Energy Code Changes: What the Design Team Needs to Know: Session 3 -- Lighting Design and the Energy Code
The topic of lighting was the subject of the third session in this series of Energy Code Changes lectures, and was held in New York City on Thursday, January 7 2010.
Hayden McKay, AIA, FIALD, FIES, LEED AP, Principal of Hayden McKay and Shoshanna Segal, LC, IALD, LEED AP, Controls Team Leader, Horten Lees Brogden Lighting Design were the two presenters.
The first part of the presentation gave us an overview of the importance that lighting is playing in the energy consumption area, as well as common perceptions of what efficiency versus effective lighting means to the overall issue.
Once again. greenhouse gases and light pollution are the driving issues in the quest for better lighting efficiency in the new codes. Lighting alone accounts for 15% of the CO2 footprint of NYC, and has risen 70% since the 1970's
An important note that was made here is that conservation without quality is NOT the answer to our problems; we cannot just reduce light output and say we have solved the issue. To do so, will result in poorly or even unsafe levels of light, creating a dysfunctional work place, as well as quality of life. Also, different spaces call for different approaches. For example, retail space can often get away with more shadow effect than would an office, where glare can be very detrimental to the productivity of the workers.
As we spend over 80% of our time indoors, it is important to have lighting that creates a stimulating and connected environment, without creating glare or vision issues. We note that only within the last century has electric (artificial light) been the mainstay of indoor lighting; prior to this,natural day lighting was the primary source, even in factories. We have all seen the photos of factories dating back to early part of the 1900's and we note the presence of skylights in the center of these buildings. Also, skylights where also used at the top of stairwells for the same purpose.
When day light is used, we need to control glare and solar heat gain. While both are comfort and productivity issue, the second will adversely effect energy consumption, if not properly controlled with shading measures. Glare can result in the silhouette effect, and can make items difficult to see or make out, due to the eye accommodation factor. When designing with day lighting -- and LEED strongly encourages this -- we need to address the issue of sky condition. Sky condition will be greatly different on a cloudy day, or be dependent on the time of day. Also, the building orientation will play a role here. In NYC, what appears to run due south really does NOT; this means that the real day time peak for lighting occurs in the afternoon hours, not at high noon.
Fenestration and floor to ceiling ratios are also an important area. IN NYC, we have a large number of buildings that have tall almost floor to ceiling windows that are excellent for day light use.
When electric luminaires are used, especially the T-5 and LED sources, care must be taken not to use them as open fixtures, as they can result in harsh conditions. It was stressed several times that the main aim here is to light the space first, and avoid specular louvers. In doing this, we create a balanced lit area, with minimal glare and shadows. This will often result in far less "task lighting" to be needed; reducing the overall plug load on the total building area being addressed.
It is also important to consider the area surfaces as well. Light colored matte finished walls result in far better lighting coverage per watt used, and we need to avoid shiny surfaces and mirrors as much as possible. However, in retail areas, where drama and effect are more important, these needs can be relaxed as needed, as long as the code is met regarding the allowable watts per square foot.
Lighting technologies are rapidly changing. Incandescent, once the mainstay of all lighting, is fast disappearing from commercial as well as residential use. Even research into improving Compact Fluorescent Lamps (CFL's) has stopped. In fact, the presenters predict that CFL's have about 20 years of use before they, too, will become extinct. (The issue with CFL's is the problem with the small amount of mercury that they contain, and how to safely recycle them.) LED lighting sources are now the hot area of research, and thus this is fast gaining presence in the market. LED sources also do NOT contain mercury. However, LED still has many pitfalls, and is not always adaptable to all projects. LED is still VERY expensive compared to other sources. Metal halide lamps are also good for large areas, and wall washing applications, as they have a good color rendition. Color rendition is also a part of the design concern, as if it causes surfaces to perceived in the wrong tone, the efforts of conservation are totally lost. The most effective lighting may not always have the highest lumen output. this especially true with LED sources, where warm white offers the best color rendition, but has a lower lumen output per watt.
In commercial sites, the linear fluorescent is still the mainstay, with the T8 and T5 lamps predominating. In general, luminaires are NOT a good choice for lighting, as distribution of light is often uneven, and shadows can result. A better approach is to use a combination of sources. Also, recessed parabolic specular fixtures should be avoided, due to the glare issues associated with them. Pendant up and down is now the best choice, as it provides both direct and indirect sources of lighting, resulting in a more even shadow-free lit area. In spite of all efforts mentioned above, task lighting is often the ONLY way to meet the code.
There are several important strategies used here.
