Cut Resistance FAQ

Are ANSI and CE EN 388 cut levels the same?

Absolutely not. The two levels are achieved with completely different testing methods and are therefore not interchangeable. Be careful that you know which cut level is shown when you’re purchasing gloves. Gloves rated cut level 3 with EN 388 might only be ANSI cut level 1.

What testing method does ANSI/ISEA 105-2011 use to determine cut resistance?

Either a Cut Protection Performance Test (CPPT) or TDM 100 Cut Test Machine can be used. The methods are very similar and both measure the amount of force (in grams) that it takes to cut through glove material for a specified length. When testing per ASTM F1790-97 the cut level is determined after a blade pass distance of 25mm. When testing per ASTM F1790-05 the cut level is determined after a blade pass distance of 20mm.

Gram Weight / Cut Level

Gram Weight / Cut Level

Does ANSI/ISEA 105-2011 specify abrasion resistance?

Yes. Rotary abrasion tests like the Taber Abrasion Test determine how many cycles it takes to wear through a glove coating or yarn with a 500g or 1000g load. ASTM D3389-05 outlines testing of coated glove fabrics. ASTM D3884-05 outlines testing for uncoated fabrics.

What testing method is used for CE EN 388?

The Coup Test utilizes a circular blade with a fixed load of 500g that moves back and forth until it cuts through the fabric sample. A cotton canvas is alternately cut and serves as a reference material. The cut resistance level is the ratio of cycles needed to cut through the test sample as compared to the reference material.

Does EN 388 measure low level and antlestslots.com high level cut resistant gloves with equal accuracy?

Not always. The Coup Test is best used when testing lower level cut-resistant gloves because high cut- resistant gloves can dull the blade, which affects the results.

What attributes does EN 388 illustrate?

The EN 388 rating doesn’t just show cut resistance. The four-digit rating also shows abrasion resistance, tear resistance, and puncture resistance.

Mechanical Protection

Mechanical Protection

How do glove coatings affect cut resistance?

Most coatings add to abrasion resistance. However, extremely thin coatings can actually negatively affect cut resistance.

What is the most accurate way to determine the cut resistance features of a glove?

The CPPT gram weight for a glove is a more thorough indication of cut resistance than just the performance level. Keep in mind that a glove that achieves a 995 (Level 2) on the CPPT provides nearly the same cut resistance as glove that achieves a 1,010 (Level 3), even though they have different performance levels.

What are the best materials for cut resistance?

There are dozens of materials to choose from. Kevlar offers good cut resistance and excellent heat resistance. Dyneema, Spectra and HPPE are breathable and soft, but still offer good cut resistance. Stainless steel and fiberglass strands are commonly woven into glove material like Kevlar and Spectra to greatly enhance cut resistance. Engineered Fibers are materials like SuperFabric provide extremely high cut resistance but good comfort. Steel mesh offers excellent blade cut resistance. Keep in mind the cut level needed for your application and the desired comfort level when choosing a glove material.

The Science of Evaporation

We all know about evaporation, right?  Water evaporates into the air.  Leave a bowl of water out, and a day or so later the water is gone.  It rains on the driveway, creating some puddles, then the sun comes out and an hour later the puddles are gone.  We say that the water has evaporated.  We see ads for “cooling apparel”, like cooling vests, neckbands and bandanas, that supposedly use evaporation to cool us off on a hot day.  But how do they work, exactly?  And why would evaporation have a cooling effect?

That”s what we”re going to dig into here.  We”re going to have a look at the Science of Evaporation.

Before we begin, we need to review a few basic principles, concepts and definitions.  You may not see right away what these things have to do with evaporation, but bear with me.  It will all come together later.

The first thing we”re going to review is the difference between potential energy and kinetic energy.  Here”s a good example.  Take a heavy brick and balance it right on the edge of a table.  Because it”s up off the floor and on the edge of the table, it has the potential of falling off the table and onto the floor.  It has potential energy.  Now nudge the brick so it falls off the table.  The instant it begins to fall through the air, its potential energy has changed to kinetic energy.  The brick is moving with speed and weight as it heads for the floor.  It”s loaded with kinetic energy.  The word kinetic basically refers to the energy of an object in motion.  If you don”t believe that the falling brick has energy, put your bare foot on the floor right where the brick will land.  I think you”ll find the results very convincing.  So now we know what kinetic energy is.

