autism spectrum disorder (asd) education environment
TRANSCRIPT
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AUTISM SPECTRUM DISORDER (ASD)
EDUCATION ENVIRONMENT Lighting Design Concerns and Recommendations
HUSSEIN MOHAMED NYCSCA
March 2014
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Table of Contents
1- INTRODUCTION ……………………………………………………………………………4
2- OCCUPANT INPUT: SURVEY RESULTS ……………………………………………....5
2.1- Main Concerns ....………………………………………………………….…………5
2.2- Design Consideration ………………………………………………………………..5
3- DETAILED DESCRIPTION OF MAIN CONCERNS ...………………………………….6
3.1- Light flicker and audible hum ………………………………………………………. 6
3.2- Uneven distribution of light in a given space ……………………………………...7
3.3- Direct line of sight to the source of light ……………………………………………8
3.4- Contrasting shadows on the wall surface ………………………………………….9
3.5- Distracting bright spots and glare ……………………………………………..…..10
3.6- Inconsistent color temperatures of the lamps ……………………………………12
4- CURRENT LIGHTING DESIGN …………………………………………………………13
4.1- Classroom ……………………………………………………………………….…..14
4.1.1- Classroom Fixture …………………………………………………………..14
4.1.2- Classroom Layout …………………………………………………………..15
4.2- Corridors, Offices and Toilets ……………………………………………………...17
4.2.1- Corridors, Toilets and Lockers Fixtures …………………………………17
4.2.2- Office Fixture ………………………………………………………………...17
4.3- Stairs …………………………………………………………………………………18
4.4- Assembly Spaces ………………………………………………………..…………18
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5- PROPOSED LIGHTING DESIGN ……………………………………………………….19
5.1- Classroom ……………………………………………………………………………20
5.1.1- Classroom Proposed Lighting Fixture …………………………………….20
5.1.2- Classroom Proposed Lighting Layout …………………………………….21
5.1.3- Three Rows vs. Two Rows .............................………………………….24
5.2- Classroom Lighting Control ……………………………….……………………….29
5.2.1- Current Classroom Lighting Control ………………………………………29
5.2.2- Classroom Proposed Lighting Control ……………………………………30
5.2.3- Classroom Control by Lutron System …………………………………….32
5.2.4- Classroom Control by Hubbell System ………………………….………..34
5.3- Corridor and Offices ………………………………………………………………...35
5.3.1- Corridor Proposed Lighting Fixture ……………………………………….36
5.3.2- Corridor Proposed Lighting Layout ……………………………………….38
5.3.3- Offices Proposed Fixture …………………………………………………..47
6- AUTOMATIC SHADE SOLUTION ……………………………………………………...49
7- DESIGNER CONSIDERATIONS ……………………………………………………….50
8- APPENDEX ..……………………………………………………………………………..52
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1- INTRODUCTION
Students with ASD face many struggles and challenges in educational environments and classrooms. Classroom and other educational facilities are designed with the intention to be bright and display a variety of objects and information to encourage interaction and learning. These stimuli can become overwhelming to a student with ASD who has difficulty focusing their attention. They may focus their attention to extraneous sights and sounds and be unable to engage in classroom activities and instruction.
Many traditional schools built in previous decades or even on conservative
budgets do not accommodate students by providing special needs classrooms. Most classrooms are designed based on economics and uniformity. There is a balance between efficient and cost effective classroom design and design that focuses on providing for the unique needs of special needs students and students with ASD. Many students with ASD are educated in standard classroom environments with the rest of their classmates and peers. Most students with mild cases of ASD are able to keep up with the curriculum but can find themselves struggling and lose focus when forced to ignore distractions. This fight to overlook distracting light and extraneous noise leads to a greater effort in learning the materials presented in class.
In the educational classrooms, fluorescent lighting is a significant source of
extraneous stimuli that not only a source of annoyance but can also trigger common symptoms of ASD. Fluorescent fixtures economically provide an acceptable uniformity and quality of illumination, but also have disadvantages that can aggravate symptoms in students with ASD.
This report will address the education environment and student considerations in
order to develop parameters and design practices that will assist new lighting designers.
