Kitchen & Bath Lighting
Mar 31, 2015
Kitchen & Bath Lighting
A good lighting design should:
Look good – both people and design space Provide the proper amount of light in every
room Be built and constructed within budget,
code, and other constraints in mind Be environmentally responsible Respond to the architecture and interior
design Produce good color Achieve the desired mood of each space Allow lighting control
The layered approach to lighting design
Begin by thinking in layers
task
decorativefocal
ambient
Decorative
Ambient
decorative
ambient
Task
Focal
Lighting Concepts
General Lighting Task Lighting Workplane Distance Footcandle Lumen Candlepower (Candelas) Watts Lamp Data Tables
Lighting Concepts general lighting
Every room must have enough illumination to navigate through it.
The amount of light will vary depending on the activities performed in the room.
General lighting is measured at the workplane level. If there is no workplane like in the livingroom it is calculated at 30” above the floor.
General lighting is measured in “footcandles”
Lighting Concepts general lighting
Even light distribution is the key to great general lighting. Fixture placement and spacing must be accurately placed based on the lamps cone of light.
LIGHT SCALLOPS
TASK LIGHTING
EDGE OF BEAM SHOULDNOT INTERSECT CABINETFRONT
General Lighting General
Lighting
Lighting Concepts task lighting
Working at the sink Working at a desk Working at a prep area Reading
Lighting Concepts workplane
Workplane – The actual or implied surface on which work happens
Distance = Lamp Ht. –workplane height
Distance = 96”-36” = 60”6'-7 3/4"
11'-9 1/4"60"
36"
18'-5"96"
Lighting Concepts footcandles
How do we measure the light on a work surface?
Footcandle – a unit of measurement that describes the amount of light on a surface, workplane, art, etc.
Lux – The European Footcandle
Lux = FC x 10.76FC = Lux x .0929
Lighting Concepts footcandles
Sphere w/ 1 foot radius 1 SF of sphere surface 1 Footcandle is the
amount of lighting falling on that surface
There are 12.57 of these one radius square curved planes in any sphere.
They are known as Steradians
Lighting Concepts lumen
Let’s talk about another form of measurement in lighting
Lumen – a unit of measurement defining the quantity of light a lamp produces.
In order to achieve the proper amount of footcandles necessary to illuminate a work surface we must know the strength of the light source.
Only then can we determine how many are needed and how far apart they are spaced.
Lighting Concepts candlepower
Candlepower – the measurement of a lamps intensity, but only if it is directional
SUNsuns intensitymeasured in lumens
mostfootcandles
more footcandles least footcandles
10°28°53°
1110lumens
1110lumens
1110lumens
1,250candlepower
3,600candlepower
16,000candlepower
5’
50 footcandles
640 footcandles
144 footcandles
Lighting Concepts beam angle
A directional lamp focuses or redirects its light energy into a cone emanating from a lamp’s lens where it is measured in candlepower.
The center of the cone has the most intense light
The edges have the least
SPILL
LIG
HT SPILL LIG
HT
2000
cand
lepow
erN
ADI
R
1000
1000
The beam angle is defined where candlepower drops off to 50%
From 50% to 10% is called spill light
200200
Lighting Concepts watts
Wattage tells us how much power or energy is burned by a lamp
Wattage tells us nothing about the amount of light a lamp can produce
A 60 watt PAR38 lamp will have ~ three times the candlepower when compared to a 75 watt R40 lamp.
Color and Reflectance
Color and Reflectance
Color Temperature
Color Rendition Index (CRI)
Reflectance
Color Temperature
Color Temperature
Color temperature is measured in Kelvin 10,000K appears blue 1000K appears red 3000K to 3600K is
considered neutral
Color Temperature
Lower color temperature means warmer color
Higher color temperature means a cooler color
Cool colors
Warm colors
Color Rendition Index
Color Rendition Index
Color Rendition Index is a scale from 1 to 100 which describes the effectiveness of a light source in reproducing accurately, an objects color. 100 being the best.
The sun has a CRI of 100 The best lamps to use are ones with a
CRI over 80 Incandescent lamps have a CRI of over
98 Fluorescents are the ones we want to be
careful with
Color and Reflectance cri
Typical 4 foot fluorescent tube cool white or warm white bulbs have a CRI of around 50 and 60 respectively
Color corrected fluorescent lamps are now available in 70 and 80 CRI and those with rare earth phosphorus reach 90
COLOR TEMP. VS CRI
Color Temperature describes how the lamp itself appears when illuminated.
CRI describes the effectiveness of a light source in reproducing accurately, an objects color.
All together now!
Lumens - define the quantity of light
Candlepower defines the intensity of light
Footcandles defines the amount of light
on a surface
All together now!
Color temperature describes how the lamp
itself appears CRI
describes the effectiveness of a light source in reproducing accurately, an objects color.
Reflectance
Reflectance – is the amount of light which reflects off an object
This quantity of light is measured in “Foot-lamberts”
The amount of light that reflects off of objects in a room adds to the overall illumination
So, reflectance must be taken into consideration when determining the Footcandle requirements for a room.