The next thing we”re going to talk about is water, and how it always exists in one of three states, or “phases”.  When it”s cold, below 32°F, it”s a solid that we call ice.  Ice is water”s solid state, or solid phase.  When it warms up, the water melts and becomes a liquid.  It enters its liquid phase.  We call that a phase change, from a solid to a liquid.  Get the water hot enough, above 212°F, and it boils and turns into a gas, which we call steam.  That”s another phase change, from a liquid to a gas.  But you don”t have to boil water to turn it into a gas.  Just leave it alone long enough (in any temperatue above freezing) and it slowly turns into a gas on its own.  When it happens this way, we call it evaporation.  The water has undergone a phase change, from a liquid to a gas, which in this case we call “vapor”.  The water has evaporated.

One more concept to examine about water.  As we all know, everything is made up of molecules.  Water is made of water molecules.  Each water molecule contains two atoms of Hydrogen and one atom of Oxygen.  That”s where H2O comes from: two H”s and one O.  Now these water molecules are loaded with kinetic energy.  (See?  I told you this would come up later.)  The water molecules are always moving, bouncing around and bumping into each other.  The temperature of the water is linked to how much kinetic energy the water molecules have, and how hard they bump into each other.  Temperature is a measure of heat, and heat is energy.  You raise the temperature of water by pouring more heat into it.  When you do that, you increase the kinetic energy of the water molecules, and they move around even faster and bump into each other even harder.

But here”s the thing.  Each of those water molecules doesn”t have exactly the same amount of kinetic energy as the others.  Some have more, some have less.  Some are moving faster, some are moving a little slower.  The temperature of the water is actually a measure of the averageamount of kinetic energy in all the water molecules taken together.  This is a key distinction, as we will see in a minute, so hang onto this.

Water Molecules <a href=

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Evaporation occurs at the surface of the water.  By far, most of the water molecules don”t have enough kinetic energy on their own to be able to punch through the surface tension of the water and escape into the air (evaporate).  But if a surface molecule gets bumped by two or three other energetic molecules in quick succession, it may gain enough energy to punch through the surface tension and escape into the air.  That molecule has successfully evaporated!  And when it does, it goes through a phase change, changing from a molecule of liquid water to a molecule of water vapor.

Seeing this mechanism at work, we can see why hot water evaporates faster than cooler water.  By pouring heat energy into the water, either from the sun or from a burner on a stove, we increase the kinetic energy of all the water molecules, so now they”re all moving faster, bumping into each other harder and more often, and more are able to reach a kinetic energy level sufficient to escape into the air.  Faster evaporation.

So okay, I get it.  Water molecules are moving fast, they bump into each other, and some on the surface attain enough energy to escape into the air.  But why would that have a cooling effect?

Here is where the key distinction I mentioned earlier comes into play.  Remember, all those water molecules don”t all have the same amount of kinetic energy.  Some have more, some have less, and the temperature of the water is actually a measure of the average amount of kinetic energy in all the water molecules taken together.  So what happens when the hottest, most energetic water molecules escape and leave?  They leave the cooler, less energetic molecules behind.  The average amount of kinetic energy of the remaining molecules is lower, and thus the temperature of the water is lower.

Here”s a sports analogy I”ve been dying to use.  A minor league baseball team has its regular lineup of eight players plus its pitching staff.  We”ll forget about the pitchers for this example because we”re talking about batting averages.  Two of the starters are each hitting .400, and the rest of the guys are only hitting .200 each.  With the two .400 hitters in the lineup, the team batting average is .250.  Then the two best hitters get called up to the majors and are replaced with two .200 hitters.  With the two high-energy hitters gone, the team batting average drops to .200.  That”s what happens with the water.  When the high-energy molecules leave, they leave the lower-energy molecules behind, so the average energy of the water is now lower.  The energy is lower so the temperature is lower.

Evaporation has cooled the water.  And if that water is in the form of sweat on your arm, your arm will feel cooler.

And if that water is soaked into an evaporative cooling bandana that you are wearing around your head, evaporation will cool that water, the bandana will feel cooler, and it will cool your head.

The cool thing (sorry, I couldn”t resist) about these evaporative cooling products is that, for their size, they are engineered to hold an amazing amount of water for a long time.  So it takes a long time for all that water to evaporate, so they are able to provide the evaporative cooling effect for a long time, much longer than if you took a handkerchief, say, got it wet and put it on your head.  That would work, but not for very long, and you”d look dumb.

Evaporative cooling products are effective and are relatively inexpensive.  Anyone working in extreme heat, whether outdoors in the summer or indoors in a steel mill or foundry or the like, would be well advised to take the threat of heat stress seriously.  A small investment in some evaporative cooling apparel for yourself will not only make you feel more comfortable while in the heat, it could very well save your life.

