Arc flash personal protective equipment (PPE) is a combination of clothing and safety equipment worn for protection from arc flash and shock hazards by a person performing electrical work.
Primarily, arc flash PPE is divided into the following subgroups:
All arc flash apparel and equipment must be given a specific arc rating to ensure that it meets or exceeds the hazard levels present where the work is to be performed.
There are many ways to achieve arc flash protection, but quite often your only option will be to use electrical arc flash PPE.
Ensuring you are covered head to toe with equipment that is properly rated is paramount to your safety.
In order to understand the arc rating, you first need to understand what it is correlated to…
The incident energy value.
Incident energy is the amount of heat energy produced by the arc flash explosion.
Typically, it’s measured in calories per square centimeter (cal/cm2).
So let’s say you are standing in front of 30 amp disconnect (600 volts) and an arc flash occurs.
You would be exposed to a certain amount of heat energy.
Let’s just say we worked it out and it was 3.7 cal/cm2.
As long as your arc flash gear had a arc rating higher than 3.7 cal/cm2 then you will be protected from the arc flash.
But how do you determine the arc rating?
If the arc rating is low, is PPE still required?
When is arc flash PPE required?
Keep reading to find out.
In order to determine arc flash PPE, you will need to know the arc flash rating of a given material. You can accomplish this by sending it for laboratory testing.
Basically, they blow up the clothing or equipment in a lab and see if it passes the test.
This depends on the type of personal protective equipment you are trying to get rated.
Each type of protection has its own standard (or standards) for testing that it must meet.
Here are the main ones:
During the testing, there are two things that can happen that determine the results of the test and therefore determine the arc rating.
At certain incident energy, you will either reach the material’s Arc Thermal Performance Value or its Breakopen Threshold Energy.
Whichever one comes first dictates the number that goes on the equipment’s tag.
Usually, it’s the arc thermal performance value or ATPV Rating.
When you are performance testing arc flash apparel you expose the material to a certain amount of heat energy.
We call that the arc flash incident energy.
The arc thermal performance value (ATPV) is the material’s ability to withstand the incident energy.
How do you determine the atpv rating?
The value is determined by the amount of incident energy required to transfer enough heat through the material to create a 50% probability that the person wearing the ppe will experience the onset of a second degree burn.
Yup, sounds crazy but this is how it works.
So… let’s say you are in an arc flash that is has an incident energy of 8 cal/cm2.
And you are wearing clothing that is rated 8 cal/cm2 (because the ATPV was 8).
Well… now there is a 50% chance that you will experience the onset of a second-degree burn.
This means the skin under your clothing is exposed to about 1.2 cal/cm2.
Another factor in performance testing your arc flash gear is determining when it will break open.
Break open is defined as a hole that’s either has an area of 16 mm2 or an opening of 25 mm in length.
The breakopen threshold energy (EBT) is similar to the ATPV…
It’s the amount of incident energy that would result in a 50% chance that breakopen occurs.
AR stands for arc rated.
FR stands for flame resistant.
All arc rated garments are flame-resistant, in fact, that’s the barrier to entry.
In order to even send a material to be tested for an arc rating, it must first meet the requirements of FR clothing standard (ASTM D-6413).
Then once it passes that test it can be sent to see if it passes the AR tests (from ASTMF 1506).
Not every garment will pass both so remember this one thing.
All arc rated clothing is flame resistant; but not all flame resistant clothing is arc rated.
Trying to figure out when arc flash PPE should be worn is not as straight forward as you might think.
But I’ve got a nice way you can approach it.
There a 4 steps to a basic risk assessment:
Step 3 is by far the most important step!
Step 1 and 2 almost always have the same answers for any electrical work.
The hazards are arc flash and shock and the severity is high (or high enough that we don’t want it to happen to us without PPE).
So really it boils down to estimating the likelihood of occurrence.
Luckily in both CSAZ462 and NFPA70E they have a table that estimates the likelihood of occurrence for you.
Simply go to that table, find the job you are doing, and if the likelihood is a “yes” then you’ll need to wear arc flash PPE.
Once you’ve completed your arc flash risk assessment and you know the likelihood of occurrence is high enough to warrant PPE you’ll need to select something suitable for the hazard.
There are two methods you can use to select the proper PPE for the job.
The first method is always preferred as it takes the guesswork out of it for the electrical worker.
But, in reality, there is much more equipment out there that is not labelled so that’s why you will also need to understand the second method.
I’ll go through each one in detail so you can understand more about them and what you have to consider before making your choice.
The incident energy analysis method requires an arc flash study to be done on the equipment in order to determine the hazard levels.
Once you have the arc flash study completed you will have labels on each piece of equipment.
On those arc flash labels will be all kinds of information required to perform the task safely but most importantly will be the incident energy.
Getting to this point will require time and resources but it will be well worth it!
At this point, determining the PPE required is easy.