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2- OCCUPANT INPUT: SURVEY RESULTS To achieve the best design in theory as well as practical usability, it is important
to understand the needs and concerns of the occupants. Teachers and special needs coordinators made significant contributions to the study by expressing the concerns and needs of the instructors and students.
2.1- Main Concerns
The most significant concerns that were addressed in the lighting design surveys were the light level of the space, noise from the fixtures, and user control. Students were bothered and stressed by high light levels, hot spots created by pools of light, shadows, and reflected glare from wall or desk surfaces. The following six points highlight the main concerns which are followed by a detailed description. 1. Light flicker and audible hum 2. Uneven distribution of light in a given space 3. Direct line of sight to the source of light 4. Contrasting shadows on the wall surface 5. Distracting bright spots and glare 6. Inconsistent color temperatures of the lamps
2.2- Design Considerations
In order to create the most user-friendly and comfortable learning environment based on these needs, the following design considerations should be taken into account 1. All light fixtures should be dimmable so that a comfortable light level can
be set by the teacher for each space. 2. High ceiling to allow the light to be distributed and reduce most direct lines
of sight of the lamp. 3. Special consideration to be given to materials and finishes in the space to
reduce reflective glare. 4. Room size should be taken into consideration to eliminate light to create
bright scalloped patterns and contrasting shadows on the wall surface.
In order to address the main concerns, the architects and designers work
together to successfully address and work solutions to the restrictive criteria.
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3- Detailed Description of Main Concerns:
3.1- Light flicker and audible hum. There are many types of ballasts for fluorescent fixtures that vary in
frequencies. It is these operating frequencies that ultimately produce the flicker and the hum that are generated by the alternating current (AC). Because of the behavioral problems and frustration triggered by the fluorescent fixtures in the general education classrooms, instructors have tried to amend the problem by providing specific area in the classroom for students with ASD to independently work.
Magnetically ballasted T12 fluorescent with flicker
LED source with flicker – note white vertical lines in photo
The flickering light or hum is in equal competition with the information being presented by the instructor. This results in an overflow of information and creates a stressful learning environment for students with ASD.
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3.2- Uneven distribution of light in a given space Vertical illumination, that is light levels measured on wall surfaces, must
balance in contrast ratio with illumination levels on the work surface to reduce fatigue and discomfort when looking up from a task. The IESNA recommends that the light levels on vertical surfaces be no greater than five times and no less than 1/3rd the light levels on the work surface. Vertical surfaces also need to be evaluated in the design. Hot spots of light can occur on wall surfaces as the result of light cut-off from the fixture.
Recessed fluorescent 2 x 4 troffer fixtures can create hot spots on vertical surfaces near the ceiling.
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3.3- Direct line of sight to the source of light The survey response said "Students will turn off the lights indicating they
are bothering them and causing them to be upset." There are no lenses or coverings to shield the lamps from direct sight. The bright light output makes it difficult for the students to "sit, concentrate, and learn." The light intensity creates a difficult environment for the students to concentrate and focus on learning material.
Indirect distribution of light allows for the source to be hidden from direct view and allows for the light to diffuse on the reflecting surface. High ceilings are best because they allow space for the light from indirect fixtures to have wider distributions when light reaches the working plane.
Teacher at school PS 120 uses a cloth to minimize direct line of sight of artificial light.
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3.4- Contrasting shadows on the wall surface. For children with autism, shadows obscured recognition of objects, so that
the children were really not able to attend to the objects but were instead distracted by shadows. It may be most effective then, in teaching children with autism, to choose a space with careful lighting and therefore the children will be less distracted by shadows.( Children with Autism Distracted by Shadows By Jody Smith )
Lights created bright scalloped patterns and contrasting shadows on the wall surface.
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3.5- Distracting bright spots and glare Reflection from the lighting on the glossy laminate hindered the students’
ability to see their work, caused them to squint, and reduced their independence and engagement in activities as staff were frequently having to reposition work to reduce glare. Finishes can affect the overall brightness of the space and could have problems with glare.
Hot spots and glare are reduced slightly with the use of indirect/direct
suspended fluorescent fixtures, however fully indirect will work better. Glazing should be located high on the walls. Shades should be used to control light levels and glare. Photo sensors shall integrate electric light fixtures and provide dimming. Use finishes with darker and muted colors to soften the light and eliminate glare off surfaces. Select surfaces with a lower reflectance value.