Learn more about the symptoms and dangers of heat stress by reading All About Heat Stress at PandaPedia.

You”ll find a wide range of cooling apparel at eSafetyStore.com.  Click here to go directly to the Cooling Apparel section.

What is a Calorie?

We see the word calorie a lot in our everyday lives, mostly associated with food and dieting. But people who work around electricity also see the word calorie in reference to arc flash ratings and clothing designed to protect workers from extremely dangerous arc flash incidents. And that’s what we’re going to talk about here: calories as they are encountered in electrical work and arc flash explosions.

Scientists define a calorie as a unit of energy equal to the amount of heat needed to raise the temperature of one gram of water by one degree Celsius.

HRC 2 ANSI Class 2 FR/Arc-Rated Cotton Fleece Zip Front Hooded Lime Sweatshirt with Cell Phone Pocket and Double Pouch Pockets - Hi Vis Green/Yellow

Picture Provided By: Vinatronics

Well, what the heck does that mean? First of all, this is all in the metric scale, so we’re talking about one gram of water, instead of, say, one ounce or one pint. Just to give you an idea about how big a gram is, there are 28 grams in one ounce. Or to put it another way, a gram is 1/28 th of an ounce. So it’s pretty small.

Also, because we are in the land of the metric scale, we use a Celsius thermometer instead of the Fahrenheit thermometer we are all used to. In the Fahrenheit world, water freezes at 32° and boils at 212°. But in the Celsius world, water freezes at 0° and boils at 100°. 1° in the Celsius world equals 1.8° in the Fahrenheit world. So a Celsius degree is almost but not quite twice as much as a Fahrenheit degree. There’s 100 Celsius degrees between when water freezes and when it boils, but there’s 180 Fahrenheit degrees between freezing and boiling.

So, going back to our definition. A calorie is a unit of energy equal to the amount of heat needed to raise the temperature of one gram of water by one degree Celsius. Take a little metal cup and put exactly one gram of water in it. Then stick a Celsius thermometer in the water and take the water’s temperature. Let’s say it’s a comfortable room temperature of 68°F. That would be 20°C. So the water’s temperature is 20° Celsius. Now, put the metal cup with the water and the Celsius thermometer on the stove, turn on the heat and watch the thermometer. When the Celsius thermometer goes from 20° to 21°, the stove has poured exactly one calorie of heat energy into that one gram of water. Doesn’t seem like much, does it?

OK, that’s all well and good, but how can I use this information in my daily life? If you’re an electrician, or a person who works around electrical junction boxes or circuit breakers, or anywhere electricity is conducted, an understanding of calories can save your life, because when you understand what a calorie is, you gain a powerful perspective on the energies released in an arc flash explosion.

A candle’s flame generates about 3.5 calories per second. You don’t have to hold the palm of your hand in the candle’s flame for one second to know that that’s plenty enough to give you a painful burn. In fact, the level of incident energy that will result in a second-degree burn is only 1.2 calories per square centimeter (cm²). A small number of calories of heat applied directly to your skin casino online can give you a nasty burn.

Now that we know what a calorie is, let’s apply that knowledge to arc flash explosions. As you may know, an arc flash, also known as an arcing fault, is a flashover of electric current through the air from one exposed live conductor to another, or to ground. This is an extremely explosive event, and can be caused by equipment corrosion, insulation failure, improperly designed equipment, accidentally touching the wrong thing, and numerous other causes.

If you happen to be standing there when an arc flash occurs, you are in big trouble. Why? Because an arc flash releases tremendous amounts of incident energy. Let’s look at a typical example. If there is an arc flash in a 480V system with 20,000 amps of fault current, and the fault lasts for just 10 cycles at 60Hz (about 1/6th of a second), the resulting energy output is a staggering 400,000 calories! A 3.5-calorie candle flame can burn your palm. What will 400,000 calories exploding in your face do to you?

Electric arcs can produce some of the highest temperatures found on Earth: up to 35,000°F. That’s four times hotter than the surface of the Sun! This kind of intense heat causes the sudden expansion of the air around it, creating a powerful blast wave. Also, all known materials vaporize at these temperatures. When materials vaporize, they expand in volume, creating an air blast that blasts out molten metal with enough force to pierce the human body.

400,000 calories. 35,000°F. Molten metal blasting out like white-hot bullets. Clearly, arc flash explosions are among the most dangerous events any worker might encounter. Fortunately, clothing exists to protect workers from arc flash events.