4%reflected
100%From Lamp
100%From Lamp
80%reflected
REFLECTANCE TABLECOLORS %
White 70-80Light cream 70-80Light yellow 55-65
Light green 45-50Pink 45-50Sky-blue 40-45Light gray 40-45
Beige 25-35Yellow ocher 25-35Light brown 25-35Olive green 25-35Orange 20-25Vermillion red 20-25Meduium gray 20-25
Dark green 10-15Dark blue 10-15Dark red 10-15Dark gray 10-15
MATERIALS %
Mirror 95Plaster 80White enamel 65-75Glazed white tiles 60-65
Maple (nat.) 60Birch (nat.) 60Light oak 40Dark oak 15-20Dark walnut 15-20
Concrete 15-40Red brick 5-25
Carbon-black 2-10
Clear glass 6-8
Ideal Ceiling 60-90Ideal walls 35-60Ideal countertops 30-50
Reflectance
Example – 10’ x 10’ kitchen Ceiling reflectance -The ceiling color is white
80% Wall reflectance
Determine the total wall area10’ x 8’ = 80 x 4 = 320 SFDivide the room into three
predominate materials. 50% is cabinetry (~160 SF)20% is windows and openings (~64 SF)30% is wallpaper (~96 SF)
Reflectance
Next assign each material a reflectance Natural maple cabinets = 60% Windows & doors = 4 % Dark green wallpaper = 15%
Next multiply each reflectance times its percentage of the total square feet .60 x .50 = .30 .04 x .20 = .008 .15 x .30 = .045Total = .353 The average wall
reflectance is 35%
Reflectance
Floor reflectance – 100SF of warm gray slate – use medium gray (25%)
Average the totals:Ceiling – 80%Walls - 35%Floor - 25%Average = 47%
Lighting Spacing Principles
Spacing Directional Lamps -
40" 40" 40"
WORKPLANE
60"
X X X
120"
40" 40" 40"
WORKPLANE
60"
X X X
120"
BRIGHTSPOT
30" 60" 30"
WORKPLANE
60"
X 2X X
120"
WORKPLANE
60"
X X
WORKPLANE
120"
20" 40" 40" 20"2X 2X
135"
55°55°
6”
Lighting Spacing Principles
Calculating Beam SpreadCalculate H the distance from luminaire to 6”
above work surfaceWith a typical 96” ceiling height and a work
surface at 36 “ the distance would be 54”
B = 55°H = 54”2 (tan27.5° * 54) = ~56” = distance between
luminaries
)*2/1(2 HBTAN
135"
56"
55°55°
63"8"
spillspill
56"
39 1/2"• 55 beam spread• 54” distance• 60 to work plane
Let’s work an example
1 3 6 "
13
6"
WOR K SUR FA C E = 3 6 " A FF
c EIL ING hEIGHT = 9 6 "
B EA M SP R EA D = 3 5 °
1 3 6 "
13
6"
WOR K SUR FA CE = 3 6 " A FF
c EIL ING hEIGHT = 9 6 "
B EA M SP R EA D = 3 5 °
1 7 " 3 4 " 3 4 " 3 4 " 1 7 "
17
"3
4"
34
"3
4"
17
"
Let’s work an example
This one exists only in a perfect world!96” Ceiling Height55º Beam Spread
191"
135"
56"
55°55°
63"8"
spillspill
56"
39 1/2"
39 1/2" 56" 56" 39 1/2"
39 1/2"
56"
191"
Another Example
This time from the real world96” Ceiling Height55 Beam Spread
178"
178"
37"
37"
37"
37"
52" 52"
52" 52"5656
72"
30"
12" 24" 24" 12"
15"
15"
30"
What beam angle is required?
NOTE: BETWEEN24" AND 27"
58° Beam Angle
27"
6"
21"
30”
15”15/27 = .5556
ATAN.5556 = 29º
29°x 2 = 58º
58/2 = 29
TAN29 = .5543
.5543 x 21 = 11.6411.64X2= ~24
72"
30"
12" 24" 24" 12"
15"
15"
30"
Lighting the sink
Page 109 in Lighting Kitchens & Baths Made Easy
12”/54” = .2222
ATAN .2 = 12.53º
12.53 x 2 = ~25º Beam Spread
Lighting Measurements
Footcandles LevelsInverse Square Law
Lighting Measurements
Recommended base Footcandle Levels – Page 48
Adjustment Factors – Page 49
Lighting Measurements
Inverse Square Law The greater the distance the
lamp is from the object or workplane, the more powerful it will need to be
The I.S. Law allows you to establish the appropriate lamp candlepower for any distance.
Lighting Measurements
Three factors:Candlepower (Cp)Footcandle (Fc)Distance (D)
If you know two factors you can calculate the third.
Inverse Square Law
Candlepower =
Footcandle =
Distance = Cp Fc
2Cp D
2D Fc
Inverse Square Law
D2
FC
CP
Inverse Square Law
Distance = 5’
Footcandles = 40
Candlepower = ?1000
Inverse Square Law
Distance =
Footcandles = 40
Candlepower = 1000
?5’
Bathroom Vanity Lighting
Side lighting recommended 30” apart