Lighting Design Basics for Businesses Points to Consider Brittany Petersen Energy Analyst National Center for Appropriate Technologies
When lighting becomes a problem How is it addressed?
Under lit workspace
Over lit workspace
Road map Basic elements of lighting design Assessment of work environment Why Energy Efficiency Application
Basic Lighting Design Where do you work? Common Commercial Spaces - Office - Warehouse - Retail - Hospitality What kind of lighting? Common Commercial Lighting - Incandescent - Compact Fluorescent (CFL) - Linear Fluorescent - High Intensity Discharge
Basic Lighting Design Office
Basic Lighting Design: Office fixtures Ceiling can Direct indirect Fixed
Basic Lighting Design: Fluorescent fixtures
Basic Lighting Design: Fluorescent fixtures Lamp produces visible light by causing phosphor to fluoresce Ballast Fixture/ Luminaire provides starting and operating current to excite phosphor in fluorescent lamps unit containing lamp and ballast
Basic Lighting Design: High bay fixtures
Basic Lighting Design: high bay fixtures Typical high intensity discharge
Basic Lighting Design: high bay fixtures Metal Halide Mercury Vapor High/Low Pressure Sodium
Basic Lighting Design: retail fixtures Track Display Fixed
Basic Lighting Design: flood bulbs Incandescent Flood CFL Flood LED Flood
Basic Lighting Design: Quality & Quantity How do you classify these two indicators in lighting design and use them to your advantage?
Basic Lighting Design: Quality Correlated Color Temperature (CCT) Describes the color appearance of the light that is produced, in terms of its warmth or coolness. The CCT relates the color appearance of the lamp to the color appearance of a reference source when the reference source is heated to a particular temperature, measured on the Kelvin (K) temperature scale. Source: Lighting Design Lab, Seattle
Basic Lighting Design: Quality
Basic Lighting Design: Quality Warm light sources are generally preferred for the home, restaurants, hospitality and high-end retail applications to create a sense of warmth and comfort, while neutral and cool light sources are generally preferred for high-activity areas such as offices, schools, supermarkets and similar applications to create a sense of alertness. cooler light sources, saturated in blue wavelengths, appear to enhance visual clarity and brightness perception at lower light levels Source: Lighting Design Lab, Seattle
Basic Lighting Design: Quality Color Rendering Index (CRI) A measurement of the amount of color shift that objects undergo when lighted by a light source as compared with the color of those same objects when seen under a reference light source of comparable color temperature. Source: Lighting Design Lab, Seattle
Basic Lighting Design: Quality CRI values generally range from 0 to 100 Older-style warm-white lamps were 52 CRI Newer-style cool white lamps are 62 Today s T8, T5 and CFL lamps range from 75-95 CRI In general, spaces that are occupied for long periods, whether it be for work or recreation, are where highest-color-rendering sources would be practical. Source: Lighting Design Lab, Seattle
Basic Lighting Design: Quantity
Basic Lighting Design: Quantity Lumens quantity of light emitted from a light source
Basic Lighting Design: Quantity Illuminance - amount of light measured on the workplane in a lighted space footcandle (unit) one lumen of light density per square foot footcandle (fc) = total lumens / area in square feet Image source: IESNA
Basic Lighting Design: Quantity
Basic Lighting Design: Quantity Orientation of space Daylighting Reflectance
Basic Lighting Design: Quantity Lumens per bulb Fixture/Luminaire direct/indirect, fixed Mount floor to ceiling height Layout
Basic Lighting Design: Review Luminaires Common Commercial Lighting - Incandescent - Compact Fluorescent (CFL) - Linear Fluorescent - High Intensity Discharge Quality Quantity Footcandles
Assessment Lighting levels Determine that the footcandle measurement falls within the IES recommendations
Assessment: Tools Hand calculations 1) Determine total number of lumens in the space 2) Measure square footage 3) Calculate footcandles Footcandle meter readings
Assessment: Tools Or... Determine whether space is over lit or under lit by checking for the following characteristics
Assessment: Too bright? Examples of over lit space:
Assessment: Too dim? Examples of under lit space:
Energy Efficiency Why does it matter?