The reflective flooring material can create glare and hot spots. This problem is avoided by dimming and adjusting the light level for the comfort of the user.
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PS 177X west wing classroom with light blue wall color has less glare which creates a more comfortable learning space.
The same above classroom (PS 177X). All the white walls produce glare on the surface of the floor.
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3.6- Consistent Color Temperatures of the Lamps. Fluorescent lamps can vary in color temperature and can also create visual
distractions and inconsistency. As a lamp reaches the end of the estimated lamp life, the color temperature can differ from when it was originally installed. As lamps are replaced as needed in various fixtures, the color temperature can vary in the fixtures creating a distracting spectrum.
Graphic of color temperature of common light sources.
Shift in color temperature in old linear fluorescent lamp can cause uneven lighting distribution in the space
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4- Current lighting Design
Fluorescent fixtures are traditionally and still currently the most popular fixture in New York City Schools because it is able to fulfill the recommendations for quality and efficiency, while still maintaining a reasonable budget. These fixtures provide efficient general illumination while maintaining an acceptable color rendering index (CRI). CRI refers to the accuracy the light emitted from the source compares to the perfect color proportions of the visual spectrum; day light has a CRI of 100, which is the highest value.
Although fluorescent fixtures are strongly encouraged for traditional classroom lighting designs, they are not recommended for autism classrooms. Fluorescent sources and fixtures have made advancements to reduce noise and flicker and other disadvantages in order to improve their overall performance and be more versatile in applications. Even with improvements to these fixtures, the brightness, flicker and hum are still strongly noticed by most students with ASD.
Fluorescent lamp construction and operation is the greatest source of
flickering. Students with ASD are able to perceive the cyclical flickering when other students may be unaffected. Ballasts that function with fluorescent lamps create the audible humming noise which is a distracting and frustrating stimuli to students with ASD. Even with improvements to ballast construction and operation and the common use of high frequency ballasts, it is not encouraged that any type of fluorescent fixture be installed in special needs or ASD classrooms.
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4.1- Classroom Most classroom type spaces constructed are similar in finishes and fixtures.
Direct/indirect, ceiling pendant fluorescent luminaires for typical classrooms measuring approximately 29’ X 26’, lighting usually consist of two (2) rows of direct /indirect with lighting distribution between 70-80% up and 20-30% down.
4.1.1- Classroom fixture
Direct/indirect lighting fixture with 2T8 fluorescent lamps supported with single air-craft cable.
4.1.2- Classroom layout Classroom lighting layout consists of two (2) rows of direct
/indirect Fixtures mounted such that the bottom of the luminaires is at 8’-0” in Early Childhood Centers and Primary Schools and 8’-6” in Intermediate Schools and High Schools, with the optimum fixture to ceiling distance ranging from 14” to 24”.
Lighting controlled by one ceiling mounted vacancy sensor and two switches located by the classroom entrance door. Each switch shall controls one lamp in each fixture on the same side of each row.
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Comparison between two regular size classrooms with standard indirect/direct fixture CR301: LED 48W fixture
CR304: linear fluorescent 2T8 fixture
Description # Luminaires Total Watts Area Density
Power Density CR301 10 476.0 W 694.1 ft² 0.7 W/ft²
power density CR304 10 580.0 W 709.6 ft² 0.8 W/ft²
Power Statistics
Description Symbol Avg Max Min Max/Min Avg/Min Avg/Max
classroom301 42.0 fc 60.6 fc 20.5 fc 3.0:1 2.0:1 0.7:1
classroom304 42.9 fc 63.1 fc 18.5 fc 3.4:1 2.3:1 0.7:1
Statistics
Symbol Label Quantity Manufacturer Catalog Number Lamp Number
Lamps
Lumens Per
Lamp
Wattage
A 10 PINNACLE
ARCHITECTURA
L LIGHTING
GLS90 SCB28 232 TWO
HORIZONTAL 32
WATT T8
LINEAR
FLUORESCENT
LAMPS RATED
AT 2800
LUMENS EACH.