Simply look at the arc flash label, find the incident energy and then make sure all of your arc flash gear is rated higher than the incident energy shown on the label.
The arc flash PPE category table method can be found in CSAZ462 and NFPA70E.
They use different numbering systems so I will refer to them by their titles.
First, you will need to reference the table titled “arc-flash PPE categories for ac systems” (or dc systems).
Choose the equipment type and voltage you are working on.
Equipment types to choose from are:
Available voltages to choose from are from 240 V up to 15 kV.
Here’s the catch (and why this method is a little more difficult).
You then need to look at the parameters for the equipment type you chose and make sure your system falls within this criteria.
If the system you are working on does not fall within the parameters described in the table then you must use the incident energy analysis method.
If it does, then simply look beside the equipment and it will tell you the category number (1 through 5).
At this point, you can go to the next table titled “personal protective equipment (PPE)”.
Each category corresponds with a minimum arc rating for the PPE.
These are the different arc flash levels of protection:
At this point, things are pretty much the same as the incident energy analysis.
The table will list out all the possibilities of apparel to wear but as long as you have your entire body covered in the appropriate PPE then you will be fine.
Just make sure that once you hit category 3 you realize that you can no longer wear the arc flash face shield… you need to go to the hood.
Now it’s time to build your arc flash kit!
But what are all the components you’ll need?
You’re going to want to try to simplify as much as possible so one thing I recommend is going to a two-part simplified approach.
This will give you an “every-day” kit rated 12 cal/cm2 and a “once-in-a-while” kit rated 40 to 100 cal/cm2 (depending on how high the arc flash levels get at your workplace).
Let’s start with the 12 cal kit.
This will be more important because you will be using it 90% of the time.
Next, you’ll need to choose your “once-in-a-while” 40 or 100 cal suit kit.
Now we will go through all the different types of arc flash ppe and go over all the things you need to know about each one.
Arc rated clothing consists of the apparel used to cover your torso, arms, and legs.
The clothing has been tested against the ASTM F1506 standard and is given either an ATPV or EBT value (whichever is lesser)…
This is the arc rating (in cal/cm2).
Arc rated clothing is by far the most important part of an electrician’s arc flash gear.
The survival rate from burn injuries drops significantly as the percentage of your body burned goes up.
This clothing covers the majority of your body, so that means, less of you gets burned and your chances of survival is much higher.
Arc flash clothing is made of either a fabric that has inherently FR fibers (such as modacrylic fibers or aramid fibers) or a non-FR fabric (such as cotton or cotton-nylon blend) which has been chemically treated to provide FR properties.
The advantage to using inherently FR fibers is that the FR properties are part of the fibers natural design and cannot be washed away or worn out.
To wash arc flash clothing at home follow these tips:
Do not use bleaching agents or products that contain bleaching agents.
Do not wring the clothing out.
Do not use an iron on the arc flash clothing.
Arc flash shirts come in a variety of styles and colors but ultimately need to perform one task.
This task is to protect a person’s torso and arms (down to the wrists) from an arc flash.
Most arc rated shirts will have an arc rating around 8 cal/cm2.
Here are some worth taking a look at:
mwg comfort weave 9.0 cal
strata arc corporate 8.5 cal
pmmi c54 long sleeve 8.0 cal
Arc flash pants are designed to protect the worker's legs.
Typically, they will have a higher arc rating than the matching shirt (usually around 12 cal/cm2)
Here are some we recommend:
mwg flexguard 8.5 cal
strata hi-viz 9.9 cal
mwg duck canvas 18 cal
Because arc flash coveralls protect the body from the wrists, to the neck, and then down to the ankles they are a better option than the shirt and pants combination.
Arc rated coveralls are typically rated higher than the shirt and pant combo but can range from 8 cal/cm2 up to 25 cal/cm2.
When shopping for arc flash coveralls keep an eye out for these brands:
oberon inherent fr 12 cal
steel grip coveralls 20 cal
strata arc global 10 cal
Sometimes electrical work is performed outside and the weather is not always favorable.
This is where arc flash rain gear comes in handy.
Arc rated rain gear testing is very similar to arc flash clothing but must also meet the requirements of the ASTM F1891 specification which calls for the material to be exposed to twice the arc rating to ensure no melting or dripping will occur.
Arc flash rain gear is designed to protect you from the elements as well as the arc flash hazard.
pmmi arc extreme 9.2 cal
mwg stormshield 10 cal
strata hi-viz waterproof 24 cal
A question that comes up a lot is “what do I wear for underwear with my arc flash clothes?”.
The most practical answer is cotton (with a small amount of elastic material).
When exposed to a direct flame, 100% cotton will burn, but the key factor is that it will not melt.
Underneath your arc flash protection, the cotton underwear will stay safe from the flames and will not catch fire and the small amount of elastic material in the waistband is considered negligible by most experts.