Energy Efficiency: Annual operating costs
Energy Efficiency: Electricity consumption
Energy Efficiency: Lighting in energy use
Energy Efficiency: Common terms Watt (W) rate of energy conversion, used by utility to measure demand 1000 W = 1 kw Kilowatt Hour (kwh) measure of energy used over time, used by utility to measure and bill for energy consumption
Energy Efficiency: Lamp efficacy Efficacy efficacy = lumens / watt Lamp efficacy is equivalent to miles per gallon in measuring efficiency
Energy Efficiency: Guidelines in design Set ambient lighting levels close to minimum recommended foot-candle values, but not below Boost lighting levels in specific areas, as needed to support specific tasks, using task lighting strategies Use lighting sources with high lumen/watt values and adequate CRI values Retrofit projects should target 1.0-1.5 Watts/square foot Consider combinations of de-lamping and re-lamping to address lighting system improvements Consider benefit of reduced lighting levels on reducing air-conditioning loads
Applications: Case studies
Applications: PAR-TV Building
Applications: PAR-TV Building Existing Fixture 40 watt incandescent Quality Quantity CCT: 2000 (warm range) CRI: 97-100 Lumens: about 1,000 per mirror Problem Too much heat in space Too much energy use
Applications: PAR-TV Building Solution: Remove incandescents, replace with linear, two foot fluorescent lamps Fixture Quality Quantity 1 lamp, 2 linear fluorescent, three per mirror CCT: 3500 (mid range) CRI: 86 Lumens: about 3,000 per mirror
Applications: Warehouse
Applications: Warehouse Existing: High bay metal halide Fixture Quality Quantity Problem 400 watt metal halide CCT: 3000 (mid range) CRI: 70 Lumens: 28,000 Metal halide depreciation Low footcandles (5-10) for the task in space
Applications: Warehouse
Applications: Warehouse Solution: high output fluorescents with occupancy sensors Fixture Quality Quantity Solution 6 lamp T5 HO CCT: 3000 (mid range) CRI: 85 Lumens: 27,000 Better CRI with little depreciation Increased footcandles (15-20) for the task in space
Applications: Warehouse Energy Savings Annual Savings = $1,500 40 fixtures with an average of 70 hours on per week Increases to $2,500 with occupancy sensors
Applications: T12 to T8 retrofit
Applications: T12 to T8 retrofit Existing: Eight foot T12 fixtures Fixture Quality Quantity Problem 2 eight foot lamps, magnetic ballast CCT: 3000 (mid range) CRI: 70 Lumens: 12,000 Poor illumination on product
Applications: T12 to T8 retrofit
Applications: T12 to T8 retrofit Solution: 4 lamp T8 fixtures Fixture Quality Quantity Solution 4 four foot lamps, electronic ballast CCT: 4100 (blue light) CRI: 86 Lumens: 8,880 Whiter light on product makes it appear as if there is more light Energy savings
Applications: T12 to T8 retrofit Energy Savings Annual Savings = $700 40 fixtures with an average of 70 hours on per week Increases to $ 1,000with installation of occupancy sensors
Applications: Relamping
Applications: Relamping Existing: 4 lamp, 32 watt, T8 fixtures Fixture Quality Quantity Problem Standard four lamp, four foot electronic ballast fixtures CCT: 2500 (warm to mid range) CRI: 78 Lumens: 10,800 Warm color temperature Higher annual energy costs
Applications: Relamping
Applications: Relamping Solution: 4 lamp, 25 watt, T8 fixtures Fixture Quality Quantity Solution Energy saving four lamp, four foot, electronic ballast fixtures CCT: 4100 (blue light) CRI: 86 Lumens: 8,880 Blue light better illuminates the work plane for reading and writing Lower annual energy costs
Applications: Relamping Energy Savings Project cost for district = $500,000 Rebate for district = $134,000 Annual Savings for district = $108,000 3.5 year simple payback
Applications: Layout upgrade
Applications: Layout upgrade Existing Some areas too dim, others too bright
Applications: Layout upgrade Ceiling finish Shading Wall finish
Applications: Layout upgrade Solution: New layout for brighter space Daylighting Wall finish Ceiling finish Cleaner appearance while saving energy!
In case you missed it... Basic elements of lighting design Identify fixture, quality and quantity of light Assessment of work environment Over lit or under lit? Application Solve lighting problems by determining what the quality and quantity of light in a given space should be