CI 2009 EAp2: Minimum Energy Performance

Exemptions are noted in 90.1-2007 Section 9.2.2.3.

The mechanical/electrical allowance is 1.5 W/sf. This is greater than most other space types. Is it the density that is too low or the light level? All of the ASHRAE lighting values are selected to make sure you can easily comply with the IESNA requirements for light level. Not sure why this would be a problem at that density level.

Is the "mechanical and eletrical" category including data hall?

As you can see there is not a category in Table 9.6.1 for a data center. The best fit seems to be the mechanical/electrical space type.

Assuming they are the plug in variety I do not think they affect any of the energy credits.

Perhaps the only one impacted might be EAc1.3 Option 2. If you are doing modeling to show compliance you may need to include these under heating.

The higher the connected load the greater the savings. This is simply a higher baseline which will always generate more "savings" than a lower baseline.

In this case it appears they retrofitted or replaced the existing lighting system which I would assume was a T12 system. For some reason they chose to install more wattage. Perhaps the old system did not provide enough light. But if you take a T12 system at 1 W/sf to a T8 system with 1.38 W/sf you will get significantly higher light levels.

By installing a higher baseline of course they are able to show more savings related to controls. In my opinion mixing up these variables inflates the "savings" associated with the controls. With a lower installed LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space., say good office design at 0.6 W/sf, the adjusted LPD would have been even better than they achieved but the "savings" would be less related to the controls. So if you are trying to show the maximum savings for controls then over-inflate the baseline.

The point of the case study was not to show that higher LPDs are better. The point was to show the impact of lighting controls.

Marcus - thanks for your thoughts. Totally agreed that the point is not to promote higher LPDs but rather to emphasize controls. And I hear what you are saying about gaming the baseline - but that's not the focus here. Forget about percentage savings against a baseline - look at the Actual lighting power. The new system had 0.26 W/sf, which is very low - in fact far lower than a good office design at 0.6 W/sf.

Unfortunately there's not much detail in the link I posted, but if I remember from the presentation, the only way they were able to achieve the high level of control that they got with a task-ambient strategy was to add more fixtures so that they could put light only where and when it was needed.

I was hoping to point out that sometimes there's friction between innovative green strategies and the way that the codes are set up. Obviously, the codes have to be written for the 99% of designers who won't pay attention to green unless they have to, but a super-efficient design like this at 0.26 W/sf wouldn't have been allowed per the letter of the code. Maybe it suggests that as energy codes get tighter, there may have to be a shift towards outcome-based verification in addition to design-based verification?

Yep not quite enough information to evaluate how they got to such a lower number. Typically a task-ambient approach will reduce LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space. not raise it.

The code LPD values are maximums, not minimums. The code would not prohibit such a low value as it relates to LEED projects. Sufficient justification would need to be provided which may have to be based on outcome-based results to be convincing enough to count.

The shift from relative comparisons to more absolute comparisons is already happening within LEED so I totally agree with your last statement.

I do love the web for being able to dig and find more info.
http://www.etcc-ca.com/images/stories/et_09.22_otf_landmark_square_final...

They had an instant 30% "savings" because they dimmed all of the lighting to 70% initial. Then using either programs or sensors will slowly increase over time to compensate for light loss factor. 5 years or so they will be operating at 100% and the "savings" no longer available.

The measured "actual" lpdLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space. of 0.24W/sf was based on a 24-hour day average. A peak of 0.61W/sf was measured. No mention of what the average or peak measured baseline was even thought they mention it was recorded between April and May.

They were only allowed to have such a high connected load of 1.33W/sf because of the additional controls allowance that gave an extra 0.26W/sf. No mention if the controls actually reduced the peak or average demand by 0.26W/sf.

Plug load has actually gone up in the office after the lighting revision. My guess is the new task lights were left on.

I don't like these controls allowances in the latest energy Codes. I think they will create an artificial "savings".

Just to stress my point. In 5 years the measured peak lighting load will be about 0.87W/sf after automatic LLF adjustment.

Designing to ASHRAE 90.1 max connected load of 1.0W/sf for an office building with occupancy sensors will have a very similar peak measured load as this office.

Nice digging Bill.

I have been at this 30 years and I have never seen a complicated lighting control system work in the long term, not even for 5 years. Most of our work is small to medium commercial so I can't comment on the big buildings with professional engineers maintaining them (maybe different in those). So I agree that credit for them is somewhat dubious.

Codes and the BD+C versions of LEED only enable the potential for a facility to be energy efficient. How it is actually operated has as much if not more affect on actual energy use. For lasting savings a smart building is one that is simple to operate, not filled with complex controls in my experience.

Who designed the ductwork? This typically requires an engineer. How about the mechanical contractor?

Section 10.4.1 clearly states that "Motors that are not included in the scope of the Energy Policy Act of 1992 have no performance requirements in this section."

So based on that and your read of EPAct 1992 I'd say they do not need to comply.

To demonstrate compliance using the performance method (Section 11) you will need to model the tenant space. This would include the scope of work plus components of the shell.

I think this approach is rarely used in CI. Are you not able to meet the prescriptive requirements of 90.1 associated with the tenant scope of work?