All right, that’s good news. But exactly what clothing should you wear to protect yourself from arc flash? The answer is: That depends on the level of risk you are likely to encounter. These levels of risk have been quantified by the National Fire Protection Association (NFPA) in their NFPA 70E standard: Standard for Electrical Safety Requirements for Employee Workplaces. Each level of risk is calculated from a number of factors, including how close you may be standing to the potential source of arc flash and the total energy that may be released.

The relative levels of risk are expressed by the Hazard/Risk Category rating, or the HRC rating, a number that represents the level of danger present at a potential arc flash source. An HRC rating of 0 represents little or no risk, whereas an HRC rating of 4 represents the most dangerous risk possible. Again, arc flash protective apparel is available for every HRC rating.

Your employer is required to perform a complete hazard assessment before any work or inspection is done near exposed, live conductors. Check with your boss and find out what level of arc flash protective apparel you should be wearing before approaching exposed, live conductors. Once you know the HRC rating of the clothing you need for your safety, I suggest that you visit eSafetyStore.com, where you will find everything you’ll need to be safe and protected in this ultra-dangerous environment.

400,000-calorie, 35,000°F arc flash explosions are cataclysmic events that can seriously ruin your day. Protect yourself with the proper protective arc flash apparel. You just might be very glad you did.

All About Heat Stress

We are entering the hot summer months, so it’s time to talk about Heat Stress. If you work outside in the hot sun, or inside with no air conditioning, it’s important to be aware of the dangers and symptoms of heat stress, and what to do if you or someone near you gets heat stress. The definition of heat stress is simple: if your body becomes overheated, you’ve got heat stress. It then becomes a question of degree (Ha! Degree! Get it?). Just a little heat stress is called Heat Exhaustion, and it’s not all that serious. You can get heat exhaustion if you sweat a lot and don’t drink enough water or take in enough salt to replace the salt you lost through sweating. You might feel weak or nauseous, and have pale, clammy skin. If you feel these symptoms, go sit in the shade, or find a cool place to rest, and drink an electrolyte beverage like Gatorade® or Sqwincher® to replace both the fluids and electrolytes (salt and others) that you lost through sweating. You can buy Gatorade and Sqwincher at eSafetyStore.com.

Gatorade at eSafetyStore

Avoid beverages with caffeine in them, like coffee, iced tea and cola, because caffeine is a diuretic, and it will make you urinate more, causing your body to lose more fluids, exactly what you don’t want to happen. A far more serious kind of heat stress is called Heat Stroke, and heat stroke can kill you. With heat stroke, you get so overheated that your body can no longer regulate its core temperature. You stop sweating, and your body cannot rid itself of excess heat. Unless you receive proper treatment promptly, you will die. Heat stroke is not that common, but it’s good to know the symptoms so that you can respond correctly and quickly.

Heat Stress Symptoms
If you’re in a very hot environment, and someone you’re near experiences mental confusion, delirium, fainting or seizures, if their body temperature is 106°F or higher, and if they have hot, dry skin, call 9- 1-1 immediately and request an ambulance. That person is experiencing heat stroke. While you’re waiting for the ambulance, do everything you can to cool the person off. If you can’t get the victim into an air conditioned room, then move him or her into the shade. Soak the victim in cool water, then find something to use to fan the victim vigorously to increase cooling. Keep working to keep them cool until the ambulance arrives. Heat stress can lead to other problems, including heat cramps, fainting and heat rash, also known as prickly heat. The treatment is basically the same as for heat exhaustion: rest in a cool place and drink plenty of an electrolyte beverage.

Heat Stress Prevention
There are a number of things you can do to prevent the onset of heat exhaustion or heat stroke. Your body cools itself through the act of sweating. The sweat on your skin evaporates, changing from liquid water to water vapor, an action which requires heat to complete. The process of evaporation pulls that heat it needs from your skin, thus cooling you off. Anything you can do to increase the rate of evaporation will cool you off faster and better. This is why a fan helps so much. Here’s a trick that takes the cooling power of evaporation to a whole other level. Take a white cotton t-shirt, soak it in water, wring it out and put it on. Now evaporation really kicks in to cool you off, and if you can sit or stand in front of a fan, the wind from the fan will supercharge the rate of evaporation, cooling you even more. And when the t-shirt dries out and stops working, just soak it again and you’re back in business. Drink plenty of fluids. Sports drinks like Gatorade® and Sqwincher® are best because they are formulated to replace the electrolytes lost through sweating, and electrolytes are critical to prevent heat stress.

Pay attention to the clothes you are wearing. Black clothing, and dark clothing in general, absorbs heat from the sun and makes you hotter. White clothing reflects that heat and keeps you cooler. So a white cotton shirt, a white hat with a wide brim, and white pants would be best for staying cooler in the sun.