Some companies do have arc flash underwear available and would be considered an upgrade to cotton underwear.
pmmi control bottoms 4.0 cal
skanwear arc boxers 6.3 cal
mwg flexsafe 4.3 cal
Once you have your arc flash clothing figured out it’s time to protect your most important asset…
You’ve really got two options:
Let’s look at each piece.
The arc flash face shield is designed to protect your face from the radiant heat energy of an arc flash as well as your eyes from the blinding light produced during the incident.
It’s not designed to protect you from projectiles (although most times it will)…
So you’ll have to keep wearing your safety glasses underneath.
Arc rated face shields will need to be worn with a class E hard-hat and an arc rated balaclava to protect the rest of your head.
As far as I know these are the two most trusted brands of face-shield on the market…
Paulson and Oberon.
The arc rated balaclava goes with the face shield and is responsible for protecting the rest of your head from the arc flash (the part that the shield doesn’t protect).
The balaclava is usually designed with a similar fabric to the clothing and is essentially an arc rated ski-mask.
Typically, the balaclava is rated 12 cal/cm2 but I’m sure you can find higher.
Trouble is, if you are following the industry standards then the option to wear the AR faceshield and balaclava is only available up to 12 cal/cm2…
After that you need to go to the hood.
oberon balaclava 12 cal
skanwear balaclava 6.5 cal
pmmi balaclava 12 cal
The arc flash hood is essentially the same technology as the face shield and balaclava but with one key difference.
Instead of being pressed against your skin, the arc flash hood is draped over the hard-hat.
This provides a significant advantage to the faceshield-balaclava combo as it gives you an air gap being the hood and your head (which improves the protection against heat).
Most hoods now come equipped with an arc flash ventilation system (so it’s not so hot).
Also, as the arc rating increases the newer face shield designs will not continue to get darker and darker (earlier models were impossible to see through at higher arc ratings).
oberon arc flash hood 40 cal
af hood ventilation system
pmmi arc flash hood
Something that may get overlooked is hearing protection.
During normal working conditions, noise may not be an issue, but in an arc flash event, the sound is extremely high and can cause damage.
If there is a chance for exposure to an arc flash then you need to have a pair of ear insert plugs to protect your hearing.
These are safe to wear under your balaclava or arc flash hood, and while some brands may melt when exposed directly to extreme heat they will not melt when underneath the protective equipment (well… if they do melt you have other issues anyway).
When it comes to protecting the hands of electrical workers you need to shift your focus more toward shock hazards.
Rubber insulated gloves with leather protectors become the primary source of protection from electrical hazards (these protect from both shock and arc flash).
In some cases, you may only require protection from arc flash so you can use arc rated gloves for these scenarios.
rubber insulated glove
bdg arc flash glove
Electrical insulated gloves must meet the requirements of ASTM D120 in order to be used for the protection against shock hazard.
Leather protectors must be worn over the rubber (to protect the integrity of the rubber) and these gloves need to meet ASTM F696.
The leather protectors do offer sufficient protection from the arc flash hazard.
Here is a snippet from the standards:
“If rubber insulating gloves with leather protectors are used, additional leather or arc-rated gloves shall not be required. The combination of rubber insulating gloves with leather protectors satisfies the arc flash protection requirement.”
Primarily the rubber gloves protect you from the shock hazard and there are a number of different “glove classes” to choose from.
Each glove class has a voltage range that it is used for.
Most electricians working on 480 or 600 volts will use a class 0 glove (which is good up to 1000 volts).
For other voltage levels you can refer to this table to determine what glove class is required.
Insulating equipment shall be inspected for damage before each day’s use using the following method:
Testing of your rubber insulated gloves must be done before the first issue and every 6 months thereafter (following the guidelines of ASTM F495).
There are two things to consider when selecting footwear for electrical workers.
First, will they stand up to an arc flash?
And secondly, do they provide any dielectric protection? Which means… will they help protect you from getting a shock?
While you can never treat you boots as your primary source of protection from shock hazard, a good pair of dielectric boots (or shoes) can provide some additional protection.
(Your rubber gloves are number one)
In the case of an arc flash there is really nothing better than leather boots.
Leather is a great protector from heat energy and most times your feet are far enough away from the source of energy that they are not exposed to the full brunt of the arc flash.
Dielectrically rated leather boots are perfect for an electrical worker.
I hope this article has helped explain arc flash PPE, if so what section has helped you the most? Do you know anyone else that would benefit from this blog? Use the share buttons below to share the content.
If you have any questions or comments, you can always reach out to me at jon.travis@leafelectricalsafety.com.
Download our free Definitive Guide to Arc Flash Studies to help get a more detailed understanding of the potential arc flash hazard at your facility.
Comments ( 1 ) jack 10 december 2022, 08:11 (Comment was edited) --> # --> ↓ --> 0 -->Thanks for helping us understand this topic. You have written it in a way that makes it very simple to understand. Thank you so much.
