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JP Bedell SDA Lighting [email protected] Blog.sdalighting.com @jamesbedell Understanding Lighting in the Age of LED Review Basic Terms Describing Light Source Points of Reference – Comparing LED to Traditional Light Sources How to Read a Cut Sheet Evaluating a Sample Writing a Specification What is a Lumen? It is the measure of the total visible light emitted by a source. How much light a source creates or delivers. SOURCE LUMENS DELIVERED LUMENS The amount of a light one candle casts one foot away. Think of this as the amount of light cast in a direction at a target area. Not emanating from the source. VERTICAL FOOT-CANDLES Light cast on vertical surfaces such as walls, faces and hanging artwork. Important for visibility, security and visual acuity. HORIZONTAL FOOT-CANDLES Light cast on horizontal surfaces like desks, countertops, and the ground. Important for task lighting, path of egress and basic visibility. This is the “tone” of white light a source creates. Think of the difference in white light from a bright sunny day and a warmly lite restaurant. Expressed in degrees kelvin Typically ranging from 2700K – 6000K Incandescent Light Bulb = 2700K - 2800K Halogen Lamp (MR16) = 2900K – 3200K Fluorescent Lamps = 2700K – 6000K Ceramic Metal Halide = 4200K (Typical) 2700K 3500K CRI is short for Color Rendering Index This is a relative scale from 0-100 rating how well light sources reflect colors back to our eyes. Commercial light sources range from 70 CRI (metal halide) To 100 CRI (High Quality Halogen) LED sources are typically 80-90+ CRI 0-10V Electronic Low Voltage Dimming (Trailing Edge) Triac Work With Your Electrical Contractor Comparing LED to Traditional Light Sources We use foot-candle targets as a guideline for providing enough light for certain tasks and spaces. The 10th Edition of the IES Handbook has broken light level recommendations down by age. Simple Orientation in space = 5-10FC Classrooms = 50 – 100FC Lobby of Office Building = 10 - 20FC Reading = 20 – 50FC Gymnasium = 20 – 50FC Museum = 50 – 100FC When evaluating traditional light sources wattage used to be the point of reference. Today it must be lumens. A 60W Incandescent Light Bulb generates 800 Lumens. Today a 9.5 watt bulb can do the same thing. Fixture Dimensions Mounting Brightness Color Temperature and CRI Beam Spread and Optical Accessories (if applicable) Wattage Dimming Compatibility Brightness Color Quality Basic Construction Manufacturer + Part Number Mounting Complete Description Required Voltage Contractor Notes Customizations Recess mounted LED adjustable accent light with 4-1/2" square aperture. Fixture provided with LED light engine capable of dimming from 3000K to 2200K in 90+CRI. Fixture provided with 0-10V dimming driver standard. Fixture provided with trim plate complete with white regress and flange. Fixture provided with New Construction housing measuring 22-1/8"L X 13"W X 7"T. Fixture input voltage is 120V. Total input wattage to fixture shall be 32 watts. Contractor to confirm channel bar requirements and and review housing size for construction feasibility. Electrical contractor to provide compatible dimmers. [email protected] Blog.sdalighting.com @jamesbedell
