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Flashcards in Sustainable Design Deck (9)
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daylight factor

the ratio of the illuminance at a point on a horizontal surface indoors to the illuminance at a point on a horizontal surface outdoors and fully open to the sky, measured at the same time under overcast skies;; direct sunlight is excluded. DF is expressed as a percentage but the percentage sign is sometimes omitted (e.g. DF 2% = DF of 2.)



the figure-eight curve that represents the angular offset of the sun from its mean position as viewed from the earth;; at any given point on the earth, if the position of the sun is notated at the same time every day for a year, the figure of the analemma is produced.


balance-point temperature

the outdoor temperature at which a building makes a transition from a heating need to a cooling need


daylight autonomy (DA)

the percentage of an area that meets a minimum daylight illuminance level for a specified fraction of the operating hours per year;; one option for receiving LEED credit in the Daylight category.


effective aperture (EA)

the product of visible transmittance and window-to-wall ratio


glazing factor

a LEED-based number calculated by taking into account window area floor area, a window geometry factor, light transmission, and a window height factor


shading coefficient (SC)

the ratio of the solar heat gain through a glazing product to the solar heat gain through an unshaded 1/8 inch thick, clear, double-strength glass under the same set of conditions;; this is a value for the glass only and does not include the frame.



the assumed height at which work is performed, usually considered to be at desk height, 30 in above the floor


4 main causes of poor indoor air quality

1) chemical contaminants from indoor sources 2) chemical contaminants from outdoor sources 3) biological contaminants 4) poor ventilation