Lighting Design Intent (an element of OPR)

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ELECTRIC LIGHTING DESIGN OPR (review of concepts from Arch 273) Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 1 Lighting Design Intent (an element of OPR) 1.

1 ELECTRIC LIGHTING DESIGN OPR (review of concepts from Arch 273) Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 1 Lighting Design Intent (an element of OPR) 1. A clear design intent should be evident in all elements of the visual field. William Lam: Perception and Lighting as Formgivers for Architecture from Some rules of thumb for good design decide what you want to accomplish so that you can then pull it off Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 2 1

2 general process flow iterations Design Process Flow Design issues intents criteria System ideas/proposals initial Preliminary design methods used (patterns, tools, ) System ideas/proposals refined Specific implementation methods (physical things) System ideas/proposals near final Document design requirements in drawings and specs System validation During design (via design firm s quality control procedures and perhaps commissioning) During construction (via contractor s quality control procedures and perhaps commissioning) During usage (via complaints or via POE; perhaps via commissioning) Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 3 Lighting Design Process Diagram Start (with the problem ) Design intent Design criteria *Design concepts *Design validation Design process: Stuff happens Lighting design methods* End (with the solution ) * to be discussed more over the next weeks Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 4 2

Issues Intents Criteria ISSUES Intent Criteria Flow into design process Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 5 Design Intent Examples of possible electric lighting intents: The

3 Issues Intents Criteria ISSUES Intent Criteria Flow into design process Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 5 Design Intent Examples of possible electric lighting intents: The lighting system will be energy efficient The lighting equipment will be easily maintained The lighting results will be reasonably comfortable The lighting will increase sales The lighting will increase productivity The lighting will enhance wayfinding The lighting will contribute to a LEED certification The lighting will win a design award Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 6 3

4 Design Criteria Some possible criteria (red) paired with intents (blue): The lighting will be energy efficient Perhaps: will meet the requirements of ASHRAE Standard Perhaps: will comply with the requirements of the 50% Advanced Energy Design Guide (AEDG) The lighting will be easily maintained Luminaires will have an increase in light loss factor (LLF) of less than 10% when cleaned every two years Lamps can be changed by custodial crew without special equipment The lighting will be reasonably comfortable 80% of occupants will rate the lighting as very comfortable The lighting will be aesthetically pleasing Appearance will be similar to three selected precedents Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 7 More examples: Design Criteria The lighting will increase sales The redesigned lighting will increase sales by 20% compared to sales under the existing lighting scheme The lighting will increase productivity The lighting will increase worker productivity by 10% compared to the productivity in existing offices [beware the Hawthorne effect] The lighting will support wayfinding the reception desk will experience 25% fewer requests for assistance in finding major functional spaces note that criteria can be quantitative (useful during design and amenable to calculations) and/or qualitative (typically amenable to judgment and POEs) Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 8 4

5 Methods Methods should never be put forward as intent or criteria (with a few rare exceptions) LED lamps are NOT an intent LED lamps are NOT a criterion LED lamps are a method (a means, not an end; a cause, not an effect) Methods may be design methods (such as software) or implementation methods (such as hardware) a method, such as daylighting, may become an intent if it is so strongly held as to be non-negotiable (even then, good daylighting is likely the real intent) Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 9 A Reminder A proposed design solution is a hypothesis You, as the designer, have a belief that IF something is implemented, THEN such and such will result* A hypothesis is a prediction, a prognosis, a wish, a wild guess (depending upon experience and extent of project research) A hypothesis is NOT a fact Hypotheses must be tested and verified Thus, design moves must be validated (they will have consequences see image on first slide) *Example hypothesis: this lighting effect, implemented in a surgical recovery room, will lead to shortened recovery times and improved patient outcomes Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 10 5

6 Design Validation Methods Validation of design moves during the design process is essential, otherwise it will be too late for the victims of a bad design decision the decision will have been built and then occupied by real people Many lighting design validation tools are available Precedents (case studies) General rules and patterns Hand calculations Computer simulations Physical models (difficulty in scaling electric light sources limits this tool this is not the case with daylighting) Full scale mock-ups (cost may limit this tool) Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 11 Implementation Methods These are the objects and systems that can produce the desired effects in a completed building Implementation methods convert concepts into physical reality Fluorescent lamps Indirect lighting fixtures Digital lighting controls Reflective wall surfaces and so on Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 12 6