2 2800 58
D 10 PINNACLE
ARCHITECTURA
L LIGHTING
LC6A35-40HO-4-
AC48G1-120-1C-W
TWO HUNDRED
FORTY WHITE
LIGHT EMITTING
DIODES (LEDS),
AIMED 10-
DEGREES
ABOVE THE
HORIZON.
240 15.93622 47.6
Luminaire Schedule
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4.2- Corridors, offices, and toilets Fluorescent tube lamps in recessed troffers are the most common fixtures
seen in educational facilities due to its efficiency and low-cost. Recessed troffers are typically measured in increments of one foot and are designed to fit conveniently into acoustical ceiling grids. The majority of the fixture housing is recessed into the ceiling plenum with the bottom edge of the fixture flush with the ceiling tiles. These fixtures house between one and four fluorescent tube lamps (T-lamps). Reflectors built into the housing will direct light down to the space while louvers or lens coverings on the bottom face of the fixture will distribute and diffuse the light. Shown below are a sketch and cross-section of typical recessed troffers.
4.2.1- Corridors, toilets and lockers fixture
Recessed 2'x4' fluorescent luminaires, with prismatic lens 2, 3 or 4 lamps
4.2.2- Offices fixture Recessed 2'x4' fluorescent luminaires, parabolic with 18 cells
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4.3- Stairs:
Most of schools use 4' fluorescent luminaires, wrap around, with vandal resistant lens. Usually fixture housing built from heavy-duty, 16-gauge one-piece cold-rolled steel, corner or surface-mounted.
4.4- Assembly spaces (Auditorium, Gym) and main lobby: The lighting designer may select luminaires suited to the aesthetic of the
spaces. Recently built schools have many LED installed in those areas.
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5- Proposed Lighting Design Lighting for the space is achieved using dimmable LED fixtures with 100% up-
light suspended to a high ceiling in area of instructions and direct LED lighting fixture with white defused lens in none instructions area. Each individual room is equipped with a separate control for on/off and dimming. Each of the instruction spaces is controlled separately by a single slide dimmer switch.
Because of the noise concerns expressed when using fluorescent ballasts, no
ballasts will be used to control the light fixtures in the Autism wing. When all lamps are on at full capacity, the light levels are an approximately 35 foot candle which is lower than the forty foot candles recommended by SCA for regular classrooms. The light levels recommended by the IESNA are an average of 30-50 foot candles (fc) for reading and writing tasks. Glare is a concern when higher light levels are required, especially in environments with reflective surfaces such as desks or whiteboards.
Day light from the windows varied the light readings in the larger Sensory
classroom depending on time of day and if there was a cloud cover. Ceiling
mount daylight sensor saves energy by dimming or turning off electric lighting
when sufficient daylight is available. The sensor adjusts the lights to take
advantage of daylight and keep a steady light level.
The high windows achieve a high amount of daylight which has shown to provide emotional and mental benefits in classroom environments. Because of the height of the windows and operating hours of the classroom, direct glare has not been a concern in the space. Automatic shades are controlled by the teachers to increase the level of control and comfort to the students.
Finishes and materials in a space can be a commonly overlooked design
element in lighting design. For the Autism wing classroom finishes, materials and colors should be a high priority and integrated well with the lights. Soft, muted colors are to be used on the walls and neutral, calm blues are to be used in the tiled and carpeted areas.
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5.1- Classroom
5.1.1- Classroom Proposed Lighting Fixture
The proposed lighting fixture will have the following features: 1. Round or rectangular with curved profile for pleasant, modern look. 2. Fully indirect LED lighting fixture with 100% up-light 3. 30K color temperature with minimum 1200 lumens/ft. for warmer
lighting environment 4. Pendant mounted with single aircraft cable 5. Flicker free Dimmable driver with 0-10v dimming option 6. Suitable for installation in continuous rows 7. Adjustable single aircraft cable mounts on 4'-0” and 8'-0” centers 8. Wide distribution to eliminate hot spots while increasing uniformity
across the ceiling.