A design team MUST have access to a copy of the Code, and reference it as needed; do not rely on COM Check alone!
Once again, we have two methods for compliance -- Prescriptive, which sets forth a rigid schedule for wattage and fixture layout, and the Performance method, which allows the team to use an integrated whole building or area approach, thus giving more flexibility in the design process. Both methods have mandatory provisions for occupancy controls and allowable exterior lighting usage levels. The NYS code, while based on 90.1 does not offer as much design choice for power allowances; hence most are now using 90.1 to comply at the NYS level, even though it is more complex.
The whole building approach is good, but offers little room for error. It is also VERY important to have good documentation as to the location and number of fixtures in your submittal. There is a need to MANUALLY INPUT total system wattages; often design teams leave out the ballast load, which can be considerable.
Area Category is also used for compliance. In this approach, each space is totaled separately, but when taken into the whole building, the proper watts per square foot are met by trade-offs from one area to another. This allows for more light intensity to be used where needed, and less where not. There is also the allowance for exemptions in this approach, but this can be time consuming. If exemptions are used, it is necessary to separate the fixtures in the submittal documents. In addition, trade-offs can ONLY be used in that space alone -- NOT elsewhere in the building. The important idea here is to get the total allowable wattage. for the entire building to met in order to comply. Total power MUST NOT exceed specified amount for project.
Other issues are:
In summary:
Useful Strategies:
Hayden McKay, AIA, FIALD, FIES, LEED AP, Principal of Hayden McKay and Shoshanna Segal, LC, IALD, LEED AP, Controls Team Leader, Horten Lees Brogden Lighting Design were the two presenters.
The first part of the presentation gave us an overview of the importance that lighting is playing in the energy consumption area, as well as common perceptions of what efficiency versus effective lighting means to the overall issue.
Once again. greenhouse gases and light pollution are the driving issues in the quest for better lighting efficiency in the new codes. Lighting alone accounts for 15% of the CO2 footprint of NYC, and has risen 70% since the 1970's
An important note that was made here is that conservation without quality is NOT the answer to our problems; we cannot just reduce light output and say we have solved the issue. To do so, will result in poorly or even unsafe levels of light, creating a dysfunctional work place, as well as quality of life. Also, different spaces call for different approaches. For example, retail space can often get away with more shadow effect than would an office, where glare can be very detrimental to the productivity of the workers.
As we spend over 80% of our time indoors, it is important to have lighting that creates a stimulating and connected environment, without creating glare or vision issues. We note that only within the last century has electric (artificial light) been the mainstay of indoor lighting; prior to this,natural day lighting was the primary source, even in factories. We have all seen the photos of factories dating back to early part of the 1900's and we note the presence of skylights in the center of these buildings. Also, skylights where also used at the top of stairwells for the same purpose.
When day light is used, we need to control glare and solar heat gain. While both are comfort and productivity issue, the second will adversely effect energy consumption, if not properly controlled with shading measures. Glare can result in the silhouette effect, and can make items difficult to see or make out, due to the eye accommodation factor. When designing with day lighting -- and LEED strongly encourages this -- we need to address the issue of sky condition. Sky condition will be greatly different on a cloudy day, or be dependent on the time of day. Also, the building orientation will play a role here. In NYC, what appears to run due south really does NOT; this means that the real day time peak for lighting occurs in the afternoon hours, not at high noon.
Fenestration and floor to ceiling ratios are also an important area. IN NYC, we have a large number of buildings that have tall almost floor to ceiling windows that are excellent for day light use.
When electric luminaires are used, especially the T-5 and LED sources, care must be taken not to use them as open fixtures, as they can result in harsh conditions. It was stressed several times that the main aim here is to light the space first, and avoid specular louvers. In doing this, we create a balanced lit area, with minimal glare and shadows. This will often result in far less "task lighting" to be needed; reducing the overall plug load on the total building area being addressed.
It is also important to consider the area surfaces as well. Light colored matte finished walls result in far better lighting coverage per watt used, and we need to avoid shiny surfaces and mirrors as much as possible. However, in retail areas, where drama and effect are more important, these needs can be relaxed as needed, as long as the code is met regarding the allowable watts per square foot.