7 Back to Lighting Design Issues Quantitative issues Illuminance Luminance Energy performance Environmental performance First cost Life-cycle cost Etc. issues become intent by assigning value/direction; and then become criteria by assigning minimum acceptable performance benchmarks Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 13 Lighting Design Issues Qualitative issues Glare Brightness (and brightness patterns) Color rendering Aesthetics Appropriateness Edginess Innovation Etc. Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 14 7

Design Issues source qualitative quantitative space type Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 15 Some Context for Lighting Design There is no unified theory of visual comfort (as

8 Design Issues source qualitative quantitative space type Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 15 Some Context for Lighting Design There is no unified theory of visual comfort (as there is with thermal comfort) there is no visual comfort zone diagram; no solid advice regarding how a bit less glare might trade off with a bit less illuminance or how color rendering might trade off with luminance. The lighting design process essentially involves addressing each issue of concern in sequence with the disaggregated nature of the process dealt with through conceptual coordination by the designer. We ll look at the issues of illuminance and glare in some detail in the following slides as these are important concerns for virtually all projects. several research attempts to develop a unified theory of human response to lighting have been conducted, but none (so far) has been useful for designers Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 16 8

9 Illuminance* On horizontal surfaces Requirements are generally a function of the visual acuity required or expected in order to complete a known task The purpose of illuminance is to provide adequate light for successful task completion Task is the key (the designer is usually addressing a defined visual task versus general space-rendering) Task location(s) are of concern Multiple tasks require providing for the worst task, or for flexibility over time, or for flexibility across space Measured in lux (SI) or footcandles (I-P) *reminder: the density of light falling on a surface; the human eye cannot detect illuminance, but can detect its result (brightness/luminance) Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 17 Illuminance On vertical surfaces If there is a vertical task (pinup, bulletin board, artwork, signage, ), then design concerns are the same as with horizontal illuminance In the absence of a defined wall-based visual task, vertical illuminance requirements are generally a function of spatial design intent To visually render the space (to avoid a cave effect) To draw attention, provide focus To reduce glare (reduce contrast) To support aesthetic intents Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 18 9

10 Visual Acuity Factors Illuminance recommendations (in the US) are generally based upon visual acuity the ability to see detail; this ability is affected by three key environmental factors: Size of detail Typically there is only minor architectural control over this factor via establishment of viewing distances or through signage design; the architect has little or no control of size for most work tasks Luminance of detail A result of illuminance and reflectance; illuminance is fully within the realm of lighting system design, while reflectance is often a property of a non-architectural object (such as the page of a book) Contrast at detail A result of task-background luminance relationships and glare condition; these factors are partially in the realm of lighting design and partially a property of the task Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 19 Visual Acuity Factors Size Luminance Contrast E E E E E E E E B F EEEEE visual acuity is also affected by the time allowed to view a task and by the condition of the viewing eye these are generally beyond the scope of architectural decisions (but must be understood by the lighting designer) easy to see more difficult Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 20 10

Design Illuminances illuminance categories from the IESNA Lighting Handbook (9 th edition) which is a guideline (not a code or standard) Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 21

11 Design Illuminances illuminance categories from the IESNA Lighting Handbook (9 th edition) which is a guideline (not a code or standard) Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 21 Illuminance Adjustments The 8 th edition of the IESNA Lighting Handbook suggested increasing illuminance by 1 category for each clear instance of a negative mitigating factor (poor eye condition, poor contrast, a highspeed task) the 9 th edition was less specific regarding such adjustments but the idea of adjustments is still valid (and recommended). In fact, such adjustments are incorporated in the current 10 th edition (see next slides) the changes in design guidance from one edition of the Handbook to the next noted above are typical of the ongoing evolution of design (around 100 years after the first electric lighting systems were introduced) Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 22 11

illuminance recommendations from the IESNA Lighting

guideline (not a code or standard) an extract from

educational facilities other building types are

Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 23

Lighting Handbook (10 th edition) an extract from

12 illuminance recommendations from the IESNA Lighting Handbook (10 th edition) which, as a reminder, is a guideline (not a code or standard) an extract from several pages of information dealing with educational facilities other building types are also addressed in similar detail Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 23 further design recommendations from the IESNA Lighting Handbook (10 th edition) an extract from several pages of information dealing with educational facilities other building types are also addressed in similar detail Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 24 12

