Daylight factor


Also found in: Medical.

Daylight factor

The ratio of interior illuminance at a given point on a given plane, usually the workplane, to the exterior illuminance under known overcast sky conditions. This is one of the key values when analyzing the quantitative aspects of daylighting. Since the outside illuminance varies a lot with weather conditions (8,000–25,000 lux), the interior illuminance alone does not provide much useful information. The acceptability of the amount of daylight reaching an interior space for a specific task can only be determined in relation to the situation outside. There is little use in computing the relation of outside and inside illuminances under sunny sky conditions.
Illustrated Dictionary of Architecture Copyright © 2012, 2002, 1998 by The McGraw-Hill Companies, Inc. All rights reserved

daylight factor

The ratio of the illumination at a point on a given plane to the illumination on a horizontal plane from the whole of an unobstructed sky of assumed or known luminance distribution; a measure of the daylight illumination at that point.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.
Mentioned in ?
References in periodicals archive ?
The results have indicated the minimum, average and maximum illuminance and daylight factor in the high-rise residential building affected by building shading effect, whereas, 30m of building separation is the best distance between buildings in terms of planning to obtain the acceptable daylight and to enhance the daylight performance in the building.
PARAMETRIC STUDIES ON BUILDING SEPARATION OF DAYLIGHT PERFORMANCE IN OBSTRUCTED LOW COST HIGH-RISE RESIDENTIAL BUILDING THROUGH COMPUTER SIMULATION TECHNIQUES IN KUALA LUMPUR, MALAYSIA
Realistically, there is no uniform sky that is uniformly illuminated so that values of the percentage daylight factor in building spaces can be directly measured.
A method to determine a single point percentage daylight factor (%DF) value from field work data
3.2 The effect of light shelves on daylight factor:
Optimal of daylighting performance with shading device via computer simulation for office building in Malaysia
Below we present the daylight factor and the daily total radiant energy of the courtyard space.
Paradigm in sustainability and environmental design: lighting utilization contributing to surplus-energy office buildings
Calculation of daylight factor DF [%] was carried out for the determination of an effect of three different types of window glasses on the indoor daylighting level in the investigated office.
Comparative study of window glass influence on daylighting in an open-plan office
The most commonly used metric for measuring daylight in a building is called the "daylight factor"--expressed as a percent of available exterior daylight.
A new & better way to calculate daylight
As an example, for London weather data with a daylight factor of 3%, 250lux (23.2fc) would be exceeded for 75% of office hours (0900-1730) (CIBSE Guide A).
Ventilation approaches for shopping malls - an examination of natural and Hybrid Strategies
An ambitious aim was to make the classrooms fully daylit, but even a complete side wall of glass allows a daylight factor only of 3.5 per cent at the back of the room.
Sustainable School: One of the most rigorous programmes ever devised ensured that this French school is environmentally appropriate in multiple ways. It has many lessons to teach
Reductions in lighting consumption are awarded for increasing daylight factors; a 20% reduction is available for a daylight factor greater than 10%, a 10% reduction available for a factor greater than 5%, and a 5% reduction available for a factor greater than 2%.
Post-occupancy performance of five low-energy schools in the UK
This study examines the impacts of aperture size (daylight factor) for four combinations of toplighting strategies and glazing types on the total yearly energy loads for a prototypical open office space situated in four different climates.
Optimal daylight factor for energy-efficient toplighting system
For the simulation of this new single zone atrium house, we used Autodesk Ecotect program to calculate the daylight factors in the worst case condition (mid winter at noon) and chose a better fenestration design for the house.
Occupancy based heating/cooling for low energy affordable housing in hot-humid climates

Encyclopedia browser ?
Full browser ?