Illumination Design PDF

# Illumination Design ## By Engr. Amando D. Lanuza, PEE ## Presenter: - A newly passed professional electrical engineer - 12 years in government service as City Electrical Engineer - A former OFW - A former Barangay Electrician - 3 time IIEE Chapter President of IIEE Sorsogon # Introduction - **Li...

# Illumination Design ## By Engr. Amando D. Lanuza, PEE ## Presenter: - A newly passed professional electrical engineer - 12 years in government service as City Electrical Engineer - A former OFW - A former Barangay Electrician - 3 time IIEE Chapter President of IIEE Sorsogon # Introduction - **Light** is a form of radiant energy from natural sources (e.g. sun and stars), and articial sources (e.g. candle and electric lamps). - It travels in a form of an electromagnetic wave, so it has wavelength and a known speed. - Like other electromagnetic radiation, it can be reflected and refracted. - **Lighting**, on the other hand, is the application of light to illuminate objects, surfaces, scenes, pictures and people. # Lighting Concepts and Units - **Luminous flux (Φ)** - All the radiated power emitted by a light source. - Is the light output of a light source. - Unit: lumen (lm) - **Luminous intensity** - The visible radiant intensity in a particular direction. - The unit of measurement is the candela (cd). - Light intensity is the measure of light output in a specified direction. - Unit: candela (cd) - **Illuminance (E)** - Is a measure of the amount of light falling on a surface. - Unit of measurement is lux (lx). - Average illumination of a surface is luminous flux per unit area. - Lux = lumens/m² - **Luminous efficacy (η)** - Indicates the efficiency of the light source with which the electrical power consumed is converted into light. - The unit of measurement is lumens per watt (lm/W). # Lighting System Design - The design for indoor lighting system general illumination is considered to be more of an art than a science and it involves many variable factors. ## Factors for indoor lighting includes: - Size and shapes of the space. - Types of finishes on ceilings, walls, and floors. - The details of the construction. - The economic consideration of both the initial and operating cost. - The compatability of the lighting system with the architectural design. - The type of activities that will be carried out in a particular area. ## Objectives and design consideration: - Determination of required level of illumination. - Quality required - Quantity required - Area atmosphere - Area description and Use - Selection of System Luminaire ## Determination of required level of illumination: - See table for recommended illumination level for different types of occupancies by Illuminating Engineering Society of North America (IESNA) ## Quality of Light - Pertains to the distribution of brightness in the lighting installation. - Involves the comfort of seeing the environment. - Factors to consider are: - brightness - contrast or luminance ratio - glare - diffuseness - color. ## Quantity required - The quantity of light involves adequate levels of illumination for the average person under normal condition. - **Area Atmosphere**: - Analyze the environment in which the lighting system will operate. - For example, are dirt, water vapor, explosive gasses, or corrosive vapor present? ## Area description and use: - A complete description is required for each area to be lighted, this includes physical characteristics such as: - room dimensions - room reflectance - work location. - Selection of system luminaire - Selection of the type of luminare for a given application depends upon the requirements and conditions stated above. ## Determining Average Illuminance - The average illuminance level can be determined when a given number of luminaires used in a space is known. - Likewise, the number of luminaires can be determined given the average illuminance level. - Within the room, the illuminance is determined based on the horizontal plane, which is considered as the work plane. - The work plane is measured at the height of the visual task. - In the office this would generally be at a height of 0.75 meter above the floor, the average height of an office table. - In the corridors, the work plane is usually considered to be the floor. - The general equation for the iluminance in a work place is: $E_{WP} = \frac{Φ_{TOTAL} \times CU \times LLF}{A_{WP}}$ ## Where: - **E_wp** - Work plane illuminance, lx - **Φ_TOTAL** - total system lamp lumen output, (lm). - **CU** - coefficient of utilization. - **LLF**- light loss factor - **A_wp** - area of work plane, m² - **Work plane