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Pendant mounted with single aircraft cable
Fully indirect with wide distribution
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5.1.2- Classroom Proposed Lighting Layout Proposed Classroom lighting layout consists of: 1. Three rows of lighting fixtures with maximum distance 8’ to 10’
between rows 2. Pendant mounted 2 feet under furnished ceiling 3. Rows are centered in the room and located two to three feet away from
the walls for better distribution and less hot spots in the walls. 4. One dimming switch installed by the entry door 5. Vacancy sensor for automatic shut-off as required by code 6. Daylight sensor to adjust artificial light based on the amount of daylight
in a room
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Rendering view for proposed ASD Classroom
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5.1.1- Three Rows VS. Two Rows
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The three rows classroom shows brighter lighting space
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No hot spot created at the wall surface for the three rows layout which is clearly noticeable in the two rows layout.
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Description Symbol Avg Max Min Max/Min Avg/Min Avg/Max
CR42-FC LEVEL 37.3 fc 49.9 fc 24.9 fc 2.0:1 1.5:1 0.7:1
wall 29.1 fc 121.3 fc 14.2 fc 8.5:1 2.0:1 0.2:1
Statistics
Poor distribution at floor and ceiling surfaces and hot spots at wall surface
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Description Symbol Avg Max Min Max/Min Avg/Min Avg/Max
CR44-FC LEVEL 40.9 fc 55.9 fc 23.9 fc 2.3:1 1.7:1 0.7:1
CR44-WALL FC 27.0 fc 41.9 fc 15.4 fc 2.7:1 1.8:1 0.6:1
Statistics
Even distribution in floor and ceiling surfaces and no hot spots at wall surface
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5.2- Classroom Lighting Control
5.2.1- Current Classroom Lighting Control
The following schematic wiring diagram presents typical classroom lighting control with a single vacancy sensor, two low
voltage switches, and one power pack
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5.2.2- Classroom Proposed Lighting Control
The proposed classroom lighting control is made of three major items:
1. Vacancy sensor
Dual technology ceiling-mount
occupancy sensor in vacancy mode
Corresponding zones will turn off
when the occupancy sensor is in
the unoccupied state (open).
2. Daylight Sensor
The sensor will work with LED
Dimming drivers and control
modules, to implement daylight
harvesting.
The sensor will maintain a specific
light level in the space, and it will
allow the control system to
automatically dim the lights when
the available daylight is high and
brighten the lights when the
available daylight is low.
3. Dimming switch
Turn the classroom lighting fixtures On and Off
Raise and lower light levels
Recall favorite light levels
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Classroom layout with fixtures and controls
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5.2.3- Classroom Control by Lutron System
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5.2.4- Classroom Control by Hubbell System
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5.3- Corridors and Offices.
The recessed fluorescent troffer is everywhere in American commercial
spaces, with 1×4, 2×2, and 2×4 troffers comprising more than 50% of the
luminaires installed in commercial applications and using more than 87
Terawatt-hours (TWh) of electrical energy per year. Consequently, energy-
efficiency improvements to this category of luminaire through the use of LED
technology can potentially yield significant energy and environmental benefits.
This report describes an exploration of troffer lighting as used in office and
classroom spaces.
Dedicated LED troffers are ready to compete with fluorescent troffers in
terms of efficacy (lumens per watt [lm/W]), and in many lighting quality issues
such as glare, light distribution, visual appearance, and color quality.
The architectural lighting industry is very familiar with fluorescent
troffers, but now that LED options are available, a more complex set of
choices has developed. Designer must evaluate how well LED products
perform compared to conventional fluorescent troffers (and each other),
which involves a wide range of criteria—much of which extends beyond the
scope of LM-79-08 testing. Some important evaluation criteria include:
Light output (lumens). Photometric distribution, direct glare, reflected glare, overhead glare,
uniformity of light on task surface, and spacing criteria. Color quality including color rendering and color appearance. Flicker, at full output and when dimmed. Dimming performance including the smoothness and minimum light output. Ease of installation Energy efficiency, or specifically, the total luminaire efficacy and lighting
power density of a typical installation.
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5.3.1- Corridor Proposed Lighting Fixture
LED Recessed Troffer
Upper reflector 98% efficient reflects light out of the fixture.
