Designing Goals Inventory Existing and Planned Conditions Lighting Designer should consider and investigate the following parameters: Space Dimensions (lengths, widths and heights): Quantitative and subjective lighting aspects are influenced by space geometry. Ceiling heights may influence general lighting approaches,-limiting application for ceiling suspended indirect, semi-indirect, or direct-indirect lighting systems. *Indirect Lighting: Architecture lighting achieved with luminaries exhibiting an indirect light distribution-90 to 100% of the light exits the luminaire upward; 0 to 10% of the light exits the luminaire downward. See Fig. 11.15e. .

*Semi-Indirect Lighting: Architecture lighting achieved with luminaries exhibiting a semi-indirect light distribution- 60 to 90% of the light exits the luminaire upward; 10 to 40% of the light exits the luminaire downward. See Fig. 11.15d *Direct-Indirect Lighting: Architecture lighting achieved with luminaries exhibiting an indirect/direct light distribution- 40 to 60% of the light exits the luminaire upward; 40 to 60% of the light exits the luminaire downward. See Fig. 11.17.

Spatial Form: Rectilinear, curvilinear, pie-shaped, amorphous Spatial Form: Rectilinear, curvilinear, pie-shaped, amorphous. Quantitative aspects, such as lighting efficiency, are greatly influenced with space shape and geometry. Generally, larger, moderate ceiling spaces (3 to 3.7 m in height) offer a more efficient use of daylight and electric light. Subjective aspects, such as spatial comprehension, are also influenced by spatial form. Long, narrow spaces with low ceilings promote a sense of enclosure or confinement particularly when downlit with no wall lighting.

Space Activities ( primary, secondary, and infrequent but critically important): if a space such as a “lobby” is used for both short-term time and long-term time activities of stay, then addressing such place as a lobby and lighting it will result in serious under lighting. Visual tasks (prioritize by importance, prioritize by time spent on each): users should be observed and queried regarding the tasks they typically perform and the importance and duration of these tasks in the planned spaces.

Occupant’s ages by group (20-40 yrs, 40-60 yrs, and 60 and above yrs): Generally 60-year-old eyes need two to three times as much light as 20-year-old eyes to perform a task to the same degree of accuracy and timeliness. Aging eyes are also more sensitive to glare than young eyes. General lighting and task lighting may elicit complaints of glare depending on the age of the population a nd on the degree (or lack) of optical control (e.g., lensing and louvering) or on the optical distribution of light. The solution is using indirect or direct-indirect lighting is less glary than direct lighting.

Furnishings (Low and open, low and closed, high and open, high and closed): Lighting system efficiency is greatly influenced by furnishings. Further, some furniture configurations create shadows that can result in complaints of too little light. Tall workstation partitions (e.g., greater than 60 inches height (1.52 m) and low ceilings (e.g., a ceiling height at or less than 2.43 m in height) along with ubiquitous binder bins or shelves all combine to reduce lighting effectiveness and introduce strong shadowing. Greater density of workstations and/or taller partitions introduce a sense of confinement.

Surface Finishes (degree of gloss, color, LRV): They affect both the quantitative and subjective aspects of light. The solution is to use high reflectances (LRVs approaching 90% for ceilings, 50% for walls, and 20% for floors) which will greatly improve lighting efficiency and overall brightness impressions. Low-reflectance surfaces are likely to create a transient adaptation problems-tired eyes and/or headaches may result during the course of a day. The gloss (degree of specularity or matteness) of surfaces will help in assessing glare (more gloss yields more glare).

*Light Reflectance Value (LRV): It represents the percentage of light that will be reflected from a surface finished in the color/finish in question. An LRV of 70 indicates 70% of the light striking the surface will be reflected. This value does not identify the specularity or gloss characteristics of the finish (e.g., matte or flat, semi-specular or semi-gloss, or specular or high-gloss). Matte finishes are less glary and are very appropriate for work settings.

Lighting (Illumances, Luminances, luminaire types, layouts, and lamping). See previous lectures and related definitions of lighting. Users’ feedback (complaints and compliments about present environment) in terms of space activities, visual tasks, and user's input.: Getting user feedback on existing conditions requires the designer to survey users. Owner feedback (Image, users' satisfaction): The designer should take stock of what the owner expects of the newly planned environment. Issues of environmental quality and budget should be addressed early in the programming phase to avoid problems in both planning and the financing of the project.

Designers’ Expectations (image, monument to owner, improve human conditions). Designers on the project will likely have openings about the owner's existing space(s).