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PVH Lemay MOB I Glare StudyAnalysis— October 15, 2007 1
Ted Shepard
Page 2
The site section indicates the light reflectance in a vertical dimension.
The lowest angles of reflectance will occur at sunrise and sunset but this
light will reflect mostly west and east respectively off of the south
elevation and will not affect the south residences.
Please let me know if you have any questions or need additional information
for this issue.
Angela K. Milewski
BHA Design, Inc.
1603 Oakridge Drive
Fort Collins, CO 80525
ph: 970.223.7577
fx: 970.223.1827
CC: "Jon Tucker"<jtucker@boulderassociates.com>, "Dean Barber'
<DeanB@mcwhinney.com>
Ted Shepard - Page 1
From: "Angela Milewski" <amilewski@bhadesign.com>
To: "Ted Shepard (tshepard@fcfov.com)" <tshepard@fcgov.com>
Date: 12119i 007 10:18:21 PM
Ted,
As we discussed today, here is the information that the architect has
developed regarding glare study to respond to the Planning and Zoning Board
condition of approval:
The Planning Code, Section 3.5.1 (E) - Building Materials states, in part,
"2) Building Materials shall not create excessive glare. If highly
reflective material - aluminum, unpainted metal, reflective glass - is used,
evaluate to determine whether glare creates significant adverse impact." and
"3) Windows - Mirror glass with a reflectivity or opacity of greater than
60% is prohibited."
The building material consists of red brick, buff colored stone and pre -cast
concrete panels and sills, green colored (antique copper cote) metal panels,
pre -weathered graphite grey metal panels, tan (Sienna) colored cement board,
and a dark bronze window frame system with grey tinted glazing. The
specified glazing has a Visible Light reflectance of 7% and a Total Solar
Energy reflectance of 13%. Due to colors and textures all other materials
are essentially non -reflective. None of the materials, including the
glazing, are considered "highly reflective".
All materials are oriented vertically or horizontally so there are no angled
surfaces to reflect the sun at irregular angles. Sunshade devices are
located at the south and west elevations to reduce the amount of sun
striking the glazing thereby reducing the amount reflected.
The site section indicates the possible glare angles on the south side of
the site on the winter solstice (12/21) when the angle of incidence is
lowest in the sky. At other times of the year the sun will strike the
building at a higher angle of incidence thereby increasing the amount of
light reflected (as opposed to the light transmitted or absorbed) but also
reducing the angle of reflectance. In summary, the sharper the angle at
which the light strikes the more the light is reflected. So the higher the
sun is in the sky the more will be reflected. However, the angle of
reflectance on a vertical surface is equal to the angle of incidence so the
reflected light doesn't travel as far from the building. On the winter
solstice less light is reflected but it is reflected farther from the
building. At other times of the year, more light is reflected as the angle
of incidence steepens, but it is not reflected as far from the building.