We are pursuing Option 2 at EAc1.3 using an energy simulation according to Appendix G.
Is the energy modelling according to Appendix G also applicable for this Prereq.? The reference guide doesn't provide a minimum percentage improvement!?
Thanks in advance!

Option 2 under EAc1.3 does not require an Appendix G model. Simply beat the efficiency levels in Table 6.8.1A-G by the required percentages in the credit requirement to qualify. No modeling required.

An Appendix G model is not an option for this prerequisite as it is not about energy saving calculation but rather about minimum code compliance.

Comply with the portions that are in your scope. Based on your description it sounds like that would primarily be lighting, and lighting controls.

Correct - existing conditions do not have to be upgraded.

If this is within the CI space, then I don't see how you exclude that, no.

For data centers the installation of client servers will be spread over time as the DC matures. The suggestion that client servers should be included seems to suggest that certification would need to wait until the DC is fully utilized or such time that 50% compliance is met! The logic is similar to C&S whereby the base building meets LEED, and for LEED-CI only the scope within the clients control needs to comply.

Hi Luis,

In the Checklists area above there is a "Hot Tip" that addresses this question: "The performance option allows the project to fail to meet some of the prescriptive requirements, provided that you gain savings in other areas so that the project as a whole does not fall outside the ASHRAE 90.1-2007 boundaries for minimum energy performance."

This approach not only means that you have to do an energy model, but I believe that you also that you have to achieve the performance targets without claiming any extra efficiencies in office equipment, as that's typically not in scope of the energy model.

Thanks for the answer Nadav.
The thing is, I'm worried about the power density reduction more than about the efficiency in office equipment. Maybe some project details will shed some light in the matter.

The lightning design for the project has an LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space. with a 5% reduction over ASHRAE standards. With the performance option we hoped to demostrate that we comply with ASHRAE, even though we are not meeting the LPD reduction requirement. Is this possible? Or the situation regarding LPD reduction is mandatory for this prerrequisite, and we can not fail to meet it, even if we demostrate savings in other areas? Any ideas?

What type of lighting do you have. Lamp type and fixture type?

Incancesent downlights or MR16 track lights are popular with architects and interiors but they will not comply with the energy codes today.

I've also seen linear fluorescent indirects in an office with a wood ceiling. The wood might not look dark but it was absorbing over half of the light.

There's a hundred unknowns about your CI office space so it's difficult to say with certainty "XYZ" is the reason. I had a LEED project where they demanded 70fc on the desktop in an open office. My compromise was I'll provide 35fc ambient lightingLighting in a space that provides for general wayfinding and visual comfort, in contrast to task lighting, which illuminates a defined area to facilitate specific visual work. and the task lighting would supply the rest. I used basket troffers with T8 lamps. It worked. Just remember to count the task lighting in your power calcs too.

Hi Bill,
These are the luminaries that we have: Philips TBS260 4xTL5-14W HFP C6 and Philips TBS260 3xTL5-14W HFP C6 and the ceiling is an Armstrong technical ceiling in color white. Unfortunately the Spanish regulation doesnt allow me to use the task lighting to supply the rest of the fc1. A footcandle (fc) is a measure of light falling on a given surface. One footcandle is defined as the quantity of light falling on a 1-square-foot area from a 1 candela light source at a distance of 1 foot (which equals 1 lumen per square foot). Footcandles can be measured both horizontally and vertically by a footcandle meter or light meter. 2. The non-metric measurement of lumens per square foot, one footcandle is the amount of light that is received one foot from a light source called a candela, which is based on the light output of a standardized candle. A common range for interior lighting is 10 to 100 footcandles, while exterior daytime levels can range from 100 to over 10,000 footcandles. Footcandles decrease with distance from the light source. The metric equivalent of a foot candle is 10.76 lux, or lumens per square meter. and we have to provide the 50fc with ambient lightingLighting in a space that provides for general wayfinding and visual comfort, in contrast to task lighting, which illuminates a defined area to facilitate specific visual work..
Philips made up an study of lighting efficiency and we have 11.85 W/m² instead of the 10.64 W/m² that we need to obtain the Prerequisite. Any suggestion to help us to reduce our W/m² ?? Thanks a lot!!

If you use the Space-by-Space method you are allowed 1.1 W/sf. That should be 11.84 W/m2.

I did a quick layout with the 4-lamp fixture you listed and I put them in a large room. Ceiling was 10' high. Fixtures were spaced 8' on center apart (with 0.81 LLF). Reflectances were normal 80-50-20. At the work surface I got 52.1 fc1. A footcandle (fc) is a measure of light falling on a given surface. One footcandle is defined as the quantity of light falling on a 1-square-foot area from a 1 candela light source at a distance of 1 foot (which equals 1 lumen per square foot). Footcandles can be measured both horizontally and vertically by a footcandle meter or light meter. 2. The non-metric measurement of lumens per square foot, one footcandle is the amount of light that is received one foot from a light source called a candela, which is based on the light output of a standardized candle. A common range for interior lighting is 10 to 100 footcandles, while exterior daytime levels can range from 100 to over 10,000 footcandles. Footcandles decrease with distance from the light source. The metric equivalent of a foot candle is 10.76 lux, or lumens per square meter. with 1.08 W/sf (11.625 W/m2)