Lighting technologies are rapidly changing. Incandescent, once the mainstay of all lighting, is fast disappearing from commercial as well as residential use. Even research into improving Compact Fluorescent Lamps (CFL's) has stopped. In fact, the presenters predict that CFL's have about 20 years of use before they, too, will become extinct. (The issue with CFL's is the problem with the small amount of mercury that they contain, and how to safely recycle them.) LED lighting sources are now the hot area of research, and thus this is fast gaining presence in the market. LED sources also do NOT contain mercury. However, LED still has many pitfalls, and is not always adaptable to all projects. LED is still VERY expensive compared to other sources. Metal halide lamps are also good for large areas, and wall washing applications, as they have a good color rendition. Color rendition is also a part of the design concern, as if it causes surfaces to perceived in the wrong tone, the efforts of conservation are totally lost. The most effective lighting may not always have the highest lumen output. this especially true with LED sources, where warm white offers the best color rendition, but has a lower lumen output per watt.
In commercial sites, the linear fluorescent is still the mainstay, with the T8 and T5 lamps predominating. In general, luminaires are NOT a good choice for lighting, as distribution of light is often uneven, and shadows can result. A better approach is to use a combination of sources. Also, recessed parabolic specular fixtures should be avoided, due to the glare issues associated with them. Pendant up and down is now the best choice, as it provides both direct and indirect sources of lighting, resulting in a more even shadow-free lit area. In spite of all efforts mentioned above, task lighting is often the ONLY way to meet the code.
There are several important strategies used here.
- Day light harvesting. When used, there is a need to control the use of electric light during the available day lit period through sensors or other switching control, such as digital timers or stand alone presets.
- Zoning. Label and properly locate all switches. The use of commissioning is highly recommended here, but NOT required by the Code. Commissioning IS needed for a LEED certified project.
- Integrated Team Effort. Focus on quality and use technology AFTER proper design.
A design team MUST have access to a copy of the Code, and reference it as needed; do not rely on COM Check alone!
Once again, we have two methods for compliance -- Prescriptive, which sets forth a rigid schedule for wattage and fixture layout, and the Performance method, which allows the team to use an integrated whole building or area approach, thus giving more flexibility in the design process. Both methods have mandatory provisions for occupancy controls and allowable exterior lighting usage levels. The NYS code, while based on 90.1 does not offer as much design choice for power allowances; hence most are now using 90.1 to comply at the NYS level, even though it is more complex.
The whole building approach is good, but offers little room for error. It is also VERY important to have good documentation as to the location and number of fixtures in your submittal. There is a need to MANUALLY INPUT total system wattages; often design teams leave out the ballast load, which can be considerable.
Area Category is also used for compliance. In this approach, each space is totaled separately, but when taken into the whole building, the proper watts per square foot are met by trade-offs from one area to another. This allows for more light intensity to be used where needed, and less where not. There is also the allowance for exemptions in this approach, but this can be time consuming. If exemptions are used, it is necessary to separate the fixtures in the submittal documents. In addition, trade-offs can ONLY be used in that space alone -- NOT elsewhere in the building. The important idea here is to get the total allowable wattage. for the entire building to met in order to comply. Total power MUST NOT exceed specified amount for project.
Other issues are:
- Wattage consumption and lighting power density
- Exit signage limited to 5 watts or less
- Mandatory controls -- for example occupancy sensors, or timers
- Voltage Drop
- Compliance Statement signed by a licensed professional
In summary:
Useful Strategies:
- Re-light rather than retrofit.
- Use tall windows to maximize day lighting effects.
- Use High Performance Glazing (.35 to .70 VLT)
- Separate metering -- now required in NYC for commercial spaces.
- Use high ceilings.
- Light spaces first.
- Use glazed interior walls between spaces to allow for day light penetration.
- Smart space plans.
- Multiple zones.
- Technology must serve NOT lead.
- Consult your Department of Buildings for latest code updates.
- Professional Statement as to whom accepts responsibility for the project.
- Owner's Statement.
- Energy analysis -- COM Check or ECC, or more detailed simulation modeling.
- Supporting Documents -- lighting layout, sensors, controls, luminaire schedule, total input wattages.
Posted by Alan L. Englander at 1/10/2010 6:01 PM 
Categories: Lighting Sources, Sky Condition, Integrated Building Design, Solar Heat Gain, Ballasts, Daylighting, Lighting Power Density, Sensors and Lighting Controls, Fenestration and Floor to Ceiling Ratios, Glare, Natural Light, Input Watts, Color Rendition, Area Category, Prescriptive and Perfomance Compliance, Whole Building Approach
Categories: Lighting Sources, Sky Condition, Integrated Building Design, Solar Heat Gain, Ballasts, Daylighting, Lighting Power Density, Sensors and Lighting Controls, Fenestration and Floor to Ceiling Ratios, Glare, Natural Light, Input Watts, Color Rendition, Area Category, Prescriptive and Perfomance Compliance, Whole Building Approach
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