illuminance, E_wp**: - The average maintained luminous flux that hits the work plane per unit area. - The unit of measurement is lx. - **Total system lamp lumen output, Φ_total**: - Refers to the quantity of light produced by all lamps that are lighting a space. - **Coefficient of utilization,CU**: - The ratio of the lumens that reaches the work plane to the total lumens given off by the lighting system - All the lumens from the lamps in a lighting system generally do not reach the work plane. - Some of them are absorbed by the floors, walls, and ceilings before reaching the work plane. - The fraction of luminous flux emitted by the lamps that reaches the work plane in a space is the coefficient of utilization. - If 50% of the light given off by the lamp reaches the work plane, then CU is 0.50, in some cases the CU can be grater than 1.0 for rooms with higher reflectances and lamps with higher efficacy. - **Light Loss Factor (LLF):** - Is the ratio of illuminance when it reaches the lower level(just before corrective action takes place) to the initial level. - The total light loss is the product of all the individual factors that contribute to the loss of light. - It is also known as the maintenance factor. - **Light Loss Factor (LLF) equation is:** - LLF = LLD x LDD x RSDD - **where:** - **LLD** - Lamp Lumen Depreciation Factor. - The depreciation of lumen output of lamp through life. - **LDD**- Lamp Dirt Depreciation Factor. - With the passage of time, dirt accumulates on lamps resulting to loss of light. - **RSDD**- Room Surface Dirt Depreciation Factor: - With the passage of time, the accumulation of dirt on the surface of the room further reduces the amount of light that reaches the work plane # Indoor Lighting Calculation - **The Lumen Method:** - This method is used to design general overall lighting of the room. - This method calculates the illuminance that represents the average of the values at all points over the entire work plane of the room. - **The average illuminace of the work plane (E)** $E = \frac{TILL \times CU \times LLF}{Area}$ - **Where:** - **TILL** = total initial lamp lumens ## Sample simplified calculation - Find out if two -36WT8 fluorescent lamps is enough to illuminate a typical dining room with dimension 3m x 4m, assuming the CU is 0.65 and LLF is 0.95. ## Solution: - Looking at the manufacturer’s data of 36WT8 fluorescent lamp, luminous flux is 3350 lm. - Using the formula: $E = \frac{TILL \times CU \times LLF}{Area} = \frac{2 \times 3350 \times 0.65 \times 0.95}{3m \times 4m} = 334.78 lux$ - Looking at the Table: Recommended level of illumination by IESNA for Dining rooms is 540 lux. - Therefore: - 2-36WT8 FL is not enough - Use 3 - sets ## Uniformity of Light - The average illumination at work plane is directly related to the maximum spacing of the luminaire to the mounting height ratio represented by: $ratio = \frac{S}{MH}$ - Where: - S = spacing of light fixtures - MH = mounting height - Assume that the mounting height of lighting fixture is 3 meters from the floor. What is the maximum spacing of fluorescent. - Recommended spacing and mounting height ratio: | Type of light | s/mh Ratio | |---|---| | Direct concentrating | 0.40 | | Direct spread | 1.20 | | Diffused | 1.30 | | Semi-direct/ indirect | 1.50 | - Using the formula: $ratio = \frac{S}{mh}$ $S = 3 × 0.40 = 1.2m$ - An office room having a dimension of 8 m x 20 m Is to be lighted with a maintained illumination. - How many 3- lamp 36wFL parabolic troffer are required? - From the formula: $N = \frac{illumination \times area}{lamp \ per \ fixture \times \ lumen \times \ CU \times \ LLF}$ - Looking at the manufacturer’s data of 36watts fluorescent lamp, luminous flux = 335000 lumens. - Recommended illumination level for offices is 1600m lux - Assume CU = 0.65 - LLF= 0.85 - Substituting values: $N = \frac{1600 (8 × 20)}{3 × 3350 × 1.0 × 0.95} = 26.8$ - Use: 24 sets or 28 to make it symmetrical - Image of a floorplan with 28 circles arranged for 3-lamp fluorescent fixtures in a symmetrical pattern. - Image of an airport terminal with fluorescent lights illuminating the concourse - The design of lighting system requires knowledge of basic lighting terms combined simple mathematical or graphical presentation and technics. - The methods and calculation in the lighting system design presented in this presentation are based on the recommended procedures of Illuminating Engineering Society of North America (IESNA). - The formula presented are only meant to be a general overview on illumination design calculation. - Image of an illuminated wall with the phrase “Thank You” in the center of the image