Great Products to Ward Off Heat Stress
There are some great products on the market that can help you to keep your cool when it’s blistering hot out there.

Evaporative Cooling Garments
These work the same way as the wet t-shirt trick that I mentioned earlier. You get them wet and put them on, and they cool you off. However, these work much better and for much longer than a simple wet t-shirt will. The typical evaporative cooling garment will have encapsulated packs of a special polymer material permanently sewn into it, either in pockets designed specifically for that purpose, or as a liner. When dry, this polymer takes up very little space. But soak it in cold water and it will absorb up to 30 times its own weight in water, swelling up into a stable gel. Put the garment on and it will keep you cool you for hours, much longer than the wet t-shirt. These products come in the form of vests, headbands, neck bandanas, hard hat liners and skull caps. They can be soaked and reused hundreds of times. They are fairly inexpensive as compared to Phase Change Cooling Garments, and they work well enough, although less so in high humidity. Evaporative cooling garments don’t work as well when the humidity is high because the air is already saturated with water vapor, so the water that you soaked the garment in has no place to evaporate to. Also, they are wet when you put them on. Some find that uncomfortable. See a full line of evaporative cooling products at eSafetyStore.com. Start at this link.

Phase Cooling at eSafetyStore
Phase Change Cooling Garments
Phase Change technology uses the science of phase change to provide cooling. Now that may sound like something only Einstein could understand, but really, we see phase change around us all the time. The simplest example is water. Water can exist as one of three phases: solid (we call it “ice”), liquid (liquid water) and gas (like water vapor, or steam). When ice melts, it changes phase, from solid to liquid. That’s a phase change. The same when water freezes. It goes from liquid to solid, another phase change. New high tech phase change cooling garments begin the same way evaporative cooling garments begin: with sewn-in pockets designed to contain encapsulated packs of a special material. However, in this case the material is a high tech phase-change material instead of the polymer. This phase- change material freezes solid at 58°F (instead of 32°F, like water). You put the encapsulated packs in the refrigerator (or in water colder than 58°) for around 40 minutes, and they quickly freeze solid. (They won’t absorb the water like the polymer will.) Then slip the packs into their pockets on the garment, and you’re good to go. There are advantages here. Freezing at 58°, these packs don’t feel uncomfortably cold against your body like ice does, yet they are plenty cool enough to keep you cool on a hot day. And they will hold steady at 58° for hours, as the phase change material slowly changes phase (“melts”) from solid back to liquid. Since they are not as cold as ice, humidity in the air won’t condense on them, so they stay dry. And since they don’t rely on evaporation, high humidity conditions won’t slow them down. One more advantage: a phase change vest will tend to weigh less than an evaporative cooling vest that’s soaked with water. But being high tech, it will be somewhat pricier than the evaporative cooling vest. Like the evaporative cooling apparel, phase change cooling garments can be used over and over. Find the very best phase-change cooling garments at eSafetyStore.com.

Circulatory Cooling
Circulatory Cooling Garments
Take about 50’ of medical grade capillary tubing and sew it into the front and back of a vest (or a shirt) in a kind of looping pattern. Then take an insulated supply hose and attach one end to the tubing in the vest and the other end to a cooler full of ice water. A pump in the cooler pumps the ice water through the supply hose and into the tubing of the vest, where it circulates around through the loops and cools you off, maintaining a temperature of between 50°F and 65°F. This demonstrates the principle of circulatory cooling. Since cool water transfers body heat away 28 times faster than air, these systems tend to work very well. The pumps are usually designed to run off a standard 110V outlet or a 12V battery. If being hooked up to a hose all day sounds inconvenient to you, manufacturers make models that are self-contained, with the ice water either in a back pack or a bottle, and the pump and battery worn on your belt. Circulatory cooling vests and shirts can be found at eSafetyStore.com.

Let’s Wrap This Up
So, what have we learned? We’ve learned the difference between heat exhaustion and heat stroke. We’ve learned to recognize the symptoms of both and what to do about it. We’ve learned what steps to take to prevent forms of heat stress from happening, and we have been introduced to a wide range of products that can help with that effort. Heat stress is one of those things that can sneak up on you. You think you’re an iron man, and then suddenly you’re not feeling so good. Don’t mess around with this. You wouldn’t go out in sub-zero weather without a good coat to keep you warm. Don’t work in brutal heat and humidity without some means of keeping yourself cool. Get yourself some kind of cooling garment like the ones described up above, and then wear it. You’ll be cool, comfortable, safe and productive. And remember, heat stroke can kill you, and once you’re dead, it’s too late to do anything about it.