Division 26 specifications are beginning to change with respect to Power Studies and Arc Flash. But there is still a lot of ground to cover.
More often than not, Electrical Engineers producing Engineering Specifiactions for new construction will specify that Power Studies including Arc Flash Studies are to be performed once the final equipment selection has been made, with results to be submitted for review in the submitted process. To make matters worse, often on the subject of Arc Flash division 26 language ends with general direction to meet NFPA-70 labeling requirement. Sometimes, if your lucky the language also specifies that the requirements in NFPA-70E should also be met. But there several problems with this approach. Here are four of them.
1. Accuracy. For an Arc Flash study to be performed accurately, conductor lengths need to be approximated as close to actual installation as reasonably possible. Often times when equipment manufacturers are looked to for the Arc Flash Studies an assumed standard conductor length is used. This means the calculated incident energy level can be higher or lower than actual making it possible for technicians to use the wrong PPE when working on energized equipment. Not wearing the correct PPE can be deadly. Wearing PPE that isn’t necessary for the task can introduce unnecessary risk. When Arc Flash Studies are performed using accurate information the technicians are provided with the information which provides them with the safest working conditions.
2.Scope. Arc Flash Studies performed during equipment selection and the shop drawing process often fall short of the full scope of coverage prescribed by NFPA-70E. As a result, for the majority of new construction Arc Flash labels are only installed on large equipment such as main switchgear, substations, and main distribution panels. In reality downstream panel boards, disconnects, and other electrical equipment may also require labeling to be compliant with NFPA-70E requirements.
3.Qualitative Information. The requirements in NFPA-70 and NFPA-70E for Arc Flash labeling don’t really match up. In fact, the NFPA-70 lacks a lot compared to 70E, especially with regard to the information required on labels.
4. Poor Coordination. Proper coordination of devices goes beyond just ensuring the closest device to the fault trips first. Through proper coordination studies device settings can be optimized to reduce incident energy available at points in the system which helps to “right-size” PPE requirements for Qualified Persons, further improving safety.
At the end of the day Electrical Engineers are responsible for ensuring the design of safe, reliable systems. This includes ensuring device settings are optimized for performance and safety and ensuring equipment is properly labeled to provide personnel with the necessary information to select the proper PPE.
For God, creating light was as simple as speaking, but for mankind, that process is a lot more complicated. For us non-deity types, no matter the application when there is need for light, some level of human engineering is required. From the stone age where illumination in a dark environment was achieved only through a concentrated effort to make fire, to the more complex process involving the recombination of holes and electrons at the P-N junction of a semiconductor called a Light Emitting Diode (LED), the evolution of bringing light into darkness has evolved through the application of science and mathematics to provide mankind with the luxury of now taking it for granted. And take it for granted we have.
When you open a door to a dark room, you instinctively feel for the light switch. When you are driving at dusk and the daylight is fading, our modern cars automatically turn on the headlights. Buildings sense daylight to dim or turn off lighting when there is sufficient ambient lighting for the required task. We truly live in a complex, yet illuminating, world. But, despite all the technological advances that allow us to take it for granted, there is still a lot of hard science and engineering happening behind the scenes.
As simple as it is to flip a switch (or have one flipped for you automatically), illumination engineering has progressed far beyond the limitations of a simple On/Off constraint. Now, the hard engineering lies in understanding and developing more of the How, How Much, When, and Where of lighting. Search the web and you’ll find countless studies on the effects of lighting on the health, safety and general well-being of people and the environment.
What? Wait! Light is a good thing, so how can it also be a bad thing?
Too much light is bad, too little light is equally bad. Pointing the light in the wrong direction is bad. Light pollution is bad. Even the wrong color of light (color temperature) in a given situation can be bad. And not just “bad” in a general sense. In some circumstances “bad” can be down-right hazardous. Too much light and glare on a roadway at night in wet conditions can cause fatal crashes. Dim headlights prevent drivers from seeing hazards in time to prevent collisions. The same is true for pilots of aircraft and ships. Improper lighting can cause all sorts of problems. Headaches, migraines, nausea, dizziness, eye strain, vision problems, etc. Even for the cave man with his fire… too much or not enough could easily give way to “bad”, even deadly, situations.