LED arrays Highly efficacious global LED platform array 3000K color temperatures
Door frame Provides easy access to the inside of the fixture
Optics Single piece extruded diffuse white lens. Controls light to create a less glare distribution. Eliminates visibility of individual LED’s
LED driver Multiple lumen packages, 0-10V dimming, battery pack options, and accessible from below for easy maintenance.
Perimeter reflectors Highly efficient microcellular PET material mixes light within the optical cavity.
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Flat panal with decorative trim
Indirect light bar LED
Single basket LED
Two baskets LED
Opal lens LED
There is a wide range of LED product-qualities which shall be reflected in the design: color, efficacy, light output, appearance, glare, and flicker. Many of these factors cannot be evaluated from a manufacturer’s specification sheet, so it is necessary for the designer to see and compare products in person, and in mockups.
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5.3.2- Corridor Proposed Lighting Layout
Case study: autistic suite Corridor at School PS 335 Queens
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Corridor with four deferent lighting arrangements
LAYOUT #1: 14’ BETWEEN (2X4) 59W FLUORESCENT FIXTURES
LAYOUT #2: 14’ BETWEEN (2X4) 49W LED FIXTURES
LAYOUT #3: 10’ BETWEEN (2X2) 33W LED FIXTURES
LAYOUT #4: 10’ BETWEEN (1X4) 33W LED FIXTURES
(1X4) LED FIXTURES (2X2) LED FIXTURES 2X4 (2X4) LED FIXTURES (2X4) FLUORESCENT FIXTURES
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Symbol Label QTY Catalog
Number
Description Lamp Number
Lamps
Lumens
per Lamp
LLF Wattage
2T8 12 LU24A-
2T8
Lucen 2x4, Architectural Recessed
fluorescent fixture
2 - 32W T8 2 2900 0.95 59
LED24 12 LU24A-
4047
2X4, FABRICATED METAL
HOUSING WITH WHITE PAINTED
INTERIOR FINISH, 2-PIECE FORMED
WHITE PAINTED METAL
REFLECTOR, 4 WHITE CIRCUIT
BOARDS EACH WITH 36 LEDS,
EXTRUDED TRANSLUCENT
FROSTED ACRYLIC DIFFUSER IN
FABRICATED WHITE PAINTED
METAL FRAME.
ONE HUNDRED FORTY-
FOUR WHITE MULTI-
CHIP LIGHT EMITTING
DIODES (LEDS),
VERTICAL BASE-UP
POSITION.
144 30.8794 0.95 48.8
LED22 17 LU22A-
4032
2X2, FABRICATED METAL
HOUSING WITH WHITE PAINTED
INTERIOR FINISH, 2 WHITE CIRCUIT
BOARDS EACH WITH 36 LEDS.
SEVENTY-TWO WHITE
MULTI-CHIP LIGHT
EMITTING DIODES
(LEDS), VERTICAL BASE-
UP POSITION.
72 41.5663 0.95 33
LED14 17 LU14A-
4030
1X4, FABRICATED METAL
HOUSING WITH WHITE PAINTED
INTERIOR FINISH, 4 WHITE CIRCUIT
BOARDS EACH WITH 36 LEDS.
