IEEE 1584-2018: Big Changes

By: Mike Enright

 

A big change took place in 2018, and for those in the electrical safety industry, it could result in big changes at your company. IEEE 1584-2018 brings a wide range of new processes, calculations, and formulae that affect the way you complete hazard analyses, and could result in big changes to your safety program—including your PPE.

Following our recent blog on the evolution of standards, practices, and organizations in charge of electrical safety, we would today like to put special attention on one of the most important standards driving the selection of safe work practices, PPE decisions, and hazard analysis—IEEE 1584: Guide for Performing Arc Flash Hazard Calculations.

With an update to the standard being announced last year after 16 years of input from electrical engineers and other industry stakeholders, the 2018 edition presents a robust upgrade to the standard.

So what led to the update? What does this standard say about the process of completing a hazard analysis and calculating incident energy? What changes does the 2018 standard make and how does it affect you?

Background: The IEEE 1584 Standard

First introduced in 2002 (IEEE 1584-2002), this standard provides techniques for designers and facility operators to apply in determining the arc flash hazard distance and the incident energy to which employees could be exposed during their work on or near electrical equipment. 

IEEE 1584: From 2002 to Today

IEEE 1584 is developed and managed by the Institute of Electrical and Electronics Engineers (IEEE), a group founded in 1963 with more than 423,000 members across 160 countries and 39 industry-specific societies who produce over 30% of the world's literature in the electrical and electronics engineering and computer science fields.

One of many standards, IEEE 1584 has a significant impact on electricians, safety professionals, and regulators in a wide range of industries, as it provides a pragmatic and empirical set of formulae to accurately estimate the  incident energy a person could be exposed to.

Remaining largely unchanged since its introduction (minor updates were issued in 2004 and 2011), the standard is widely accepted and adopted, recognized by OSHA and NFPA 70E as a method to estimate arc flash boundary and incident energy when performing an arc flash risk assessment.

A Need for Change

While the initial standard and subsequent updates did provide a basic framework, it was by no means a comprehensive standard, and many IEEE papers identified parameters that were not considered that could lead to incident energy and hazard levels higher than previously thought. In some areas, it could also lower energies. Further, collaboration between the NFPA and IEEE brought to light even more research around arc flash events and the variables that affect their severity. For example, the following questions were left unanswered:

• What if the electrodes were horizontal instead of vertical?
• What about different size enclosures?
• What about DC arc flash?

With more than 1,800 tests under their belt, the working group who developed the standard constructed a new arc flash model, providing formulas which are more accurate—albeit more complex—than previous standards.

IEEE 1584-2018: A Brief Look at the Standard

With a wide variety of changes to the standard, many electricians and safety professionals, it’s important to get the right information on how to complete arc flash studies.

IEEE 1584-2018 is a considerable rewrite of the 2002 document, but the major impact of the revisions can be summarized as the following items:

• Presents a more complex calculation method.
• The calculations are more robust, handling the full range of voltage from 208 to 15,000 volts.
• Identifies additional electrode configurations.
• Adjusts the results based upon enclosure size, and for systems less than 600 volts, the depth of the enclosure.
• Calculates an adjustment factor for variation of arc current.
• Refines how small, low voltage systems are addressed.
• Removes 125kVA Rule, 85% Rule

Additionally, the new standard takes into consideration other parameters including blast pressure (slow burn vs. rapid energy release), sound pressure and associated hearing loss and light.

Calculation Methods

Providing more accuracy, the IEEE 1584-2018 standard also adds more complexity for those completing the studies. As the new standard addresses different configurations/physical arrangement of components and expands the voltage range, new formulas were added, including the following variables:

• Configurations (VCB, VCBB, HCB, VOA, HOA)
• V_oc
• Bolted Fault Current (I_bf)
• Working Distance
• Duration (Breaker or fuse curve)
• Gap
• Enclosure Size

Electrode Classifications

Likely the largest change added in the 2018 standard, IEEE 1584-2018 includes the effects of both horizontal (HCB, HOA) and vertical conductor orientations (VCB, VOA, VCBB), plus refined models for arc current variation and enclosure size effects on the incident energy. Instead of just using VCB and VOA, the 2018 version includes the following:

• HCB: Horizontal conductors/electrodes inside a metal box/enclosure.
• HOA: Horizontal conductors/electrodes in open air.
• VCB: Vertical conductors/electrodes inside a metal box/enclosure.
• VCBB: Vertical conductors/electrodes terminated in an insulating barrier inside a metal box/enclosure.
• VOA: Vertical conductors/electrodes in open air.