13 Glare A negative visual sensation resulting from excessive brightness or excessive contrast in the field of view. Glare can be categorized by: Degree of impact: blinding, disability, discomfort Source/receiver relationship: direct or reflected Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 25 Glare: Degree of Impact Blinding glare: vision is temporarily disrupted (zero visual acuity for some period of time) Example: oncoming car headlights at night (a result of excessive contrast) Example: looking at the sun through a window (a result of absolute brightness) Source may be direct or reflected (although most commonly it is direct) Blinding glare should never be encountered in a building (but occasionally it is due to bad design) Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 26 13

Glare: Degree of Impact Disability glare: visual acuity is reduced; the viewer is physically less able to effectively complete visual tasks Example: a reflected image of a light fixture seen in a

contrast) Source may be direct or reflected (either is likely) and the negative effect is often a result of contrast versus absolute brightness Disability glare is undesirable in a building, but

org Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 27 Glare: Degree of Impact Discomfort glare: visual acuity is not measurably reduced, but glare has intruded into the viewer s

14 Glare: Degree of Impact Disability glare: visual acuity is reduced; the viewer is physically less able to effectively complete visual tasks Example: a reflected image of a light fixture seen in a computer screen (a reflected glare situation, commonly called a veiling reflection) Example: looking at a TV that is located in front of a bright window (a direct glare situation, due to excessive contrast) Source may be direct or reflected (either is likely) and the negative effect is often a result of contrast versus absolute brightness Disability glare is undesirable in a building, but budget constraints may make total elimination difficult commons.wikimedia.org Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 27 Glare: Degree of Impact Discomfort glare: visual acuity is not measurably reduced, but glare has intruded into the viewer s consciousness; a viewer may be psychologically less able to complete visual tasks Example: reflection of ambient light from a computer screen (no image is seen but contrast is reduced, leading to eye strain) Example: marginal brightness ratios in a room that make occupants feel depressed Source may be direct or reflected and the effect is usually a result of contrast versus absolute brightness; the key issue may often be attention-diversion Discomfort glare is undesirable in a building, but is very difficult to totally eliminate (due to budget limits and the qualitative nature of the problem) Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 28 14

Glare: Source Direct glare: a too-bright object or too-great-acontrast scene is in the line of sight of an observer (no intervening transmitter is involved) This should be readily predictable during

com Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 29 Glare: Source Reflected glare: a too-bright object (the most common situation) or too-great-a-contrast scene (less common) is brought

15 Glare: Source Direct glare: a too-bright object or too-great-acontrast scene is in the line of sight of an observer (no intervening transmitter is involved) This should be readily predictable during design, and thus readily solvable simply: Ask yourself what s going to be too bright (more technically, too luminous) Then, reduce brightness (luminance) or block views to the source Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 29 Glare: Source Reflected glare: a too-bright object (the most common situation) or too-great-a-contrast scene (less common) is brought into the line of sight of an observer by the intervention of a reflective surface This combination of factors is not necessarily obvious during design, thus some brainstorming is needed Ask yourself what s going to be too bright Ask yourself what s likely to be reflective Then, consider the possible geometries between the above elements and users of the space and take appropriate action Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 30 15

Glare Summary Glare Is a perception, not a physical artifact Requires a human receptor/evaluator There is no glare in an unoccupied room Perceptions will vary from person to person

Glare cannot be measured by equipment (but luminance can be measured) Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 31 Sparkle: A positive visual sensation caused by high

16 Glare Summary Glare Is a perception, not a physical artifact Requires a human receptor/evaluator There is no glare in an unoccupied room Perceptions will vary from person to person Design to mitigate glare often relies upon patterns from past experiences or statistical likelihoods Glare cannot be admitted through a window (but intense light can be admitted) Glare cannot be measured by equipment (but luminance can be measured) Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 31 Sparkle: A positive visual sensation caused by high brightness or contrast sparkle or glare? ball four (just a little bit off the plate) if not sparkle, then very expensive glare Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 32 16

ResearcH JournaL 2011 / VOL

ResearcH JournaL 2011 / VOL 03.01 www.perkinswill.com PERKINS+WILL RESEARCH JOURNAL / VOL 03.01 04. UNDERSTANDING GLARE: Design Methods for Improving Visual Comfort David Mead, NCARB, IES, LEED AP BD+C,