Make sure to measure your floor area from the centerline of the interior walls, and outside surface of the exterior walls. It helps. The gross floor areaGross floor area (based on ASHRAE definition) is the sum of the floor areas of the spaces within the building, including basements, mezzanine and intermediate‐floored tiers, and penthouses wi th headroom height of 7.5 ft (2.2 meters) or greater. Measurements m ust be taken from the exterior 39 faces of exterior walls OR from the centerline of walls separating buildings, OR (for LEED CI certifying spaces) from the centerline of walls separating spaces. Excludes non‐en closed (or non‐enclosable) roofed‐over areas such as exterior covered walkways, porches, terraces or steps, roof overhangs, and similar features. Excludes air shafts, pipe trenches, and chimneys. Excludes floor area dedicated to the parking and circulation of motor vehicles. ( Note that while excluded features may not be part of the gross floor area, and therefore technically not a part of the LEED project building, they may still be required to be a part of the overall LEED project and subject to MPRs, prerequisites, and credits.) should always be the same regardless of how the walls are laid out.

Sorry, forgot about the 10% below ASHRAE part of this credit.

If you were allowed to get the average down to 47 fc1. A footcandle (fc) is a measure of light falling on a given surface. One footcandle is defined as the quantity of light falling on a 1-square-foot area from a 1 candela light source at a distance of 1 foot (which equals 1 lumen per square foot). Footcandles can be measured both horizontally and vertically by a footcandle meter or light meter. 2. The non-metric measurement of lumens per square foot, one footcandle is the amount of light that is received one foot from a light source called a candela, which is based on the light output of a standardized candle. A common range for interior lighting is 10 to 100 footcandles, while exterior daytime levels can range from 100 to over 10,000 footcandles. Footcandles decrease with distance from the light source. The metric equivalent of a foot candle is 10.76 lux, or lumens per square meter. you can make this energy requirement with 0.95 W/sf. Tell them this is maintained light levels and that the initial light level will be 50 fc.

You will need some flexibility somewhere. Task lights are preferred. I also played with the floor reflectance and if you bump it up to 30% this will work. But I doubt they'll want a carpet that light because it stains easily. Sorry, I can't help more. Anyone else got ideas.

Hi Bill,
Thanks a lot for your help. I just had a meeting with the client this morning and agreed on using taks lights to reduce the luminaires of the ceiling so we will reduce the number of luminaires and add task lights on every work station.
Thanks again!!!

What about using the performance option? In that case you need to comply with ASHRAE standards but not with 10% below ASHRAE. This is how I understand the credit, but maybe I'm wrong. What do you think Bill?

In COMcheck the Options tab lets you add Exemptions and Allowances. You can claim an allowance for decorative lighting. But it needs to be switched separate from normal lighting and normally off during non-business hours.

The uploads are optional. So only supply them if you are actually changing anything. The reviewers will appreciated that since they have to read everything.

Your lighting power calculation should only include room, in which you change more than 50% of the lighting or if you add to the existing lighting power. That does also apply to task lights. For the sensors required, we always apply the mandatory provisions to the all the lighting existing or new. The lighting control credit EA 1.2 also requires you to included existing lighting no matter what.
I hope that helps.

Thank you very much for your reply. That was very helpful. Would switches on a timer verses occupant sensors be acceptable? Our office has switches in locations that make occupant sensors not practical.

I might not have understood everything that you are asking. Let me know if I missed something.

You only have to comply with lights that are part of this project's scope of work.

You are correct, extra interior allowance cannot be used for lighting outside.

It sounds like the decorative facade lighting is all you have outside of the building.

How close are you? You get an extra 5% if you read 9.4.5. If the facade allowance total is 100W then with the 5% adder you get 105W. That's all there is. You either need to lower the wattage or increase the area that is considered illuminated by these lights. Sorry I can't help much.

It depends if the products are covert by the energy star rating. For instance microwaves aren't covered by energy star, so you don't include them. You also have to watch the details of each products category like vending machines are rated by Energy Star but not snack vending machines. Check their homepage for the details.

If you are referring to the energy modeling per ASHREA 90.1 appendix G, than the answer is no. You can achieve Silver without doing that. But you will have to perform other calculations for instance in regards to your lighting power (see LEED online forms).

Jason, If these lights are outside so not in a conditioned space, you will include it in the exterior lighting calculations. So even thought this is a commercial interior project, you might want to provide the ASHREA compliance forms for exterior lighting.

Jason, it sounds like your multi-purpose room will require an occupancy sensor based on ASHRAE 90.1-2007 Section 9.4.1.2 Space Control.

Kim,

i'm confused, because, i have 2 project which been awarded with gold and the other with silver but we did not installed any occupancy sensors at this "function" area.

Jason, if your "function" area is enclosed by ceiling-height partitions and is classified as a classroom, conference/meeting room, or employee lunch/break room, and you're following the 90.1-2007 compliance path for LEED 2009, you'll need an occupancy sensor in that space (unless the function space has multi-scene lighting control).