ONE HUNDRED FORTY-
FOUR WHITE MULTI-
CHIP LIGHT EMITTING
DIODES (LEDS),
VERTICAL BASE-UP
144 20.0543 0.95 32.4
Luminaire Schedule
Description # Luminaires Total Watts Area Density
CORRIDOR LPD-14' BETWEEN (2X4)
2T8 FIXTURES
12 708.0 W 1318.9 ft² 0.5 W/ft²
CORRIDOR LPD-14' BETWEEN (2X4)
LED FIXTURES
12 585.6 W 1318.9 ft² 0.4 W/ft²
CORRIDOR LPD-10' BETWEEN (2X2)
LED FIXTURES
17 561.0 W 1318.9 ft² 0.4 W/ft²
CORRIDOR LPD-10' BETWEEN (1X4)
LED FIXTURES
17 550.8 W 1318.9 ft² 0.4 W/ft²
Power Statistics
Description Symbol Avg Max Min Max/Min Avg/Min Avg/Max
CORRIDOR FC-14' BETWEEN (2X4)
2T8 FIXTURES
23.9 fc 32.3 fc 13.8 fc 2.3:1 1.7:1 0.7:1
CORRIDOR FC-14' BETWEEN (2X4)
LED FIXTURES
23.7 fc 31.4 fc 11.5 fc 2.7:1 2.1:1 0.8:1
CORRIDOR FC-10' BETWEEN (2X2)
LED FIXTURES
22.5 fc 28.2 fc 15.2 fc 1.9:1 1.5:1 0.8:1
CORRIDOR FC-10' BETWEEN (1X4)
LED FIXTURES
22.5 fc 31.2 fc 9.8 fc 3.2:1 2.3:1 0.7:1
Statistics
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Layout #1: 14’ between (2X4) recessed fluorescent fixture with 2T8 (Current SCA standard layout for corridors)
Brightness
Illuminance Brightness
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Layout #2: 14’ between (2X4) recessed 49W LED fixture
Brightness
Illuminance Brightness
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Layout #3: 10’ between (2X2) recessed 33W LED fixture
Brightness
Illuminance Brightness
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Layout #4: 10’ between (1X4) recessed 33W LED fixture
Brightness
Illuminance Brightness
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Current SCA layout with LED fixtures 10’ apart
Description Symbol Avg Max Min Max/Min Avg/Min Avg/Max
CORRIDOR FC-10' BETWEEN (2X4)
33W LED FIXTURES
21.2 fc 25.1 fc 9.4 fc 2.7:1 2.3:1 0.8:1
Statistics
Symbol Label Quantity Manufacturer Catalog
Number
Description Lamp F
i
Lumens
Per
Light
Loss
Wattage
LED24 16 PINNACLE
ARCHITECTURA
L LIGHTING
LU24A-4032 FABRICATED METAL HOUSING WITH WHITE
PAINTED INTERIOR FINISH, 4 WHITE CIRCUIT
BOARDS EACH WITH 36 LEDS, EXTRUDED
TRANSLUCENT FROSTED ACRYLIC DIFFUSER IN
FABRICATED WHITE PAINTED METAL FRAME.
DIFFUSER FROSTED BOTH SIDES.
ONE HUNDRED FORTY-
FOUR WHITE MULTI-CHIP
LIGHT EMITTING DIODES
(LEDS), VERTICAL BASE-
UP POSITION.
L
U
2
4
A
-
20.3051 0.95 32.4
Luminaire Schedule
Description # Luminaires Total Watts Area Density
CORRIDOR LPD- 10' BETWEEN (2X4)
33W LED FIXTURES
16 518.4 W 1318.9 ft² 0.4 W/ft²
Power Statistics
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Layout #5: 10’ between (2X4) recessed 33W LED fixture
Illuminance Brightness
Brightness
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5.3.3- Office Proposed Fixture
LED technology allows recessed lighting fixture to have the best possible combination of lighting control
and brightness – with efficiencies that are almost 20% higher than other recessed lighting products.
CCuurrrreenntt PPrrooppoosseedd
Typical parabolics create harsh shadows, dark cave-like environments, and glare.
Batwing distribution luminaires provide excellent glare control, distribution, increased brightness on the walls, and softer shadows.
Batwing distribution
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6- Automatic Shade Solution
Automatic control switch which looks similar to the lighting dimming switch
Helps the students stay focused
Eliminates glare from the desk surface and reduces strain on students' eyes.
Shades will filter the sun’s harsh rays and provide the optimal light level for the class
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7- DESIGNER CONSIDERATIONS
The highest consideration and priority is to create a comforting, calm, and peaceful environment for special needs students. The table below summarizes important considerations and recommendations for ASD classroom design.
ITEM DESIGN CONSIDERATIONS DESIGN RECOMMENDATIONS
Physical Layout of
Space
Most special needs teachers and coordinators recommended classrooms with smaller closed classroom areas and short hallways.
Provide lighting and controls for each logically separated area of use. High ceilings minimum of 10 and maximum of 13' are optimal.
Room Finishes
Finishes can affect the overall brightness of the space and could have problems with glare.
Use finishes with darker and muted colors to soften the light and eliminate glare off surfaces. Select surfaces with a lower reflectance value.
