Home Lighting Design – Daylighting Design
This article develops a unique and extensive daylighting design program for home lighting design to address code and much more. Home lighting design policy for most homes these days: let daylight in with qualifications: maybe not too much, not too little, depends where, depends how, how about when, depends on what which is shining, etc. It is a natural lighting design program.
The Home Lighting Design Code: IRC 303.1 effectively and bluntly presents that for daylighting design, at least in a bedroom, the “aggregate glazing area” must not be less than 8% of the floor area from that room. (CABO is more difficult, fewer exceptions). [Please note that this presentation has no direct connection with emergency egress.]
Natural lighting design practice at home? Who knows. The author has had reactions from “exactly correct” to “not that important around here” to “what are you talking about” from building authorities having jurisdiction. If others consider it at all, it would be for sleeping areas only is my expectation.
AGGREGATE GLAZING AREA
To begin with, the otherwise undefined term aggregate glazing area is interpreted to mean a translucent surface: glass, clear plastic, etc. and unassociated frames, sashes, sills, moldings and the like. What Marvin Windows and Doors defines as “Lite”, Pella as “Visible Glass”, Loewen as “Exposed Glass Area”, etc.
Please note that if some people were not interested in these surface areas, the big window actors would not resolve it in print. This custom home designer is interested.
THE NATURAL LIGHT HOME PROGRAM FOR NATURAL LIGHT DESIGN
A daylighting program for home lighting, or lighting program, accomplishes four purposes.
First, it defines the ratio of glazing area added to interior surface area in each major space of a residence, including habitable rooms, hallways, walk-in closets, service spaces for workshops and laundries, garages, etc.
Second, it compares the actual aggregate glazing area to the calculated code target for each parent space and presents the difference in square feet of glazing area or, increasingly likely, in percent of the target glazing area; the latter seems easier to understand.
Third, it selectively comments through suggestions, prompts, and definitions on important aspects of daylighting as warranted by the designers’ opinions.
Fourth, it provides the opportunity to identify persistently dark spaces or parts of spaces distant enough from a natural light source to be considered unlit or not penetrated by a natural light source, for example, a space considerably removed from the daylight from a covered porch, an exceptionally deep interior space.
The schedule structure is presented as a multi-column table. From the left, let’s see: a space to give; its area in square feet; 8% of that area in square feet; aggregate glazing area of that space in square feet (usually to one decimal place); the arithmetic and percentage difference between the 8% and the added glazing column; and comments as appropriate. Comments may include but are not limited to modular, dark, code compliant (for sleeping areas), etc.
Home lighting experts place definable limits on the amount of useful natural light that can enter a space. These limits can be found, for example, in Lighting Design Basics by Mark Karlen and James Benya, John Wiley & Sons, Inc., 2004, p.34 and Interior Lighting For Designers 4th Edition by Gary Gordon, John Wiley & Sons, Inc. . . ., 1957, p.53ff. While this aspect of daylight penetration in daylighting analysis can be critical, consideration of adjustment related to daylighting is, in the author’s opinion, well worth the effort as a precautionary design alert for comfort. and security.
The Home Daylighting Design program features several bases or inputs for home design analysis – 16 in all.
1. Of himself for natural light, in the compass orientation of the house and, where appropriate, its suitability and in the personal assessment of infiltration and suitability in daytime spaces.
2. Ventilation as cross-quality control in the cross-ventilation of bedrooms and more occupied rooms, in addition to the indicative dimensioning and location of both supplies and returns.
3. UV intrusion indicator of where it can be determined as less welcome and its power diminished.
4. Natural heat buildup indicator for professional HVAC care and various means of design to decrease.
5. Definition of daylight glare, especially in areas, such as stairs, where glare threatens safety.
6. Qualification for code compliance of glazing area added to space surface area in sleeping areas, notably more problematic in such spaces within one-and-a-half story structures in L2.
7. Suggestive guide to artificial lighting at all times, in particular ambient lighting and lighting controls.
8. Final cross check of window and door size and site in elevations, plan view(s), and window schedule (and possibly door schedule).
9. Excellent perspective on the consequences of exterior design on interior functionality, occasionally leading to marginal to major design changes.
10. Guide to increase the layers in spaces with little natural light.
11. Guide for rating continuous service in spaces with no and very little natural light.
12. Guide to modify the dimensions of the fenestration.
13. Guide to modify the location of the fenestrations.
14. Motivation in single-story deep spaces with exterior decks to penetrate those decks with ceiling niches, sunscreen, skylight, clerestory, etc.
15. Motivation in deep single-story spaces with or without exterior decks to add clerestory and light wells through dormers and other window design modifications.
16. Motivation, particularly in floor-and-a-half designs, to necessarily add dormers, skylights, skylight tubes, clerestory, light wells, and other window design modifications.
Comment: Please note major bug fixes in recent days for safe and convenient window sizing and placement, exterior door composition, light fixtures, and light reflecting and absorbing features they can be a repair expense and a major physical inconvenience.