Michael Myer, Pacific Northwest National Laboratory: Good afternoon, and welcome to my poster presentation on connected lighting systems, batteries, and emergency lighting. I'm Michael Myer and I'm with Pacific Northwest National Laboratory. The why, what, and how of our project.
We are focusing on emergency lighting and the use of batteries for emergency lighting, possibly to explore other uses of those batteries when they are not in emergency operations. The what, we had to analyze what is the typical energy capacity for emergency lighting and possibly could those batteries be used in non-emergency periods. And the how, well, we researched emergency lighting configurations and we use the DOE prototype models to determine energy capacity for emergency lighting. We'll go more into detail shortly.
A brief overview of emergency lighting operations. You first have generators which provide only emergency power and no emergency lighting. These have fallen out of favor recently because of fuel concerns and management and Superstorm Sandy showed what a challenge some of these can be in a true operational paradigm.
The next are centralized batteries, sometimes known as inverters or a few other different names. Again, they only provide emergency power and that the emergency lighting is provided by the circuits connected to the batteries. They are becoming more common as better battery technology is available and cheaper battery technology.
Another more common use of emergency lighting is known as the bug eye. These are discrete individual units. There is a battery behind the plastic molding that charges when the circuit is getting power. When there is no power in the space, these automatically turn on, and they’re a low cost first option. However aesthetically, they are often not chosen because, well, they look like bug eyes.
Finally, the integral battery. The idea is that this is inside the fixture, it's charging at all times, and that when there is no power, it turns on the fixture at a reduced light output than a normal output. It is an aesthetic option because you're reusing the existing lighting.
As I mentioned, we use what are known as the DOE prototype models. They are 16 models as shown on the screen. They represent roughly 80% of the constructed building stock. They're used for energy code analysis and they exist for different locations and climates, so that was not as important for this analysis.
How the models work is that they are divided into a total area and then the building space is allocated, as shown in these two columns. We then took what’s known as the power density to determine the lighting power allowance, the LPA, this comes from the energy code 90.1 2016 and 2019 to determine what the total potential load for the space could be and would be. We also use some information from the 90.1 model to determine the illuminance, this helped estimate what some of the emergency lighting would look like.
We then modified the model to say, "Hey, would this space actually use emergency lighting or would it be needed?" And then from there we determined a typical picture type, number of quantities, as well as a nominal wattage to determine the emergency lighting for this entire building.
Emergency lighting is dictated in the United States by three overarching codes and standards, NFPA 101, NEC 70, and UL 924. They all relate to the location, the type of equipment, and how it all works.
Finally though, the local authority having jurisdiction, this being your fire marshal or your building code, officials have the ultimate say. They may require more equipment in places than is just required by the strict reading of the code. A great example of this is sometimes bathrooms or other spaces that are common but do not meet the two entry-exit requirement specified by code. But for safety reasons, code officials often like to have those covered. There are other ones that are more buildings specific or location specific.
In general, emergency lighting must turn on within 10 seconds of the loss of power. Illumination must be provided for 90 minutes. It must provide an average of one foot candle along the path of egress. However, your local authority having jurisdiction may require more. The path of egress is also subject to the AHJ and that they may define that depending on your building layout, more people might choose to go a different way and you might be required to add a little more lighting in that area.
Finally, emergency systems must be turned on and checked regularly. Depending on your configuration, they might need to be checked monthly and some need to be operated for 90 minutes a year. That gives us an opportunity to use those batteries during those times and other times for possible grid-related activities.
We took those models, those DOE prototypes, as shown in a simulation on the screen, and we actually developed a process for estimating the energy capacity, what is the total load that battery may need to be able to provide for that 90 minutes. We model all 16 DOE prototype buildings in a 10% total picture for emergency lighting scenario, 20% total picture scenario, and then finally, if 0.1 watts per square foot was dedicated to emergency lighting.
As I mentioned, we did this for all 16 models, and these are just a summary of some of the data that we're generating from this report. We're determining the fixture density for emergency lighting, the potential capacity, as well as the energy capacity, the watt hours per square foot, which allows us to do additional analysis and comparisons. I've been working on this project with my colleague, Michael Poplawski, we are in the final process of getting our results published and we look forward to sharing those with you. Thank you.