Arc Flash protective clothing testing – what you need to know

Arc Flash protective clothing testing – what you need to know

We’re proud of the rigorous testing all of our Arc Flash protective clothing are put through to ensure they will perform in the event of an Arc Flash incident. All our core Arc Flash protective clothing products meet the international standard for protection against Arc Flash incidents, IEC 61482.

But what testing do our Arc Flash protective clothing products go through to earn their place in our brochure? And how can you use the results to be sure you order the right kit?

There are two main methods of testing for Arc Flash incidents – open arc and box testing. All of our Arc Flash protective clothing is tested using at least one of these methods, some are tested using both. You can see videos of both testing methods here.

Arc Flash testing methods – open arc

Open arc testing is used to give an Arc Thermal Performance Value (ATPV), which is the maximum thermal energy any Arc Flash protective clothing can withstand until the wearer would get second-degree burns.

This is measured in kilojoules/square metre (kj/m2) which is converted into what’s known as a cal rating – or calories/ square centimetre (cal/cm2).

Read more about the benefits of layering Arc Flash protective clothing to increase the cal rating protection it offers in our helpful blog here.

Arc Flash protective clothing tested this way could also be given an Energy Break-Open Threshold (EBT) value, which is the highest incident energy exposure value before holes start to form in the fabric. The holes would allow heat or flames through, risking injury.

Risk assessments should calculate the worst case scenario energy for an Arc Flash incident and the clothing’s ATPV value needs to be higher to protect people.

Arc flash protective clothing testing methods – box testing

Just as the name suggests, box testing uses electrodes arranged in a box in a specified way to produce the electrical arc.

There are two versions of the test. The ‘material box test’ measures heat transfer and checks radiant heat against the Stoll Curve boundary, which is a basic threshold for predicting burns. The result indicates how much radiant heat will cause second-degree burns.

The ‘garment box test’ is a visual assessment only. Garments tested using the Box Test method are defined as tested to either Class 1 or Class 2:

  • Class 1 tests at an Arc current of 4kA and Arc duration of 500 ms
  • Class 2 tests at an Arc current of 7kA and Arc duration of 500 ms

It’s not just about the fabric of Arc Flash Protective Clothing

It’s important that not only the fabric but the whole garment is tested to ensure that the way it is put together and any fastenings do not reduce the protection it offers.

That’s why we use ThermSAFE ™ zips, poppers and buttons, made from the same material NASA uses in its space suits. Our threads are flame resistant, meaning you can be sure that the whole of our garment, not just the fabric, meet the standards.

Using our Arc Flash Protective Clothing testing information

All of our garments have a visible label showing the type and level of protection offered. Check out our detailed blog about using the symbols on the labels to make an at-a-glance assessment of whether you’re wearing the right gear.

Your risk assessment should identify the cal rating needed for the task as well as whether the Arc Flash protective clothing needs to perform to Class 1 (4kA) or Class 2 (7kA) standards.

You’ll find all of the information about what tests have been carried out and the results for every product in our brochure and online to make it easy for you to know what will give you the right level of protection.

Advice when you need it

Our dedicated Arc Flash specialists are just a phone call away. We live and breathe Arc Flash – we don’t make PPE for any other purpose – so they can talk you through the risks for your industry, whether that’s petrochemical, utilities, rail, power generation or industrial electrical.

Call us on 01482 428458 for specialist advice.

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