Over the decades since the illuminating properties of fire was first observed, mankind has learned a lot about the importance of proper lighting practices. Today, when it comes to lighting systems design, engineers and designers take all of these factors into consideration. Manufacturers design fixtures for specific applications to ensure the fixtures perform in a manner consistent with providing the optimal lighting levels for a given application. Wall sconces just aren’t sufficient for roadway lighting, and high bay fixtures would amount to extreme overkill for lighting your bathroom. Electrical Engineers producing lighting designs work with lighting and lighting controls vendors and manufacturers to ensure the proper fixture and controllability is selected for the right application, to ensure the proper how, how much, when and where that meets the needs for the specific application.
Part of this process involves an engineering study commonly referred to as Photometrics, to help assess the expected performance of a selected fixture in a given application. In some cases, Glare, a general sensation produced when the perceivable illumination level is sufficiently greater than what the eyes are adapted to, is a significant concern which may warrant a Glare study to ensure measures are taken in the design to prevent hazards due to glare. These, and others, are important steps towards ensuring the desired lighting performance is achieved to provide a safe, comfortable environment.
But who determines the how much, how, where, and when of lighting design?
It is virtually impossible to finitely define the exact optimal lighting parameters for every conceivable circumstance. Building floorplans, ceiling heights, the reflectance properties of surfaces in the space, roadway configurations, and even the geographical location of project, are all factors that are taken into consideration when producing lighting designs. Sure, there are some applications that can be standardized to a degree, but for the most part there’s just too many variables at play to permit the hard definition of optimal conditions to be rigidly applied to every situation uniformly. Mankind tends to learn from mistakes, and thankfully, as a species it is in our nature to pass on that knowledge to future generations. Lighting design is no exception.
The Illumination Engineering Society (IES) was formed in 1906 and is widely recognized as the “technical and educational authority” on illumination. Essentially, it serves as the go to source for understanding important factors that should be considered in the design for a given application and provides recommendations for appropriate lighting levels for those applications. In addition to the IES, various building codes even identify minimum requirements in specific cases, such as lighting levels for the egress path in buildings, and other circumstances deemed important for public safety.
At the end of the day, the goal is the same. To provide light where it is needed, when it is needed, in a manner that is reliable, safe, and comfortable. Though we can’t quite speak light into existence from nothing, we’ve taken great strides to close that gap as much as humanly possible. And we are doing so in a manner that ensures we can take it for granted, enjoying it’s benefit in a way that is routinely second nature.
its in the details...
Sometimes the difference between a satisfied customer and a repeat customer comes down to the little details. No matter what line of work you are in, this applies. When it comes to electrical design for building systems, finding opportunities for creativity and innovation within the confines of building code is difficult, but not impossible.
Over the last decade I’ve had the pleasure of developing engineering designs on a wide variety of projects from sports and healthcare, to assisted living and hospitality. Every project has had its own set of challenges and opportunities, each equally rewarding. But my first lesson in the value of small details came while working as a contractor.
While in college I got an electricians license and worked a little in residential construction. On one particular project, I stepped outside the box a little and took a different approach on the layout for the above counter receptacles in the kitchen. For Dwellings, The NEC requires a minimum of two small appliance circuits in the kitchen. These are separate from dedicated circuits, such as those that may serve the dishwasher, refrigerator, etc. A lot of times contractors will install these circuit in such a manner that one circuit serves one half of the counter space, and the second circuit serves the other half. However, on this project I took a different approach in laying out the circuits, by alternating the receptacles between the two circuits so that no two adjacent receptacles were on the same circuit. My reasoning was that should someone be in the kitchen cooking and accidentally trip the GFCI, they could simply unplug from the one receptacle and plug into the adjacent one, without having to stop and hunt down the reset button. The owner later expressed their gratitude adding the extra touch, which his wife found very thoughtful.
