How to protect your hands against arc flash

How to protect your hands against arc flash

7/11/2017 - SPI

What’s an arc flash?

An arc flash is an electric explosion that can happen along energized equipment such as an air conditioner, conveyor or even a lightbulb. When electrons move on a conductor back and forth – like on a wire – a small area outside of that conductor is energized. Voltage can push those electrons off the conductive surface and on the atoms in the air. These atoms become ions because they now have an electric charge.

The air around us is a good insulation to prevent those ions from triggering an explosion, but still, arc flash can occur. If another conductor enters this energized area, a wrench, moisture in the air, dust build up or a worker’s hand, the electrons will travel to that new path. As the electrons are moving between conductors, an arc occurs. We see this every day on a smaller scale when switching on a lightbulb. However, on a larger scale, the arc between two conductors generates very intense heat. Arc flashes can reach almost 20,000-degree Celsius, four times hotter than the temperature on the surface of the sun. According to the voltage of the machine, workers located at more than 7 meters, equivalent to the length of two cars, are still at risk of suffering second-degree burns.

Superior Glove has produced a video that illustrates what is an arc flash, with an interesting perspective regarding hand protection:

 

How to protect yourself against arc flash?

The only foolproof way to eliminate the risk of an arc flash is to de-energize the equipment through lockout and tagout procedures.

Here are some steps to implement in order to ensure the safety of the work teams when working on energized equipment:

  • Provide a safety program with defined responsibilities.
  • Calculate the arc flash risk level.
  • Use appropriate personal protective equipment (PPE) for all workers.
  • Train workers on arc flash hazards.
  • Use the appropriate tools to work safely.
  • Implement equipment lockout/tagout procedures.

Also, if your teams must work with energized equipment, the Canadian standard CSA Z462 used since January 2009, as well as the American standard NFPA 2112, will help you define the approach limits designed to protect employees.

Approach limits

Safe distance
It’s the farthest distance from the energy source. If an arc flash is produced, this limit is the distance where the employee won’t be affected.

Limited approach
This is the minimal distance where unqualified personnel can safely access. No unskilled person can get passed this boundary toward the energized equipment. Qualified people must use the appropriate personal protective equipment and be trained to perform the required work before crossing this limit.

Restricted approach
This boundary can only be crossed by qualified personnel wearing the appropriate personal protective equipment. The qualified workers must also possess an approved plan signed off for the work to be carried out.

Prohibited approach
Only qualified personnel wearing the appropriate PPE can cross the threshold of the prohibited approach boundary. Workers also need specific training to work on energized equipment, a detailed plan justifying the necessity of performing this work as well as a risk assessment to cross that limit.

Selecting work equipment: protecting your hands!

To intervene on energized equipment, workers require protection. The human body is vulnerable to an arc flash, and the following information found in this article concerning gloves is also applicable to any other personal protective equipment.

When selecting gloves designed for arc flash protection, we need to look at the glove’s ATPV (Arc Thermal Performance Value). The ATPV represents the incident energy rate with a 50% chance of causing second-degree burns. For example, with a glove having an ATPV value of 8.2 cal/cm² you have a fifty percent chance of suffering from a second-degree burn caused by an 8.2 cal/cm² arc flash. Therefore, the higher the ATPV rate, the more protective the glove.

Dexterity® Protective Gloves Against Arc Flash

The Dexterity glove is a protective glove against arc flashes and the thinnest on the market. With 18 gauges, it protects efficiently against flames and arc flashes while providing excellent dexterity.

Scientifically designed to be flame resistant, these gloves offer a category 2 protective rate, an APTV value of 8.2 cal/cm², as well as an ANSI level 3 cut protection to protect workers from both arc flashes and cuts.

The flexible and comfortable neoprene palm is flame resistant and offers an exceptional grip without hindering dexterity, making this glove perfect for mining and oil and gas industries where arc flash protection is essential.

These gloves are also compatible with touchscreens and are latex free.

Characteristics

  • 18-gauge gloves with arc flash protection
  • Protective shell made of 18 g Kevlar® composite threads
  • Tested against level 2 arc flashes, ATPV value of 8.2 cal/cm2
  • Flame-resistant, non-slip neoprene palm
  • Compatible with touchscreens

“The palm coating is one of the best additions to arc flash gloves. When the international association responsible for evaluating the glove’s protection has designed the tests, the decision has been made to classify the gloves according to their protection rating at their least protected area, such as the back of the hand. Therefore, a glove can be classified with an arc flash protective value of 8 cal/cm², but the coating on the palm can confer a protection up to 50 cal/cm². So, palm coatings are great for arc flash protection as fingers and palms are the parts most affected by the heat of an arc flash.”

Hugh Hoagland, ArcWear Founder