impact of interior design changes on office based lighting schemes
TRANSCRIPT
Impact of Interior Design Changes on Office-Based Lighting Schemes
PCN224-Applied Lighting Jordan Agustin
Project Aim
○ Investigation how various interior design changes affect lighting scheme performance.
○ Results used to develop a “Design Issues Guide” on how to minimise negative impact on the lighting scheme when making interior fitout changes.
Project Scope
○ Standard Office Fitout ● 2.7m ceiling ht. ● Task Lighting provided by single luminaire type
(recessed fluorescent) – No accent/specialty lighting ● 350m2 floor space ● Windows on 3 sides, services behind 4th. ● Electric Lighting only considered
○ Variations of design elements, and the study of the effects on Illuminance and Uniformity
Design Variables
○ Wall colour and texture changes (reflectance) ○ Desk Colour changes (reflectance) ○ Partition height changes (Obstruction) ○ Partition material and colour changes
(reflectance) ○ Desk/partition layout change (obstruction) ○ Floor coverings (reflectance)
Space Configuration
○ Std Grid Configuration
○ Windows on 3 sides
Base Scheme Performance
○ Performance specs allow for MF = .57 (spot replacement, OR
○ Group replacement, E(avge) = 320lx ● Not critical what the specs are, only need to know
what they are to measure change
E(max) E(min) E(avge)U(min/ avge) E(av direct) E(av indirect)
502 337 398 0.85 341 57
Design Change – Colour Scheme
○ Very simple modification ● Huge reflectance variation possible (ρ=7% - 90%+) ● AS1680.1:2006 Section 6.3 does recommends wall
reflectance be less < 0.8 and >0.3 ● Modern design trends - may not always select
compatible colours.
Design Change – Colour Scheme
Average Illuminance at the Working Plane vs. Wall Reflectance
0
50
100
150
200
250
300
350
400
450
500
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Wall Reflectance
Wor
king
Pla
ne A
vera
ge Il
lum
inan
ce
E(avge)E(Indirect)Poly. (E(avge))Poly. (E(Indirect))
Design Change – Colour Scheme
Uniformity at the Working Plane vs. Wall Reflectance
0.8
0.81
0.82
0.83
0.84
0.85
0.86
0.87
0.88
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Wall Reflectance
Wor
king
Pla
ne U
nifo
rmity
U(min/avge)Poly. (U(min/avge))
Design Change – Colour Scheme
○ Decrease wall reflectance by 50%: ● Average illuminance -6%, ● Uniformity -2%
○ Wall reflectance and colour selection does not significantly affect average illuminance and uniformity.
○ Other negative design implications of excessively high or low surface reflectances
Design Change – Desk Colour
○ A change in colour scheme is also likely to mean that furniture colours will change.
○ Desktops in an open plan office environment represent a large surface area ● Direct illumination reflected back up onto ceiling and
walls, contributing to the indirect component ● Wide selection of laminates and finishes available
(ρ=15% - 80%+)
Design Change – Desk Colour
Average Illuminance at the Working Plane vs. Desk Reflectance
0
50
100
150
200
250
300
350
400
450
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Desktop Reflectance
Wor
king
Pla
ne A
vera
ge Il
lum
inan
ce
E(avge)E(Indirect)Poly. (E(avge))Poly. (E(Indirect))
Design Change – Desk Colour
Uniformity at the Working Plane vs. Desk Reflectance
0.8
0.81
0.82
0.83
0.84
0.85
0.86
0.87
0.88
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Desktop Reflectance
Wor
king
Pla
ne U
nifo
rmity
U(min/avge)Poly. (U(min/avge))
Design Change – Desk Colour
○ Desktop reflectance does not significantly affect average illuminance and uniformity.
○ Affecting the indirect flux component by increasing surface reflectances can see average illuminance go up, but uniformity decreases.
○ Other negative design implications of excessively high or low surface reflectances
Design Change – Partitions
○ Introduction of vertical obstructions above the working plane.
○ Design changes so far have affected the indirect component only
○ Partitions will have an effect on direct illumination as well as indirect.
Design Change – Partitions
Design Change – Partitions
Average Illuminance at the Working Plane vs. Partition Ht. above Working Plane
0
50
100
150
200
250
300
350
400
450
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Partition Height Above Work Plane
Wor
kpla
ne A
vera
ge Il
lum
inan
ce
E(avge, ρ=.2)
E(avge,ρ=.5)
E(min, ρ=.2)
E(min, ρ=.5)
Poly. (E(avge, ρ=.2))
Poly. (E(avge,ρ=.5))
Poly. (E(min, ρ=.2))
Poly. (E(min, ρ=.5))
Design Change – Partitions
Uniformity at the Working Plane vs. Partition Ht. above Working Plane
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Partition Height Above Work Plane
Wor
kpla
ne U
nifo
rmity
U(min/avge,ρ=.2)
U(min/avge,ρ=.5)
Poly. (U(min/avge,ρ=.2))
Poly. (U(min/avge,ρ=.5))
Design Change – Partitions
○ Partition height has a significant effect on average illuminance ● Significant impact on minimum value
○ Partition reflectance also affects the result, but to a much lesser extent ● Indirect flux component.
