. Use a heat map, a reflected
ceiling plan, and room sections to help communicate your solution. Discuss your results as described in
the Discussion section of this assignment sheet. Provide proof of your calculations and methods in an
appendix. Clearly state any simplifying assumptions used in your calculations. Any spreadsheets or
scripts used should be submitted (setup to prove your calculations), referenced in the appendix, and
submitted via Canvas.
Spring 2022
A 16-ft long, 12-ft wide, 9-ft tall, hospital patient room is designed to have daylighting and electric
lighting. You will focus your analysis on the nighttime condition in which electric lighting must
meet the illumination needs of the space. Use the Lumen Method to evaluate two different
luminaire options of your choosing, and use the inverse square cosine law approach to confirm
adequate illuminance distribution across the workplane for the selected luminaire option.
Electric Lighting Analysis: The Lumen Method
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Select a horizontal workplane illuminance design criterion for the nighttime electric
lighting condition. (Use lux or footcandles. Be consistent with units throughout your
analysis and report.)
Identify at least two luminaire options. To get you started in your search, one "big name"
lighting manufacturer is Acuity Brands (https://www.acuitybrands.com/products). Look for
a photometry report (PDF file) that has a Coefficient of Utilization table before selecting
the luminaire. You do not need to select a luminaire that is labeled as a healthcare-
specific product but do select an option that is appropriate for the function and scale of
the room.
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Use the Lumen Method to determine the final average illuminance, Ē, on the workplane.
Document the following information and assumptions in the appendix:
O
Room cavity ratio
O
Floor cavity ratio
O
Ceiling cavity ratio
Effective ceiling cavity reflectance
O Effective floor cavity reflectance
O Photometric report (cut sheet) for your selected luminaire
O Interpolated CU for your luminaire
O Light Loss Factor (set equal to 1 for this project)
O The minimum number of luminaires necessary to meet your design criterion
Select one option to recommend to the client.
Determine the final average illuminance, Ē, on the workplane (using a real number of
luminaires).
Electric Lighting Analysis: Inverse Square Cosine Law
Now, use your direct illuminance calculation tool (Excel-based tool from Assignment 3) to
analyze the room with the selected luminaire.
Use calculation points spaced one feet apart on the workplane (2.5' AFF) and assume
the origin to be at the northwest corner of the room.
1 AREN 3540 Illumination I
Discussion
● Describe your initial luminaire alternatives.
Give a justification for and describe your final luminaire selection and layout.
Discuss the final illuminance result (magnitude and distribution) using the Lumen Method
and inverse square cosine law approaches.
Discuss how much and why the results of the two calculation approaches differ if they do.
During your analysis process, the client presented you with a luminaire option similar to
the one you selected, and it claims to provide germicidal ultraviolet (GUV) disinfection.
Describe what information must be collected in order for you to use your architectural
lighting analysis expertise to validate the GUV disinfection claim.
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Spring 2022
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