Light Source Direct line of sight to the lamp should be avoided. Even light distribution to reduce shadows.
Fully indirect light should be used. Pendant mounted fixtures installed 2’ under furnished ceiling. Other direct lighting fixtures should have a white defused lens.
Lamps High CRI of 85 or greater, warm color temperature of 3000-3500K.
Use LED Fixtures with 90 CRI and 3000k color temperature.
Light Fixtures Flicker decreases with an increase in lamp operating frequency. Noise also decreases in electronic ballast. However, the flicker and noise both will still exists in fluorescent lights.
LED Fixtures do not require a ballast for operation and therefore eliminate the problems with noise. Flicker free LED driver should be used in case of dimming
Light Levels Students reported visual brightness as a source of anxiety and frustration. Lower light levels best suit their needs.
Reduce light levels to an average of 25-35 fc opposed to the traditional levels of 30-50 fc.
Lighting Controls
Light levels need to be adjusted to the intended use of the classroom or the comfort level of the students.
Dimming all lamps equally will lower the light levels and still provide even light distribution. Controls should be available for each lighting area.
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ITEM DESIGN CONSIDERATIONS DESIGN RECOMMENDATIONS
Day-lighting Provides quality light into the space and a comforting connection to the outdoor environment.
Glazing should be located high on the walls. Shades should be used to control light levels and glare. Daylight sensors shall integrate electric light fixtures and provide dimming.
Energy Energy standards limit the w/ft2
allowed. The more efficient the lamp and fixture assembly the better.
LED lighting is the most efficient source of light in the market. Calculations based on building-area method can achieve as low as 0.8 w/ft2 by using LED lighting.
Contrast Ratio Contrast ratios should meet the recommendations prescribed in the IESNA Handbook.
From the working surface to a vertical surface in the direct line of sight, the contrast ratio should be limited to a difference of 1 to 3. A ratio of 1 to 5 is acceptable for vertical surfaces but not immediately in the line of sight.
Maintenance Lamps with longer lamp life and less lumen depreciation and accessible fixtures
LED lamp life ranges 40,000 -60,000 hrs which will not require frequent replacement. Use accessible housing LED fixtures with replaceable LED boards.
Vertical Illumination
Vertical surfaces should be as evenly illuminated as possible with limited shadowing and a contrast
Select fixtures with a wider distribution for indirect light source and controlled distribution for direct light source to avoid sharp light cut-offs and it will also provide general illumination on wall surfaces. Corridor fixture spacing should not be more than 10' apart.
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8- APPENDIX
Appendix A: Luminaire Distribution Photographs
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Table A1. Product descriptions and classification.
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Table A2. Basic performance characteristics.
All measurements were taken by independent photometric testing laboratories according to LM-
79-08. Only one sample of each product was tested. All measurements are for in-situ
performance, if applicable; refer to Table 1 for luminaire configurations.
1. Product L did not undergo full LM-79 testing via an independent laboratory. Information listed was measured by PNNL. 2. CALiPER testing for the following luminaires showed significantly lower luminaire lumens than expected from the
manufacturer-provided photometric files: type I (86%), type K (84%), type P (78%), and type W (56%). Types I and K are fluorescent benchmarks, and this may reflect a difference between relative photometry and absolute photometry. CALiPER has seen reductions up to 15% in past evaluations for fluorescent luminaires. The differences for LED luminaires P and W were not explained. All other CALiPER test results were within 10% of expected values.
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Appendix B: Polar Plots of Luminous Intensity Distribution
Figure B1: Polar plots of luminous intensity for product types A through I. Plots are not to scale.
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Figure B2: Polar plots of luminous intensity for product types J through R. Plots are not to scale.
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Figure B3: Polar plots of luminous intensity for product types S through X. Plots are not to scale.
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Appendix C: Flicker Waveforms
Figure C1: Dimming and flicker characteristics for product types A through D.
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Figure C2: Dimming and flicker characteristics for product types E through H.
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Figure C3: Dimming and flicker characteristics for product types I through M.
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Figure C4: Dimming and flicker characteristics for product types N through Q.
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Figure C5: Dimming and flicker characteristics for product types R through U.
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Figure C6: Dimming and flicker characteristics for product types V through X.
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