○ Location of minimum values no longer on the perimeter.
○ User-defined lighting (or other) to correct this
Design Change – Partition Arrangement
Design Change – Partition Arrangement
Average Illuminance at the Working Plane vs. Partition Ht. above Working Plane (diagonal arrangement)
0
50
100
150
200
250
300
350
400
450
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Partition Height Above Work Plane
Wor
kpla
ne A
vera
ge Il
lum
inan
ce
E(avge, ρ=.2)
E(avge,ρ=.5)
E(min, ρ=.2)
E(min, ρ=.5)
Poly. (E(avge, ρ=.2))
Poly. (E(avge,ρ=.5))
Poly. (E(min, ρ=.2))
Poly. (E(min, ρ=.5))
Design Change – Partition Arrangement
Uniformity at the Working Plane vs. Partition Ht. above Working Plane (diagonal arrangement)
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Partition Height Above Work Plane
Wor
kpla
ne U
nifo
rmity
U(min/avge,ρ=.2)
U(min/avge,ρ=.5)
Poly. (U(min/avge,ρ=.2))
Poly. (U(min/avge,ρ=.5))
Design Change – Partition Arrangement
○ The difference between partition orientations is minimal.
Design Change - Floor Finish
○ Inappropriate selection can lead to premature wear, more obvious staining through use, slip hazard or glare
○ Floor surface types vary widely ● Carpet, timber veneer, ultra-modern epoxy finishes.
○ Whilst other room surfaces, (walls, ceilings) degrade over time, flooring degrades faster, given the constant, direct and harsh use this surface is subject to.
Design Change - Floor Finish
Average Illuminance vs. Floor Reflection (with Walls ρ=0.5, Desks ρ=0.5 Partitions 1.2m ρ=0.2)
335
340
345
350
355
360
365
370
375
0% 10% 20% 30% 40% 50% 60%
Floor Reflectance
Ave
rage
Wor
king
Pla
ne Il
lum
inan
ce
E(avge)Poly. (E(avge))
Design Change - Floor Finish
Uniformity vs. Floor Reflection (with Walls ρ=0.5, Desks ρ=0.5 Partitions 1.2m ρ=0.2)
0.13
0.14
0.15
0.16
0.17
0% 10% 20% 30% 40% 50% 60%
Floor Reflectance
Wor
king
Pla
ne U
nifo
rmity
U(min/avge)Poly. (U(min/avge))
Design Change - Floor Finish
○ Increasing reflectance by 50%: ● E(avge) = 2% ● Ρ = +7%
○ Minimum impact on these 2 key performance criteria
Conclusions
○ Design changes affecting indirect component have a smaller impact on Average Illuminance and Uniformity ● (paint and surface finishes)
○ Compound effect of multiple changes can represent a substantial change overall.
○ Design changes affecting direct component have a greater impact on Average Illuminance and Uniformity ● Partitions and other vertical obstructions
Design Guide
○ Make the information generic ● Factor the changes
○ Establish base performance ● What assumptions were made:
• Did the lighting design consider the inclusion of any furniture/partitioning in the space?
• What was the assumed Ceiling reflectance? • What was the assumed Wall reflectance? • What was the assumed Floor reflectance? • What was the assumed Maintenance Factor?
Design Guide
○ Assess the Interior Design Changes ● Apply factors to the base performance (Illuminance
and Uniformity)
○ Determine if further input is required from Lighting Designer ● Redesign lighting scheme ● Input on other options for task lighting improvements
• User-defined task lighting • Daylight Integration
Design Guide
Working Plane Illuminance and Uniformity Variance for Wall Colour Changes
Surface Reflectances E(avge) U(min/avge)
Ceiling Colour/ Reflectance No Change Wall Colour/
Reflectance
0%
Floor Colour/ Material
No Change
0.94 0.95
14% 0.95 0.95
40% 0.96 0.98
70% 0.98 0.99
100% 1.00 1.00
124% 1.02 1.01
148% 1.04 1.01
168% 1.06 1.02
184% 1.07 1.01
198% 1.09 1.01
○ Example of Table for Wall Reflectance changes
Design Guide
○ Educate Interior Designers ○ Provide guidelines for them to involve Lighting
Designers further, or curtail design modifications within acceptable limits (for lighting performance)
○ Promotes thought on lighting issues