A Design Chart to Determine the Sizing
of Vertical Windows for Daylighting
Shady Shawky Saifelnasr
Abstract
The main objective of this paper is to introduce a simple
quick tool for architects represented by a design chart that
determines the sizing of vertical windows for providing
minimum or average amount of daylight as a function of
the properties of the window, the room, and the
surrounding environment. One of the most important
purposes for introducing windows to a building envelope
is providing adequate daylight suitable for the different
uses within the different functional spaces. And daylighting might be one of the main reasons for the sizing of
those windows. Different calculation methods could be
used for daylight calculation and analysis; formula
methods, graphical methods, scale models, and computer
programs. Although formula methods are not the most
accurate daylighting calculation method, they could be
used as a rule of thumb especially within the preliminary
stages of design. The proposed design charts are derived
from formula methods to be used by architects as a simple
quick tool that could be used for both design and analysis.
They could be used within the design process by finding
the sizing of vertical windows. Moreover, they could be
used in the analysis of an existing case by finding the
available daylight factor. The design charts are a combination of more than one graph to include most of the
specifications of the window, the room, and the surrounding environment, to find the sizing of vertical
windows, that would ensure the minimum or average
amount of daylight for any city all over the world, within
the low, middle, or high latitudes.
Keywords
Design charts Á Sizing windows Á Daylighting
1 Introduction
As a valuable building asset, a window can provide several
functional aspects such as daylighting, natural ventilation,
and/or views (Friedman 2012). And the window sizing could
be a result of one or more of those aspects. But conflicts with
other building systems should be considered while sizing a
window, e.g., oversizing a window can increase unwanted
heat transfer, i.e., increase heat gain during summer and
increase heat loss during winter (Lechner 2008).
In this paper, the author tries to represent a quick tool for
finding the window area that can provide a minimum amount
of daylighting needed for most basic applications.
1.1 Nomenclature
DF Design Daylight Factor
1 (Pohl 2011) %
s
Transmittance of Glazing
2 (Phillips 2004) %
R
Average Internal Surface Reflectance %
h
Sky Exposure Angle °
W
Window Area m
2
A
Floor Area m
2
RA Total Area of Internal Surfaces m
2
1.2 Background and Previous Studies
Previous studies proposed methods of sizing for daylight
apertures in the form of tables or graphs. Those tables or
graphs were either designed for a specific location, i.e., city,
or they were for studying the effect of certain specific
S. S. Saifelnasr (&)
October University for Modern Sciences and Arts “MSA”, Cairo,
Egypt
e-mail: ssaifelnasr@msa.eun.eg
1
The daylight factor (DF) expresses the daylight available as a
percentage of the daylight concurrently available out of doors.
2
Glazing is a transparent material used for windows for the admission
of light, e.g., glass. There are basically three types of glazing, namely,
clear glazing, tinted glass, and miscellaneous glazing, e.g., patterned
glass, wired glass, laminated glass, glass blocks, and high-tech glazing.
© Springer Nature Switzerland AG 2020
M. Mateev and J. Nightingale (eds.), Sustainable Development and Social Responsibility—Volume 1,
Advances in Science, Technology & Innovation, https://doi.org/10.1007/978-3-030-32922-8_2
13
of Vertical Windows for Daylighting
Shady Shawky Saifelnasr
Abstract
The main objective of this paper is to introduce a simple
quick tool for architects represented by a design chart that
determines the sizing of vertical windows for providing
minimum or average amount of daylight as a function of
the properties of the window, the room, and the
surrounding environment. One of the most important
purposes for introducing windows to a building envelope
is providing adequate daylight suitable for the different
uses within the different functional spaces. And daylighting might be one of the main reasons for the sizing of
those windows. Different calculation methods could be
used for daylight calculation and analysis; formula
methods, graphical methods, scale models, and computer
programs. Although formula methods are not the most
accurate daylighting calculation method, they could be
used as a rule of thumb especially within the preliminary
stages of design. The proposed design charts are derived
from formula methods to be used by architects as a simple
quick tool that could be used for both design and analysis.
They could be used within the design process by finding
the sizing of vertical windows. Moreover, they could be
used in the analysis of an existing case by finding the
available daylight factor. The design charts are a combination of more than one graph to include most of the
specifications of the window, the room, and the surrounding environment, to find the sizing of vertical
windows, that would ensure the minimum or average
amount of daylight for any city all over the world, within
the low, middle, or high latitudes.
Keywords
Design charts Á Sizing windows Á Daylighting
1 Introduction
As a valuable building asset, a window can provide several
functional aspects such as daylighting, natural ventilation,
and/or views (Friedman 2012). And the window sizing could
be a result of one or more of those aspects. But conflicts with
other building systems should be considered while sizing a
window, e.g., oversizing a window can increase unwanted
heat transfer, i.e., increase heat gain during summer and
increase heat loss during winter (Lechner 2008).
In this paper, the author tries to represent a quick tool for
finding the window area that can provide a minimum amount
of daylighting needed for most basic applications.
1.1 Nomenclature
DF Design Daylight Factor
1 (Pohl 2011) %
s
Transmittance of Glazing
2 (Phillips 2004) %
R
Average Internal Surface Reflectance %
h
Sky Exposure Angle °
W
Window Area m
2
A
Floor Area m
2
RA Total Area of Internal Surfaces m
2
1.2 Background and Previous Studies
Previous studies proposed methods of sizing for daylight
apertures in the form of tables or graphs. Those tables or
graphs were either designed for a specific location, i.e., city,
or they were for studying the effect of certain specific
S. S. Saifelnasr (&)
October University for Modern Sciences and Arts “MSA”, Cairo,
Egypt
e-mail: ssaifelnasr@msa.eun.eg
1
The daylight factor (DF) expresses the daylight available as a
percentage of the daylight concurrently available out of doors.
2
Glazing is a transparent material used for windows for the admission
of light, e.g., glass. There are basically three types of glazing, namely,
clear glazing, tinted glass, and miscellaneous glazing, e.g., patterned
glass, wired glass, laminated glass, glass blocks, and high-tech glazing.
© Springer Nature Switzerland AG 2020
M. Mateev and J. Nightingale (eds.), Sustainable Development and Social Responsibility—Volume 1,
Advances in Science, Technology & Innovation, https://doi.org/10.1007/978-3-030-32922-8_2
13