When an arc flash takes place, each of these behave differently. For instance, an HCB will direct an arc flash directly out of the enclosure, as well as resulting in the highest incident energy. Alternatively, a VCBB will direct an arc inside of an enclosure until it hits a barrier. While this does raise new questions on how to detect and classify equipment, it allows for more accurate measures.

Changes in Enclosure Size

With changes in the configuration comes new calculations based on enclosure size and depth. The size of the box (width, height and depth) changes the direction and concentration of the arc flash. An increase in box size (width X height) leads to a decrease in the incident energy level 18 inches from the panel. However, a decrease in box depth leads to an increase of the incident energy at 18 inches from the panel.

Likely Higher Incident Energy

The 2002 version of IEEE 1584 recognized that there was some statistical deviation in the equations, therefore the worst-case incident energy was determined based upon the clearing time at 100% of the arcing current compared to that at 85% of the arcing current. Now the calculation is tightened up and an arcing current variation factor is calculated and applied to determine the lower end arcing current. This now applies to all voltages from 208-volts to 15,000-volts.

DC Arc Flash Addressed

While change may be on the horizon pertaining to DC Arc flash calculations, IEEE uses the same methodology for now, but makes special note that there will be a focus on DC arc flash, due to questions raised in “Arc Flash Calculations of Exposures to DC Systems” Doan, D.R., and “DC Arc Models and Incident-Energy Calculations,” R.F. Ammerman, T. Gammon, J.P. Nelson and P.K. Sen.

Staying Safe: New Standards, Higher Incident Energy, More Complexity

While there is nothing saying you need to retest everything immediately, the next time that you complete an analysis, the processes will be different and the analysis could result in different results. Before completing your incident energy analysis (every five years or when you make a change), it’s likely that you will need to upgrade software, take time to identify the different types of enclosures and sizes, relabel many of your systems, and possibly update your PPE.

As many of the standards could result in higher incident energy calculations, you may find out that the PPE you have is no longer the PPE you need when completing a task. For those using a two-level PPE system, it is likely that those HCB or VCBB enclosures with incident energy near your PPE upper limit should now be considered to be tasks requiring a higher level of PPE, at least until you can have your arc-flash hazard analysis re-evaluated based upon the new guideline.

At Enespro, we designed a 40 Cal PPE CAT 4 suit that is so lightweight, mobile, and comfortable, it could replace your two-level CAT 2 & 4 program with a one-level CAT 4 program. Our 40 CAL AirLite™ is so comfortable, it gives you the freedom to err on the conservative side without the hassles that come from wearing a traditional CAT 40 suit. Get to know more about this product that is taking the industry by storm by visiting www.EnesproPPE.com to read up on our mission to shatter the status quo, and if you need bulk orders, contact us for a quote at www.EnesproPPE.com/pages/request-a-quote.

Higher Incident Energy? See Why More Companies Are Opting for the One-Suit Approach

In the wake of new IEEE 1584-2018 Standards, you may notice that incident energy levels are higher than initially expected. Paired with a conservative approach that exists in the NFPA 70E PPE tables, and you may see that your CAT 2 suits are getting less and less use. But did you know that a one-suit approach is now a reality?

Thanks to innovations in the electrical PPE market, companies are finding that they can cover all four PPE categories with a single suit—without sacrificing the satisfaction of workers.

But don’t just take our word for it. LidCo Electrical Contractors, a safety-conscious organization with over 35 years serving commercial and industrial customers in Central Massachusetts recently opted to do just that, replacing their legacy PPE with Enespro’s 40 CAL AirLite™ kits in each service van.

The results were astounding. Not only did it increase use among workers, employees found the suit so lightweight, breathable, and comfortable that the company was able to move to a one suit approach. Ready to learn more? Read the entire case study below.