On a different project, the breaker panel was installed on an exterior wall and the roof pitch left very little room for future access to the wall cavity above the panel, for running future circuits. A couple years later the owners needed to add a circuit and were able to do so quickly and easily without requiring cutting the drywall. This saved them time and money on their project. They sent me a note to thank me for putting in a 2-inch spare conduit and 90-degree sweep providing an access path from the attic to the panel.
I haven’t worked as an electrician for many years now, but I’ve carried these experiences, and others like them, over into my design projects over the years and from time to time a client expresses their appreciation for the extra touch, and for thinking outside the box. Living within the guidelines of a heavily developed building code, there are still opportunities to think creatively and add extra, personal touches. True customer service goes far beyond responsiveness, schedule and budget. Sometimes the best customer services can be found in just paying attention to the little things.
ELECTRICAL SPACES FOR ARCHITECTS
For non-sparky types, identifying electrical space requirements for systems rated 600 Volts or Less, can be a little confusing. A couple years ago I was working with an Architect on a project reviewing the space requirements when she jokingly suggested one might need an algorithm constructed to solve all the If/Then statements. In reality, the NEC isn’t that complicated, but there are a few details that require special attention and are easily overlooked in the design process.
The following is a short overview covering some of the more common questions I have encountered on design projects. Refer to NFPA 70 for a comprehensive description of space requirements.
Additionally, the following are a few common misconceptions I've encountered:
Space... the final frontier
In building design where every square foot comes at an increasingly higher cost, space is a premium. Owners and Developers want to maximize usable space, leaving building systems designers to fight for every inch they can get. When it comes to MEP systems, mechanical usually ends up taking up the most space due to the sheer size of the equipment needed to keep the building conditioned. This often leaves electrical engineers scrambling for space to locate panels and transformers. It is a sort of quiet struggle, a battle of sorts, that has raged on for decades. A struggle no project is immune to.
But with practice comes experience, and with experience comes insight. Here are a three simple things Electrical Engineers and Designers can do early on in the project to help ensure the space they need is there, even when "there" may not be defined yet.
1. Arm the Architect
REVIT is a powerful tool. Early on in a design project, even before Architectural backgrounds are available. Electrical Engineers and Designers can generate conceptual layouts for electrical spaces. These concepts should include room dimensions, orientations, the number, size, and swing of needed doors, required louvres for ventilation, etc. Additionally, the conceptual room plans should also include equipment layouts, showing panel locations, types (recessed/surface mount), switchgear locations, and other equipment that will be potentially needed for the building.
Arming the Architect with qualitative and quantitative information of this sort, provides them with something tangible that they can use early on as they work to develop the initial floorplans and programmatic design for spaces. It also helps to put a contextual size parameter to a system that for the most part is largely out-of-sight, out-of mind.
2. Get on the "M" Train
Don't forget that your Mechanical counterpart is also fighting for space. Knowing the types of systems they are planning for early on, and the approximate size of that equipment, will help you understand the potential spaces they will be asking for within the building. Often times, panels and transformers can be located in shared spaces with some of this equipment, which ultimately will reduce the amount of dedicated electrical space needed for the project.
3. Defend the Flag
One thing that is true in any project.... communication is key to success. Providing the Architect with conceptual space needs up front, and understanding the mechanical space needs, is a good start but it isn't enough. The only way to make sure electrical space requirements don't get lost in the shuffle is to keep those conversations going. Provide updates to required space needs as the design progresses. Be aware of other systems and adjacent spaces, and how they impact constructibility for electrical systems, such as conduit routing and piping. Keep conflicting systems out of your space, such as water and drainage lines. Plant your flag(s) and defend them.